Dissertations / Theses: 'Device-To-Device'

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Sahlström, Nathalie. "Secure device to device communication." Thesis, KTH, Kommunikationsteori, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146611.

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Since wireless communication has become a standard feature in the daily life, smartphones and tablets among other things are integrated with the Bluetooth technology. While in some parts of the day wireless communication can be used for searching the internet and share information on social networks without the need of having a secure connection, there are some other parts where the security might become of high importance. When the technology gets integrated in companies the security problem becomes more evident. This is because when the radio signals spread in the medium they can be accessed by anyone that is in reach in the network and the information that was sent may not be intended for everyone. To secure the network from unintended users becomes important when handling fragile information, which companies may deal with daily. This paper gives an introduction on which security features and techniques that already exist in some personal area networks. From this it has been clear that a security feature could be implemented on the baseband layer of Bluetooth to increase the secrecy during the transmission since at the moment security is only implemented on higher layers using encryption algorithms. This paper proposes a conceptual idea of improving the secrecy in the network by using a wiretap code that is implemented before the error-correction coding in the Bluetooth's baseband. By disabling the ARQ scheme in Bluetooth one can modulate the channel as a Packet Erasure Channel that will lose packet with a certain probability. By using a nested code structure, the message can then be securely sent by using a higher rate than what the eavesdropper can recover due to the amount of errors the received signal will have. The performance of the concept is evaluated with the secrecy throughput, secrecy outage and the leakage.

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Alhalabi, Ashraf S. A. <1985&gt. "Device-To-Device Wireless Communications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/7845/1/Thesis_%D9%90Ashraf.pdf.

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The main topic investigated in this thesis is related to characterization of the performance of D2D wireless networks. Given this broad objective, analytical framework models based on stochastic geometry have been proposed. One of them deals with the study of the coverage probability of both cellular networks and D2D networks whereas the others are related to dynamic mobility models in which the effects of blockages on the link lifetime have been studied. On the other hand, the experimental activity based on UWB using passive tags has been presented in which a localization system based on the ultra-wideband (UWB) technology and high-level architectures to improve the cyclists safety has been proposed.

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Shimotakahara, Kevin. "Device to Device Communications for Smart Grid." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40656.

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This thesis identifies and addresses two barriers to the adoption of Long Term Evolution (LTE) Device-to-Device (D2D) communication enabled smart grid applications in out of core network coverage regions. The first barrier is the lack of accessible simulation software for engineers to develop and test the feasibility of their D2D LTE enabled smart grid application designs. The second barrier is the lack of a distributed resource allocation algorithm for LTE D2D communications that has been tailored to the needs of smart grid applications. A solution was proposed to the first barrier in the form of a simulator constructed in Matlab/Simulink used to simulate power systems and the underlying communication system, i.e., D2D communication protocol stack of Long Term Evolution (LTE). The simulator is built using Matlab's LTE System Toolbox, SimEvents, and Simscape Power Systems in addition to an in-house developed interface software to facilitate D2D communications in smart grid applications. To test the simulator, a simple fault location, isolation, and restoration (FLISR) application was implemented using the simulator to show that the LTE message timing is consistent with the relay signaling in the power system. A solution was proposed to the second barrier in the form of a multi-agent Q-learning based resource allocation algorithm that allows Long Term Evolution (LTE) enabled device-to-device (D2D) communication agents to generate orthogonal transmission schedules outside of network coverage. This algorithm reduces packet drop rates (PDR) in distributed D2D communication networks to meet the quality of service requirements of microgrid communications. The PDR and latency performance of the proposed algorithm was compared to the existing random self-allocation mechanism introduced under the Third Generation Partnership Project's LTE Release 12. The proposed algorithm outperformed the LTE algorithm for all tested scenarios, demonstrating 20-40% absolute reductions in PDR and 10-20 ms reductions in latency for all microgrid applications.

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Daghal, Asaad. "Content delivery through device to device communication." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/65771/.

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Content caching at mobile user devices (UDs) utilizing device to device (D2D) communication has recently been proposed as an exiting and innovative technology to offload network data traffic and enhance the performance of mobile networks, in terms of latency, throughput, energy consumption, and so on. In this thesis, a novel method of content delivery using multiple devices to single device (MDSD) communication through D2D links is presented. In this method, the Zipf distribution with exponent shape parameter is adopted to model the content caching popularity for the analysis of the achievable signal to interference plus noise ratio (SINR). In order to investigate the advantage of the proposed MDSD method, firstly, a closed-form expression of the outage probability is theoretically derived for a single D2D communication to evaluate the success of content delivery to the reference UD. Secondly, the expression of the outage probability for MDSD communication is derived, where the outage probability is analysed as a function of content caching popularity, the density of UDs, and the size of cooperative area. The research work is further extended to address the frequency reuse among different UDs in one cell, where a frequency band factor is introduced, and the optimal radius of the cooperative area is introduced and analysed. The analytical results, validated by the simulation results, show that the outage probability decreases drastically when the popularity of the content increases, or the radius of the cooperative area increases. Using the given closed-form expression of the outage probability, the area spectral efficiency (ASE) of the system is presented. Furthermore, the results show that as the frequency band factor increases, the outage probability decreases, as well as the ASE decreases. Finally, it is shown that the MDSD outperforms the single D2D-based method.

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Shalmashi, Serveh. "Cooperative Spectrum Sharing and Device-to-Device Communications." Licentiate thesis, KTH, Radio Systems Laboratory (RS Lab), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145013.

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The steep growth in the mobile data traffic has gained a lot of attention in recent years. This growth is mainly the result of emerging applications, multimedia services, and revolutions in the device technology. With current deployments and radio resources, operators will not be able to cope with the growing demands. Consequently, there is a need to either provide new resources or increase the efficiency of what is available. Proposed solutions for accommodating growing data traffic are based on improvements in three dimensions: efficient use of radio resources especially the spectrum, technology advancements, and densifying the current infrastructure. In this thesis, we focus on the spectrum dimension. Providing more spectrum is a long-term process. However, increasing the spectrum usage and efficiency can be put rapidly in practice. We discuss potential solutions in the area of spectrum sharing. Among enabling technologies to facilitate spectrum sharing, we consider the cognitive radio and device-to-device (D2D) communications. In order to gain from sharing the spectrum, systems need to somehow deal with extra sources of interference. In the first part of the thesis, we consider a primary-secondary sharing model in cognitive radio networks. We employ the cooperative communication method in order to facilitate the access of the secondary system to the licensed spectrum of the primary system, and therefore increase the spectrum usage. The cooperation between the two systems is formed provided that it is beneficial for the primary system. In this way, the primary users' quality-of-service can be preserved while at the same time the secondary users can access the spectrum. This cooperative approach prevents both systems from concurrent transmissions. As a consequence, the need for interference control techniques are eliminated. We evaluate different models and transmission schemes and optimize the corresponding parameters to quantify the gain resulting from cooperative spectrum sharing. In the second part of the thesis, we consider spectrum sharing within one system between different types of users. This is done in the context of D2D communications where close proximity users can transmit directly to each other. For this type of communications, either dedicated resources are allocated or resources of the cellular users are reused. We first study the feasibility of cooperation between D2D and cellular users and identify the scenarios where it can be beneficial. Then we take on a challenging problem which guarantees the gain from the D2D communication, namely the mode selection. For this problem, we characterize the decision criteria that determines if D2D communication is gainful. Next, we focus on the problem of interference in D2D communications underlaying cellular networks, where the same spectrum is reused in the spatial domain. In such scenarios, the potential gain is determined by how the interference is managed, which in turn depends on the amount of available information at the base station. The more information is required, the more signaling is needed. In this part of the thesis, we address the trade-off between the signaling overhead and the performance of the system and propose a novel approach for interference control which requires very little information on the D2D users.

QC 20140509

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Gupta, Shruti. "Energy harvesting aided device-to-device communication networks." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/415790/.

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With the ever growing demands of power and bandwidth by users, energy and spectral efficiency emanated as key criteria for designing future wireless networks. Therefore, in this thesis energy harvesting (EH) aided device-to-device (D2D) communication is designed for improving both the key design criteria, which is an intricate journey from the realm of individual analysis of EH and D2D communication to that of amalgamating the two techniques. Specifically, with the widespread use of energy hungry smart devices, these devices become dis-functional due to outage of batteries, which can be avoided by introduction of EH capability at these nodes. In this context, an energy efficient successive relaying based network is conceived using rechargeable source and relay nodes having limited buffers for both their energy and data storage. An optimal and sub-optimal transmission policies are designed for the maximisation of the network throughput with non-causal knowledge of energy arrivals by the deadline. On the other hand, for exploiting the spectrum efficiently, D2D communication is invoked which brings in new interference scenarios that may be circumvented by incorporating fractional frequency reuse (FFR) or soft frequency reuse (SFR) in OFDMA cellular networks. By carefully considering the downlink resource reuse of the D2D links, beneficial frequency allocation schemes are proposed, when the macrocell has employed FFR or SFR. The coverage probability and the capacity of D2D links are analytically derived under the proposed schemes. It is imperative to integrate the benefits of EH and D2D communication aided systems for creating unparalleled opportunities in emerging applications. Therefore, a system is designed that comprises of EH aided D2D links relying on downlink resource reuse with the goal of maximizing the sum-rate of the D2D links, without degrading the quality of service (QoS) requirement of the MUs. A pair of joint resource block and power allocation algorithms are proposed for the D2D links, when there is non-causal (off-line) and causal (on-line) knowledge of the EH profiles at the D2D transmitters. For the sake of further accentuating design flexibility and alleviating the demands of increased spectral resources, previously designed EH aided D2D communication is investigated in conjunction with heterogeneous network (HetNet). An algorithmic solution is proposed with the aim of maximising the sum-rate of these D2D links in the downlink of two-tier HetNet without unduly degrading MU’s throughput, when two tiers share spectrum under following regimes: (a) orthogonal, (b) co-channel and (c) the proposed coorthogonal. Low complexity heuristic methods are also proposed, which demonstrate that the optimization of the D2D-MU matching is indeed crucial for the system considered.

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Chen, Xue. "Efficient Device to Device Communication Underlaying Heterogeneous Networks." DigitalCommons@USU, 2016. https://digitalcommons.usu.edu/etd/4673.

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Device-to-Device communications have the great potential to bring significant performance boost to the conventional heterogeneous network by reusing cellular resources. In cellular networks, Device-to-Device communication is defined as two user equipments in a close range communicating directly with each other without going through the base station, thus offloading cellular traffic from cellular networks. In addition to improve network spectral efficiency, D2D communication can also improve energy efficiency and user experience. However, the co-existence of D2D communication on the same spectrum with cellular users can cause severe interference to the primary cellular users. Thus the performance of cellular users must be assured when supporting underlay D2D users. In this work, we have investigated cross-layer optimization, resource allocation and interference management schemes to improve user experience, system spectral efficiency and energy efficiency for D2D communication underlaying heterogeneous networks. By exploiting frequency reuse and multi-user diversity, this research work aims to design wireless system level algorithms to utilize the spectrum and energy resources efficiently in the next generation wireless heterogeneous network.

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Feng, Junyi. "Device-to-Device Communications in LTE-Advanced Network." Télécom Bretagne, 2013. http://www.telecom-bretagne.eu/publications/publication.php?idpublication=14215.

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La communication device-to-device (D2D) est un nouvel aspect prometteur dans les réseaux LTE-Advanced. Elle est mise en place pour permettre une détection efficace et une communication de proximité entre mobiles. Grâce aux capacités D2D, les mobiles de proximité sont capables de se détecter entre eux en utilisant la technologie radio LTE et de communiquer entre eux via un lien direct. Cette thèse porte sur la conception, la coordination et les tests d'un réseau hybride avec la technologie D2D et les communications cellulaires. Les exigences de conception et les choix des fonctions dans la couche physique et MAC qui permettent la détection D2D et la communication reposant sur les réseaux LTE sont analysés. De plus, une stratégie de planification centralisée dans la station de base est proposée afin de coordonner les communications de données D2D en liaison descendante pour le réseau LTE FDD. Cette stratégie de planification combine de multiple techniques telles que le mode de sélection, l'allocation des ressources et d'énergie, afin d'améliorer les performances des utilisateurs dans une cellule. Enfin, les performances des communications de données D2D reposant sur le système LTE sont mesurées à partir d'un simulateur, au niveau système, avec un scénario comportant de multiples liens de communication
Device-to-device (D2D) communication is a promising new feature in LTE-Advanced networks. It is brought up to enable efficient discovery and communication between proximate devices. With D2D capability, devices in physical proximity could be able to discover each other using LTE radio technology and to communicate with each other via a direct data path. This thesis is concerned with the design, coordination and testing of a hybrid D2D and cellular network. Design requirements and choices in physical and MAC layer functions to support D2D discovery and communication underlaying LTE networks are analyzed. In addition, a centralized scheduling strategy in base station is proposed to coordinate D2D data communication operating in LTE spectrum. The scheduling strategy combines multiple techniques, including mode selection, resource and power allocation, to jointly achieve an overall user performance improvement in a cell. Finally the performances of D2D data communication underlaying LTE system are calibrated in a multi-link scenario via system-level simulation

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Verenzuela, Daniel. "Scalability of Device-to-Device Communications in Cellular Networks." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187444.

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In current cellular networks the demand of traffic is rapidly increasing and new techniques need to be developed to accommodate future service requirements. Device-to-Device (D2D) communications is one technique that has been proposed to improve the performance of the system by allowing devices to communicate directly without routing traffic through the base station. This technique has the means to improved performance and support new proximity based services. Nowadays new applications based on geographical proximity are becoming more and more popular suggesting that D2D communications will have a high de- mand in the near future. Thus the study of the scalability of D2D communications is of paramount importance. We define the scalability of D2D communications underlay cellular networks as the maximum number of D2D links that can share the cellular resources while assuring QoS to both D2D links and cellular users. In this thesis we study the scalability of D2D communication underlay cellu- lar networks in a multi-cell environment. We propose interference coordination schemes to maximize the number of D2D links while assuring QoS to D2D links and cellular users. Three interference coordination schemes have been proposed considering dif- ferent levels of available channel state information (CSI). The first scheme is called no CSI centralized (N-CSIC) scheme and it is based on a centralized solution where no CSI is needed. The second is partial CSI distributed (P-CSID) scheme and it is based on a distributed solution where partial CSI is available. The last scheme is named full CSI optimal (F-CSIOp) scheme and it is achieved by formulating an optimization problem considering full CSI to be available. Extensive mathematical and numerical analysis is conducted to develop and evaluate the proposed schemes. The results show that F-CSIOp scheme offers the best performance followed by the P-CSID and finally N-CSIC, thus a clear relationship is found between complexity and performance. The P-CSID offers a practical solution for a low complexity interference co- ordination scheme that achieves good scalability and capacity for a wide range of strict QoS requirements. Moreover the results show that further improvement can be achieved if proper selection of the involved parameters is done along with the implementations of closed loop power control (CLPC) schemes. The N-CSIC scheme provides a good solution for low SINR values of D2D links when the QoS of cellular users is low. Thus it is a good candidate for applications like sensor networks or M2M communications where the SINR requirements are rather low and there are no primary users to impose more interference constraints. Finally we conclude that good scalability and capacity can be achieved with the proposed low complexity interference coordination schemes for D2D communications and provide interesting topics for future research.

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Shi, Qing. "A first principles investigation of device-to-device variability." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121532.

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In this thesis, we present first principles simulations to investigate the device-todevice variation induced by random discrete dopant (RDD) in Si nanoFET channels. Our simulations are from atomic first principles and parameter-free, by combining nonequilibrium Green's functions (NEGF) with the density functional theory (DFT). To deal with the problem of disorder scattering and configuration averaging, the coherent potential approximation (CPA) and nonequilibrium vertex correction (NVC) theory are employed. To calculate the variance of the conductance due to RDD, a local concentration approximation (LCA) on top and beyond the CPA-NVC theory is applied. Our first principles simulations provide not only the average conductance but also the variance of it. A systematic review of the quantum transport and electronic structure theory is made, including the physics, mathematics and simulation algorithms behind the NEGF-DFT, the CPA-NVC and finally the LCA methods. Our ab initio results show that for uniform doping of the Si nanoFET channel, the variation of the OFFstate leakage current decreases dramatically with increasing doping concentration or channel length; in localized doping, doping close to the channel center can have much smaller current variation than the corresponding uniform doping. Our ab inito results provide a vivid physical picture as why large device-to-device variation is expected in very small structures having small number of impurity atoms. The results also indicate that device-to-device variation induced by RDD in Si nanoFET channels can be suppressed by choosing an appropriate doping strategy. Our numerical data is organized by fitting to the WKB tunneling formula.
Dans ce mémoire, nous présentons des simulations à partir des premiers principes pour l'étude des variations dispositif-à-dispositif induites par dopant ponctuel aléatoire (RDD) dans des canaux nanoFET en Si. Nos simulations sont à partir des premiers principes atomiques et libres de paramètre, en combinant les fonctions de Green hors équilibre (NEFG) avec la théorie de la fonctionnelle de densité (DFT). Afin d'adresser le problème de la dispersion dûe au désordre et aux moyennes de configuration, l'approximation du potentiel cohérent (CPA) et la correction vertex hors équilibre (NVC) sont employées. Afin de calculer la variance de la conductance dûe au RDD, une approximation de la concentration locale (LCA) est appliquée par-dessus et au-delà de la théorie CPA-NVC. Nos simulations à partir des premiers principes fournissent non seulement la conductance moyenne mais aussi sa variance. Une revue systématique de la théorie du transport quantique et de la structure électronique est faite, incluant la physique, les mathématiques et les algorithmes de simulation derrière les méthodes NEFG-DFT, CPA-NVC et finallement LCA. Nos résultats ab initio montrent que pour un dopage uniforme du canal nanoFET en Si, la variation du courant de fuite à l'état OFF diminue de manière dramatique avec l'augmentation de la concentration de dopage ou de la longueur du canal ; dans le cas de dopage localisé, un dopage proche du centre du canal peut avoir une variation du courant plus petite qu'un dopage uniforme. Nos résultats ab inito fournissent une image physique claire de la raison pour laquelle une large variation dispositif-àdispositif peut être attendue dans des structures très petites comportant un petit nombre d'impuretés. Les résultats indiquent aussi que la variation dispositif-à-dispositif induite par RDD dans les canaux nanOFET en Si peut être supprimée en choisissant une stratégie de dopage approprié. Nos données numériques sont organisées par ajustement à la formule d'effet tunnel WKB.

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Idris, Fakrulradzi. "Resource allocation for energy efficient device-to-device communications." Thesis, University of Manchester, 2019. https://www.research.manchester.ac.uk/portal/en/theses/resource-allocation-for-energy-efficient-devicetodevice-communications(fe38ee57-5947-497e-a744-373937f7f9ab).html.

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Device-to-Device (D2D) communication is one of the technologies for next generation communication system. Unlike traditional cellular network, D2D allows proximity users to communicate directly with each other without routing the data through a base station. The main aim of this study is to improve the overall energy efficiency (EE) of D2D communications overlaying cellular system. To reduce the complexity of joint EE optimization, we decompose the main EE problem into two subproblems; resource efficiency (RE) optimization in the first stage and EE optimization for D2D pairs in the second stage. Firstly, we propose an alternative two-stage RE-EE scheme for a single cellular user equipment (CUE) and a D2D pair utilizing uplink spectrum. Later, we extend this work for multiple CUEs and D2D pairs by considering the downlink orthogonal frequency division multiple access (OFDMA). By exploiting a range of optimization tools including the Bisection method, interior point algorithm, fractional programming, Dinkelbach approach, Lagrange dual decomposition, difference of convex functions, and concave-convex procedure, the original non-convex problems are solved and we present iterative two-stage RE-EE solutions. Simulation results demonstrate that the proposed two-stage scheme for uplink scenario outperforms the cellular mode and dedicated mode of communications and the performance is close to the global optimal solution. The results also show that the proposed schemes for downlink resource sharing provide improved system EE performance with significant gain on EE for D2D users compared to a two-stage EE-EE solution, which is obtained numerically. Furthermore, the RE and EE optimization for non-orthogonal multiple access (NOMA) are considered to study the effect of users' access to the whole spectrum. The results indicate that the proposed RE scheme for NOMA with D2D communications achieves higher system EE compared to the OFDMA based schemes.

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Vlachos, Christoforos. "Integrating device-to-device communications in 5G cellular networks." Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/integrating-devicetodevice-communications-in-5g-cellular-networks(b4700367-dfd1-41df-b880-651bdb3b0b7b).html.

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The evolution of wireless networks towards 5G dictates the integration of a mul-titude of heterogeneous radio access technologies to the traditional macro-cell systems. Equipping the network with numerous small cell nodes, such as fem-tocell and picocell base stations (BSs), implies a spectrum efficient and network performance improving solution to support the rapidly increasing user demands. However, this can be proven to be a cost-inefficient method that increases the capital and operational expenditures of the network operators as well as the power consumption, especially in low-traffic network conditions where a number of BSs should be switched-off. To this end, device-centric solutions that leverage the potentials stemming from the proximity, mobility and increased dynamics of user devices should be considered. To this end, direct, proximity-based Device-to-Device (D2D) communication, where two close-ranged user equipments (UEs) are able to exchange data by bypassing the BS, is expected to play predominant role in improving the overall network welfare and ease part of the traffic developed on the BSs side. This thesis focuses on the soft integration of inband D2D communications in emerging cellular networks where D2D-enabled devices utilize the licensed spec-trum. In the introductory part of the thesis we highlight the merits that this communication paradigm can offer in terms of spectrum utilization, energy sav-ing, delay reduction and data rate improvement. We also provide an overview of the D2D use cases that enable opportunities for new services, its potential in improving the overall network performance as well as its offloading capability that can ease the traffic employed along the network. In the sequel, we proceed with our proposed methodology that aims at easing the coexistence of cellular and D2D users in emerging cellular networks. One of the main contributions of the thesis is the optimization of cell association for D2D UEs (DUEs). Cell association for D2D communications is an unexplored area and a rather fertile ground for research. Following the conventional motif, a user device would preferably couple with a high power macro cell BS that provides the user with the highest signal power. However, with the advent of D2D com-munications, this could be proven to be highly inefficient for users that want to communicate directly and are associated with different BSs because BS intercom-munication complexity and access delay is introduced. To this end, we propose a number of optimization formulations for D2D-based cell association that takes into consideration not only the nature of the inband D2D communications (un-derlay or overlay), but also performance-hindering factors such as user density, interference and so on. Other than the throughput enhancing and power saving attributes of the proposed framework, notable resource efficiency improvement is achieved. Indicatively, for both underlay and overlay D2D communications, more than 12% and 45% radio resource utilization mitigation is ensured compared to baseline methods. On top of optimizing cell association for D2D communications, we further investigate the problem of resource allocation in different D2D underlaying cellu-lar network scenarios where DUEs are permitted to reuse the cellular resources and, therefore, high levels of interference need to be prevented. By consider-ing different deployment scenarios, we propose a set of low-complexity heuristic algorithms with the aim to achieve high data rate performance for D2D com-munications with respect to meeting the cellular users’ quality of service (QoS) requirements. The proposed algorithms are evaluated in high-traffic networking scenarios where D2D communications underlay relay-enabled cellular networks. In aggregate, more than 10% of sum throughput performance is achieved against various resource allocation techniques. In the sequel, we explore the dynamics of virtualizing the radio resources for efficient sharing as, nowadays, we are witnessing higher network heterogeneity and the emergence of multiple stakeholders with the overarching need to significantly reduce deployment costs and achieve a sustainable network operation. Network virtualization has emerged as a promising technique to overcome the complexity of current network operation as well as facilitate inter-operators’ sharing. There-fore, disruptive approaches to manage radio and network-virtualized resources are expected to be a catalyst element of future mobile network architectures. Despite the fact that a number of solutions for radio access network (RAN) virtualization emerged over the last few years, it is worth pointing out that little attention has been placed on issues related to D2D virtualization. Therefore, based on the integration of an inter-tenant controller that enables the radio resource sharing between multiple operators, we devise a set of efficient algorithms to optimize the throughput performance of D2D communications in virtualized environments as well as reduce the utilization levels of the allocated radio resources. More than 12% of sum-rate performance improvement compared to legacy, intra-tenant ap-proaches where the radio resources are assigned based on which device initiates the communication per case. Finally, a summary of the research outcomes along with some future directions for D2D communications concludes this thesis.

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Ali, S. (Samad). "Full duplex device-to-device communication in cellular networks." Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201411081977.

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To address the problem of radio spectrum congestion due to increasing demand for wireless communications services, cellular communication systems are going towards small cells with small transmit powers. At the same time, in-band fullduplex (FD) radio design has gained considerable attention due to achievements in signal processing that can make design of full-duplex radios possible for systems with small transmit power. In theory full-duplex radios can double the spectral efficiency of the system. However existing radios still do not provide enough self-interference (SI) cancelation to be used in large transmit power systems. Meanwhile device-to-device communication (D2D) is seen as a promising idea to increase the performance of wireless networks. In D2D, users in vicinity communicate directly without going through base station. So far, very limited work has been carried out to study the applicability of available full-duplex radios in D2D. In this thesis, we investigate full-duplex D2D and amount of self-interference cancelation required in D2D in cellular systems. While D2D users share the same radio resources with cellular users, both cellular and D2D pair will receive interference. Resource allocation and interference management become crucial in D2D communication. Both uplink and downlink resource sharing are considered. In uplink resource sharing, to handle the interference on the base station power control is used in D2D transmitter. To deal with the interference at D2D receivers from cellular user’s uplink transmission, interference-limited-area (ILA) method is used to select users with negligible interference on them. When D2D pair is using downlink resources of cellular users, users receive interference from D2D transmissions. Limiting this interference is also done using ILA method. On the other hand, for the purpose of resource sharing, the user with smallest downlink transmit power is selected to minimize the interference on D2D receivers. Half-duplex (HD) and full-duplex D2D scenarios are considered in both uplink and downlink resource sharing. Simulations show that how much of self-interference cancelation is required in different scenarios. Effects of the numbers of the selected users for resource sharing, distance between D2D users and also inter-cell interference is studied. It can be concluded that using available full-duplex radios in D2D communication can almost reach the theoretical doubling of throughput in full-duplex mode compared to half-duplex mode.

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Chour, Hussein. "Full-Duplex Device-to-Device Communication for 5G Network." Thesis, CentraleSupélec, 2019. http://www.theses.fr/2019CSUP0002.

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Avec la croissance rapide de la demande de trafic de données des clients, l'amélioration de la capacité du système et l'augmentation du débit des utilisateurs sont devenues des préoccupations essentielles pour le futur réseau de communication sans fil de cinquième génération. Dans ce contexte, la communication terminal-à-terminal (Device-to-Device D2D) et le Full Duplex (FD) sont proposés comme solutions potentielles pour augmenter l’efficacité spectrale et le débit des utilisateurs dans un réseau cellulaire. Le D2D permet à deux périphériques proches de communiquer sans participation de la station de base ou avec une participation limitée. D'autre part, la communication en FD permet une transmission et une réception simultanées dans la même bande de fréquence. En raison de la propriété de distance courte des liaisons D2D, exploiter la technologie FD dans la communication D2D est un excellent choix pour améliorer encore plus l’efficacité spectrale cellulaire et le débit des utilisateurs. Cependant, les émetteurs-récepteurs FD constituent de nouveau défis pour la communication D2D. Par exemple, en FD les émetteurs-récepteurs ne peuvent pas supprimer d’une manière parfaite l’auto-interférence (SI) générée au niveau des récepteurs lors de la transmission des données (par le propre émetteur du dispositif cellulaire). Ainsi, l’auto-interférence résiduelle qui est étroitement liée à la valeur de la puissance de l’émetteur affecte fortement les performances de la transmission FD. De plus, la technique en FD crée des interférences supplémentaires dans le réseau, ce qui peut dégrader ses performances par rapport à la transmission en semi-duplex (Half-duplex HD). Ainsi, une bonne gestion des ressources radio est nécessaire pour exploiter les avantages de la FD et garantir la qualité de service (QoS) des utilisateurs. Les travaux de cette thèse portent sur l'allocation de puissance et l'attribution de canaux d'un réseau FD-D2D. En particulier, cette thèse aborde d’abord le problème de l’allocation de puissance et propose une méthode d'allocation de puissance (PA) optimale centralisée simple mais efficace, puis développe le schéma optimal conjoint d’AP et d’AC pour un réseau FD-D2D. Un algorithme de complexité réduite CATPA, basé sur une allocation CA suivie d'une allocation PA, est aussi développée et proposé. La thèse présente à la fin une stratégie efficace d'AP décentralisée en utilisant les outils de la théorie des jeux
With the rapidly growing of the customers' data traffic demand, improving the system capacity and increasing the user throughput have become essential concerns for the future 5G wireless communication network. In this context, D2D communication and FD are proposed as potential solutions to increase the spatial spectrum utilization and the user rate in a cellular network. D2D allows two nearby devices to communicate without BS participation or with limited participation. On the other hand, FD communication enables simultaneous transmission and reception in the same frequency band. Due to the short distance property of D2D links, exploiting the FD technology in D2D communication is an excellent choice to further improve the cellular spectrum efficiency and the users’ throughput. However, practical FD transceivers add new challenges for D2D communication. For instance, the existing FD devices cannot perfectly eliminate the SI imposed on the receiver by the node’s own transmitter. Thus, the RSI which is tightly related to the transmitter power value highly affects the performance of FD transmission. Moreover, the FD technique creates additional interference in the network which may degrade its performance when compared with the half-duplex transmission. Thus, proper radio resource management is needed to exploit the benefits of FD and guarantee the QoS of the users. The works in this dissertation focus on the PA and CA of a FD-D2D network. In particular, this thesis first addresses the PA problem and proposes a simple yet efficient centralized optimal PA framework, and next, it derives the optimal joint PA and CA scheme for an FD-D2D network. A simple sub-optimal algorithm for resource allocation named CATPA, based on CA followed by PA, is also derived and proposed. This dissertation also develops, in the end, an efficient decentralized PA using game theory tools that will be an essential part of future works in the context of distributed radio resource management

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Uyoata, Uyoata Etuk. "Relay assisted device-to-device communication with channel uncertainty." Doctoral thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/31309.

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The gains of direct communication between user equipment in a network may not be fully realised due to the separation between the user equipment and due to the fading that the channel between these user equipment experiences. In order to fully realise the gains that direct (device-to-device) communication promises, idle user equipment can be exploited to serve as relays to enforce device-to-device communication. The availability of potential relay user equipment creates a problem: a way to select the relay user equipment. Moreover, unlike infrastructure relays, user equipment are carried around by people and these users are self-interested. Thus the problem of relay selection goes beyond choosing which device to assist in relayed communication but catering for user self-interest. Another problem in wireless communication is the unavailability of perfect channel state information. This reality creates uncertainty in the channel and so in designing selection algorithms, channel uncertainty awareness needs to be a consideration. Therefore the work in this thesis considers the design of relay user equipment selection algorithms that are not only device centric but that are relay user equipment centric. Furthermore, the designed algorithms are channel uncertainty aware. Firstly, a stable matching based relay user equipment selection algorithm is put forward for underlay device-to-device communication. A channel uncertainty aware approach is proposed to cater to imperfect channel state information at the devices. The algorithm is combined with a rate based mode selection algorithm. Next, to cater to the queue state at the relay user equipment, a cross-layer selection algorithm is proposed for a twoway decode and forward relay set up. The algorithm proposed employs deterministic uncertainty constraint in the interference channel, solving the selection algorithm in a heuristic fashion. Then a cluster head selection algorithm is proposed for device-to-device group communication constrained by channel uncertainty in the interference channel. The formulated rate maximization problem is solved for deterministic and probabilistic constraint scenarios, and the problem extended to a multiple-input single-out scenario for which robust beamforming was designed. Finally, relay utility and social distance based selection algorithms are proposed for full duplex decode and forward device-to-device communication set up. A worst-case approach is proposed for a full channel uncertainty scenario. The results from computer simulations indicate that the proposed algorithms offer spectral efficiency, fairness and energy efficiency gains. The results also showed clearly the deterioration in the performance of networks when perfect channel state information is assumed.

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Han, Yanyan. "Ultra-Large-Scale Crowdsensing in Device-to-Device Networks." Thesis, University of Louisiana at Lafayette, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10266292.

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Crowdsourcing is emerging as a new data-collection, solution-finding, and opinion-seeking model that obtains needed services, ideas, or content by soliciting contributions from a large crowd of public participants. D2D based crowdsensing is particularly desired when the initiator cannot directly reach out to the participants or the conventional approaches for data transportation are costly. This dissertation studies the ultra-large scale crowdsensing applications in such mobile D2D networks. First, I proposed and addressed MCC(Minimum-Cost Crowdsourcing) problem by exploring a multi-dimensional design space to seek an optimal solution that minimizes the total crowdsensing cost while satisfying the coverage probability over the FoI. In particular, three strategies (or options) are in consideration: task allocation strategy, data processing strategy and computation offloading strategy. The difficulty is to determine the three options for each node in order to minimize the overall system cost. Second, there are a class of applications, where the originator is only allowed to recruit a given number of participants. Therefore, from the perspective of limited participants, we proposed a competition based participant recruitment mechanism to wisely choose the set of nodes while achieving the best benefit. I have proposed a dynamic programming algorithm as a first attack to this problem, followed by two distributed alternatives, which prove to be more practical and adaptive. During the above two topics, we find the existing routing protocols cannot efficiently support the ultra-large scale crowdsensing, thus we built a resource constrained routing protocol in D2D, aiming to approach the large-scale, bandwidth-hungry crowdsensing task in a more efficient way. With the requirement of restricted node storage and link bandwidth as well as end-to-end delay, I formulated a non-linear traffic allocation optimization problem with an approximation algorithm and distributed heuristic solution. Finally, I have carried out extensive complexity analysis, simulation, prototyping and implementation, experimentation and performance evaluation. Through the step-by-step exploration and verification, I have demonstrated the efficiency of the proposed heuristics and revealed empirical insights into the design tradeoffs and practical considerations in D2D-based crowdsourcing.

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17

Usman, Muhammad. "Energy Efficiency and Privacy in Device-to-Device Communication." Doctoral thesis, Università degli studi di Trento, 2017. https://hdl.handle.net/11572/368413.

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Mobile data traffic has increased many folds in recent years and current cellular networks are undeniably overloaded to meet the escalating user's demands of higher bandwidth and data rates. To meet such demands, Device-to-Device (D2D) communication is regarded as a potential solution to solve the capacity bottleneck problem in legacy cellular networks. Apart from offloading cellular traffic, D2D communication, due to its intrinsic property to rely on proximity, enables a broad range of proximity-based applications for both public safety and commercial users. Some potential applications, among others, include, proximity-based social interactions, exchange of information, advertisements and Vehicle-to-Vehicle (V2V) communication. The success of D2D communication depends upon the scenarios in which the users in the proximity interact with each other. Although there is a lot of work on resource allocation and interference management in D2D networks, very few works focus on the architectural aspects of D2D communication, emphasizing the benchmarking of energy efficiency for different application scenarios. In this dissertation, we benchmark the energy consumption of D2D User Equipments (UEs) in different application scenarios. To this end, first we consider a scenario wherein different UEs, interested in sharing the same service, form a Mobile Cloud (MC). Since, some UEs can involve in multiple services/applications at a time, there is a possibility of interacting with multiple MCs. In this regard, we find that there is a threshold for the number of UEs in each MC, who can participate in multiple applications, beyond which legacy cellular communication starts performing better in terms of overall energy consumption of all UEs in the system. Thereafter, we extend the concept of MC to build a multi-hop D2D network and evaluate the energy consumption of UEs for a content distribution application across the network. In this work, we optimize the size of an MC to get the maximum energy savings. Apart from many advantages, D2D communication poses potential challenges in terms of security and privacy. As a solution, we propose to bootstrap trust in D2D UEs before establishing any connection with unknown users. In particular, we propose Pretty Good Privacy (PGP) and reputation based mechanisms in D2D networks. Finally, to preserve user's privacy and to secure the contents, we propose to encrypt the contents cached at D2D nodes (or any other caching server). In particular, we leverage convergent encryption that can provide an extra benefit of eliminating duplicate contents from the caching server.

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Usman, Muhammad. "Energy Efficiency and Privacy in Device-to-Device Communication." Doctoral thesis, University of Trento, 2017. http://eprints-phd.biblio.unitn.it/2736/1/Dissertation.pdf.

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Mobile data traffic has increased many folds in recent years and current cellular networks are undeniably overloaded to meet the escalating user's demands of higher bandwidth and data rates. To meet such demands, Device-to-Device (D2D) communication is regarded as a potential solution to solve the capacity bottleneck problem in legacy cellular networks. Apart from offloading cellular traffic, D2D communication, due to its intrinsic property to rely on proximity, enables a broad range of proximity-based applications for both public safety and commercial users. Some potential applications, among others, include, proximity-based social interactions, exchange of information, advertisements and Vehicle-to-Vehicle (V2V) communication. The success of D2D communication depends upon the scenarios in which the users in the proximity interact with each other. Although there is a lot of work on resource allocation and interference management in D2D networks, very few works focus on the architectural aspects of D2D communication, emphasizing the benchmarking of energy efficiency for different application scenarios. In this dissertation, we benchmark the energy consumption of D2D User Equipments (UEs) in different application scenarios. To this end, first we consider a scenario wherein different UEs, interested in sharing the same service, form a Mobile Cloud (MC). Since, some UEs can involve in multiple services/applications at a time, there is a possibility of interacting with multiple MCs. In this regard, we find that there is a threshold for the number of UEs in each MC, who can participate in multiple applications, beyond which legacy cellular communication starts performing better in terms of overall energy consumption of all UEs in the system. Thereafter, we extend the concept of MC to build a multi-hop D2D network and evaluate the energy consumption of UEs for a content distribution application across the network. In this work, we optimize the size of an MC to get the maximum energy savings. Apart from many advantages, D2D communication poses potential challenges in terms of security and privacy. As a solution, we propose to bootstrap trust in D2D UEs before establishing any connection with unknown users. In particular, we propose Pretty Good Privacy (PGP) and reputation based mechanisms in D2D networks. Finally, to preserve user's privacy and to secure the contents, we propose to encrypt the contents cached at D2D nodes (or any other caching server). In particular, we leverage convergent encryption that can provide an extra benefit of eliminating duplicate contents from the caching server.

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19

Bertier, Clément. "Quantification in Device-to-Device Networks : from Link Estimation to Graph Utility." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS250.

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Les communications d'appareil à appareil (D2D) sont utiles dans plusieurs domaines, e.g. le déléstage mobile, car elles ne coûtent qu’une fraction du prix d’une communication cellulaire. Dans cette thèse, nous soutenons que la compréhension de l'utilité potentielle derrière les communications directes est la clé pour quantifier les réseaux de contact. Tout d'abord, nous considérons le problème de l'estimation de l'importance d'un nœud dans de grandes topologies dynamiques. Nous proposons une approche nouvelle pour estimer les centralités à partir d'une base de données préétablie, où l'estimation est basée sur les coordonnées géographiques du nœud au lieu de l'identifiant du nœud. Deuxièmement, nous quantifions la valeur des liens directs grâce à une campagne de mesure expérimentale via Android. Nous proposons un modèle pour estimer la limite supérieure du débit D2D en fonction de la distance entre les appareils. Troisièmement, nous étudions les différences entre la quantification traditionnelle d'un contact et notre modèle. Entre autres résultats, nous révélons que lorsque l'on considère un débit adaptatif en fonction de la distance entre deux appareils, l'échange de données longue distance représente plus de 50% du total des données échangées dans l'ensemble du réseau. Nous proposons un outil pour extraire le volume de données obtenues à partir de traces mobilité
Device-to-device (D2D) communications are valuable in several domains, such as data offloading and diffusion, as their cost is only a fraction of what regular cellular communication would have. In this thesis, we argue that understanding the potential utility behind direct communications is key to quantifying the realization of contact networks. We tackle related questions from two distinct, yet complementary contributions. Firstly, we consider the problem of estimating the importance of a node in large dynamic topologies. We propose a novel approach to estimate centralities based on a pre-established database, where the estimation is based on the geographical coordinates of the node instead of the identifier of the node. Doing so enables us to estimate the centrality of a node for a fraction of the computational cost. Secondly, we quantify the value of direct links through an experimental measurement campaign. Using an Android tool of our making, we derived a model to obtain an estimate of the upper-bound of D2D throughput based on the distance between the devices. Thirdly, we investigate the differences between the traditional quantification of a contact and the model extracted from our measurements campaigns. Among other results, we reveal that when considering an adaptive throughput according to the distance between two devices, the long-distance data-exchange makes up more than 50% of the total data exchanged in the entire network. We propose a tool to extract from mobility datasets the volume of data obtained, based on specific contact quantification strategies

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George, Geordie. "Device-to-device communication and wearable networks harnessing spatial proximity." Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/404986.

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Spatially proximal devices wanting to exchange information are expected to become more prevalent in wireless networks, rendering the option for direct device-to-device (D2D) communication increasingly important. On the one hand, within networks where communication via infrastructure has been the convention, enabling such an option for short-range and single-hop communication between co-located devices might potentially bring about performance benefits on several accounts. On the other hand, in the realm of networks where direct interaction between devices has been an obvious option, there is a growing demand for supporting extreme-data-rate applications and much denser deployments of simultaneous transmissions. This dissertation explores these aspects by addressing two main problems: (i) analyzing the performance benefits of D2D communication integrated into cellular mobile networks, and (ii) investigating the feasibility of mmWave (millimeter wave) frequencies for personal networks of wearable (body-born) devices in enclosed settings. Under sufficient spatial locality in wireless traffic within cellular networks, the D2D mode of communication can be leveraged to employ a denser spectral reuse, thereby achieving very high area spectral efficiencies (bits/s/Hz per unit area). Enabling D2D entails a reshaping of the network topology comprising the sources of useful signal and harmful interference from the vantage of each receiver, which is a factor that delimits network performance fundamentally. Therefore, to gauge the performance gains of D2D and to identify the challenges thereof, it is essential to model D2D communication in a large multicellular setting, without missing key features of the ensuing interference environment. In this regard, we develop a robust analytical framework, utilizing tools from stochastic geometry. The dissertation propounds a novel approach to the application of stochastic geometry that is shown to improve the simplicity, accuracy, and generality of wireless network analysis. The performance evaluation conducted using the framework, while demonstrating the potential of D2D, also indicates the need for managing the interference surge. Prompted by this, and to illustrate the flexibility of the framework, we further extended it to incorporate interference protection schemes based on exclusion regions and the benefits thereof are assessed. The presence of multiple wearable networks—each comprising several on-body device-pairs worn by people—in proximity might result in an extreme density of simultaneous wireless transmissions. Such a scenario is expected to become commonplace in enclosed settings, e.g., commuter trains, subways, airplanes, airports or offices, and be further challenging due to an increasing demand for data-rate-intensive wireless applications in wearable technology. This combination of very-short-range communication, high-data-rate applications, and dense spectral reuse seems to render operation at mmWave frequencies a suitable candidate; add to that the possibility of accommodating antenna arrays within devices for directional beamforming. Hence, we investigate the feasibility of enclosed mmWave wearable networks, with a particular focus on appropriately modeling the impact of propagation mechanisms at these frequencies. In the propagation modeling, specular reflections off surfaces are explicitly accounted for, as they are expected to contribute useful signal power while, at the same time, intensify the interference. Recognizing the increased prominence of blocking by obstacles, body-blockages in the direct and reflected propagation paths are also modeled. The impact of these mechanisms on the spectral efficiency of the network is evaluated, aided by the application of stochastic geometry and random shape theory. Under relevant indoor settings, and in the plausible absence of strong direct signal, the reliability of surface reflections in providing useful signal power for efficient communication is investigated and the need for directional antennas is established.
Se espera que los dispositivos espacialmente proximales que desean intercambiar información se vuelvan más frecuentes en redes inalámbricas, lo que hace cada vez más importante la opción para la comunicación directa de dispositivo-a-dispositivo (D2D). Por un lado, dentro de las redes en las que la comunicación a través de la infraestructura ha sido la convención, permitir tal opción para la comunicación de corto alcance y single-hop entre dispositivos ubicados conjuntamente podría potencialmente generar beneficios de rendimiento en varios aspectos. Por otro lado, en el ámbito de las redes en las que la interacción directa entre dispositivos ha sido una opción obvia, existe una demanda creciente de soportar aplicaciones de velocidad extrema de datos e implementaciones mucho más densas de transmisiones simultáneas. Esta disertación explora dichos aspectos abordando dos problemas principales: (i) analizando los beneficios de rendimiento de la comunicación D2D integrada en las redes móviles celulares y (ii) investigando la viabilidad de las frecuencias mmWave (onda milimétrica) para redes personales de dispositivos wearables (usado en el cuerpo) en entornos cerrados. Bajo suficiente localidad espacial en el tráfico inalámbrico en redes celulares, el modo de comunicación D2D puede ser apalancado para emplear una reutilización espectral más densa, logrando así eficiencias espectrales de área muy alta (bits/s/Hz por unidad de área). La habilitación de D2D implica una remodelación de la topología de red que comprende las fuentes de señal útil e interferencia perjudicial desde la ventaja de cada receptor, lo cual es un factor que delimita el funcionamiento de la red de manera fundamental. Por tanto, para medir las ganancias de rendimiento de D2D y para identificar los retos de la misma, es esencial para modelar la comunicación D2D en un gran ajuste multicelular, sin faltar las características clave del entorno de interferencia resultante. En este sentido, se desarrolla un sólido marco analítico, utilizando herramientas de geometría estocástica. La disertación propone un nuevo enfoque para la aplicación de la geometría estocástica para mejorar la simplicidad, precisión y generalidad del análisis de redes inalámbricas. La evaluación realizada utilizando dicho enfoque, al mismo tiempo que demuestra el potencial de D2D, también indica la necesidad de manejar la oleada de interferencia. Impulsado por estos resultados, y para ilustrar la flexibilidad del marco, también se amplía para incorporar esquemas de protección contra interferencias basados en regiones de exclusión y se evalúan sus los beneficios. La presencia de redes wearables múltiples—cada una de las cuales comprende varios pares de dispositivos en el cuerpo desgastados por personas—en proximidad puede dar como resultado una densidad extrema de transmisiones inalámbricas simultáneas. Se espera que este escenario se convierta habitual en entornos cerrados, por ejemplo, trenes de cercanías, subterráneos, aviones, aeropuertos u oficinas, y será un reto adicional debido a la creciente demanda de aplicaciones inalámbricas intensivas en datos en tecnología wearable. Esta combinación de comunicaciones de muy corto alcance, en aplicaciones de alta velocidad de datos y de reutilización espectral densa parece hacer que la operación en las frecuencias mmWave sea un candidato adecuado; se añade la posibilidad de alojar conjuntos de antenas dentro de dispositivos para el beamforming direccionales. Por tanto, también se investiga la viabilidad de las redes wearables mmWave cerradas, con especial énfasis en modelar apropiadamente el impacto de los mecanismos de propagación en estas frecuencias. En el modelado de propagación, las reflexiones especulares de las superficies se explican explícitamente, ya que se espera que contribuyan a la potencia de la señal útil, mientras que, al mismo tiempo, intensificar la interferencia. Reconociendo la mayor prominencia del bloqueo por obstáculos, también se modelan los bloqueos corporales en los caminos de propagación directa y reflejada. El impacto de estos mecanismos en la eficiencia espectral de la red se evalúa, ayudado por la aplicación de la geometría estocástica y la teoría de la forma aleatoria. Bajo configuraciones internas relevantes, y en la ausencia plausible de señal directa fuerte, se investiga la fiabilidad de las reflexiones superficiales proporcionando potencia de señal útil para una comunicación eficiente y se establece la necesidad de antenas direccionales.

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Wu, Yue. "Advanced technologies for device-to-device communications underlaying cellular networks." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/15391/.

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The past few years have seen a major change in cellular networks, as explosive growth in data demands requires more and more network capacity and backhaul capability. New wireless technologies have been proposed to tackle these challenges. One of the emerging technologies is device-to-device (D2D) communications. It enables two cellular user equipment (UEs) in proximity to communicate with each other directly reusing cellular radio resources. In this case, D2D is able to offload data traffic from central base stations (BSs) and significantly improve the spectrum efficiency of a cellular network, and thus is one of the key technologies for the next generation cellular systems. Radio resource management (RRM) for D2D communications and how to effectively exploit the potential benefits of D2D are two paramount challenges to D2D communications underlaying cellular networks. In this thesis, we focus on four problems related to these two challenges. In Chapter 2, we utilise the mixed integer non-linear programming (MINLP) to model and solve the RRM optimisation problems for D2D communications. Firstly we consider the RRM optimisation problem for D2D communications underlaying the single carrier frequency division multiple access (SC-FDMA) system and devise a heuristic sub-optimal solution to it. Then we propose an optimised RRM mechanism for multi-hop D2D communications with network coding (NC). NC has been proven as an efficient technique to improve the throughput of ad-hoc networks and thus we apply it to multi-hop D2D communications. We devise an optimal solution to the RRM optimisation problem for multi-hop D2D communications with NC. In Chapter 3, we investigate how the location of the D2D transmitter in a cell may affect the RRM mechanism and the performance of D2D communications. We propose two optimised location-based RRM mechanisms for D2D, which maximise the throughput and the energy efficiency of D2D, respectively. We show that, by considering the location information of the D2D transmitter, the MINLP problem of RRM for D2D communications can be transformed into a convex optimisation problem, which can be efficiently solved by the method of Lagrangian multipliers. In Chapter 4, we propose a D2D-based P2P le sharing system, which is called Iunius. The Iunius system features: 1) a wireless P2P protocol based on Bittorrent protocol in the application layer; 2) a simple centralised routing mechanism for multi-hop D2D communications; 3) an interference cancellation technique for conventional cellular (CC) uplink communications; and 4) a radio resource management scheme to mitigate the interference between CC and D2D communications that share the cellular uplink radio resources while maximising the throughput of D2D communications. We show that with the properly designed application layer protocol and the optimised RRM for D2D communications, Iunius can significantly improve the quality of experience (QoE) of users and offload local traffic from the base station. In Chapter 5, we combine LTE-unlicensed with D2D communications. We utilise LTE-unlicensed to enable the operation of D2D in unlicensed bands. We show that not only can this improve the throughput of D2D communications, but also allow D2D to work in the cell central area, which normally regarded as a “forbidden area” for D2D in existing works. We achieve these results mainly through numerical optimisation and simulations. We utilise a wide range of numerical optimisation theories in our works. Instead of utilising the general numerical optimisation algorithms to solve the optimisation problems, we modify them to be suitable for the specific problems, thereby reducing the computational complexity. Finally, we evaluate our proposed algorithms and systems through sophisticated numerical simulations. We have developed a complete system-level simulation framework for D2D communications and we open-source it in Github: https://github.com/mathwuyue/py- wireless-sys-sim.

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Lin, Charlie. "Photonic device design flow : from mask layout to device measurement." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43510.

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Mask layout design is an important part in silicon photonic device design flow; the space used and the quality of the mask directly affect the cost of fabrication and quality of the outcome. To effectively minimize time spent on drawing masks, fixing design violations, and reducing unused spacings between each structure, we use effective approaches in the mask design process to ensure the listed criteria are met. Using the PCell and the hierarchy drawing methods, GDS files that contain different device parameters can be generated efficiently. As a result, direct GDS modeling efficiency is improved. An experimental setup that is capable of obtaining high quality measurement data is critical to device measurement. The concept of an automated measurement station can effectively reduce work needed from the experimenter while providing quality results. With the implemented fiber-to-fiber and fiber array automated measurement station, multi-device measurement can be set up to run automatically in minutes whereas traditional manual measurement stations require one's presence and constant attention. In this thesis, we have illustrated several mask drawing approaches and showed the drawing steps of two masks in detail. We have described two automated experimental setups, fiber-to-fiber and fiber array, in detail and included various measurement results to show the capabilities of these two stations.

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Hasan, Monowar. "Radio Resource Management for Relay-Aided Device-to-Device Communication." IEEE, 2013. http://hdl.handle.net/1993/30531.

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In this thesis, performance of relay-assisted Device-to-device (D2D) communication is investigated where D2D traffic is carried through relay nodes. I develop resource management schemes to maximize end-to-end rate as well as conversing rate requirements for cellular and D2D UEs under total power constraint. I also develop a low-complexity distributed solution using the concept of message passing. Considering the uncertainties in wireless links (e.g., when interference from other relay nodes and the link gains are not exactly known), I extend the formulation using robust resource allocation techniques. In addition, a distributed solution approach using stable matching is developed to allocate radio resources in an efficient and computationally inexpensive way under the bounded channel uncertainties. Numerical results show that, there is a distance threshold beyond which relay-assisted D2D communication significantly improves network performance at the cost of small increase in end-to-end delay when compared to conventional approach.

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Bashar, A. M. A. Elman. "Online Distributed Depository Selection in Opportunistic Device-to-Device Networks." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10163336.

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Device-to-device (D2D) is a new paradigm in cellular networks that enhances network performance by introducing increased spectral efficiency and reduced communication delay. Efficient data dissemination is indispensable for supporting many D2D applications such as content distribution and location-aware advertisement. In this work, I investigate a new and interesting data dissemination problem where the receivers are not explicitly known and data must be disseminated to the receivers within a probabilistic delay budget. I propose to exploit data depositories, which can temporarily house data and deliver them to interested receivers upon requests. I formally formulate the delay-constrained profit maximization problem for data deposition in D2D networks and show its NP-hardness. Under the unique mobile opportunistic network setting, a practical solution for such problem must be distributed, localized, and online. To this end, I introduce three algorithms for Direct Online Selection of 1-Depository, Direct Online Selection of L-Depositories, and Mixed Online Selection of L-Depositories. To demonstrate and evaluate the system, I implement a prototype using Google Nexus handsets and conduct experiments for five weeks. I further carry out simulations based on real-world mobility traces for evaluation of large-scale networks and various network settings that are impractical to experiment.

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Hosny, Sameh Shawky Ibrahim. "MOBILITY AND CONTENT TRADING IN DEVICE-TO-DEVICE CACHING NETWORKS." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480629254438794.

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Kai, Yuan. "Resource management for cellular-assisted device-to-device (D2D) communications." Thesis, University of Kent, 2018. https://kar.kent.ac.uk/66874/.

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Device-to-Device (D2D) communication has become a promising candidate for future wireless communication systems to improve the system spectral efficiency, while reducing the latency and energy consumption of individual communication. With the assistance of cellular network, D2D communications can greatly reduce the transmit distance by utilizing the spatial dispersive nature of ever increasing user devices. Further, substantial spectrum reuse gain can be achieved due to the short transmit distance of D2D communication. It, however, significantly complicates the resource management and performance analysis of D2D communication underlaid cellular networks. Despite an increasing amount of academic attention and industrial interests, how to evaluate the system performance advantages of D2D communications with resource management remains largely unknown. On account of the proximity requirement of D2D communication, the resource management of D2D communication generally consists of admission access control and resource allocation. Resource allocation of cellular assisted D2D communications is very challenging when frequency reuse is considered among multiple D2D pairs within a cell, as intense inter D2D interference is difficult to tackle and generally causes extremely large amount of signaling overheads for channel state information (CSI) acquisition. Hence, the first part of this thesis is devoted to the resource allocation of cellular assisted D2D communication and the performance analysis. A novel resource allocation scheme for cellular assisted D2D communication is developed with low signaling overhead, while maintaining high spectral efficiency. By utilizing the spatial dispersive nature of D2D pairs, a geography-based sub-cell division strategy is proposed to group the D2D pairs into multiple disjoint clusters, and sub-cell resource allocation is performed independently for the D2D pairs within each sub-cell without the need of any prior knowledge of inter D2D interference. Under the proposed resource allocation scheme, tractable approximation for the inter D2D interference modeling is obtained and a computationally efficient expression for the average ergodic sum capacity of the cell is derived. The expression further allows us to obtain the optimal number of sub-cells that maximizes the average ergodic sum capacity of the cell. It is shown that with small CSI feedback, the system capacity/spectral efficiency can be improved significantly by adopting the proposed resource allocation scheme, especially in dense D2D deployment scenario. The investigation of use cases for cellular assisted D2D communication is another important topic which has direct effect on the performance evaluation of D2D communication. Thanks to the spatial dispersive nature of devices, D2D communication can be utilized to harvest the vast amount of the idle computation power and storage space distributed at the devices, which yields sufficient capacities for performing computation-intensive and latency-critical tasks. Therefore, the second part of this thesis focuses on the D2D communication assisted Mobile Edge Computing (MEC) network. The admission access control of D2D communication is determined by both disciplines of mobile computing and wireless communications. Specifically, the energy minimization problem in D2D assisted MEC networks is addressed with the latency constraint of each individual task and the computing resource constraint of each computing entity. The energy minimization problem is formed as a two-stage optimization problem. At the first stage, an initial feasibility problem is formed to maximize the number of executed tasks, and the global energy minimization problem is tackled in the second stage while maintaining the maximum number of executed tasks. Both of the optimization problems in two stages are NP-hard, therefore a low-complexity algorithm is developed for the initial feasibility problem with a supplementary algorithm further proposed for energy minimization. Simulation results demonstrate the near-optimal performance of the proposed algorithms and the fact that the number of executed tasks is greatly increased and the energy consumption per executed task is significantly reduced with the assistance of D2D communication in MEC networks, especially in dense user scenario.

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Le, Minh. "Universal Mobile Service Execution Framework for Device-To-Device Collaborations." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7032.

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There are high demands of effective and high-performance of collaborations between mobile devices in the places where traditional Internet connections are unavailable, unreliable, or significantly overburdened, such as on a battlefield, disaster zones, isolated rural areas, or crowded public venues. To enable collaboration among the devices in opportunistic networks, code offloading and Remote Method Invocation are the two major mechanisms to ensure code portions of applications are successfully transmitted to and executed on the remote platforms. Although these domains are highly enjoyed in research for a decade, the limitations of multi-device connectivity, system error handling or cross platform compatibility prohibit these technologies from being broadly applied in the mobile industry. To address the above problems, we designed and developed UMSEF - an Universal Mobile Service Execution Framework, which is an innovative and radical approach for mobile computing in opportunistic networks. Our solution is built as a component-based mobile middleware architecture that is flexible and adaptive with multiple network topologies, tolerant for network errors and compatible for multiple platforms. We provided an effective algorithm to estimate the resource availability of a device for higher performance and energy consumption and a novel platform for mobile remote method invocation based on declarative annotations over multi-group device networks. The experiments in reality exposes our approach not only achieve the better performance and energy consumption, but can be extended to large-scaled ubiquitous or IoT systems.

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Li, Yujin. "Mobility and Traffic Correlations in Device-to-Device (D2D) Communication Networks." Thesis, North Carolina State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3690209.

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29

Landi, Maicol. "Comunicazione device-to-device attraverso tecnologia WiFi-Direct: una valutazione sperimentale." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8967/.

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30

Chevillon, Romain. "Efficacité énergétique des communications Device-to-Device dans les réseaux hétérogènes." Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4072/document.

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L'objectif de cette thèse est l'étude de l'efficacité énergétique des communications D2D dans les réseaux hétérogènes. Nous proposons dans un premier temps d'analyser la consommation énergétique d'un réseau de trois appareils, puis introduisons une nouvelle topologie prenant en compte l'entropie de données, afin d'augmenter l'efficacité énergétique globale. Par la suite, nous étudions la consommation énergétique et l'influence des interférences sur une cellule dans le cas pratique d'une catastrophe naturelle. Nous introduisons alors un nouveau protocole d'allocation de ressources basé sur le clustering en Fuzzy C-Means. Nous utilisons ensuite des outils et métriques issus de la géométrie stochastique afin d'analyser et de comparer l'efficacité énergétique et spectrale au sein de plusieurs types de réseaux munis de communications D2D. Dans un deuxième temps, nous introduisons les notions d'antennes directionnelles avec des ondes millimétriques. Pour ce faire, nous évaluons l'influence du canal millimétrique et introduisons les concepts de blocage, et de modèles sectorisés d'antennes, à des fins mathématiques. L'utilisation d'ondes millimétriques, et plus particulièrement d'antennes directionnelles ULA, s'avère être un choix totalement opportun dans l'objectif premier de cette thèse qui est d'augmenter à la fois l'efficacité spectrale (donc le débit) et l'efficacité énergétique au sein d'un réseau hétérogène comprenant des communications D2D
The objective of this thesis is the study of the energy efficiency of D2D communications in heterogeneous networks. We first propose to analyze the energy consumption of a three device, then introduce a new topology taking into account the data entropy, in order to increase the overall energy efficiency. Subsequently, we study the energy consumption and the influence of interference in a cell for the use case of a natural disaster. We then introduce a new resource allocation protocol based on Fuzzy C-Means clustering. We then use tools and metrics from stochastic geometry to analyze and compare energy and spectral efficiency among multiple types of networks comprising D2D communications. The first study is done on a network in which the cellular and WiFi resources are shared. In a second step, we introduce the notions of directional antennas with millimeter waves. To do this, we evaluate the influence of the mmWave channel and introduce the concepts of blocking, and sectored models of antennas, for mathematical purposes. The use of millimeter waves, and more particularly ULA directional antennas, proves to be a totally appropriate choice in the primary objective of this thesis, which is to increase both the spectral efficiency (therefore the bit rate) and the energy efficiency within a heterogeneous network including D2D communications

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Mustafa, Hafiz Atta Ul. "Spatial and social paradigms for coverage analysis in device to device networks." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/813277/.

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The traditional approaches towards capacity gain, ubiquitous coverage and energy efficient green cellular communication call for network densification using small cell deployments. This network densification has been a successful strategy; however network operational/capital expenditure (OPEX/CAPEX) and energy efficiency concerns, due to large number of deployments, cannot be ignored. The network controlled underlay device-to-device (D2D) densification is one alternate solution that can offer lower OPEX/CAPEX, huge capacity, improved energy efficiency, increased area spectral efficiency, ubiquitous coverage, and very low end-to-end latency. However, this coexistence poses challenging interference management due to intra-cell cross-tier interference. In order to analyse the effect of intra-cell cross-tier interference, I have provided Stochastic framework for coverage analysis of primary cellular user. The basic model considers homogeneous Poisson point process (PPP) as spatial distribution of mobile users in the coverage area. This model has been extended to capture inhomogeneity and clustering effect. Therefore, I have used Permanental Cox process, a subclass of doubly Stochastic Poisson process where inhomogeneity is dictated by random intensity measure and clustering effect is governed by homophilic relation that exists due to spatial correlation between mobile users. The D2D pairing is realized by nearest neighbour distribution function. In this context, I have proposed Euler Characteristic based approach to approximate intractable random intensity measure and subsequently derive nearest neighbour distribution function. I have proposed the threshold and spatial extent of excursion set of chi-squared random field as interference control parameters to select different cluster sizes for D2D communication. Further, I have considered both spatial and social layers for D2D pairing. In social domain, I consider common content requests and model the joint spatial and social distribution as proximity based independently marked homogeneous PPP. The proximity considers physical distance between D2D nodes whereas social relationship is modelled as Zipf based marks. I apply these two paradigms to analyse the effect of intra-cell cross-tier interference on average coverage probability of distance-proportional power-controlled primary cellular user.

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Ibrahim, Rita. "Utilisation des communications Device-to-Device pour améliorer l'efficacité des réseaux cellulaires." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC002/document.

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Cette thèse étudie les communications directes entre les mobiles, appelées communications D2D, en tant que technique prometteuse pour améliorer les futurs réseaux cellulaires. Cette technologie permet une communication directe entre deux terminaux mobiles sans passer par la station de base. La modélisation, l'évaluation et l'optimisation des différents aspects des communications D2D constituent les objectifs fondamentaux de cette thèse et sont réalisés principalement à l'aide des outils mathématiques suivants: la théorie des files d'attente, l'optimisation de Lyapunov et les processus de décision markovien partiellement observable POMDP. Les résultats de cette étude sont présentés en trois parties. Dans la première partie, nous étudions un schéma de sélection entre mode cellulaire et mode D2D. Nous dérivons les régions de stabilité des scénarios suivants: réseaux cellulaires purs et réseaux cellulaires où les communications D2D sont activées. Une comparaison entre ces deux scénarios conduit à l'élaboration d'un algorithme de sélection entre le mode cellulaire et le mode D2D qui permet d'améliorer la capacité du réseau. Dans la deuxième partie, nous développons un algorithme d'allocation de ressources des communications D2D. Les utilisateurs D2D sont en mesure d'estimer leur propre qualité de canal, cependant la station de base a besoin de recevoir des messages de signalisation pour acquérir cette information. Sur la base de cette connaissance disponibles au niveau des utilisateurs D2D, une approche d'allocation des ressources est proposée afin d'améliorer l'efficacité énergétique des communications D2D. La version distribuée de cet algorithme s'avère plus performante que celle centralisée. Dans le schéma distribué des collisions peuvent se produire durant la transmission de l'état des canaux D2D ; ainsi un algorithme de réduction des collisions est élaboré. En outre, la mise en œuvre des algorithmes centralisé et distribué dans un réseau cellulaire, type LTE, est décrite en détails. Dans la troisième partie, nous étudions une politique de sélection des relais D2D mobiles. La mobilité des relais représente un des principaux défis que rencontre toute stratégie de sélection de relais. Le problème est modélisé par un processus contraint de décision markovien partiellement observable qui prend en compte le dynamisme des relais et vise à trouver la politique de sélection de relais qui optimise la performance du réseau cellulaire sous des contraintes de coût
This thesis considers Device-to-Device (D2D) communications as a promising technique for enhancing future cellular networks. Modeling, evaluating and optimizing D2D features are the fundamental goals of this thesis and are mainly achieved using the following mathematical tools: queuing theory, Lyapunov optimization and Partially Observed Markov Decision Process (POMDP). The findings of this study are presented in three parts. In the first part, we investigate a D2D mode selection scheme. We derive the queuing stability regions of both scenarios: pure cellular networks and D2D-enabled cellular networks. Comparing both scenarios leads us to elaborate a D2D vs cellular mode selection design that improves the capacity of the network. In the second part, we develop a D2D resource allocation algorithm. We observe that D2D users are able to estimate their local Channel State Information (CSI), however the base station needs some signaling exchange to acquire this information. Based on the D2D users' knowledge of their local CSI, we provide an energy efficient resource allocation framework that shows how distributed scheduling outperforms centralized one. In the distributed approach, collisions may occur between the different CSI reporting; thus, we propose a collision reduction algorithm. Moreover, we give a detailed description on how both centralized and distributed algorithms can be implemented in practice. In the third part, we propose a mobile relay selection policy in a D2D relay-aided network. Relays' mobility appears as a crucial challenge for defining the strategy of selecting the optimal D2D relays. The problem is formulated as a constrained POMDP which captures the dynamism of the relays and aims to find the optimal relay selection policy that maximizes the performance of the network under cost constraints

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Kirby, Brenden. "Power Supply to Mobile Device." Thesis, Högskolan i Halmstad, Akademin för informationsteknologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-39828.

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While technology develops, many devices are becoming portable and battery driven. These devices are among us and are unconditionally a part of today’s society. The usage and the surrounding environment of these devices can vary depending on the intended functionality and purpose. Varying environmental conditions impact the devices charging method. This report covers the development and implementation of a printed circuit board. The circuit board is going to be used as a prototype for future testing for a portable device which the company VectorizeMove [1] is developing. The circuit board contains multiple charging methods and a voltage regulation system. The charging methods include inductive charging and micro USB charging. The charging systems are designed for a lithium polymer battery which are charged through different phases which prevent damage to the battery. The voltage regulation system is implemented to test and ensure a stable voltage output for the components included in the company's device.
Medan teknik utvecklas blir många bärbara enheter batteridriven. Dessa enheter är bland oss och är ovillkorligen en del av dagens samhälle. Användningen och omgivningen av dessa enheter kan variera beroende på avsedd funktionalitet och syfte. Varierande miljöförhållanden kan påverkar laddningsmetoden för dessa enheter. Denna rapport omfattar utveckling och genomförande av ett kretskort. Kretskortet kommer att användas som prototyp för framtida testning för en bärbar enhet som företaget VectorizeMove [1] utvecklar. Kretskortet innehåller flera laddningsmetoder och ett spänningsregleringssystem. Laddningsmetoderna inkluderar induktiv laddning och micro USBladdning. Laddningssystemen är konstruerade för ett litium polymer batteri som laddas genom olika faser som förhindrar skador på batteriet. Spänningsregleringssystemet implementeras för att testa och säkerställa en stabil spänningsutgång för komponenterna som ingår i företagets enhet.

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Pradini, Aidilla. "Power Control and Resource Allocation for Device-to-Device Communications in Cellular Networks." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-128351.

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Device-to-device (D2D) communications in cellular networks will improve traditional cellular systems in many ways. By allowing user equipment (UE) in proximity to communicate through direct links, the transmitter would be able to transmit with lower power while the receiver could still receive better-quality signals. Both spectrum and energy eciency can be signicantly increased. Moreover, D2D communications in cellular networks will make an eective way for emerging proximity-based services. The introduction of D2D links into a cellular network complicates the interference situation. Traditional macro-cellular links will experience high interference from D2D links, especially if D2D links are reusing the cellular radio resources. This amplies the importance of power control and resource allocation techniques to mitigate interference. This thesis evaluates the performance of three power control algorithms, namely LTE power control, utility maximization, and hybrid power control. LTE power control plays the role of the most practical power control scheme as it has been standardized. Utility maximization power control is an optimal distributed power control designed to improve spectrum and energy eciency in a balanced manner. Hybrid power control is a scheme proposed in this thesis, which combines LTE power control for the cellular UEs and utility maximization power control for the D2D UEs. It is designed to have compatibility with existing LTE system as well as to protect cellular links. Four resource allocation algorithms are considered in this thesis, namely random resource allocation, balanced random allocation (BRA), cellular protection allocation (CPA), and minimum interference (MinInterf) allocation. They are all heuristic algorithms with dierent degrees of complexity. Numerical results are obtained with Monte Carlo simulations, modelling a cellular system with randomly dropped UEs in each iteration. System performance metrics resulted from dierent power control and resource allocation algorithms are evaluated and compared. The performance metrics of interest include both spectrum and energy eciency, SINR, and transmit power. The results show that LTE power control performs well in terms of D2D UEs' SINR if the path loss compensation factor is set to a suciently high value, e.g. 0.8. Meanwhile, the performance of utility maximization power control depends heavily on its tuning parameter. If the parameter is low, high spectrum efciency is achieved in the exchange of high transmit power, or vice versa. Hybrid power control is proven to yield better cellular UEs' SINR compared to other power control algorithms. This depends on an interference threshold parameter. If the threshold parameter is lower, the cellular links are better protected. Simulation results also show that the MinInterf allocation algorithm is superior than other resource allocation algorithms in terms of UEs' SINR. However, MinInterf is a complex algorithm which requires the knowledge of all cellular and D2D link qualities. Therefore, it might be preferable to use either of three other algorithms. Simulation results show that BRA performs better than random resource allocation, although in many cases their performance metrics are almost identical. CPA algorithm performs slightly better than random resource allocation and BRA in the low-SINR region, but it performs badly in the high-SINR region.

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Shalmashi, Serveh. "Device-to-Device Communications for Future Cellular Networks : Challenges, Trade-Offs, and Coexistence." Doctoral thesis, KTH, Radio Systems Laboratory (RS Lab), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-168145.

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The steep growth in mobile data traffic has gained a lot of attention in recent years. With current infrastructure deployments and radio resources, operators will not be able to cope with the upcoming demands. Consequently, discussions of the next generation of mobile networks, referred to as the fifth generation (5G), have started in both academia and industry. In addition to more capacity, stringent requirements for improving energy efficiency, decreasing delays, and increasing reliability have been envisioned in 5G. Many solutions have been put forward, one of them being device-to-device (D2D) communications where users in close proximity can transmit directly to one another bypassing the base station (BS). In this thesis, we identify trade-offs and challenges of integrating D2D communications into cellular networks and propose potential solutions. To maximize gains from such integration, resource allocation and interference management are key factors. We start by introducing cooperation between D2D and cellular users in order to minimize any interference between the two user types and identifying the scenarios where this cooperation can be beneficial. It is shown that an increase in the number of cellular users within the coverage area and in the size of the cell is associated with a higher probability of cooperation. With this cooperation, we can potentially increase the number of connected devices, reduce the delay, increase the cell sum rate, and offload an overloaded cell. Next, we consider D2D communications underlaying the uplink of cellular networks. In such a scenario, any potential gain from resource sharing (time, frequency, or space) is determined by how the interference is managed. The quality and performance of the interference management techniques depend on the availability of the channel state information (CSI) and the location of nodes as well as the frequency of updates regarding such information. The more information is required, the more signaling is needed, which results in higher power consumption by the users. We investigate the trade-off between the availability of full CSI, which necessitates instantaneous information, and that of limited CSI, which requires infrequent updates. Our results show that with limited CSI, a good performance (in terms of the sum rate of both user types) can be achieved if a small performance loss is tolerated by cellular users. In addition, we propose a novel approach for interference management which only requires the information on the number of D2D users without any knowledge about their CSI. This blind approach can achieve a small outage probability with very low computational complexity when the number of scheduled D2D users is small. We then study the problem of mode selection, i.e., if a user should transmit in the D2D mode or in the conventional cellular mode. We identify the decision criteria for both overlay and underlay scenarios with two different objectives. We find out that the D2D communication is beneficial in macro cells or at cell boundaries. The area in which D2D mode is optimal varies with the objective of the network, transmit power, required quality-of-service, and the number of BS antennas. In the second part of this thesis, we study the effects of integration and coexistence of underlay D2D communications with another promising technology proposed for 5G, namely massive multiple-input-multiple-output (MIMO). Potential benefits of both technologies are known individually, but the possibility of and performance gains from their coexistence are not adequately addressed. We evaluate the performance of this hybrid network in terms of energy efficiency and the average sum rate. Comprehensive analysis reveals that the performance highly depends on the D2D user density. We conclude that underlay D2D communications can only coexist with massive MIMO systems in the regime of low D2D user density. By introducing a high number of D2D users, gains from the massive MIMO technology degrade rapidly, and therefore in this case, the D2D communications should use the overlay approach rather than the underlay, or the network should only allow a subset of D2D transmissions to be active at a time.
Den stora ökningen i mobildatatrafik de senaste åren har tilldragit sig mycket intresse. Med nuvarande infrastruktur och radioresurser kommer inte mobiloperatörerna att kunna hantera de kommande kraven. Därför har diskussioner kring den femte generationens (5G) mobila nätverk startat inom både akademin och industrin. Utöver högre kapacitet så kommer strikta krav på ökad energieffektivitet, minskad fördröjning samt ökad tillförlitlighet att planeras för 5G. En av många lösningar som har föreslagits är enhet-till-enhetskommunikation (device-to-device communications, D2D, på engelska), vilket innebär att närliggande mobilanvändare kan sända direkt till varandra utan att gå genom basstationen. I denna avhandling identifierar vi kompromisser och problem kring, samt föreslår lösningar för, integrering av D2D-kommunikation i cellulära nätverk. Viktiga faktorer för att maximera vinsten av sådan integrering är resursallokering och störningshantering. Avhandlingen börjar med att beskriva samarbetet mellan D2D- och cellulära användare för att minska störningen mellan de två användartyperna, samt för att identifiera scenarier där denna typ av samarbete kan vara fördelaktigt. Vi visar att samarbetssannolikheten ökar med antalet cellulära användare i täckningsområdet, samt när cellstorleken ökar. Denna typ av samarbete kan användas för att öka antalet ansluta enheter, minska fördröjningen, öka cellsummadatataken eller avlasta överlastade celler. Härnäst studerar vi D2D-kommunikation underliggande upplänken i cellulära nätverk. I ett sådant scenario bestäms eventuell vinst från resursdelning (t.ex. i tid, frekvens eller rymd) av hur störningen hanteras. Kvaliteten och prestandan hos störningshanteringen beror på tillgängligheten av kanalkännedom och information om nodernas position, samt uppdateringsfrekvensen för dessa. Ju mer information som behövs, desto mer signalering krävs, vilket leder till högre effektförbrukning hos användarna. Vi undersöker kompromissen mellan fullt tillgänglig kanalkännedom, vilket kräver momentan information, och ett scenario där kanalkännedomen är begränsad, vilket enbart kräver uppdatering med låg frekvens. Våra resultat visar att god summadatatakt kan uppnås när enbart begränsad kanalkännedom är tillgänglig, om en liten prestandaförlust tillåts för cellulära användare. Vi föreslår dessutom en ny metod för störningshantering som enbart kräver information om antalet D2D-användare, utan vetskap om deras kanalkännedom. Denna blinda metod kan uppnå hög täckningssannolikhet med låg beräkningskomplexitet när antalet schemalagda D2D-användare är lågt. Vi studerar även lägesvalsproblemet, dvs. om en användare ska sända i D2D-läge eller i konventionellt cellulärt läge. Vi karaktäriserar beslutskriterierna för både överliggande och underliggande scenarier med två olika objektivfunktioner och visar att D2D-kommunikation är fördelaktig i makroceller samt vid cellkanterna. Området för D2D-optimalitet varierar med objektivfunktionen för nätverket, sändeffekten, servicekvalitetskraven och antalet basstationsantenner. I den andra delen av avhandlingen så studerar vi effekter kring integrering och samexistens av underliggande D2D-kommunikation med en annan lovande teknologi för 5G, nämligen massiv multiple input-multiple output (massiv MIMO). De individuella fördelarna för de två teknologierna är välkända, men eventuella prestandavinster när teknologierna samexisterar har inte studeras tillräckligt. Vi undersöker prestanda i detta hybridnätverk i termer av energieffektivitet och genomsnittlig summadatatakt. En noggrann analys visar att prestandan beror på tätheten av D2D-användare. Vi drar slutsatsen att underliggande D2D-kommunikation bara kan samexistera med massiv MIMO när tätheten av D2D-användare är låg. När det existerar många D2D-användare minskas prestandavinsten från massiv MIMO snabbt och därför bör D2D-kommunikationen ske i överliggande läge istället för underliggande läge. Alternativt kan nätverket tillåta att enbart en delmängd av D2D-sändningar är aktiva samtidigt.

QC 20150529

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Ghazanfari, A. (Amin). "Coordinated beamforming and power control for network controlled Device-to-Device (D2D) communication." Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201401111003.

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Since the integration of data services into cellular communications, cellular operators are struggling to harness the overwhelming data traffic on their networks. Underlay Device-to-Device (D2D) communication is a new and promising paradigm which allows proximate mobile users to have direct communication over the cellular spectrum that may be reused by other cellular users in the same cell. This new paradigm is proposed to assist the cellular operators to deal with the booming demand of mobile users. Recent studies have shown that underlay D2D communication significantly increases the cellular network capacity, and enables cellular operators to support rich multimedia services. However, reusing cellular resources for both D2D and cellular communication introduces interference issues. In such systems, interference management is of utmost importance because improper interference coordination may lead to a self-destructive network. Power control and beamforming appears to be viable techniques for interference management which can also be used to enhance the energy efficiency of the system. Network coordinated sum power optimization schemes for D2D communications underlaying uplink and downlink cellular spectrum is considered in this thesis. In particular, the system optimization target is to minimize the sum transmission power while guaranteeing the user specific rate constraints. Novel algorithms are proposed to solve the power minimization problem optimally. For the uplink, the problem is solved using joint transmit power control and receive beamforming algorithm. The downlink problem is reformulated as a second-order cone program (SOCP), and thus, it can be solved efficiently via standard SOCP solvers. Moreover, a decentralized algorithm is proposed that reduces the amount of control information exchange in comparison to the centralized approach. The performance of the proposed algorithms is compared with the conventional cellular scheme. Simulation results demonstrate that the proposed underlay D2D communication approach is capable of achieving significant performance gains over the conventional cellular scheme. Results also illustrate that the power consumption of the system is highly affected by the location of the interfering cellular user and whether the resources are shared in uplink or downlink. Therefore, four different resource sharing areas are defined for D2D communications. These areas specify the type of resources (i.e., downlink and uplink) suitable for D2D communication.

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37

Yuan, Hu. "Device-to-device communication in cellular networks : multi-hop path selection and performance." Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/91038/.

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Over the past decade, the proliferation of internet equipment and an increasing number of people moving into cities have significantly influenced mobile data demand density and intensity. To accommodate the increasing demands, the fifth generation (5G) wireless systems standards emerged in 2014. Device-to-device communications (D2D) is one of the three primary technologies to address the key performance indicators of the 5G network. D2D communications enable devices to communicate data information directly with each other without access to a fixed wireless infrastructure. The potential advantages of D2D communications include throughput enhancement, device energy saving and coverage expansion. The economic attraction to mobile operators is that significant capacity and coverage gains can be achieved without having to invest in network-side hardware upgrades or new cell deployments. However, there are technical challenges related to D2D and conventional cellular communication (CC) in co-existence, especially their mutual interference due to spectrum sharing. A novel interference-aware-routing for multi-hop D2D is introduced for reducing the mutual interference. The first verification scenario of interference-aware-routing is that in a real urban environment. D2D is used for relaying data across the urban terrain, in the presence of CC communications. Different wireless routing algorithms are considered, namely: shortest-path-routing, interference-aware-routing, and broadcast-routing. In general, the interference-aware-routing achieves a better performance of reliability and there is a fundamental trade-off between D2D and CC outage performances, due to their mutual interference relationship. Then an analytical stochastic geometry framework is developed to compare the performance of shortest-path-routing and interference-aware-routing. Based on the results, the spatial operational envelopes for different D2D routing algorithms and CC transmissions based on the user equipment (UEs) physical locations are defined. There is a forbidden area of D2D because of the interference from the base stations (BSs), so the collision probability of the D2D multi-hop path hitting the defined D2D forbidden area is analysed. Depend on the result of the collision probability, a dynamic switching strategy between D2D and CC communications in order to minimise mutual interference is proposed. A blind gradient-based transmission switching strategy is developed to avoid collision within the collision area and only requires knowledge of the distances to the serving base station of the current user and the final destination user. In the final part of my research, the concept of LTE-U (Long term evolution for Unlicensed Spectrum), which suggests that LTE can operate in the unlicensed spectrum with significant modifications to its transmission protocols, is investigated. How the envisaged D2D networks can efficiently scale their capacity by utilising the unlicensed spectrum with appropriately designed LTE-Unlicensed protocols is examined.

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38

Singh, Rahul Kumar. "Algorithm on Device to Device Communication." Thesis, 2015. http://ethesis.nitrkl.ac.in/7286/1/Algorithm_Singh_2015.pdf.

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Mobile communication services is already assumed very important in many ways, like mobile data, video and TV services now becomes the part of the everyday of human life. In view growing demand of the data for these services is increasing day by day. For this we need to increase our capacity in order to give these services to the end user. For this we going to introduce an application of device to device communication in which device are communicate with each other with the help of cellular networks. D2D communication decreases the load on the mobile network and increase in spectral efficiency. In this thesis we going to evolved a method in which D2D communication will controlled by the cellar networks. For the achievement of the given minimum SINR we derived a minimum distance relation between two D2D links which is operating simultaneously. For the fulfillment of these minimum requirement we develop an idea for the grouping and scheduling of the links so that they can operate simultaneously. Finally, we perform the simulation in different situation to see the effect of how the cell is populated with the varying the links and also we see that how we achieve the minimum required SINR in different situation.

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39

Lin, Xingqin. "Integrated cellular and device-to-device networks." Thesis, 2014. http://hdl.handle.net/2152/28386.

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Device-to-device (D2D) networking enables direct discovery and communication between cellular subscribers that are in proximity, thus bypassing the base stations (BSs). In principle, exploiting direct communication between nearby mobile devices will improve spectrum utilization, overall throughput, and energy consumption, while enabling new peer-to-peer and location-based applications and services. D2D-enabled broadband communication technology is also required by public safety networks that must function when cellular networks are not available. Integrating D2D into cellular networks, however, poses many challenges and risks to the long-standing cellular architecture, which is centered around the BSs. This dissertation identifies outstanding technical challenges in D2D-enabled cellular networks and addresses them with novel models and fundamental analysis. First, this dissertation develops a baseline hybrid network model consisting of both ad hoc nodes and cellular infrastructure. This model uses Poisson point processes to model the random and unpredictable locations of mobile users. It also captures key features of multicast D2D including multicast receiver heterogeneity and retransmissions while being tractable for analytical purpose. Several important multicast D2D metrics including coverage probability, mean number of covered receivers per multicast session, and multicast throughput are analytically characterized under the proposed model. Second, D2D mode selection which means that a potential D2D pair can switch between direct and cellular modes is incorporated into the hybrid network model. The extended model is applied to study spectrum sharing between cellular and D2D communications. Two spectrum sharing models, overlay and underlay, are investigated under a unified analytical framework. Analytical rate expressions are derived and applied to optimize the design of spectrum sharing. It is found that, from an overall mean-rate perspective, both overlay and underlay bring performance improvements (vs. pure cellular). Third, the single-antenna hybrid network model is extended to multi-antenna transmission to study the interplay between massive MIMO (multi-input multiple-output) and underlaid D2D networking. The spectral efficiency of such multi-antenna hybrid networks is investigated under both perfect and imperfect channel state information (CSI) assumptions. Compared to the case without D2D, there is a loss in cellular spectral efficiency due to D2D underlay. With perfect CSI, the loss can be completely overcome if the number of canceled D2D interfering signals is scaled appropriately. With imperfect CSI, in addition to pilot contamination, a new asymptotic underlay contamination effect arises. Finally, motivated by the fact that transmissions in D2D discovery are usually not or imperfectly synchronized, this dissertation studies the effect of asynchronous multicarrier transmission and proposes a tractable signal-to-interference-plus-noise ratio (SINR) model. The proposed model is used to analytically characterize system-level performance of asynchronous wireless networks. The loss from lack of synchronization is quantified, and several solutions are proposed and compared to mitigate the loss.
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40

Chun-WeiKuo and 郭淳蔚. "4G LTE Device-to-Device Distributed Communication." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/54ttmz.

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碩士
國立成功大學
電腦與通信工程研究所
102
4G LTE is widespread in the world, recent years. Except having a higher transmitting speed than 3rd-generation(3G), also include more efficient resource allocation. However, there always exists an issue of power consumption of mobility equipment. Accordingly, we will introduce a technology called “Device-to-Device communication” undelaying LTE, which connect each equipment without Base Station (BS) and only need to make a link between two devices. Due to this way, the purpose of reducing power consumption can be realized. In the case of how much power should transmitter transmit, we will introduce an algorithm named “Alternating Direction Method of Multiplier”. We put these two methods jointly to find out the optimal solution of minimum power consumption.

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41

Segundo, Edvaldo de Sousa Soares. "Interferência em comunicações Device-to-Device D2D." Master's thesis, 2017. http://hdl.handle.net/10071/15102.

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A constante necessidade de aumento da capacidade de rede para atender às crescentes demandas dos assinantes, leva a indústria de telecomunicações, apoiada pela comunidade científica, a criar novos paradigmas que suportem requisitos de taxa de dados binários elevados dentro da rede de acesso sem fio existente de forma eficiente e eficaz. Para responder a este desafio, a Comunicação Device-to-Device (D2D) em redes celulares é vista como uma solução promissora. Deste modo, a presente dissertação consiste na exploração do modelo de comunicação D2D (Device-to-Device), mediante o desenvolvimento de várias rotinas de comunicação D2D dentro de uma estrutura de rede celular LTE-A, usando simuladores já existentes, nomeadamente, simuladores de sistema em JAVA e simuladores de ligação em MatLab, afim de analisar o eventual aumento de capacidade da comunicação D2D para rede celular. Tipicamente, as comunicações em D2D permitem que os utilizadores localizados na proximidade, possam comunicar diretamente sem a intervenção da estação base (BS - Base Station). Essa comunicação pode permitir ritmos binários muito elevados, baixos atrasos e poupança de energia. Nesta dissertação alterou-se o simulador de sistema celular existente para incluir as comunicações D2D e as suas interferências, sendo apresentados os resultados obtidos. Os resultados obtidos por simulação confirmaram o que se esperava, nomeadamente, aumento dos ritmos binários nas comunicações D2D e redução do atraso.
The continuing need to increase network capacity to meet growing subscriber demands leads the telecommunications industry, backed by the scientific community, to create new paradigms that support high binary data rate requirements within the existing wireless access network efficiently and effectively. To meet this challenge, Device-toDevice (D2D) Communication in cellular networks is seen as a promising solution. Thus, the present dissertation consists of the exploitation of the D2D (Device-toDevice) communication model, by developing several D2D communication routines within a LTE-A cellular network structure, using existing simulators, namely, simulator of system in JAVA and simulator of link in MatLab, in order to analyze the possible increase of capacity of D2D communication for cellular network. Typically, D2D communications allow users located in close proximity to communicate directly without the intervention of the base station (BS - Base Station). This communication can allow very high binary rates, low delays and energy savings. In this dissertation, the existing cellular system simulator was modified to include D2D communications and their interference, and the results obtained were presented. Simulation results have confirmed what was expected, namely, increasing bit rate with D2D communications and lower delays.

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42

Elsemary, Hadeer. "Secure Routing in Intelligent Device-to-Device Communications." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-002B-7CC7-3.

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Álvarez, Flor. "Secure device-to-device communication for emergency response." Phd thesis, 2020. https://tuprints.ulb.tu-darmstadt.de/11486/7/thesis_flor-alvarez_feb_2020.pdf.

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Mobile devices have the potential to make a significant impact during disasters. However, their practical impact is severely limited by the loss of access to mobile communication infrastructure: Precisely, when there is a surge in demand for communications from people in a disaster zone, this capacity for communications is severely curtailed. This loss of communications undermines the effectiveness of the many recent innovations in the use of smartphones and similar devices to mitigate the effects of disasters. While various solutions have been proposed, e. g., by having handsets form wireless ad hoc networks, none are complete: Some are specific to certain mobile operating systems or operating system versions. Others result in unacceptably increased energy consumption, flattening the batteries of phones at a time when users need to conserve energy due to the loss of access to opportunities to recharge their mobile devices. Realistic user behaviour, including patterns of movement and communications, are also rarely addressed. Further, security is rarely considered in a comprehensive and satisfying manner, leaving users exposed to a variety of potential attacks. Thus there is a compelling need to find more effective solutions for communications, energy management, and security of mobile devices operating in disaster conditions. To address these shortcomings, this thesis provides a suite of comprehensive solutions that contribute to facilitate secure device-to-device communication for emergency response. This thesis works to solve these problems by: (i) Conducting a large-scale field-trial to understand and analyze civilians’ behaviour during disaster scenarios; (ii) Proposing a practical, lightweight scheme for bootstrapping device-to-device security, that is tailored for local urban operations representative of disaster scenarios; (iii) Realizing novel energy management strategies for the neighbour discovery problem, which deliver significant energy savings in return for only a minimal reduction in neighbour discovery efficiency; (iv) The description of novel concepts for using devices in a smart city environment that remain functional following a disaster to support communications among mobile devices. In short, this thesis adds considerably to the understanding of the difficulties in the formation of direct device-to-device communications networks composed primarily of civilians’ mobile devices, and how several facets of this problem can be mitigated. Several of the proposed enhancements are also implemented. Thus, this thesis also takes essential steps in the direction of realizing such solutions to demonstrate their feasibility on real devices, intending to improve the tools available to civilians post-disaster.

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44

Hu, Chia-Wei, and 胡家維. "Interference-Aware Device-to-Device (D2D) Mode selection." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/49069984592961086957.

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碩士
國立交通大學
電子研究所
105
In this work, we consider device-to-device (D2D) communication underlaying a cellular network and focus on the mode selection of the new arrival D2D pair with existing D2D pairs. We also utilize two mode selection rules which is based on signal to interference noise ratio (SINR) and capacity. Each selection rule are discussed with two different sets of precoders. The first set is block diagonalization (BD) precoder for cellular users and zero forcing (ZF) precoder for D2D users. The second set is signal-to-leakage-and-noise ratio (SLNR) precoder with two different derivations for cellular users and D2D pairs, respectively. Our evaluation results show that utilizing SLNR precoders can not only achieve a suboptimal performance but also require much less limitations than BD and ZF. The simulation also shows that underlay mode is the best mode for new arrival D2D pair whether the existing D2D pairs are in underlay or overlay mode. In addition, resource allocation is a critical factor for improving the sum rate of the whole cell.

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45

HouChieh and 后婕. "Device to device messanger with Wifi Direct/BLE." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/9xsxs4.

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碩士
國立臺北科技大學
電子工程系研究所
105
With the popularity of mobile networks, since a significant increase in network usage causes the congestion and results in the increasing delay from the cellular core network, the device-to-device (D2D) communication is considered. We utilize Bluetooth low energy (BLE) and WiFi to develop a D2D messenger using Multipeer Connectivity Framework based on iOS for Apple mobile devices. In the situation when the received signal from the cellular network is weak, BLE and WiFi can be utilized to communicate with nearby friends without the infrastructure constraints such as the deployment of cellular base stations. However, decentralized messenger covers a relatively small range compared to the messenger that typically requires the support of centralized server and the Internet. Therefore, in the nearby users discovery stage, wireless routing is adopted based on the neighbor information exchange to establish a routing table to extend the transmission coverage. Besides, a decentralized message synchronization mechanism is designed to enable offline users to exchange previously unsuccessful messages after the communication mode is resumed. We implement the D2D messenger and test it with various experiments, including the comparison of transmission rate versus multi-hops, to verify the feasibility of decentralized D2D communication and multi-hop transmission. Our developed software will provide a D2D communication application above the network layer, and it can be directly combined in the future 5G system based on the D2D.

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46

Chou, Fu-sheng, and 周富勝. "Handover Mechanism Based on Device-to-Device Communication." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/66cbf7.

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碩士
國立中山大學
資訊工程學系研究所
106
The 3rd Generation Partnership Project (3GPP) formulated a standard of “Proximity Services” (ProSe), also called “Device-to-Device” (D2D) communication, which is a promising technology to provide high throughput and low latency services between end-users. Handover is an essential issue in wireless networks, especially for the mobility of a user equipment (UE). We need to transfer the connection from the source eNB to target eNB so that the UE can achieve the better quality. The main idea of this paper is that the two D2D devices can communicate directly without additional transmissions through a base station, but their control signals must connect to the eNBs so that the base stations can adjust the power of devices and allocate the resources. And in the current standard of handover mechanism, the number of unnecessary handover could be increased by the effect of shadowing fading. Moreover, LTE-A only considers the handover procedure of single user; the handover mechanism for a D2D pair is not standardized. When a D2D pair moves around the cell boundary, the control signal of two UEs may connect to different base stations. The latency could be increased due to the exchange of D2D related information. Hence, we propose a mechanism of handover decision and timing based on D2D communication in order to minimize the signaling overhead. We hope that two D2D devices can connect to the same eNB as much as possible for a lower signaling overhead. First, we predict the target eNB based on the movement of the two devices and the relationship of signal with the neighboring eNBs. Second, we collaborate two D2D devices with eNBs to make a handover decision in the light of the received power or the stability of connection. Simulation results validate that the proposed scheme can reduce the number of handoffs and the signaling overhead to achieve a better performance.

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47

Alam, M., D. Yang, Jonathan Rodriguez, and Raed A. Abd-Alhameed. "Secure device-to-device communication in LTE-A." 2014. http://hdl.handle.net/10454/8061.

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no
Enabling D2D communications over LTE-A networks can provide many benefits in terms of throughput, energy consumption, traffic load, and so on. It also enables new commercial services such as location-based advertising. For these reasons, D2D communications has become a hot topic in both the academic and industrial communities. However, many research works are focused on node discovery, radio resource management, and other aspects, while the issue of security is less addressed. In this article, we intend to provide an overview of the security architecture, threads, and requirements. Based on these requirements, we propose several potential solutions by reusing the existing security mechanisms. Promising topics related to secure D2D communications for future research are also discussed.

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48

Chin, Heng-Li, and 靳亨立. "Group-based Device-to-Device/Vehicle-to-VehicleMobility Management Scheme." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/58t734.

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碩士
國立臺灣大學
電信工程學研究所
105
Device-to-Device (D2D) and Vehicle-to-Vehicle (V2V) are proximity-based techniques that allow nearby User Equipments (UE) or vehicles to communicate directly. The concept of D2D/V2V clustering is one of the usage scenarios that exploits D2D/V2V technique. It covers the formation of D2D/V2V clusters/group using D2D/V2V discovery and the selection of a cluster head/leader, which in turn serves as a communication relay between the group members and the network. D2D/V2V clustering improves spectral efficiency, energy efficiency, and fairness. However, despite having been proposed since Third Generation Partnership Project (3GPP) Rel-12, few research works have been focused on the mobility of D2D/V2V cluster/group. When a moving D2D/V2V cluster/group reaches the cell boundary, handover is expected to reliably switch the entire cluster/group to a suitable neighbouring BS. On the other hand, whenever a cluster member/follower moves away from the group, a procedure is needed to switch this cluster member/follower from D2D/V2V communication mode to cellular communication mode. To meet these requirements, a novel group-based D2D/V2V mobility management scheme is proposed. This scheme not only ensures service continuity of the D2D/V2V links of group during handover, but also covers connection transition procedure to reliably switch the cluster members/followers from D2D/V2V communication mode to cellular communication mode. Moreover, a swapping mechanism is proposed to maintain good cellular connection between the D2D/V2V cluster/group and the network. Simulation is conducted to compare the performance of the proposed scheme against the conventional Long Term Evolution (LTE) handover scheme. Results show that the proposed scheme can achieve lower handover failure rate, better D2D/V2V service continuity, lower total handover transition interruption time, and lower total transition interruption time.

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49

KUO, WEI-LIANG, and 郭威良. "Device Discovery for Device-to-Device Broadcast and Unicast Communication in LTE Networks." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/36013658804248079297.

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碩士
國立中正大學
通訊工程研究所
104
In the traditional telecommunication, mobiles communicate with other devices have to go through an eNodeB. With the help of eNodeB, communication data are able to transmite to the receivers. However, if the transmitters and receivers are in the same network coverage, the traditional way seems to be waste resources. Therefoe, the 3GPP standard organization has developed the fourth-generation communication system (Long Term Evolution Advanced , LTE-Advanced).In the 4G LTE system, Proximity D2D Communications was proposed. This communication technology could raise the radio resource utilization, increase communication speed, offload the cell communication load, and increase communication capacity. With the short distance feature, user equipments can recive the better signal quality to increase power and frequency efficiency. In this thesis, we focus on user equipments discovery. There are two types of discovery: Unicast discovery and Broadcast discovery. In the unicast discovery, we focus on the better channel quality and the higher discovery success ratio. In the unicast discovery, UEs have to discovery each other. Transmitter transmits the request signal to receiver, and the receiver transmits the response signal back to transmitter. We consider four factors that could affect system performance, including request retransmitted times, transmition power, DRU selection, transmision power control. In the Broadcast discovery, we focus on the discovered devices as much as possible. We consider two resource scheduling mechanisms in this discovery type. In particular the coordinating schedule can reduce the probability of collision with the eNodeB help.

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50

Chiu, How-Yuan, and 邱浩原. "Queue-Aware Resource Allocation for Device-to-Device Communications." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/9yrqn9.

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碩士
國立交通大學
電信工程研究所
102
Facing the rapid growth of cellular data traffic, device-to-device (D2D) communicaiton becomes more and more important nowadays. In the thesis, we propose a resource allocation algorithm that takes into consideration several network factors, including power, throughput gain, and queue stability. We first use a power control algorithm to decide the transmission power. In addition, we use the weighted matching algorithm to find the optimal device that could share a channel with a specific user equipment (UE). However, a throughput-oriented solution may lead to a starvation problem. We proposed a queue-aware reosurce allocation scheme which takes both arrival rate, service rate, and current queue size into account. The proposed queue-aware resource allocation scheme could reduce the average queueing delay without decreasing the network throughput.

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Dissertations / Theses on the topic 'Device-To-Device'

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