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Venkatachalaiah, Suresh, and suresh@catt rmit edu au. "Mobility prediction and Multicasting in Wireless Networks: Performance and Analysis." RMIT University. Electrical and Computer Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070301.130037.
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Handoff is a call handling mechanism that is invoked when a mobile node moves from one cell to another. Such movement may lead to degradation in performance for wireless networks as a result of packet losses. A promising technique proposed in this thesis is to apply multicasting techniques aided by mobility prediction in order to improve handoff performance. In this thesis, we present a method that uses a Grey model for mobility prediction and a fuzzy logic controller that has been fine-tuned using evolutionary algorithms in order to improve prediction accuracy. We also compare the self-tuning algorithm with two evolutionary algorithms in terms of accuracy and their convergence times. Our proposed method takes into account signal strengths from the base stations and predicts the signal strength of the next candidate base station in order to provide improved handover performance. The primary decision for mobility prediction is the accurate prediction of signal strengths obtained from the base stations and remove any unwanted errors in the prediction using suitable optimisation techniques. Furthermore, the model includes the procedures of fine-tuning the predicted data using fuzzy parameters. We also propose suitable multicasting algorithms to minimise the reservation of overall network resource requirements during handoff with the mobility prediction information. To be able to efficiently solve the problem, the situation is modelled using a multicast tree that is defined to maintain connectivity with the mobile node, whilst ensuring bandwidth guarantees and a minimum hop-count. In this approach, we have tried to solve the problem by balancing two objectives through putting a weight on each of two costs. We provide a detailed description of an algorithm to implement join and prune mechanisms, which will help to build an optimal multicast tree with QoS requirements during handoff as well as incorporating dynamic changes in the positions of mobile nodes. An analysis of how mobility prediction helps in the selection of potential Access Routers (AR) with QoS requirements - which affects the multicast group size and bandwidth cost of the multicast tree -- is presented. The proposed technique tries to minimise the number of multicast tree join and prune operations. Our results show that the expected size of the multicast group increases linearly with an increase in the number of selected destination AR's for multicast during handoff. We observe that the expected number of joins and prunes from the multicast tree increases with group size. A special simulation model was developed to demonstrate both homogeneous and heterogeneous handoff which is an emerging requirement for fourth generation mobile networks. The model incorporates our mobility prediction model for heterogeneous handoff between the Wireless LAN and a cellular network. The results presented in this thesis for mobility prediction, multicasting techniques and heterogeneous handoff include proposed algorithms and models which aid in the understanding, analysing and reducing of overheads during handoff.
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Shafin, Rubayet. "3D Massive MIMO and Artificial Intelligence for Next Generation Wireless Networks." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97633.
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3-dimensional (3D) massive multiple-input-multiple-output (MIMO)/full dimensional (FD) MIMO and application of artificial intelligence are two main driving forces for next generation wireless systems. This dissertation focuses on aspects of channel estimation and precoding for 3D massive MIMO systems and application of deep reinforcement learning (DRL) for MIMO broadcast beam synthesis. To be specific, downlink (DL) precoding and power allocation strategies are identified for a time-division-duplex (TDD) multi-cell multi-user massive FD-MIMO network. Utilizing channel reciprocity, DL channel state information (CSI) feedback is eliminated and the DL multi-user MIMO precoding is linked to the uplink (UL) direction of arrival (DoA) estimation through estimation of signal parameters via rotational invariance technique (ESPRIT). Assuming non-orthogonal/non-ideal spreading sequences of the UL pilots, the performance of the UL DoA estimation is analytically characterized and the characterized DoA estimation error is incorporated into the corresponding DL precoding and power allocation strategy. Simulation results verify the accuracy of our analytical characterization of the DoA estimation and demonstrate that the introduced multi-user MIMO precoding and power allocation strategy outperforms existing zero-forcing based massive MIMO strategies.
In 3D massive MIMO systems, especially in TDD mode, a base station (BS) relies on the uplink sounding signals from mobile stations to obtain the spatial information for downlink MIMO processing. Accordingly, multi-dimensional parameter estimation of MIMO channel becomes crucial for such systems to realize the predicted capacity gains. In this work, we also study the joint estimation of elevation and azimuth angles as well as the delay parameters for 3D massive MIMO orthogonal frequency division multiplexing (OFDM) systems under a parametric channel modeling. We introduce a matrix-based joint parameter estimation method, and analytically characterize its performance for massive MIMO OFDM systems. Results show that antenna array configuration at the BS plays a critical role in determining the underlying channel estimation performance, and the characterized MSEs match well with the simulated ones. Also, the joint parametric channel estimation outperforms the MMSEbased channel estimation in terms of the correlation between the estimated channel and the real channel.
Beamforming in MIMO systems is one of the key technologies for modern wireless communication. Creating wide common beams are essential for enhancing the coverage of cellular network and for improving the broadcast operation for control signals. However, in order to maximize the coverage, patterns for broadcast beams need to be adapted based on the users' movement over time. In this dissertation, we present a MIMO broadcast beam optimization framework using deep reinforcement learning. Our proposed solution can autonomously and dynamically adapt the MIMO broadcast beam parameters based on user' distribution in the network. Extensive simulation results show that the introduced algorithm can achieve the optimal coverage, and converge to the oracle solution for both single cell and multiple cell environment and for both periodic and Markov mobility patterns.<br>Doctor of Philosophy<br>Multiple-input-multiple-output (MIMO) is a technology where a transmitter with multiple antennas communicates with one or multipe receivers having multiple antennas. 3- dimensional (3D) massive MIMO is a recently developed technology where a base station (BS) or cell tower with a large number of antennas placed in a two dimensional array communicates with hundreds of user terminals simultaneously. 3D massive MIMO/full dimensional (FD) MIMO and application of artificial intelligence are two main driving forces for next generation wireless systems. This dissertation focuses on aspects of channel estimation and precoding for 3D massive MIMO systems and application of deep reinforcement learning (DRL) for MIMO broadcast beam synthesis. To be specific, downlink (DL) precoding and power allocation strategies are identified for a time-division-duplex (TDD) multi-cell multi-user massive FD-MIMO network. Utilizing channel reciprocity, DL channel state information (CSI) feedback is eliminated and the DL multi-user MIMO precoding is linked to the uplink (UL) direction of arrival (DoA) estimation through estimation of signal parameters via rotational invariance technique (ESPRIT). Assuming non-orthogonal/non-ideal spreading sequences of the UL pilots, the performance of the UL DoA estimation is analytically characterized and the characterized DoA estimation error is incorporated into the corresponding DL precoding and power allocation strategy. Simulation results verify the accuracy of our analytical characterization of the DoA estimation and demonstrate that the introduced multi-user MIMO precoding and power allocation strategy outperforms existing zero-forcing based massive MIMO strategies.
In 3D massive MIMO systems, especially in TDD mode, a BS relies on the uplink sounding signals from mobile stations to obtain the spatial information for downlink MIMO processing. Accordingly, multi-dimensional parameter estimation of MIMO channel becomes crucial for such systems to realize the predicted capacity gains. In this work, we also study the joint estimation of elevation and azimuth angles as well as the delay parameters for 3D massive MIMO orthogonal frequency division multiplexing (OFDM) systems under a parametric channel modeling. We introduce a matrix-based joint parameter estimation method, and analytically characterize its performance for massive MIMO OFDM systems. Results show that antenna array configuration at the BS plays a critical role in determining the underlying channel estimation performance, and the characterized MSEs match well with the simulated ones. Also, the joint parametric channel estimation outperforms the MMSE-based channel estimation in terms of the correlation between the estimated channel and the real channel. Beamforming in MIMO systems is one of the key technologies for modern wireless communication. Creating wide common beams are essential for enhancing the coverage of cellular network and for improving the broadcast operation for control signals. However, in order to maximize the coverage, patterns for broadcast beams need to be adapted based on the users' movement over time. In this dissertation, we present a MIMO broadcast beam optimization framework using deep reinforcement learning. Our proposed solution can autonomously and dynamically adapt the MIMO broadcast beam parameters based on user' distribution in the network. Extensive simulation results show that the introduced algorithm can achieve the optimal coverage, and converge to the oracle solution for both single cell and multiple cell environment and for both periodic and Markov mobility patterns.
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Nordio, Alessandro. "Advanced signal processing algorithms for 3rd generation wireless mobile systems /." [S.l.] : [s.n.], 2002. http://library.epfl.ch/theses/?nr=2550.
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Yew, Alvin. "Policy-based management of context-aware services in 3rd Generation mobile networks." Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/843082/.
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Current 3rd Generation (3G) mobile networks have the ability to deploy and offer context- aware services. 3G service frameworks such as the Open Service Access and the Location Service provide context-aware services easy access to the user's context. Service adaptation is fundamental to context-aware service provisioning and to the realisation of the Virtual Home Environment concept, which is now an integral part of the 3G service framework. The additional complexity in service adaptation inherent in context-aware services, however, requires a powerful and appropriate management framework to control service behaviour. Policy-based management, a proven solution in the network management field, is an appropriate framework to manage adaptable context-aware services as it reduces complexity through a rule-based approach of mapping events and conditions to management actions to achieve management goals. 3GPP has incorporated a policy management interface in the OSA specifications but has not provided any mappings or bindings to the underlying 3G network to achieve its realisation. This thesis proposes a framework that realizes the OSA policy management API while maintaining strict compliance to the plethora of 3G specifications regarding the underlying 3G network. It explores the various operating requirements for deploying the policy-based management framework including the various 3G business models, the VHE concept, and the context-aware service adaptation requirements. Solutions to managing and enforcing multi-dimensional context-aware service adaptation are also presented in this thesis. A policy information model to aid the creation of context-aware service adaptation policies was designed and developed with strict compliance to the various 3G specifications. A prototype of the framework was implemented as a proof of concept and its evaluation is provided with an empirical analysis of its performance.
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Shepstone, Sven E. "AAL2 switching node to support voice services in 3rd and 4th generation networks." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/9773.
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Includes bibliographical references.<br>The research community and industry alike have, over the past decade, been showing considerable interest in packet-switching networks to support voice services as well as data services. A technology that was standardised to accommodate these delay-sensitive requirements is Asynchronous Transfer Mode (ATM), which deals particularly well at transporting uncompressed voice and data. However, due to the exponential increase in wireless applications and their supporting access technologies, a need has arisen for an infrastructure in the wide area network to support and maintain the QoS requirements of low-bit rate, compressed voice. An adaptation layer known as AAL2 was re-standardised to support these specialised voice services. However, a severe side-effect of using AAL2 with traditional ATM switches results in inefficient routing and waste-age of resources. In this study, a design for an AAL2 switching node will be proposed to address the above-mentioned issues. The design is comprised of modules that perform the following functions: Buffering, payload interrogation, protocol translations, packet classification, packet re- routing, timing, scheduling and support for signalling and management interfacing. The supporting architecture is targeted towards an embedded >286-based computing system, which itself is overlaid upon one or several ports of a high-speed, research-oriented ATM switch, known as the Washington University Gigabit Switch (WUGS). In order to evaluate the operation and performance of the AAL2 switch architecture, a testbed is proposed and implemented, comprising the AAL2 switch at the core, with a supporting infrastructure to emulate the generation and analysis of low bit-rate voice traffic over an AAL2 connection. By conducting a set of experiments, a series of operational and performance results will be presented. Particular focus will be placed on the performance and efficiency of the AAL2 layer over ATM, as well as the ability of the switch to route packets from multiple sources to a set of output connections in the correct manner.
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Velayutham, Aravind Murugesan. "Transport Protocols for Next Generation Wireless Data Networks." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6957.
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Emerging wireless networks are characterized by increased heterogeneity in wireless access technologies as well as increased peer-to-peer communication among wireless hosts.
The heterogeneity among wireless access interfaces mainly exists because of the fact that different wireless technologies deliver different performance trade-offs.
Further, more and more infrastructure-less wireless networks such as ad-hoc networks are
emerging to address several application scenarios including military and disaster recovery. These infrastructure-less wireless networks are characterized by the peer-to-peer communication
model. In this thesis, we propose transport protocols that tackle the challenges that arise
due to the above-mentioned properties of state-of-the-art wireless data networks.
The main contributions of this work are as follows:
1. We determine the ideal nature and granularity of transport adaptation for efficient operation in heterogeneous wireless data networks by performing comprehensive experimental analysis. We then design and implement a runtime adaptive transport framework, *TP, which accommodates the capabilities of the ideal transport adaptation solution.
2. We prove that conversational transport protocols are not efficient under peer-to-peer wireless data networks. We then design and implement NCTP which is a non-conversational transport protocol.
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Wang, Qi. "Mobility support architectures for next-generation wireless networks." Thesis, University of Plymouth, 2006. http://hdl.handle.net/10026.1/2078.
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With the convergence of the wireless networks and the Internet and the booming demand for multimedia applications, the next-generation (beyond the third generation, or B3G) wireless systems are expected to be all IP-based and provide real-time and non-real-time mobile services anywhere and anytime. Powerful and efficient mobility support is thus the key enabler to fulfil such an attractive vision by supporting various mobility scenarios. This thesis contributes to this interesting while challenging topic. After a literature review on mobility support architectures and protocols, the thesis starts presenting our contributions with a generic multi-layer mobility support framework, which provides a general approach to meet the challenges of handling comprehensive mobility issues. The cross-layer design methodology is introduced to coordinate the protocol layers for optimised system design. Particularly, a flexible and efficient cross-layer signalling scheme is proposed for interlayer interactions. The proposed generic framework is then narrowed down with several fundamental building blocks identified to be focused on as follows. As widely adopted, we assume that the IP-based access networks are organised into administrative domains, which are inter-connected through a global IP-based wired core network. For a mobile user who roams from one domain to another, macro (inter-domain) mobility management should be in place for global location tracking and effective handoff support for both real-time and non-real-lime applications. Mobile IP (MIP) and the Session Initiation Protocol (SIP) are being adopted as the two dominant standard-based macro-mobility architectures, each of which has mobility entities and messages in its own right. The work explores the joint optimisations and interactions of MIP and SIP when utilising the complementary power of both protocols. Two distinctive integrated MIP-SIP architectures are designed and evaluated, compared with their hybrid alternatives and other approaches. The overall analytical and simulation results shown significant performance improvements in terms of cost-efficiency, among other metrics. Subsequently, for the micro (intra-domain) mobility scenario where a mobile user moves across IP subnets within a domain, a micro mobility management architecture is needed to support fast handoffs and constrain signalling messaging loads incurred by intra-domain movements within the domain. The Hierarchical MIPv6 (HMIPv6) and the Fast Handovers for MIPv6 (FMIPv6) protocols are selected to fulfil the design requirements. The work proposes enhancements to these protocols and combines them in an optimised way. resulting in notably improved performances in contrast to a number of alternative approaches.
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Zhang, Shunqing. "Cooperative relay in the next generation wireless networks /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20ZHANGS.
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Arino, Perez Victor. "Efficient Key Generation and Distributionon Wireless Sensor Networks." Thesis, KTH, Kommunikationsnät, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-141493.
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Wireless Sensor Networks have become popular during the last years. The introduction ofIPv6 which broadened the address space available, IEEE802.15.4 and adaption layers such as6loWPAN have allowed the intercommunication of small devices. These networks are usefulin many scenarios such as civil monitoring, mining, battle eld operations, as well as consumerproducts. Hence, practical security solutions for the intercommunication must be provided,ensuring privacy, authenticity, integrity and data freshness. In most cases, WSN nodes arenot tamper-proof and have very limited available resources and capabilities which makes PKIcurrently not attractive for this environment. At the same time, key pre-distribution providetoo low security for most applications. Therefore, the communication bootstrapping or thekey generation and distribution problem is an important concern to be addressed with theadditional di culty of the constrained capabilities of WSN nodes. In this thesis, a solution tothis problem is described. It makes use of ECDH and the curve K-163 for key exchange, AESCCM-128 for symmetric encryption to lower the processing overhead and a partial challengesolving chain as well as a TAS to provide strong authentication. Several hash functions havebeen analysed as well as several random number generating approaches. At the same time, inorder to t the key generation and distribution algorithms together with the regular sensoroperation, code optimizations were carried out on the cryptographic library Relic-Toolkit,reducing the memory footprint in 4KB; code reductions on Contiki OS allowed it to run usingonly 18KB of ash; and the peripheral drivers developed for the CC430 reduced as well thecomputation time. The solution allows to generate and distribute the keys in situ and isproved to be resilient to most adversaries while taking into account scalability, portability,energy consumption and making it suitable for consumer applications.
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Nader, Gustavo. "Ultra Wideband Interference on Third-Generation Wireless Networks." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/30046.
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As a license-exempt technology, Ultra Wideband (UWB) can be used for numerous commercial and military applications, including ranging, sensing, low-range networking and multimedia consumer products. In the networking and consumer fields, the technology is envisioned to reach the mass market, with a very high density of UWB devices per home and office. The technology is based on the concept of transmitting a signal with very low power spectral density (PSD), while occupying a very wide bandwidth. In principle, the low emissions mask protects incumbent systems operating in the same spectrum from being interfered with, while the wide bandwidth offers the possibility of high data rates, in excess of 250 Mbps.
UWB has been regulated to operate in the 3.1 to 10.6 GHz portion of the spectrum, with an emissions mask for the lower and upper bands outside this range. The commercial wireless mobile services based on third generation (3G) networks occupy a portion of the spectrum in the 2 GHz band, falling under the UWB emissions mask.
UWB and UMTS (Universal Mobile Telephone Systems) devices will coexist, sharing the same spectrum.
In this research, we investigate the UWB-3G coexistence problem, analyzing the impact of UWB on UMTS networks. Firstly, we review the mathematical model of the UWB signal, its temporal and spectral properties. We then analyze and model the effects of the UWB signal on a narrowband receiver. Next, we characterize the response of the UMTS receiver to UWB interference, determining its statistical behavior, and establishing a model to replicate it. We continue by proposing a link level model that offers a first order quantitative estimate of the impact of a UWB interferer on a UMTS victim receiver, demonstrating the potentially harmful effect of UWB on the UMTS link. We elaborate on that initial evidence by proposing and implementing a practical systemlevel algorithm to realistically simulate the behavior of the UMTS network in the presence of multiple sources of UWB interference.
We complete the research by performing UMTS system level simulations under various conditions of UWB interference, with the purpose of assessing its impact upon a typical UMTS network. We analyze the sensitivity of the main UWB parameters affecting UMTS performance, investigating the coverage and capacity performance aspects of the network. The proposed analysis methodology creates a framework to characterize the impact that mass-deployed UWB can have on the performance of a 3G system.
The literature on UWB-3G coexistence is inconclusive, and even contradictory, as to the impact UWB can have on the performance of third-generation wireless networks. While some studies show that UWB can be highly detrimental to 3G networks, others have concluded that both systems can gracefully coexist. Through this study, we found that at the current emissions limits regulated for UWB, a mass uptake of this technology can negatively affect the performance of third-generation (3G) wireless networks. The quality of service experienced by a 3G user in close proximity to an active UWB device can be noticeably degraded, in the form of reduced coverage range, poor voice quality (for a voice call), lower data rates (for a data session) or, in a extreme situation, complete service blockage. As the ratio of UWB devices surrounding a 3G user grows, the degradation becomes increasingly more evident. We determined that in order for UWB tocoexist with 3G networks without causing any performance degradation, a minimum power backoff of 20 dB should be applied to the current emission limits.<br>Ph. D.
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Gluhak, Alexander Daniel. "Multicast service delivery in next generation wireless networks." Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/842851/.
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Mobile network operators have recently started looking into ways to increase their own network scalability, in order to support a large number of customers with new bandwidth consuming multimedia services. The two most promising solutions identified are to extend the existing networks with multicast capabilities and to cooperate with network operators of different wireless access technologies. As a consequence of these trends, a next generation network environment will allow mobile users to receive multimedia service data from a variety of multicast capable access networks. Although considerable progress has been made with the standardisation of multicast mechanisms such as Multimedia Broadcast and Multicast Services (MBMS) for UMTS networks, shortcomings still exist in emerging multicast technologies and their interworking with each other. One of the critical realisations leading to this research was the observation that the establishment and release of multicast bearers, particularly in UMTS networks, requires signalling intensive procedures, as compared to the simple mechanisms of IP multicast on the Internet. Especially for services such as location based multicast services, where a user is expected to change multicast groups more frequently, a considerable signalling burden may be added to a network. This is hardly acceptable for mobile networks, where wireless resources are valuable and scarce. One contribution made in this thesis extends the currently defined mechanisms in MBMS to allow the concurrent delivery of different versions of location based content using the same multicast bearer service. It is shown by simulation study that the proposed mechanism achieves significant signalling savings, especially over the air interface, compared to the case where separate multicast bearer services are utilised for the delivery of different location specific flows. Another significant observation was that the current receiver driven service model of IP multicast is not suitable to allow efficient multicast delivery in a wireless network environment with multiple access networks. This thesis argues that efficient multicast delivery requires mechanisms for delivery coordination, in order to avoid the same multicast traffic being delivered via multiple access networks to the same location. Based on a detailed analysis of the shortcomings of current IP multicast group management mechanism, two incremental solutions to achieve multicast delivery coordination in next generation networks are developed and their advantages and disadvantages thoroughly studied. The first approach achieves delivery coordination by introducing a group management support as a session layer solution, leaving the operation of current existing IP multicast mechanisms completely unchanged. The second approach provides a solution on the network layer to achieve multicast delivery coordination, and requires the modification of the current IP multicast group management mechanisms. Proof-of-concept prototypes are built to demonstrate the feasibility of both solutions. An evaluation of their performance is achieved by analytical and simulation study and is complemented by a testbed study of the prototypes.
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Zhu, Fang. "Optimizations for vertical handoff in next generation wireless networks." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0012983.
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Wang, Xudong. "Medium access control protocols for next generation wireless networks." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/13267.
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Mudesir, Abdurazak [Verfasser]. "Interference Modeling for Next Generation Wireless Networks / Abdurazak Mudesir." Bremen : IRC-Library, Information Resource Center der Jacobs University Bremen, 2011. http://d-nb.info/1035018284/34.
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Rawi, Anas F. Al. "Next generation wireless networks optimisation over heterogeneous traffic environments." Thesis, University of Newcastle Upon Tyne, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540384.
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Akhtar, Nadeem. "Routing and interworking protocols for next generation wireless networks." Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/2243/.
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Hayes, T. "Routing protocols for next generation mobile wireless sensor networks." Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/63977/.
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The recent research interest in wireless sensor networks has caused the development of many new applications and subsequently, these emerging applications have ever increasing requirements. One such requirement is that of mobility, which has inspired an entirely new array of applications in the form of mobile wireless sensor networks (MWSNs). In terms of communications, MWSNs present a challenging environment due to the high rate at which the topology may be changing. As such, the motivation of this work is to investigate potential communications solutions, in order to satisfy the performance demands of new and future MWSN applications. As such this work begins by characterising and evaluating the requirement of a large variety of these emerging applications. This thesis focuses on the area of routing, which is concerned with the reliable and timely delivery of data from multiple, mobile sensor nodes to a data sink. For this purpose the technique of gradient routing was identified as a suitable solution, since data can quickly be passed down a known gradient that is anchored at the sink. However, in a mobile network, keeping the gradient up-to-date is a key issue. This work proposes the novel use of a global time division multiple access (GTDMA) MAC as a solution to this problem, which mitigates the need for regularly flooding the network. Additionally, the concept of blind forwarding is utilised for its low overhead and high reliability through its inherent route diversity. The key contribution of this thesis is in three novel routing protocols, which use the aforementioned principles. The first protocol, PHASeR, uses a hop-count metric and encapsulates data from multiple nodes in its packets. The hop-count metric was chosen because it is simple and requires no additional hardware. The inclusion of encapsulation is intended to enable the protocol to cope with network congestion. The second protocol, LASeR, utilises location awareness to maintain a gradient and performs no encapsulation. Since many applications require location awareness, the communications systems may also take advantage of this readily available information and it can be used as a gradient metric. This protocol uses no encapsulation in order to reduce delay times. The third protocol, RASeR, uses the hop-count metric as a gradient and also does not perform encapsulation. The reduced delay time and the relaxed requirement for any existing method of location awareness makes this the most widely applicable of the three protocols. In addition to analytical expressions being derived, all three protocols are thoroughly tested through simulation. Results show the protocols to improve on the state-of-the-art and yield excellent performance over varying speeds, node numbers and data generation rates. LASeR shows the lowest overhead and delay, which comes from the advantage of having available location information. Alternatively, at the expense of increased overhead, RASeR gives comparatively high performance metrics without the need for location information. Overall, RASeR can be suitably deployed in the widest range of applications, which is taken further by including four additional modes of operation. These include a supersede mode for applications in which the timely delivery of the most recent data is prioritised. A reverse flooding mechanism, to enable the sink to broadcast control messages to the sensor nodes. An energy saving mode, which uses sleep cycles to reduce the networks power consumption, and finally a pseudo acknowledgement scheme to increase the reliability of the protocol. These additions enable RASeR to satisfy the needs of some of the most demanding MWSN applications. In order to assess the practicality of implementation, RASeR was also evaluated using a small testbed of mobile nodes. The successful results display the protocols feasibility to be implemented on commercially available hardware and its potential to be deployed in the real world. Furthermore, a key issue in the real world deployment of networks, is security and for this reason a fourth routing protocol was designed called RASeR-S. RASeR-S is based on RASeR, but introduces the use of encryption and suggests a security framework that should be followed in order to significantly reduce the possibility of a security threat. Whilst the main focus of this work is routing, alternative MAC layers are assessed for LASeR. Unlike the other two protocols, LASeR uses available location information to determine its gradient and as such, it is not reliant on the GTDMA MAC. For this reason several MAC layers are tested and the novel idea of dedicated sensing slots is introduced, as well as a network division multiple access scheme. The selected and proposed MACs are simulated and the GTDMA and two proposed protocols are shown to give the best results in certain scenarios. This work demonstrates the high levels of performance that can be achieved using gradient orientated routing in a mobile network. It has also shown that the use of a GTDMA MAC is an efficient solution to the gradient maintenance problem. The high impact of this work comes from the versatility and reliability of the presented routing protocols, which means they are able to meet the requirements of a large number of MWSN applications. Additionally, given the importance of security, RASeR-S has been designed to provide a secure and adaptable routing solution for vulnerable or sensitive applications.
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Jafari, Amir Hossein. "Dense small cell networks for next generation wireless systems." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/20644/.
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Obayiuwana, Enoruwa. "Efficient radio resource management in next generation wireless networks." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/24473.
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The current decade has witnessed a phenomenal growth in mobile wireless communication
networks and subscribers. In 2015, mobile wireless devices and connections were reported to have grown to about 7.9 billion, exceeding human
population. The explosive growth in mobile wireless communication network subscribers has created a huge demand for wireless network capacity,
ubiquitous wireless network coverage, and enhanced Quality of Service (QoS). These demands have led to several challenging problems for wireless
communication networks operators and designers. The Next Generation Wireless Networks (NGWNs) will support high mobility communications, such as
communication in high-speed rails. Mobile users in such high mobility environment demand reliable QoS, however, such users are plagued with a
poor signal-tonoise ratio, due to the high vehicular penetration loss, increased transmission outage and handover information overhead, leading
to poor QoS provisioning for the networks' mobile users. Providing a reliable QoS for high mobility users remains one of the unique challenges
for NGWNs. The increased wireless network capacity and coverage of NGWNs means that mobile communication users at the cell-edge should have
enhanced network performance. However, due to path loss (path attenuation), interference, and radio background noise, mobile communication
users at the cell-edge can experience relatively poor transmission channel qualities and subsequently forced to transmit at a low bit transmission
rate, even when the wireless communication networks can support high bit transmission rate. Furthermore, the NGWNs are envisioned to be Heterogeneous
Wireless Networks (HWNs). The NGWNs are going to be the integration platform of diverse homogeneous wireless communication networks for a convergent
wireless communication network. The HWNs support single and multiple calls (group calls), simultaneously. Decision making is an integral core of radio
resource management. One crucial decision making in HWNs is network selection. Network selection addresses the problem of how to select the best
available access network for a given network user connection. For the integrated platform of HWNs to be truly seamless and
efficient, a robust and stable wireless access network selection algorithm is needed. To meet these challenges for the
different mobile wireless communication network users, the NGWNs will have to provide a great leap in wireless network capacity, coverage,
QoS, and radio resource utilization. Moving wireless communication networks (mobile hotspots) have been proposed as a solution to providing
reliable QoS to high mobility users. In this thesis, an Adaptive Thinning Mobility Aware (ATMA) Call Admission Control (CAC) algorithm for
improving the QoS and radio resource utilization of the mobile hotspot networks, which are of critical importance for communicating nodes
in moving wireless networks is proposed. The performance of proposed ATMA CAC scheme is investigated and compare it with the traditional
CAC scheme. The ATMA scheme exploits the mobility events in the highspeed mobility communication environment and the calls (new and
handoff calls) generation pattern to enhance the QoS (new call blocking and
handoff call dropping probabilities) of the mobile users. The numbers of new and
handoff calls in wireless communication networks are dynamic random processes that can be
effectively modeled by the Continuous Furthermore, the NGWNs are envisioned to be Heterogeneous Wireless Networks (HWNs).
The NGWNs are going to be the integration platform of diverse homogeneous wireless communication networks for a convergent
wireless communication network. The HWNs support single and multiple calls (group calls), simultaneously. Decision making is an
integral core of radio resource management. One crucial decision making in HWNs is network selection. Network selection addresses
the problem of how to select the best available access network for a given network user connection. For the integrated platform of
HWNs to be truly seamless and efficient, a robust and stable wireless access network selection algorithm is needed. To meet these
challenges for the different mobile wireless communication network users, the NGWNs will have to provide a great leap in wireless
network capacity, coverage, QoS, and radio resource utilization. Moving wireless communication networks (mobile hotspots) have been
proposed as a solution to providing reliable QoS to high mobility users. In this thesis, an Adaptive Thinning Mobility Aware (ATMA)
Call Admission Control (CAC) algorithm for improving the QoS and radio resource utilization of the mobile hotspot networks, which are
of critical importance for communicating nodes in moving wireless networks is proposed.
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Tunaru, Iulia. "Physical layer secret key generation for decentralized wireless networks." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S081/document.
Full textAbstract:
Dans cette thèse on s’est intéressé aux méthodes de génération de clés secrètes symétriques en utilisant la couche physique ultra large bande impulsionnelle (IR-UWB). Les travaux ont été réalisés selon trois axes, les deux premiers concernant la communication point-à-point et le dernier, les communications coopératives. Tout d’abord, la quantification des signaux typiques IR-UWB (soit directement échantillonnés, soit estimés) a été investiguée, principalement du point de vue du compromis entre la robustesse (ou réciprocité) des séquences binaires obtenues et leur caractère aléatoire. Différents algorithmes de quantification valorisant l’information temporelle offerte par les canaux IR-UWB pour améliorer ce compromis ont alors été proposés. Ensuite, des études concernant les échanges publics nécessaires à l’étape de réconciliation (visant la correction d’éventuels désaccords entre les séquences binaires générées de part et d’autre du lien) ont montré qu’il était possible d’être plus robuste face aux attaques passives en utilisant des informations de plus haut niveau, inhérentes à cette technologie et disponibles à moindre coût (ex. via une estimation précise du temps de vol aller-retour). Finalement, une nouvelle méthode a été développée afin d’étendre les schémas de génération de clé point-à-point à plusieurs nœuds (trois dans nos études) en utilisant directement la couche physique fournie par les liens radio entre les nœuds<br>Emerging decentralized wireless systems, such as sensor or ad-hoc networks, will demand an adequate level of security in order to protect the private and often sensitive information that they carry. The main security mechanism for confidentiality in such networks is symmetric cryptography, which requires the sharing of a symmetric key between the two legitimate parties. According to the principles of physical layer security, wireless devices within the communication range can exploit the wireless channel in order to protect their communications. Due to the theoretical reciprocity of wireless channels, the spatial decorrelation property (e.g., in rich scattering environments), as well as the fine temporal resolution of the Impulse Radio - Ultra Wideband (IR-UWB) technology, directly sampled received signals or estimated channel impulse responses (CIRs) can be used for symmetric secret key extraction under the information-theoretic source model. Firstly, we are interested in the impact of quantization and channel estimation algorithms on the reciprocity and on the random aspect of the generated keys. Secondly, we investigate alternative ways of limiting public exchanges needed for the reconciliation phase. Finally, we develop a new signal-based method that extends the point-to-point source model to cooperative contexts with several nodes intending to establish a group key
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Pagtzis, Theodoros. "Advanced IPv6 mobility management for next generation wireless access networks." Thesis, University College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430738.
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Yarkan, Serhan. "Environment, channel, and interference awareness for next generation wireless networks." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003269.
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ROCHA, RAFAEL MACHADO DA. "A SERVICE NEGOTIATION SIMULATION FRAMEWORK FOR NEXT GENERATION WIRELESS NETWORKS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=11707@1.
Full textAbstract:
As Redes de comunicação sem fio estão cada vez mais
presentes no dia-a-
dia das pessoas. Falar com amigos, ouvir música, ver
televisão, fazer
compras, são exemplos de atividades que podem ser
realizadas hoje em dia por
uma grande variedade de tipos de redes sem fio. Os
dispositivos móveis de hoje
possuem diversas interfaces de rede, possibilitando ao
usuário escolher qual
delas irá utilizar. Devido à mobilidade oferecida por
dispositivos móveis, a cada
nova localidade, diferentes tipos de rede e cenários para
utilização de um
serviço se configuram. Algumas soluções e propostas estão
sendo estudadas
para permitir que o usuário escolha a melhor conexão de
rede para a utilização
de um serviço, dependendo da situação em que este se
encontre. Porém, poucas
análises são apresentadas para que as provedoras de redes e
serviços possam
oferecer esta melhor conexão. Mobilidade, liberdade de
escolha do usuário,
variedade de conexões de rede e tipos de serviço são
desafios que as provedoras
começam a encontrar. Por outro lado, a possibilidade de
captar novos clientes,
aumentar seu volume de vendas de serviços e sua conseqüente
participação no
mercado, são oportunidades que surgem neste novo cenário.
Um framework
em sistemas multi-agentes é proposto com o objetivo de se
analisar este novo
cenário e exercitar soluções que sejam úteis tanto para
clientes, quanto para
provedoras de redes sem fio. Estratégias para definição do
preço de um serviço
pelo lado da provedora e estratégias para escolha do melhor
serviço oferecido
por uma provedora do lado do cliente, com a utilização de
informação de
contexto, são objetos de analise. Na solução, a informação
de contexto é
representada pelo modelo de ontologias proposto pelo
DynaCIP e um algoritmo
de tomada de decisão utilizado pelo agente é proposto,
embora o framework
flexibilize a utilização de outros algoritmos. A
instanciação do framework para
um cenário de redes sem fio de nova geração é implementado
e discutido na
proposta.<br>The Wireless communication networks are increasingly
present in
people`s lives. Talking to friends, listening music,
watching television, buying
things, are examples of activities that nowadays can be
accomplished by a great
variety of wireless networks. Modern mobile devices have a
diversity of
network interfaces, for users to choose from. Due to
mobility offered by mobile
devices, different types and scenarios of networks appear
at every new location.
Some proposals and solutions are been studied to allow
users to choose the best
network connection for a specific service utilization,
depending on the current
user`s task. But, few proposals are presented to allow
network and service
providers to provide these best connection. Mobility,
user`s freedom of choice,
variety of network connections and types of service are
challenges that the
providers are beginning to find. Moreover, the ability to
attract new customers,
increase your services sales volume and its consequent
market share, are
opportunities that arise in this new scenario. A multi-
agent systems framework
is proposed with the aim to examine this new scenario and
exercise solutions
that are useful both for customers, and for wireless
network providers. Contextaware
strategies for provider`s service pricing and for
customer`s best choice of
service provided are subject to review. In the solution,
context information is
represented in the ontology model proposed by DynaCIP and
an algorithm for
decision-making used by the agent is proposed, although the
framework flexible
the use of other algorithms. A framework instantiation for
a next generation
wireless networks scenario is implemented and discussed in
the proposal.
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Adedoyin, Mary Abosede. "Efficient radio resource management for future generation heterogeneous wireless networks." Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/27873.
Full textAbstract:
The heterogeneous deployment of small cells (e.g., femtocells) in the coverage area of the traditional macrocells is a cost-efficient solution to provide network capacity, indoor coverage and green communications towards sustainable environments in the future fifth generation (5G) wireless networks. However, the unplanned and ultra-dense deployment of femtocells with their uncoordinated operations will result in technical challenges such as severe interference, a significant increase in total energy consumption, unfairness in radio resource sharing and inadequate quality of service provisioning. Therefore, there is a need to develop efficient radio resource management algorithms that will address the above-mentioned technical challenges. The aim of this thesis is to develop and evaluate new efficient radio resource management algorithms that will be implemented in cognitive radio enabled femtocells to guarantee the economical sustainability of broadband wireless communications and users' quality of service in terms of throughput and fairness. Cognitive Radio (CR) technology with the Dynamic Spectrum Access (DSA) and stochastic process are the key technologies utilized in this research to increase the spectrum efficiency and energy efficiency at limited interference. This thesis essentially investigates three research issues relating to the efficient radio resource management: Firstly, a self-organizing radio resource management algorithm for radio resource allocation and interference management is proposed. The algorithm considers the effect of imperfect spectrum sensing in detecting the available transmission opportunities to maximize the throughput of femtocell users while keeping interference below pre-determined thresholds and ensuring fairness in radio resource sharing among users. Secondly, the effect of maximizing the energy efficiency and the spectrum efficiency individually on radio resource management is investigated. Then, an energy-efficient radio resource management algorithm and a spectrum-efficient radio resource management algorithm are proposed for green communication, to improve the probabilities of spectrum access and further increase the network capacity for sustainable environments. Also, a joint maximization of the energy efficiency and spectrum efficiency of the overall networks is considered since joint optimization of energy efficiency and spectrum efficiency is one of the goals of 5G wireless networks. Unfortunately, maximizing the energy efficiency results in low performance of the spectrum efficiency and vice versa. Therefore, there is an investigation on how to balance the trade-off that arises when maximizing both the energy efficiency and the spectrum efficiency simultaneously. Hence, a joint energy efficiency and spectrum efficiency trade-off algorithm is proposed for radio resource allocation in ultra-dense heterogeneous networks based on orthogonal frequency division multiple access. Lastly, a joint radio resource allocation with adaptive modulation and coding scheme is proposed to minimize the total transmit power across femtocells by considering the location and the service requirements of each user in the network. The performance of the proposed algorithms is evaluated by simulation and numerical analysis to demonstrate the impact of ultra-dense deployment of femtocells on the macrocell networks. The results show that the proposed algorithms offer improved performance in terms of throughput, fairness, power control, spectrum efficiency and energy efficiency. Also, the proposed algorithms display excellent performance in dynamic wireless environments.
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Akan, Ozgur Baris. "Advanced Transport Protocols for Next Generation Heterogeneous Wireless Network Architectures." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5231.
Full textAbstract:
The revolutionary advances in the wireless communication technologies are inspiring the researchers to envision the next generation wireless networking architectures, i.e., Next Generation Wireless Internet (NGWI), InterPlaNetary (IPN) Internet, and Wireless Sensor Networks (WSN). There exist significant technological challenges for the realization of these envisioned next generation network architectures. NGWI will be the convergence of the Internet and heterogeneous wireless architectures, which have diverse characteristics and hence pose different sets of research challenges, to achieve anywhere, anytime seamless service to the mobile users. Similarly, the unique characteristics and challenges posed by deep space communications call for novel networking protocols to realize the IPN Internet objective. Furthermore, in order to realize the potential gains of WSN, it is imperative that communication challenges imposed by resource constraints of sensor nodes must be efficiently addressed with novel solutions tailored to the WSN paradigm. The objective of this research is to develop new advanced transport protocols for reliable data transport and real-time multimedia delivery in the next generation heterogeneous wireless network architectures. More specifically, the analytical rate control (ARC) protocol for real-time multimedia delivery is first proposed for wired/wireless hybrid networks. Next, a new rate control scheme (RCS) is proposed to achieve high throughput performance and fairness for real-time multimedia traffic over the satellite links. The unified adaptive transport layer (ATL) suite and its protocols for both reliable data transport (TCP-ATL) and real-time multimedia delivery (RCP-ATL) are introduced for the NGWI. A new reliable transport protocol for data transport in the IPN Internet (TP-Planet) is then proposed to address the unique challenges of the IPN Internet backbone links. A new integrated tranmission protocol (ITP) is then proposed for reliable data transport over multihop IPN Internet paths. Finally, the event-to-sink reliable transport (ESRT) protocol is proposed to achieve reliable event transport with minimum energy expenditure in WSN.
26
Ribeiro, Leila Zurba. "Traffic Dimensioning for Multimedia Wireless Networks." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/27199.
Full textAbstract:
Wireless operators adopting third-generation (3G) technologies and those migrating from second-generation (2G) to 3G face a number of challenges related to traffic modeling, demand characterization, and performance analysis, which are key elements in the processes of designing, dimensioning and optimizing their network infrastructure.
Traditional traffic modeling assumptions used for circuit-switched voice traffic no longer hold true with the convergence of voice and data over packet-switched infrastructures. Self-similar models need to be explored to appropriately account for the burstiness that packet traffic is expected to exhibit in all time scales. The task of demand characterization must include an accurate description of the multiple user profiles and service classes the network is expected to support, with their distinct geographical distributions, as well as forecasts of how the market should evolve over near and medium terms. The appropriate assessment of the quality of service becomes a more complex issue as new metrics and more intricate dependencies have to be considered when providing a varying range of services and applications that include voice, real-time, and non-real time data. All those points have to be considered by the operator to obtain a proper dimensioning, resource allocation, and rollout plan for system deployment. Additionally, any practical optimization strategy has to rely on accurate estimates of expected demand and growth in demand.
In this research, we propose a practical framework to characterize the traffic offered to multimedia wireless systems that allows proper dimensioning and optimization of the system for a particular demand scenario. The framework proposed includes a methodology to quantitatively and qualitatively describe the traffic offered to multimedia wireless systems, solutions to model that traffic as practical inputs for simulation analysis, and investigation of demand-sensitive techniques for system dimensioning and performance optimization.
We consider both theoretical and practical aspects related to the dimensioning of hybrid traffic (voice and data) for mobile wireless networks. We start by discussing wireless systems and traffic theory, with characterization of the main metrics and models that describe the users’ voice and data demand, presenting a review of the most recent developments in the area. The concept of service class is used to specify parameters that depend on the application type, performance requirements and traffic characteristics for a given service. Then we present the concept of “user profile,“ which ties together a given combination of service class, propagation environment and terminal type. Next, we propose a practical approach to explore the dynamics of user geographical distribution in creating multi-service, multi-class traffic layers that serve as input for network traffic simulation algorithms. The concept of quality-of-service (QoS) is also discussed, focusing on the physical layer for 3G systems. We explore system simulation as a way to dimension a system given its traffic demand characterization. In that context, we propose techniques to translate geographical distributions of user profiles into the actual number of active users of each layer, which is the key parameter to be used as input in simulations.
System level simulations are executed for UMTS systems, with the purpose of validating the methodology proposed here.
We complete the proposed framework by applying all elements together in the process of dimensioning and optimization of 3G wireless networks using the demand characterization for the system as input. We investigate the effects of modifying some elements in the system configuration such as network topology, radio-frequency (RF) configuration, and radio resource management (RRM) parameters, using strategies that are sensitive to traffic geographical distribution.
Case study simulations are performed for Universal Mobile Telecommunications System (UMTS) networks, and multiple system variables (such as antenna tilts, pilot powers, and RRM parameters) are optimized using traffic sensitive strategies, which result in significant improvements in the overall system capacity and performance. Results obtained in the case studies, allied to a generic discussion of the trade-offs involved in the proposed framework, demonstrate the close dependence between the processes of system dimensioning and optimization with the accurate modeling of traffic demand offered to the system.<br>Ph. D.
27
Nkansah-Gyekye, Yaw. "An intelligent vertical handoff decision algorithm in next generation wireless networks." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_2726_1307443785.
Full textAbstract:
<p>The objective of the thesis research is to design such vertical handoff decision algorithms in order for mobile field workers and other mobile users equipped with contemporary multimode mobile devices to communicate seamlessly in the NGWN. In order to tackle this research objective, we used fuzzy logic and fuzzy inference systems to design a suitable handoff initiation algorithm that can handle imprecision and uncertainties in data and process multiple vertical handoff initiation parameters (criteria)<br>used the fuzzy multiple attributes decision making method and context awareness to design a suitable access network selection function that can handle a tradeoff among many handoff metrics including quality of service requirements (such as network conditions and system performance), mobile terminal conditions, power requirements, application types, user preferences, and a price model<br>used genetic algorithms and simulated annealing to optimise the access network selection function in order to dynamically select the optimal available access network for handoff<br>and we focused in particular on an interesting use case: vertical handoff decision between mobile WiMAX and UMTS access networks. The implementation of our handoff decision algorithm will provide a network selection mechanism to help mobile users select the best wireless access network among all available wireless access networks, that is, one that provides always best connected services to users.</p>
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Bocus, Mohammud Zubeir. "Resource allocation for scalable video transmission over next-generation wireless networks." Thesis, University of Bristol, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.566697.
Full textAbstract:
Advancements in broadband wireless networks and video compression tech- nologies have led to a tremendous increase in the demand for wireless multimedia services over recent years. Popular wireless transmission techniques enabling en- hanced throughput include orthogonal frequency division multiplexing (OFDM) while the recent video coding standard, namely the H.264/ AYC, enables up to twice the compression efficiency to be attained relative to previous video com- pression techniques. Regardless of these developments, the highly dynamic and unpredictable nature of wireless channels, along with the requirements for main- taining the quality of service (Q08) and seamless video playback for all users, impose severe constraints on the design of wireless multimedia systems. A video coding technique that has been developed for such environments is the scalable video coding (8YC), which allows parts of the encoded bitstream to be discarded in response to a drop in the channel quality. However, state-of-the-art resource allocation techniques for SYC transmission over the wireless medium suffer from high computational complexity. Low-complexity, sub-optimal alternatives, on the other hand, are not always adequate. Given the sparse nature of spectrum resources, and the paradigm shift in spectrum access with the advent of cognitive radio systems, it is evident that sub-optimal algorithms having large optimality gaps are not desired. In fact, such approaches would be in contradiction to the definition of spectrum efficient, cognitive radio systems. In this thesis, resource allocation schemes for the transmission of H.264 SYC over wireless networks are investigated. In particular, OFDM systems are consid- ered, including OFDM-based cognitive radio networks. Cross-layer optimisation techniques for fine grain scalable (FGS) video sequences are analysed. Although the problem is initially non-convex and has non-polynomial-time (NP) complex- ity, low complexity techniques are derived that lead to solutions very close to the optimal. Resource allocation schemes for coarse grain scalable (CGS) and medium grain scalable (MGS) sequences over OFDM-based cognitive systems are also investigated. As opposed to FGS, CGS/MGS do not allow an encoded bitstream to be truncated at random bit location. Consequently, new methods are derived that focus on this particular type of video coding. The presence of multiple antennas at the cognitive transmitter and their effect on the aggregate visual quality of all secondary users are also discussed. Furthermore, a joint call admission control (CAC) and resource allocation for the transmission of CGS and MGS video sequences over orthogonal frequency division multiple access (OFDMA) are analysed. This scheme considers the sce- narios where the available channel resources are not enough to support the video data of all users. Finally, rate-adaptation techniques for scalable video transmission over wire- less networks are presented. Rate-adaptation refers to the methods by which the encoding parameters of the video coding are adapted in response to the chan- nel conditions. Interestingly, it is shown that under a given channel condition, increasing the granularity of a scalable sequence lead to diminishing returns in terms of the rate achieved. Moreover, the transmission of scalable sequences over cognitive radio networks where perfect channel knowledge is not available is investigated. The effect of the granularity of the bitstream on the interference observed by incumbent users is also presented. It is shown that the probability of exceeding the interference threshold can be significantly reduced by proper specification of the video encoding parameters.
29
Tawil, Rami. "A distributed vertical handover decision for the fourth generation wireless networks." Paris 6, 2009. http://www.theses.fr/2009PA066113.
Full textAbstract:
Dans cette thèse nous proposons une décision de handover vertical distribuée (DVHD) pour la quatrième generation des réseaux sans-fils, le DVHD tend à fournir des services continus pour les noeuds mobiles. La quatrième génération de réseau sans fil (FGWN) se compose de réseaux hétérogènes, telles que: Universal Mobile Telecommunication System (UMTS), WiFi et WiMax. Ces technologies fournissent aux utilisateurs une gamme de services qui peuvent être obtenues en se déplaçant entre les réseaux. La question de la mobilité est l'un des intérêts majeurs pour la FGWN, pendant celui-ci, un utilisateur mobile peut subir desévènements de transfert (handover). Une des questions majeures dans le FGWN est la prise de décision pendant le déplacement du mobile. Le Vertical Handoff décision (VHD) est la tâche avec lequel le un décideur de handover choisit le réseau auxquel il va se connecter. La solution DVHD diminue le délai de handover et la consommation d'énergie de la part du nœud mobile. L'idée principale du système est de grouper les réseaux en clusters virtuels, alors si le noeud mobile entre dans la zone de couverture d'un cluster, il communiquera avec le premier réseau disponible pour récupérer des informations sur son environnement, et de prendre la bonne décision. Deux autres extensions sont ajouté le S-DVHD et le T-DVHD qui sert à securiser les communication entre les entités et de créer des relations de confiance entre ces entités
30
Elsayed, Medhat. "Machine Learning-Enabled Radio Resource Management for Next-Generation Wireless Networks." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42476.
Full textAbstract:
A new era of wireless networks is evolving, thanks to the significant advances in communications and networking technologies. In parallel, wireless services are witnessing a tremendous change due to increasingly heterogeneous and stringent demands, whose quality of service requirements are expanding in several dimensions, putting pressure on mobile networks. Examples of those services are augmented and virtual reality, as well as self-driving cars. Furthermore, many physical systems are witnessing a dramatic shift into autonomy by enabling the devices of those systems to communicate and transfer control and data information among themselves. Examples of those systems are microgrids, vehicles, etc. As such, the mobile network indeed requires a revolutionary shift in the way radio resources are assigned to those services, i.e., RRM.
In RRM, radio resources such as spectrum and power are assigned to users of the network according to various metrics such as throughput, latency, and reliability. Several methods have been adopted for RRM such as optimization-based methods, heuristics and so on. However, these methods are facing several challenges such as complexity, scalability, optimality, ability to learn dynamic environments. In particular, a common problem in conventional RRM methods is the failure to adapt to the changing situations. For example, optimization-based methods perform well under static network conditions, where an optimal solution is obtained for a snapshot of the network. This leads to higher complexity as the network is required to solve the optimization at every time slot. Machine learning constitutes a promising tool for RRM with the aim to address the conflicting objectives, i.e., KPIs, complexity, scalability, etc.
In this thesis, we study the use of reinforcement learning and its derivatives for improving network KPIs. We highlight the advantages of each reinforcement learning method under the studied network scenarios. In addition, we highlight the gains and trade-offs among the proposed learning techniques as well as the baseline methods that rely on either optimization or heuristics. Finally, we present the challenges facing the application of reinforcement learning to wireless networks and propose some future directions and open problems toward an autonomous wireless network.
The contributions of this thesis can be summarized as follows. First, reinforcement learning methods, and in particular model-free Q-learning, experience large convergence time due to the large state-action space. As such, deep reinforcement learning was employed to improve generalization and speed up the convergence. Second, the design of the state and reward functions impact the performance of the wireless network. Despite the simplicity of this observation, it turns out to be a key one for designing autonomous wireless systems. In particular, in order to facilitate autonomy, agents need to have the ability to learn/adjust their goals. In this thesis, we propose transfer in reinforcement learning to address this point, where knowledge is transferred between expert and learner agents with simple and complex tasks, respectively. As such, the learner agent aims to learn a more complex task using the knowledge transferred from an expert performing a simpler (partial) task.
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Nader, Gustavo. "Radio Link Performance of Third Generation (3G) Technologies For Wireless Networks." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/32251.
Full textAbstract:
Third generation wireless mobile communication networks are characterized by the increasing utilization of data services â e-mail, web browsing, video streaming, etc. Such services allow the transition of the network from circuit switched to packet switched operation (circuit switched operation will still be supported), resulting in increased overall network performance.
These new data services require increased bandwidth and data throughput, due to their intrinsic nature. Examples are graphics-intensive web browsing and video streaming, the latter being delay sensitive and requiring priority over less sensitive services such as e-mail. This increasing demand for bandwidth and throughput has driven the work of third generation standardization committees, resulting in the specification of improved modulation and coding schemes, besides the introduction of more advanced link quality control mechanisms.
Among the several proposals for the evolution from 2G to 3G, GPRS (General Packet Radio Services) and EDGE (Enhanced Data Rates for GSM Evolution) stand out as transitional solutions for existing TDMA IS-136 and GSM networks (they are also referred to as 2.5G systems). In the CDMA arena, WCDMA (Wideband CDMA) has emerged as the most widely adopted solution, with CDMA 2000, an evolution from IS-95, also being considered.
This thesis compiles and analyzes the results of the work by the standardization committees involved in the specification of 3G standards, focusing on the receiver performance in the presence of additive noise, fading and interference. Such performance results will ultimately determine design and optimization conditions for 3G networks.
This document concerns the description of the TDMA-based 2.5G solutions that allow the introduction of multimedia and enhanced data services to existing 2G networks. It focuses on GPRS and EDGE. It also addresses WCDMA â a 3G spread spectrum solution. Such proposals permit the utilization of existing spectrum with increased efficiency, yielding extended network capacity and laying the ground for full support of wireless multimedia applications. The study is focused on the link implementation aspect of these solutions, showing the impact of the modulation schemes and link quality control mechanisms on the performance of the radio link.<br>Master of Science
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Haldar, Kuheli L. Ph D. "Efficient Quality of Service Provision Techniques in Next Generation Wireless Networks." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1397235725.
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Achieng, Robert Otieno. "A QoS enabling queuing scheme for Fourth Generation wireless access networks." Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/5230.
Full textAbstract:
Word processed copy.<br>Includes bibliographical references (leaves 70-74).<br>This research proposes a scheme to accomplish the task of network selection; this is achieved by enhancing existing QoS provisioning approaches. The scheme models the radio access network as a network of queuing nodes. With the model, the link layer QoS statistics of user traffic in each available path through the network is determined. The author postulates that the statistics indicate the QoS capabilities of the network and can therefore be used to select the best network to serve the mobile user.
34
Huang, Weilan. "Cross-layer design for ad hoc and infrastructured next-generation wireless networks /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?ECED%202007%20HUANGW.
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Tsiakas, Panagiotis. "Adaptive load balancing routing algorithms for the next generation wireless telecommunications networks." Thesis, Brunel University, 2009. http://bura.brunel.ac.uk/handle/2438/7509.
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With the rapid development of wireless networks, mesh networks are evolving as a new important technology, presenting a high research and commercial interest. Additionally, wireless mesh networks have a wide variety of applications, offering the ability to provide network access in both rural and urban areas with low cost of maintenance. One of the main functionalities of a wireless mesh network is load balancing routing, which is the procedure of finding the best, according to some criteria, routes that data need to follow to transfer from one node to another. Routing is one of the state-of-the-art areas of research because the current algorithms and protocols are not efficient and effective due to the diversity of the characteristics of these networks. In this thesis, two new routing algorithms have been developed for No Intra-Cell Interference (NICI) and Limited Intra-Cell Interference (LICI) networks based on WiMAX, the most advanced wireless technology ready for deployment. The algorithms created are based on the classical Dijkstra and Ford-Fulkerson algorithms and can be implemented in the cases of unicast and multicast transmission respectively.
36
Zhang, Yang. "Intelligent genetic algorithms for next-generation broadband multi-carrier CDMA wireless networks." Thesis, Brunel University, 2008. http://bura.brunel.ac.uk/handle/2438/7298.
Full textAbstract:
This dissertation proposes a novel intelligent system architecture for next-generation broadband multi-carrier CDMA wireless networks. In our system, two novel and similar intelligent genetic algorithms, namely Minimum Distance guided GAs (MDGAs) are invented for both peak-to-average power ratio (PAPR) reduction at the transmitter side and multi-user detection (MUD) at the receiver side. Meanwhile, we derive a theoretical BER performance analysis for the proposed MC-CDMA system in A WGN channel. Our analytical results show that the theoretical BER performance of synchronized MC-CDMA system is the same as that of the synchronized DS-CDMA system which is also used as a theoretical guidance of our novel MUD receiver design. In contrast to traditional GAs, our MDGAs start with a balanced ratio of exploration and exploitation which is maintained throughout the process. In our algorithms, a new replacement strategy is designed which increases significantly the convergence rate and reduces dramatically computational complexity as compared to the conventional GAs. The simulation results demonstrate that, if compared to those schemes using exhaustive search and traditional GAs, (1) our MDGA-based P APR reduction scheme achieves 99.52% and 50+% reductions in computational complexity, respectively; (2) our MDGA-based MUD scheme achieves 99.54% and 50+% reductions in computational complexity, respectively. The use of one core MDGA solution for both issues can ease the hardware design and dramatically reduce the implementation cost in practice.
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GUPTA, ANANYA. "DECENTRALIZED KEY GENERATION SCHEME FOR CELLULAR-BASED HETEROGENEOUS WIRELESS Ad Hoc NETWORKS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1153347454.
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Orimolade, Joseph Folorunsho. "Access network selection schemes for multiple calls in next generation wireless networks." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/25380.
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There is an increasing demand for internet services by mobile subscribers over the wireless access networks, with limited radio resources and capacity constraints. A viable solution to this capacity crunch is the deployment of heterogeneous networks. However, in this wireless environment, the choice of the most appropriate Radio Access Technology (RAT) that can Tsustain or meet the quality of service (QoS) requirements of users' applications require careful planning and cost efficient radio resource management methods. Previous research works on access network selection have focused on selecting a suitable RAT for a user's single call request. With the present request for multiple calls over wireless access networks, where each call has different QoS requirements and the available networks exhibit dynamic channel conditions, the choice of a suitable RAT capable of providing the "Always Best Connected" (ABC) experience for the user becomes a challenge. In this thesis, the problem of selecting the suitable RAT that is capable of meeting the QoS requirements for multiple call requests by mobile users in access networks is investigated. In addressing this problem, we proposed the use of Complex PRoprtional ASsesment (COPRAS) and Consensus-based Multi-Attribute Group Decision Making (MAGDM) techniques as novel and viable RAT selection methods for a grouped-multiple call. The performance of the proposed COPRAS multi-attribute decision making approach to RAT selection for a grouped-call has been evaluated through simulations in different network scenarios. The results show that the COPRAS method, which is simple and flexible, is more efficient in the selection of appropriate RAT for group multiple calls. The COPRAS method reduces handoff frequency and is computationally inexpensive when compared with other methods such as the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Simple Additive Weighting (SAW) and Multiplicative Exponent Weighting (MEW). The application of the proposed consensus-based algorithm in the selection of a suitable RAT for group-multiple calls, comprising of voice, video-streaming, and file-downloading has been intensively investigated. This algorithm aggregates the QoS requirement of the individual application into a collective QoS for the group calls. This new and novel approach to RAT selection for a grouped-call measures and compares the consensus degree of the collective solution and individual solution against a predefined threshold value. Using the methods of coincidence among preferences and coincidence among solutions with a predefined consensus threshold of 0.9, we evaluated the performance of the consensus-based RAT selection scheme through simulations under different network scenarios. The obtained results show that both methods of coincidences have the capability to select the most suitable RAT for a group of multiple calls. However, the method of coincidence among solutions achieves better results in terms of accuracy, it is less complex and the number of iteration before achieving the predefined consensus threshold is reduced. A utility-based RAT selection method for parallel traffic-streaming in an overlapped heterogeneous wireless network has also been developed. The RAT selection method was modeled with constraints on terminal battery power, service cost and network congestion to select a specified number of RATs that optimizes the terminal interface utility. The results obtained show an optimum RAT selection strategy that maximizes the terminal utility and selects the best RAT combinations for user's parallel-streaming for voice, video and file-download.
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Strohmeier, Martin. "Security in next generation air traffic communication networks." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:c5c61de4-ffef-479e-9f49-de38c2a8e9ec.
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A multitude of wireless technologies are used by air traffic communication systems during different flight phases. From a conceptual perspective, all of them are insecure as security was never part of their design and the evolution of wireless security in aviation did not keep up with the state of the art. Recent contributions from academic and hacking communities have exploited this inherent vulnerability and demonstrated attacks on some of these technologies. However, these inputs revealed that a large discrepancy between the security perspective and the point of view of the aviation community exists. In this thesis, we aim to bridge this gap and combine wireless security knowledge with the perspective of aviation professionals to improve the safety of air traffic communication networks. To achieve this, we develop a comprehensive new threat model and analyse potential vulnerabilities, attacks, and countermeasures. Since not all of the required aviation knowledge is codified in academic publications, we examine the relevant aviation standards and also survey 242 international aviation experts. Besides extracting their domain knowledge, we analyse the awareness of the aviation community concerning the security of their wireless systems and collect expert opinions on the potential impact of concrete attack scenarios using insecure technologies. Based on our analysis, we propose countermeasures to secure air traffic communication that work transparently alongside existing technologies. We discuss, implement, and evaluate three different approaches based on physical and data link layer information obtained from live aircraft. We show that our countermeasures are able to defend against the injection of false data into air traffic control systems and can significantly and immediately improve the security of air traffic communication networks under the existing real-world constraints. Finally, we analyse the privacy consequences of open air traffic control protocols. We examine sensitive aircraft movements to detect large-scale events in the real world and illustrate the futility of current attempts to maintain privacy for aircraft owners.
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Toycan, Mehmet. "Next generation optical access networks and wireless integration featuring ultra-wide-band technology." Thesis, University of Essex, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510509.
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Ranjbar, Mohammad. "Optimal Signaling Strategies and Fundamental Limits of Next-Generation Energy-Efficient Wireless Networks." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1564677171677636.
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Purle, David J. "Frequency hopped code division multiple access techniques for future wireless communications." Thesis, University of Bristol, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281833.
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Sabir, Essaïd. "MAC protocols design and a cross-layered QoS framework for next generation wireless networks." Phd thesis, Université d'Avignon, 2010. http://tel.archives-ouvertes.fr/tel-00544071.
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Ce manuscrit est centré sur la conception, l'amélioration et l'évaluation des protocoles des couches RESEAU, MAC et PHY. En particulier, nous nous focalisons sur la conception de nouveaux protocoles distribués pour une utilisation optimale/améliorée des ressources radio disponibles. Par ailleurs, nous caractérisons les performances des réseaux ad hoc à accès aléatoire au canal en utilisant des paramètres de plusieurs couches avec aptitude de transfert d'information (data forwarding). La majeure partie de nos analyses se base sur le concept d'interaction entre les couches OSI (cross-layer). En effet, cette nouvelle et attractive approche est devenue en peu de temps omniprésente dans le domaine de recherche et développement et dans le domaine industriel. Les métriques de performances qui nous intéressent sont la stabilité des files d'attentes de transfert, le débit, le délai et la consommation d'énergie. Principalement, la compréhension de l'interaction entre les couches MAC/PHY et routage du standard IEEE 802.11e DCF/EDCF, d'une part, et l'interaction entre noeuds en terme d'interférences, d'autre part, constituent le coeur central de notre travail
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Ho, Lester Tse Wee. "Self-organising algorithms for fourth generation wireless networks and its analysis using complexity metrics." Thesis, Queen Mary, University of London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407388.
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Awad, Hazem Abdul'Aal A. M. "The optical sensor mote : a novel device for enabling next generation Wireless Sensor Networks." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=22707.
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Recent advances in micro-electronics and communications have fuelled research in Wireless Sensor Networks (WSNs). WSNs are a collection of low power, low cost, small form factor devices referred to as sensor motes interconnected in a random manner to establish a network. Despite wide ranging research into a range of applications, significant limitations stand in the way of utilizing WSNs to monitor large scale/area environments. Optical sensing techniques are well suited for monitoring a large variety of environmental variables such as temperature, pressure, humidity, and gas concentrations. However, traditional optical sensing techniques rely on bulky solutions including spectroscopic equipment and fibre based approaches. On the other hand, photonic crystals have caused a revolution in integrated optics as they allow functionalities not possible before; however little has been reported on their use as integrated optical sensors. The research work combines the diverse but related fields of WSNs, integrated optics, and Photonic Crystals. A novel platform, the optical sensor mote, is proposed and its key building blocks are experimentally demonstrated as a feasibility study. Specifically, multi-gas sensors based on the slow light phenomenon in photonic crystal waveguides are theoretically and experimentally demonstrated. These sensors can sense multiple gases without the need of any physical changes. They can also be integrated with electronics to yield an optical sensor mote of small form factor which is stable, multi-functional, and cost-effective. The optical sensor mote represents a significant step towards enabling the wide spread use of WSNs to monitor large scale/area environments and providing a highly integrated mote platform amenable to mass production and providing multi-functions.
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Tiemeni, Ghislaine Livie Ngangom. "Performance estimation of wireless networks using traffic generation and monitoring on a mobile device." University of the Western Cape, 2015. http://hdl.handle.net/11394/4777.
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In this study, a traffic generator software package namely MTGawn was developed to run packet generation and evaluation on a mobile device. The call generating software system is able to: simulate voice over Internet protocol calls as well as user datagram protocol and transmission control protocol between mobile phones over a wireless network and analyse network data similar to computer-based network monitoring tools such as Iperf and D-ITG but is self-contained on a mobile device. This entailed porting a ‘stripped down’ version of a packet generation and monitoring system with functionality as found in open source tools for a mobile platform. This mobile system is able to generate and monitor traffic over any network interface on a mobile device, and calculate the standard quality of service metrics. The tool was compared to a computer–based tool namely distributed Internet traffic generator (D-ITG) in the same environment and, in most cases, MTGawn reported comparable results to D-ITG. The important motivation for this software was to ease feasibility testing and monitoring in the field by using an affordable and rechargeable technology such as a mobile device. The system was tested in a testbed and can be used in rural areas where a mobile device is more suitable than a PC or laptop. The main challenge was to port and adapt an open source packet generator to an Android platform and to provide a suitable touchscreen interface for the tool.<br>>Magister Scientiae - MSc
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Gungor, Onur. "INFORMATION THEORY ENABLED SECURE WIRELESS COMMUNICATION, KEY GENERATION AND AUTHENTICATION." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406298547.
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Shah, Pratik. "Feasibility study of secure and robust location determination in current generation of wireless sensor networks." NCSU, 2006. http://www.lib.ncsu.edu/theses/available/etd-01062006-120251/.
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Location Determination has been a fundamental requirement in many wireless sensor network applications. Various schemes have been proposed to solve this problem. These schemes depend on the measurement of physical quantities such as time of flight, angle of arrival, time difference of arrival and signal strength for location determination. Measurements in the real world are also affected by environmental conditions and contain unavoidable errors. Statistical techniques such as MMSE have been shown to be tolerant towards such errors. However in hostile environments, attackers can alter the measurements significantly to render these proposed schemes useless. Security mechanisms such as authentication and encryption can thwart external attacks such as eavesdropping and spoofing. However, attacks specific to location determination schemes differ from conventional security attacks and have been shown to be successful even when adequate security mechanisms are in place. Recently AR-MMSE, LMS and Voting-based schemes have been proposed to resist these attacks. A technique has also been proposed for detection of attacker nodes. This thesis presents the design and implementation of a nesC [[8] library that achieves secure and robust location determination using these techniques and provides a simple interface that can be used by high level applications. A working system was built using Cricket sensors to evaluate the feasibility of the techniques along with basic security mechanisms. We measure the tradeoffs between the time required for computation, memory consumption and the accuracy of the estimated location. We also measure the accuracy of the estimated location under various degrees of attack for both 2-dimensional and 3- dimensional scenarios. Our experimental results show that in a 2-dimensional system, even with 2 malicious Beacon Nodes out of 8, the maximum increase in error is less than 8 cm for all three techniques when the maximum error is 2 cm without any malicious Beacon Nodes. In case of 3-dimensional system with 1 malicious Beacon Node out of 8, the maximum increase is less than 20 cm with maximum error of about 10 cm when no malicious Beacon Nodes are present.
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Teerapittayanon, Surat. "Performance enhancements in next generation wireless networks using network coding : a case study in WiMAX." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/76816.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (p. 125-130).<br>In this thesis, we design and implement a network-coding-enhanced network architecture for next generation wireless networks. The architecture applies intra-session random linear network coding as a packet erasure code below the IP layer. Using WiMAX as a case study, a series of point-to-point single-interface experiments are conducted to compare the performance of the architecture to that of HARQ and ARQ mechanisms. The performance measures are packet loss percentage, throughput and file transfer delay. The experiments use the Global Environment for Network Innovations (GENI) WiMAX platforms. UDP traffic considered; Iperf and UDP based File Transfer Protocol (UFTP) are used as measurement applications. The proposed architecture substantially decreases packet loss percentage from around 11-32% to nearly 0%. Compared to HARQ and ARQ mechanisms, the architecture can offer up to 5.9 times gain in throughput and 5.5 times reduction in end-to-end fi le transfer delay.<br>by Surat Teerapittayanon.<br>M.Eng.
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Isautier, Pierre Paul Roger. "Autonomous receivers for next-generation of high-speed optical communication networks." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54418.
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Advances in fiber optic communications and the convergence of the optical-wireless network will dramatically increase the network heterogeneity and complexity. The goal of our research is to create smart receivers that can autonomously identify and demodulate, without prior knowledge, nearly any signal emerging from the next-generation of high-speed optical communication networks.