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Dissertations / Theses on the topic 'Co-channel interference'
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Lynch, Jamel Pleasant. "Co-Channel Interference In Bluetooth Piconets." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35741.
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Bluetoothâ ¢ is an emerging short-range RF wireless voice and data communication technology expected to spread widely in a couple of years. The open specification technology eliminates the need for cables to connect mobile phones, portable computers and countless other devices to each other from all different manufacturers.
This thesis provides an overview of the emerging Bluetoothâ ¢ technology and investigates the performance of Bluetoothâ ¢ data networks in various network topologies simulated from actual usage scenarios. Using a typical office environment, the study examines the probability and effects of Co-Channel interference as Bluetoothâ ¢ ad-hoc networks are formed in adjacent offices. A computer aided simulation tool, MATLAB simulates a low to highly dense interfering Bluetoothâ ¢ environment which provides the parameters to evaluate the bluetooth co-channel interference and performance. Several metrics are identified to predict Bluetoothâ ¢ performance in a piconet after a collision has occurred: data through put, the probability of frequency collision, transmitter - receiver distance, and power received. Next, to predict Bluetooth performance we also need to define what constitutes a lost packet. Finally, a Bluetoothâ ¢network simulation is developed to measure the metrics, given occurrence of the lost packets.Master of Science
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Detert, Thorben. "Low complexity co-channel interference cancellation." Göttingen Sierke, 2008. http://d-nb.info/991223314/04.
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Li, Yuan. "Multiuser Detection for Co-channel Interference Cancellation." 京都大学 (Kyoto University), 2000. http://hdl.handle.net/2433/180902.
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Won, Jonghyun. "Co-channel interference suppression for ofdm systems." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001170.
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Patterson, John E. "Co-channel interference mitigation using satellite based receivers." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/44642.
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Approved for public release; distribution is unlimitedThis thesis investigates a means to mitigate co-channel interference from fourth generation cellular signals in order to support passive synthetic aperture radar (SAR) imaging using those same signals. Synthetic aperture radar is a staple of the military and intelligence communities, but the active transmission required for such images informs the target of the imaging process. Use of passive signals, such as the orthogonal frequency-division multiplexing (OFDM) signals of fourth generation cellular systems, is an attractive option, but co-channel interference mitigation is required. A method to separate the transmitted signals that leverages the estimated signal delays between multiple transmitters and receivers is examined for narrowband and wideband signals. Multiple methods of assessing recovery performance are proposed. The impact of noise is considered, as is the impact of collection geometry on recovery perfor-mance, and recovery of OFDM signals is evaluated. Signal interpolation is a critical element of the proposed recovery process, and two methods are compared for accuracy and speed of computation.
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Yu, Hyungseok. "Performance of cooperative relaying systems with co-channel interference." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45744.
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The cooperative relaying scheme is a promising technique for increasing the capacity and reliability of wireless communication.
Even though extensive research has performed in information theoretical aspect, there are still many unresolved practical problems of cooperative relaying system.
This dissertation analyzes the performance of cooperative decode-and-forward (DF) relaying systems in the presence of multiple interferers and improve network throughput for these systems.
We propose and summarize various systems in the view of network topology, transmission structure, and slot allocation.
We present closed-form expressions for the end-to-end outage probability, average symbol-error-probability, average packet-error-probability, and network throughput of the proposed systems.
This dissertation shows that the robustness of the destination against interference is more important than robustness of the relay against interference from an interference management perspective, and increasing the number of branches yields better outage and error performance improvements against shadowing than increasing the number of hops.
In cellular networks, the cooperative diversity systems can outperform the dual-Rx antenna system, but only when the relay is located in a relatively small portion of the total cell area with respect the the destination mobile terminal.
The results also show that since the effective regions of the uplink and the downlink do not overlap, different relays should be utilized for cell sectorization in the uplink and the downlink.
Finally, the proposed variable-slot selection DF scheme can reduce the system complexity and make the maximum throughput point in the low and moderate signal-to-interference-plus-noise ratio region.
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M, M. Galib Asadullah. "Robust wireless communications under co-channel interference and jamming." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22571.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Gordon L. Stuber; Committee Member: Alfred D. Andrew; Committee Member: John A. Buck; Committee Member: Steven W. McLaughlin; Committee Member: Ye (Geoffrey) Li.
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Welborn, Matthew L. "Co-channel interference rejection using a model-based demodulator." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-01312009-063544/.
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Austin, Mark David. "Handoff algorithms and co-channel interference analysis for microcellular systems." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/15349.
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Murata, Hidekazu. "NONLINEAR CO-CHANNEL INTERFERENCE CANCELLATION TECHNIQUE FOR DIGITAL MOBILE COMMUNICATIONS." Kyoto University, 2000. http://hdl.handle.net/2433/181010.
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Ali, Mohamad Jaafar. "Wireless body area networks : co-channel interference mitigation & avoidance." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB252/document.
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L’amélioration de la qualité et de l’efficacité en santé est un réel enjeu sociétal. Elle implique la surveillance continue des paramètres vitaux ou de l’état mental du sujet. Les champs d’applications sont vastes : l’application la plus importante est la surveillance des patients à distance. Les avancées en micro-électronique, capteurs et réseaux sans-fil permettent aujourd’hui le développement de systèmes ambulatoires performants pour le monitoring de paramètres physiologiques, capables de prendre en compte d’importantes contraintes techniques : forte intégration pour la réduction de la taille et faible consommation pour une plus grande autonomie [1]. Cependant, la conception de ce type de réseaux de capteurs médicaux WBANs (Wireles Body Area Networks) se heurte à un certain nombre de difficultés techniques, provenant des contraintes imposées par les capacités réduites des capteurs individuels : basse puissance, énergie limitée et faible capacité de stockage. Ces difficultés requièrent des solutions différentes, encore très embryonnaires, selon l’application visée (monitoring à but médical). La forte mobilité et le changement rapide de la topologie du réseau dévoilent un verrou scientifique et social. En outre, l’interférence de différents capteurs constituant le WBAN augmente la difficulté de la mise en place de ce type de réseaux. De nombreuses solutions dans la littérature ont été étudiées, comme nous allons illustrer dans ce manuscrit, néanmoins elles restent limitées. Nous nous intéresserons tout particulièrement à la gestion des interférences Intra- et Inter-WBAN, leur impacte sur la fiabilité des transmissions (des liens) et la durée de vie de ce type de réseaux. Plus précisément, nous abordons ces problématiques en se basant sur des modélisations théoriques et analytiques et avec une conception pratique des solutions proposées. Afin d’atteindre les objectifs cités ci-dessous, nous abordons quatre solutions : • Une gestion des interférences intra-WBAN • Une gestion coopérative des interférences Inter-WBAN • Une gestion non coopérative des interférences, Inter-WBAN • Une gestion des interférences WBAN dans un contexte IoT Dans la première partie de cette thèse et afin de répondre en partie aux problèmes de gestion des interférences Intra-WBAN. Nous présentons deux mécanismes pour le WBAN : (a) CFTIM qui alloue dynamiquement des slots et des canaux dit- stables (avec un taux d’interférences le bas possible dans le temps) pour réduire les interférences intra-WBAN. (b) IAA ajuste dynamiquement la taille du superframe et limite le nombre de canaux à 2 pour abaisser les interférences Intra-WBAN et ainsi économiser l’énergie. Une validation avec un model probabiliste est proposé afin de valider théoriquement l’efficacité de notre solution. Les résultats de la simulation démontrent l’efficacité du CFTIM et de l’IAA en termes de réduction de la probabilité d’interférence, l’extension de la durée de vie du réseau et l’amélioration du débit et de la fiabilité des transmissions. Notre seconde contribution, propose une gestion coopératives des interférences Inter-WBAN en utilisant des codes orthogonaux. Motivé par un approvisionnement temporel distribué basé sur la norme [2] IEEE 802.15.6, nous proposons deux solutions. (a) DTRC qui fournit à chaque WBAN les connaissances sur les superframes qui se chevauchent. Le second, (b) OCAIM qui attribue des codes orthogonaux aux capteurs appartenant à deux listes de groupe de capteur en interférences de deux WBAN différents (SIL). Les résultats démontrent qu’OCAIM diminue les interférences, améliore le débit et préserve la ressources énergétiques. La troisième partie nous a permis d’aborder la gestion des interférences, mais cette fois ci d’une manière non-coopérative en se basant sur l’affectation couple Slot/Canal. Plus précisément, nous proposons deux schémas basés sur les carrés latins. (...)A Wireless Body Area Network (WBAN) is a short-range network that consists of a coordinator (Crd) and a collection of low-power sensors that can be implanted in or attached to the human body. Basically, WBANs can provide real-time patient monitoring and serve in various applications such as ubiquitous health-care, consumer electronics, military, sports, etc. [1]. As the license-free 2.4 GHz ISM band is widely used among WBANs and across other wireless technologies, the fundamental problem is to mitigate the resulting co-channel interference. Other serious problems are to extend the network lifetime and to ensure reliable transmission within WBANs, which is an urgent requirement for health-care applications. Therefore, in this thesis, we conduct a systematic research on a few number of research problems related to radio co-channel interference, energy consumption, and network reliability. Specifically, we address the following problems ranging from theoretical modeling and analysis to practical protocol design: • Intra-WBAN interference mitigation and avoidance • Cooperative inter-WBAN interference mitigation and avoidance • Non-cooperative inter-WBAN interference mitigation and avoidance • Interference mitigation and avoidance in WBANs with IoT Firstly, to mitigate the intra-WBAN interference, we present two mechanisms for a WBAN. The first is called CSMA to Flexible TDMA combination for Interference Mitigation, namely, CFTIM, which dynamically allocates time-slots and stable channels to lower the intra-WBAN interference. The second is called Interference Avoidance Algorithm, namely IAA that dynamically adjusts the superframe length and limits the number of channels to 2 to lower the intra-WBAN interference and save energy. Theoretically, we derive a probabilistic model that proves the SINR outage probability is lowered. Simulation results demonstrate the effectiveness and the efficiency of CFTIM and IAA in terms of lowering the probability of interference, extending network lifetime, improving throughput and reliability. Secondly, we address the problem of interference among cooperative WBANs through using orthogonal codes. Motivated by distributed time provisioning supported in IEEE 802.15.6 standard [2], we propose two schemes. The first is called Distributed Time Correlation Reference, namely, DTRC that provides each WBAN with the knowledge about which superframes overlap with each other. The second is called Orthogonal Code Allocation Algorithm for Interference Mitigation, namely, OCAIM, that allocates orthogonal codes to interfering sensors belonging to sensor interference lists (SILs), which are generated based on the exchange of power-based information among WBANs. Mathematically, we derive the successful and collision probabilities of frames transmissions. Extensive simulations are conducted and the results demonstrate that OCAIM can diminish the interference, improve the throughput and save the power resource. Thirdly, we address the problem of co-channel interference among non-cooperative WBANs through time-slot and channel hopping. Specifically, we propose two schemes that are based on Latin rectangles. The first is called Distributed Algorithm for Interference mitigation using Latin rectangles, namely, DAIL that allocates a single channel to a timeslot combination to each sensor to diminish inter-WBAN interference and to yield better schedules of the medium access within each WBAN. The second is called Channel Hopping for Interference Mitigation, namely, CHIM, which generates a predictable interference free transmission schedule for all sensors within a WBAN. CHIM applies the channel switching only when a sensor experiences interference to save the power resource. Furthermore, we present an analytical model that derives bounds on collision probability and throughput for sensors transmissions. (...)
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Paterson, Gavin John. "Adaptive nonlinear equaliser structures for intersymbol and co-channel interference suppression." Thesis, University of Strathclyde, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436832.
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Zoualfaghari, Mohammad Hossein. "Co-channel interference reduction in Optical Code Division Multiple Access systems." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5819/.
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In this thesis few new code sets and a multi-user interference (MUI) cancellation scheme have been proposed for Optical Code Division Multiple Access (OCDMA) systems, which can be employed in the next generation of global communication networks to enhance their existing systems’ performance dramatically. The initial evaluation of the proposed code sets shows that their implementation improves the performance, decreases the BER and increases security considerably. Also the proposed MUI cancellation scheme totally removes all the cross-talk and interference between the active users within the network. These novel schemes and codes can be easily implemented in the optical packet switched networks. Optical switching has the ability of bandwidth manipulation at the wavelength level (e.g. with optical circuit/packet/burst switching); the capability to accommodate a wide range of traffic distributions, and also to make dynamic resource reservations possible. This thesis first gives a brief overview of co-channel interference reduction in OCDMA networks, then proposes two novel code sets, Uniform Cross-Correlation Modified Prime Code (UC-MPC) and Transposed UC-MPC (T-UCMPC), along with their evaluation and analysis in various systems, including IP routing over an OCDMA network. Thereafter, the new MUI cancellation scheme is proposed and then the proposed code sets and the MUI cancellation scheme are implemented and analysed in a laboratory-based experimental test bed. Finally the conclusion of this research is discussed.
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Raghavan, Srini. "Effects of Co-Channel Interference with Frequency Offset on PSK Signals." International Foundation for Telemetering, 1987. http://hdl.handle.net/10150/615286.
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International Telemetering Conference Proceedings / October 26-29, 1987 / Town and Country Hotel, San Diego, CaliforniaThe sharing of C-band between microwave terrestrial and satellite communication systems invariably introduces interference from one system into the other. Such co-channel interference becomes even more important in satellite receive stations with smaller antennas and must be minimized to achieve system performance objectives. In this paper, co-channel interference due to two TD2 (FDM/FM) carriers into a satellite receive system, receiving binary phase-shift keyed (BPSK) signal, is considered. It is shown that the frequency offset of the TD2 carriers from the BPSK carrier can be used to minimize co-channel interference effects. Equations are given which compute the bit error rate (BER) of BPSK signals in the presence of an interfering unmodulated carrier. They are followed by some results due to TD2 carrier interference.
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Charalabopoulos, Grigorios. "Radial basis function neural networks for channel equalization and co-channel interference cancellation in OFDM." Thesis, King's College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416116.
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Luschi, Carlo. "Probabilistic techniques for equalization of the mobile radio channel in the presence of co-channel interference." Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/12489.
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This thesis studies the problem of soft-output equalization of the mobile radio channel in interference-limited environments, where it is often difficult to obtain an accurate statistical model of the (non-Gaussian) disturbance. The first part of the thesis proposes a new technique for single-channel MAP trellis equalization in the presence of multipath and non-Gaussian interference. The approach is based on the non-parametric estimation of the density function of the overall disturbance by means of kernel smoothing. The work considers the problem of density estimation with limited volume of data, and addresses the use of a whitening filter in the presence of coloured interference. As an application, simulation results are provided for the GSM system, showing a significant performance improvement with respect to the trellis equalizer based on the Gaussian assumption. The second part of the thesis considers the case of an antenna array receiver, and studies a simple method to derive the reliability information at the output of a deterministic decision-feedback least-squares space-time equalizer. Computer simulations for the Enhanced Data Rates for GSM Evolution (EDGE)/Enhanced General Packet Radio Service (EGPRS) system show that the receiver performance can be significantly improved by a soft-output calculation based on short-term statistics of the equalizer output error. The thesis also addresses the additional use of soft-decision feedback, which provides further robustness to the proposed soft-output equalizer. The study shows the relevance of probabilistic processing for robust equalization of the wireless channel in the presence of non-Gaussian interference, and emphasizes the advantages of strategies that do not rely on a statistical model of the disturbance.
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Carter, Paul Patrick Simon. "A study of co-channel interference in a digital mobile radio system." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240240.
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He, Rong. "AMPS co-channel interference rejection techniques and their impact on system capacity." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-10022008-063026/.
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Ahmed, Yasir. "A Model-Based Approach to Demodulation of Co-Channel MSK Signals." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/36265.
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Co-channel interference limits the capacity of cellular systems, reduces the throughput of
wireless local area networks, and is the major hurdle in deployment of high altitude communication platforms. It is also a problem for systems operating in unlicensed bands such as the 2.4 GHz ISM band and for narrowband systems that have been overlaid with spread spectrum systems.
In this work we have developed model-based techniques for the demodulation of co-channel
MSK signals. It is shown that MSK signals can be written in the linear model form, hence a minimum variance unbiased (MVU) estimator exists that satisfies the Cramer-Rao lower bound (CRLB) with equality. This framework allows us to derive the
best estimators for a single-user and a two-user case. These concepts can also be extended to wideband signals and it is shown that the MVU estimator for Direct Sequence Spread Spectrum signals is in fact a decorrelator-based multiuser detector.
However, this simple linear representation does not always exist for continuous phase modulations. Furthermore, these linear estimators require perfect channel state information and phase synchronization at the receiver, which is not always implemented in wireless communication systems. To overcome these shortcomings of the linear estimation techniques, we employed an autoregressive modeling approach. It is well
known that the AR model can accurately represent peaks in the spectrum and therefore can be used as a general FM demodulator. It does not require knowledge of the exact signal model or phase synchronization at the receiver. Since it is a non-coherent reception technique, its performance is compared to that of the limiter discriminator. Simulation results have shown that model-based demodulators can give significant gains for certain phase and frequency offsets between the desired signal and an interferer.Master of Science
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Smith, Justin L. "New sharing method between the Fixed Satellite Service and the Aeronautical Mobile Satellite Service in the 14.0-14.5 GHz band." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/31049.
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In the US, the 14.0-14.5 GHz band is allocated on a primary basis to the Radio-Navigation and the FSS with a secondary allocation to the LMSS. The Radio-Navigation service is the use of RADAR for navigation. An example of Radio-Navigation is the ground proximity radar used for airplane collision avoidance. FSS stands for the Fixed Satellite Service. In general, an FSS is a satellite network consisting of a geo-stationary satellite and non-movable earth stations on the ground. An example of an FSS is the earth terminals used at gas stations to verify credit cards and centrally track inventory. The 14.0-14.5 GHz band is also allocated on a secondary basis to the LMSS or Land Mobile Satellite Service. This is a satellite network with a satellite and a movable terrestrial non-aeronautical earth station. An example of an LMSS is a system called Omnitracs, which provides a satellite-based data connection for the trucking industry. AMSS stands for the Aeronautical Mobile Satellite Service. An AMSS is an LMSS dedicated only to airplanes.
The CPM or Conference Preparatory Meeting after WRC or World Radio Conference-2000 decided there was an urgent need for technical and regulatory studies covering sharing between the FSS and the AMSS. The requirement for a report on the studies was added to the WRC-2003 agenda. The WRC also stipulated that the studies must demonstrate that sharing between the FSS and the AMSS is feasible enough to allocate AMSS a secondary status in the band. The studies need to be completed before WRC-2003. AMSS contends that sharing is feasible if their service can meet the same PFD limits of the LMSS. Presently, the FCC has licensed the AMSS on an experimental non-interference basis.
The FSS contends that characteristics are needed of the AMSS system and a detailed sharing study be completed to verify sharing is feasible. The FSS believes that sharing may not be feasible if the same transponder is used for AMSS and FSS. The FSS perceives that the AMSS is asking for a super secondary status. Super secondary status implies that the AMSS would only be required to adhere to PFD limits on individual aircraft and not for multiple aircraft in view of a victim FSS receiver. Future studies will clarify this issue.
The issues associated with the sharing analysis are; the modeling of the orbital separation of the satellites, the atmospheric interference into the communication link and the availability of the communication link between the FSS and the AMSS.
The issues associated with modeling of the simulation are the static, verses dynamic modeling environments and developing a dynamic software tool to track airplane movement. This thesis plans to propose a new sharing methodology between the FSS and the AMSS that could be contributed to the WRC-2003 agenda.
Three systems examples were provided at ITU meetings inresponse to the WRC-2003 agenda item. The three systems will abide by the ITU-R S.728 EIRP limits. The three systems indicate that static analysis shows that sharing is feasible involving only one aircraft as the interfere. This is not a reasonable solution for a real time environment because there is only one aircraft used. It is necessary for the link to support multiple aircraft.
The factors that indicate sharing is feasible are: non-harmful interference to the victim and reasonable enough link margin in the interfere system to make it viable. A viable system in the case of aircraft would include high-speed internet and video. The AMSS interfere system cannot propose a power limit that will not allow it to close itâ s own link.
In order to mitigate the interference, systems can agree to certain interference mitigation techniques. The different techniques are: transmitting power control, geostationary arc avoidance angle and orbital arc separation.
Power control as described above is the centralized control of the interfering antenna into the victim. This is done by simulating the interference environment and pre-scheduling the decreases of the transmitting power. This is a feasible solution except that it decreases the availability and thru-put of the interfere system. This approach can make the system have unrealistic link margins and spotty availability due to the pre-scheduled power control.
Another technique is the geostationary arc avoidance angle. This technique is not applicable since both the AMSS and FSS use geostationary orbits.
The third technique is geostationary separation. This technique requires co-channel systems to maintain a certain orbital spacing between them. FSS systems in certain bands have a minimum of 3 degrees of orbital spacing between co-channel systems. Since the AMSS has 01/25/03 a mobile terrestrial system (aircraft) as part of the link, it requires a higher orbital separation between it and the FSS system. The results of dynamic analysis indicate that this technique is feasible at 10 degree orbital spacing.
The Monte Carlo analysis completed for this thesis simulated the results of four scenarios: co-located, 3 degree, and 5 and 10-degree orbital separation. It can be determined from the results that the interference decreases as the orbital separation increases. These simulations were done based on a 10 aircraft interfere scenario.Master of Science
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See, Chong Meng Samson. "Space-time processing for wireless mobile communications." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/25284.
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Intersymbol interference (ISI) and co-channel interference (CCI) are two major obstacles to high speed data transmission in wireless cellular communications systems. Unlike thermal noise, their effects cannot be removed by increasing the signal power and are time-varying due to the relative motion between the transmitters and receivers. Space-time processing offers a signal processing framework to optimally integrate the spatial and temporal properties of the signal for maximal signal reception and at the same time, mitigate the ISI and CCI impairments. In this thesis, we focus on the development of this emerging technology to combat the undesirable effects of ISI and CCL We first develop a convenient mathematical model to parameterize the space-time multipath channel based on signal path power, directions and times of arrival. Starting from the continuous time-domain, we derive compact expressions of the vector space-time channel model that lead to the notion of block space-time manifold, Under certain identifiability conditions, the noiseless vector-channel outputs will lie on a subspace constructed from a set. of basis belonging to the block space-time manifold. This is an important observation as many high resolution array processing algorithms Can be applied directly to estimate the multi path channel parameters. Next we focus on the development of semi-blind channel identification and equalization algorithms for fast time-varying multi path channels. Specifically. we develop space-time processing algorithms for wireless TDMA networks that use short burst data formats with extremely short training data. sequences. Due to the latter, the estimated channel parameters are extremely unreliable for equalization with conventional adaptive methods. We approach the channel acquisition, tracking and equalization problems jointly, and exploit the richness of the inherent structural relationship between the channel parameters and the data sequence by repeated use of available data through a forward- backward optimization procedure. This enables the fuller exploitation of the available data. Our simulation studies show that significant performance gains are achieved over conventional methods. In the final part of this thesis, we address the problem identifying and equalizing multi path communication channels in the presence of strong CCl. By considering CCI as stochasic processes, we find that temporal diversity can be gained by observing the channel outputs from a tapped delay line. Together with the assertion that the finite alphabet property of the information sequences can offer additional information about the channel parameters and the noise-plus-covariance matrix, we develop a spatial temporal algorithm, iterative reweighting alternating minimization, to estimate the channel parameters and information sequence in a weighted least squares framework. The proposed algorithm is robust as it does not require knowledge of the number of CCI nor their structural information. Simulation studies demonstrate its efficacy over many reported methods.
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Durak, Adem. "Evaluation and methods to reduce co-channel interference on the reverse channel of a CDMA cellular system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA361164.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, March 1999.Thesis advisor(s): Tri T. Ha, Ralph D. Hippenstiel. "March 1999". Includes bibliographical references (p. 91-92). Also available online.
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Argyros, Andreas. "Analysis of Wideband Code Division Multiple Access (WCDMA) system with co-channel interference." Thesis, Monterey, California. Naval Postgraduate School, 2007. http://hdl.handle.net/10945/55195.
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Approved for public release; distribution is unlimited.The Wideband Code Division Multiple Access is a third generation air interface, initiated in European Union research projects at the start of the 1990s. The standard emerged by the end of 1999 as part of the 3GPP standardization process. It was designed to support multiple simultaneous services with high quality services through an increased data rate. This research examines the properties and parameters of the WCDMA system to determine the feasibility of intercepting and exploiting this technology with known assets. It explores this possibility by looking at link analysis, adaptive antennas and co-channel interference canceling techniques to determine if the interception of WCDMA signals is possible.
Lieutenant Junior Grade, Hellenic Navy
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Ekanthalingam, Ravikanth. "Amplitude Estimation of Minimum Shift Keying in the presence of Co-channel interference." Ohio University / OhioLINK, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1107802525.
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Mayer, Tanya G. "Evaluation of and methods to reduce co-channel interference on the forward channel of a CDMA cellular system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA358985.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 1998."December 1998." Thesis advisor(s): Tri T. Ha, R. Clark Robertson. Includes bibliographical references (p. 81). Also available online.
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Sahin, Mustafa. "Baseband receiver algorithms for 4G co-channel femtocells." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003283.
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Chhabra, Saurbh. "An Analytical Tool for Calculating Co-Channel Interference in Satellite Links That Utilize Frequency Reuse." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35122.
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This thesis presents the results of the development of a user-friendly computer code (in MATLAB) that can be used to calculate co-channel interferences, both in the downlink and in the uplink of a single satellite/space-based mobile communications system, due to the reuse of frequencies in spot beams or coverage cells. The analysis and computer code can be applied to any type of satellite or platform elevated at any height above earth. The cells or beams are defined in the angular domain, as measured from the satellite or the elevated platform, and cell centers are arranged in a hexagonal lattice. The calculation is only for a given instant of time for which the system parameters are input into the program.
The results obtained in one program run are for the overall carrier to interference ratio (CIR) along with CIR for both the uplink and downlink paths. An overall carrier to noise plus interference ratio (CNIR) is also calculated, which exemplifies the degradation in the carrier to noise ratio (CNR) of the system.
Comparisons for systems with differing system scenarios are also made. For example, overall CIRs are compared for different reuse numbers (3, 4, 7, and 13) in LEO and GEO satellite systems.
In conclusion, as expected, it is observed that the co-channel interference generally increases as we decrease the reuse number employed for the frequency reuse in the cells. It is also observed that co-channel interference can cause substantial degradation to the overall CNR of a system.Master of Science
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Khwandah, Sinan. "System optimisation and radio planning for future LTE-advanced." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/13822.
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This work is related to wireless communication. In this Thesis three main issues are addressed for future cellular networks: power consumption, interference and mobility. These issues continue to be a burden on the system’s performance as long as technology keeps evolving. In the presented chapters, the focus was to introduce greater intelligence to the LTE system algorithms and bring to them a dynamic and self-organizing approach. The first approach concerns power consumption in wireless terminals. The currently applied solution to save energy is the DRX mechanism. It organizes the time when the terminal wakes up and starts receiving data, and when it goes into sleep mode in order to save its battery power. The current DRX is described as static or fixed which makes its parameters unsuitable for the nature of the bursty traffic. In this work an adaptive DRX mechanism is proposed and evaluated as the wireless terminal battery saving algorithm. The second approach is co-channel interference mitigation. To increase the system’s capacity and avoid spectrum scarcity, small cells such as Femtocells are deployed and operate on the same frequency bands as the Macrocell. Although these small nodes increase the system capacity, however, the challenges will be in the femtocells planning and management in addition to the interference issues. Here a dynamic interference cancellation approach is presented to enable the Femtocell to track the allocated resources to the Macro-users, and to avoid using them. The third approach concerns mobility management in heterogeneous networks. The wireless terminal may have different mobility levels during handover which increases the handover failures due to failure in handover commands and aging of the reported parameters. This issue is presented in detail with the aim to avoid performance degradation and improve the reporting mechanisms during fast mobility levels. For this regard the presented method proposes more cooperation between the serving cell and the end-user so that the large amount of overhead and measurement are reduced. Simulations with different configurations are conducted to present the results of the proposed models. Results show that the proposed models bring improvements to the LTE system. The enhanced self-organized architecture in the three presented approaches performs well in terms of power saving, dynamic spectrum utilization by Femtocells, and mitigation of sudden throughput degradation due to the serving cell’s downlink signal outage during mobility.
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Padaki, Aditya V. "Fundamentals of Efficient Spectrum Access and Co-existence with Receiver Nonlinearity." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/81958.
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RF front-ends are nonlinear systems that have nonlinear frequency response and, hence, can impair receiver performance by harmful adjacent channel interference in non-intuitive ways. Next generation wireless networks will see unprecedented diversity across receiver and radio technologies accessing the same band of spectrum in spatio-temporal proximity. Ensuring adjacent channel co-existence is of prime importance for successful deployment and operations of next generation wireless networks. Vulnerabilities of receiver front-end can have a severe detrimental effect on network performance and spectrum co-existence. This dissertation addresses the technological challenges in understanding and accounting for receiver sensitivities in the design of next generation wireless networks. The dissertation has four major contributions.
In the first contribution, we seek to understand how receiver nonlinearity impacts performance. We propose a computationally efficient framework to evaluate the adjacent channel interference in a given radio/spectrum environment. We develop novel tractable representation of receiver front-end nonlinearity to specify the adjacent channel signals that contribute to the interference at the desired channel and the total adjacent channel interference power at a given desired channel.
In the second contribution, we seek to understand how the impact of receiver nonlinearity performance can be quantified. We quantify receiver performance in the presence of adjacent channel interference using information theoretic metrics. We evaluate the limits on achievable rate accounting for RF front-end nonlinearity and provide a framework to compare disparate receivers by forming generalized metrics.
In the third contribution, we seek to understand how the impact of receiver nonlinearity can be managed at the network level. We develop novel and comprehensive wireless network management frameworks that account for the RF nonlinearity, impairments, and diversity of heterogeneous wireless devices. We further develop computationally efficient algorithms to optimize the proposed framework and examine network level performance. We demonstrate through extensive network simulations that the proposed receiver-centric frameworks provide substantially high spectrum efficiency gains over receiver-agnostic spectrum access in dense and diverse next generation wireless networks.
In the fourth contribution, we seek to understand how scalable interference networks are with receiver nonlinearity. We propose practical achievable schemes for interference avoidance and assess the scalability of the next generation wireless networks with interference due to receiver nonlinearity. Further, we develop an algorithmic scheme to evaluate the upper bound on scalability of nonlinear interference networks. This provides valuable insights on scalability and schemes for nonlinear adjacent channel interference avoidance in next generation shared spectrum networks.Ph. D.
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Richardson, A. J. "The effects of co-channel interference on digital transmission in mobile radio area coverage systems." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356289.
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Aranda-Cubillo, Jaime. "Analysis and evaluation of nyquist-I pulses impaired by inter-symbol and co-channel interference." Tesis, Universidad de Chile, 2019. http://repositorio.uchile.cl/handle/2250/170455.
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Tesis para optar al grado de Magíster en Ciencias de la Ingeniería, Mención EléctricaMemoria para optar al título de Ingeniero Civil Eléctrico
Las actuales tendencias en los sistemas de comunicaciones inalámbricas, nos llevan a dis- eñar sistemas con un eficiente uso del espectro, ya que los requisitos de tasas de transmisión, de manera conservadora, se duplican cada año. La transmisión de señales a altas tasas genera interferencia inter-simbólica (ISI), efecto que degrada el rendimiento de los sistemas de comu- nicaciones. El diseño de señales libres de ISI en canales limitados en banda fue un problema abordado por Nyquist. El primer criterio de Nyquist (Nyquist-I), garantiza que una secuen- cia de pulsos será libre de ISI siempre y cuando sea muestreada en múltiplos del tiempo de símbolo. De la misma forma, el desarrollo de nuevas tecnologías, como Machine to Machine Communication (M2MC), Internet of Things (IoT) o redes móviles 5G, han introducido una gran cantidad de dispositivos demandando también un uso eficiente del espectro. En estos ambientes, la detección de datos de un usuario a menudo se corrompe por señales de otros usuarios ubicados en distancias cercanas o moderadas que usan la misma banda de frecuen- cia. El objetivo del re-uso de frecuencias es incrementar la eficiencia espectral. Este tipo de interferencia es llamada interferencia co-canal (CCI) y afecta negativamente el desempeño de los sistemas de comunicaciones. Así, la evaluación de diferentes pulsos de Nyquist-I, que mitigan los efectos de interferencias, es de considerable interés. En el presente trabajo se realiza la evaluación, comparación y análisis de distintos pulsos de Nyquist-I, considerando los efectos de la ISI, CCI y simultáneamente, ISI y CCI en sistemas banda-base y pasa-banda. Se considera la respuesta completa y truncada de los pulsos. Además se consideran 2 modelos para representar los efectos del CCI, el modelo sinusoidal y Preciso. Este análisis se realiza debido a que el tópico es escasamente tratado en la literatura. Luego, para realizar una comparación justa, los parámetros de los pulsos son optimizados considerando restricciones en el dominio de la frecuencia para condiciones particulares de los sistemas de comunicaciones. Los pulsos se evaluan principalmente en términos de la probabilidad de error de bit (BER) y, en todos los casos se presenta su comportamiento en el dominio de la frecuencia. Lo resultados indican que existen diferencias significativas en cuanto al desempeño de los pulsos, considerando distintos tipos de interferencias y tipos de respuesta. Los resultados anteriores pueden ser utilizados para hacer un diseño más eficiente de los sistemas de comunicaciones o también crear filtros adaptativos que modifiquen sus parámetros considerando las condiciones particulares de propagación.
FONDECYT Iniciacion, Grant No. 11160517
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Haghdad, Mehdi, and Kamilo Feher. "PERFORMANCE OF FQPSK TRANSCEIVERS IN A COMPLEX REAL-LIFE INTERFERENCE ENVIRONMENT." International Foundation for Telemetering, 2000. http://hdl.handle.net/10150/606773.
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International Telemetering Conference Proceedings / October 23-26, 2000 / Town & Country Hotel and Conference Center, San Diego, CaliforniaThe Bit Error Rate (BER) performance of FQPSK modulated signals in the presence of the Co-Channel Interference (CCI) and Additive White Gaussian Noise (AWGN) is evaluated and improved. A Non- Linearly Amplified (NLA) FQPSK modulated signal with the data rate of 1Mb/s and carrier frequency of 70 MHz is interfered with a sinusoidal signal at different frequencies. As the relative distance of the center frequency of the Co-channel interference (CCI) changes, different BER are obtained. The effect of the CCI decreases as the CCI center frequency moves away from the center of the modulated signal. In order to improve the BER in the presence of the CCI, a hard limited filter is added at the receiver input. The hard limited filter has a different amplification factor for different signal strength. As a result, the amplification factor for the CCI, which is normally a weaker signal, is smaller than the actual signal. This means that the signal is amplified more than the interference and as a result the CCI is suppressed and the BER rate improves. The results of both simulations and measurements are obtained for different CCI center frequencies, before and after the improvements.
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Khalab, Jamal M. "Multirate adaptive array techniques for cancellation of co-channel interference in direct sequence spread spectrum systems." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294700.
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Erdogan, Veysel. "A simulation of MPSK communications system performance in the presence of wideband noise and co-channel interference." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA358438.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 1998."December 1998." Thesis advisor(s): Jovan Lebaric, Clark Robertson. Includes bibliographical references (p. 103). Also available online.
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Tsiridis, Konstantinos. "Time domain simulation MFSK communications system performance in the presence of wideband noise and co-channel interference." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA358436.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 1998."December 1998." Thesis advisor(s): Jovan Lebaric, Clark Robertson, David C. Jenn. Includes bibliographical references (p. 127). Also available online.
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Grant, Andrew G. "Performance of orthogonal frequency division multiplexing in a high noise, low signal-to-noise ratio environment with co-channel interference." Thesis, Monterey, California. Naval Postgraduate School, 2005. http://hdl.handle.net/10945/1782.
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Orthogonal Frequency Division Multiplexing (OFDM) is fast becoming the signal modulation technique of choice for many commercial and military wireless applications. Its resilience to cochannel interference and bandwidth efficiency make it ideal for many different applications. With its increasing popularity among disparate facets of society, it becomes likelier that enemy militaries and/or nonmilitary combatants will utilize the technique or a system that uses the technique. In light of this development, the need to develop techniques and algorithms to enable detection becomes apparent. This thesis will attempt to develop a model for OFDM and measure its performance in a multipath, outdoor environment with low signal-to-noise ratio, high noise and cochannel interference. Because of the unpredictability of the outdoor environment and the proliferation of various OFDM standards, the simulation will utilize only one algorithm for modeling outdoor environments and the IEEE 802.11a standard.
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Sajid, Attique. "Detection of a low power communication signal in the presence of a strong co-channel TV broadcast interference using Kalman filter." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/44663.
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Approved for public release; distribution is unlimitedThis research focuses on the detection of a low power communication signal in the presence of a strong co-channel television broadcast interference signal. The presence of strong co-channel interference makes the recovery of the desired weak power signal impossible using conventional filtering techniques that are based on time and frequency characteristics of the signals. The second-generation digital video broadcasting terrestrial (DVB-T2) standard is employed as co-channel interference in an additive white Gaussian noise channel. The weak signal is assumed to have a considerably smaller bandwidth than the TV interference and negligible phase-shift due to multipath. By using two antennas at the receiver, channel diversity can be exploited, and the weak signal can be recovered using Kalman filter (KF), assuming the channels seen by the two antennas are independent and time-invariant. Moreover, the transmitted co-channel interference is modeled as the state of a dynamic system whose input is the signal received at one antenna and the output is the signal received at the second antenna. Within this framework, the state can be estimated by a KF. Channel estimation is performed using DVB-T2 pilots. Performance of the system is evaluated at different signal-to-noise ratio (SNR) and signal-to-interference ratio (SIR). Results show that the weak signal can be reconstructed with bit error ratio (BER) of 10-3 or less under most SNR and SIR conditions considered in the study.
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Nguyen, Anh-Minh Ngoc. "High-Quality Detection in Heavy-Traffic Avionic Communication System Using Interference Cancellation Techniques." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29069.
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This dissertation focuses on quantifying the effects of multi-user co-channel interference for an avionic communication system operating in a heavy-traffic aeronautical mobile environment and proposes advanced interference cancellation techniques to mitigate the interference.
The dissertation consists of two parts. The first part of the work investigates the use of a visualization method to quantify and characterize the multi-user co-channel interference (multiple access interference) effects impinging on an avionic communication system. The interference is caused by complex interactions of thousands of RF signals transmitted from thousands of aircraft; each attempts to access a common communication channel, which is governed by a specific channel contention access protocol. The visualization method transforms the co-channel interference, which is specified in terms of signal-overlaps (signal collisions), from a visual representation to a matrix representation for further statistical analysis. It is found that the statistical Poisson and its cumulative distribution provide the best estimates of multi-user co-channel interference. It is shown, using Monte Carlo simulation, that the co-channel interference of a victim aircraft operating in the heavy-traffic environment could result in as high as eight signal-overlaps. This constitutes to approximately 83.4% of success rate in signal detection for the entire three thousand aircraft environment using conventional FSK receiver. One key finding shows that high-quality communications, up to 98.5% success rate, is achievable if only three overlapping signals can be decoded successfully. The interference results found in the first part set the stage for interference cancellation research in the second part.
The second part of the work proposes the use of advanced interference cancellation techniques, namely sequential interference cancellation (SIC) and parallel interference cancellation (PIC), as potential solutions to mitigating the interference effects. These techniques can be implemented in radio receivers to perform multi-signal decoding functionality to remove the required interferers (three overlapping signals) so that high-quality communication, as described in the first part, can be achieved. Various performance graphs are shown for B-FSK and B-PSK for both SIC and PIC techniques. One key finding is that the system performance can be improved substantially to an additional 15% in signal reception success rate by using SIC or PIC. This means that critical information transmitted from 450 aircraft (out of approximately three thousand aircraft in the environment) is preserved and successfully decoded. Multi-signal decoding using these interference cancellation receivers comes at a small penalty of 2 - 4.5 dBs in Eb/No when sufficient signal-to-interference (SIR) ratio (7-12 dB) is provided.Ph. D.
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Jung, Haejoon. "Experimentation and physical layer modeling for opportunistic large array-based networks." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51798.
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The objective of this dissertation is to better understand the impact of the range extension and interference effects of opportunistic large arrays (OLAs), in the context of cooperative routing in multi-hop ad hoc networks. OLAs are a type of concurrent cooperative transmission (CCT), in which the number and location of nodes that will participate in a particular CCT cannot be known a priori. The motivation of this research is that the previous CCT research simplifies or neglects significant issues that impact the CCT-based network performance. Therefore, to develop and design more efficient and realistic OLA-based protocols, we clarify and examine through experimentation and analysis the simplified or neglected characteristics of CCT, which should be considered in the network-level system design. The main contributions of this research are (i) intra-flow interference analysis and throughput optimization in both disk- and strip-shaped networks, for multi-packet OLA transmission, (ii) CCT link modeling focusing on path-loss disparity and link asymmetry, (iii) demonstration of CCT range-extension and OLA-based routing using a software-defined radio (SDR) test-bed, (iv) a new OLA-based routing protocol with practical error control algorithm. In the throughput optimization in presence of the intra-channel interference, we analyze the feasibility condition of spatially pipelined OLA transmissions using the same channel and present numerical results with various system parameters. In the CCT link model, we provide the impact of path-loss disparity that are inherent in a virtual multiple-input-single-output (VMISO) link and propose an approximate model to calculate outage rates in high signal-to-noise-ratio (SNR) regime. Moreover, we present why link asymmetry is relatively more severe in CCT compared to single-input-single-output (SISO) links. The experimental studies show actual measurement values of the CCT range extension and realistic performance evaluation of OLA-based routing. Lastly, OLA with primary route set-up (OLA-PRISE) is proposed with a practical route recovery technique.
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RamaSarma, Vaidyanathan. "A Coverage Area Estimation Model for Interference-Limited Non-Line-of-Sight Point-to-Multipoint Fixed Broadband Wireless Communication Systems." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35276.
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First-generation, line-of-sight (LOS) fixed broadband wireless access techniques have been around for several years. However, services based on this technology have been limited in scope to service areas where transceivers can communicate with their base stations, unimpeded by trees, buildings and other obstructions. This limitation has serious consequences in that the system can deliver only 50% to 70% coverage within a given cell radius, thus affecting earned revenue. Next generation broadband fixed wireless access techniques are aimed at achieving a coverage area greater than 90%. To achieve this target, these techniques must be based on a point-to-multipoint (PMP) cellular architecture with low base station antennas, thus possessing the ability to operate in true non-line-of-sight (NLOS) conditions. A possible limiting factor for these systems is link degradation due to interference.
This thesis presents a new model to estimate the levels of co-channel interference for such systems operating within the 3.5 GHz multichannel multipoint distribution service (MMDS) band. The model is site-specific in that it uses statistical building/roof height distribution parameters obtained from practically modeling several metropolitan cities in the U.S. using geographic information system (GIS) tools. This helps to obtain a realistic estimate and helps analyze the tradeoff between cell radius and modulation complexity. Together, these allow the system designer to decide on an optimal location for placement of customer premises equipment (CPE) within a given cell area.Master of Science
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Argyriou, Andreas. "Probability of symbol error for coherent and non-coherent detection of M-ary frequency-shift keyed (MFSK) signals affected by co-channel interference and additive white Gaussian noise (AWGN) in a fading channel." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA376826.
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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, March 2000.Thesis advisor(s): Lebaric, Jovan; Robertson, Clark. Includes bibliographical references (p. 289). Also available online.
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TACCA, BERNARDO. "Implementation of iterative multiuser joint detection techniques in a dvb-rcs satellite scenario." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/902.
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Con la crescita vertiginosa delle telecomunicazioni, è divenuto sempre più importante un uso efficiente dello spettro a disposizione: l’ottimizzazione del piano di riutilizzo delle frequenze è quindi fondamentale per le attuali reti satellitari, in quanto la banda è ormai una risorsa estremamente preziosa. Lo scopo del presente lavoro di Dottorato è quello di sviluppare una nuova metodologia per migliorare l’utilizzo della banda disponibile nel Return Link (RL) di un satellite multibeam. Il metodo proposto permette l’uso della stessa frequenza per beam adiacenti (mentre solitamente beam adiacenti utilizzano bande differenti per non interferire tra loro alle antenne del satellite) e mitiga l’Interferenza Co-Canale (CCI) risultante adottando un appropriato algoritmo Multiuser Joint Detection (MUD) alla gateway, ovvero, per sopprimere l’interferenza CCI, tutti i canali sono demodulati assieme. Lo scenario di riferimento è quello di un sistema satellitare in cui la gateway supporta una comunicazione bidirezionale verso terminali utente equipaggiati con antenne di apertura relativamente piccola e che trasmettono a bassa potenza. Il RL implementa uno standard DVB-RCS ottimizzato, operante con utenti TDMA a basso bit-rate (fino a qualche Mbit/s), essendo questo lo schema maggiormente in uso per lo scenario in esame. La tecnica MUD selezionata si basa sull’adattamento di strategie iterative (o turbo) di cancellazione d’interferenza già presenti in letteratura, ma analizzate principalmente per sistemi CDMA. Sono state effettuate simulazioni complete del demodulatore in scenari generali, rappresentativi di casi reali, le quali hanno dimostrato una ragionevole complessità dell’algoritmo di mitigazione proposto ed un’efficace riduzione dell’interferenza CCI. Linee guida dettagliate sono riportate alla fine della tesi.With the explosive growth of telecommunications, the efficient use of available spectrum is becoming increasingly important: tightened frequency reuse planning is a pressing need in satellite networks, as the frequency spectrum has become an extremely precious resource. The purpose of this work is to develop a novel methodology for improving the bandwidth utilization on the Reverse Link (RL) of a multibeam satellite. The proposed method permits the frequency reuse for adjacent beams (usually adjacent beams employ different modulation bands so as not to interfere at the satellite antennas) and mitigates the resulting Co-Channel Interference (CCI) using a suitable Multiuser Joint Detection (MUD) algorithm at the gateway side, that is all the channels are demodulated together in order to suppress the CCI interference. The reference scenario will be a satellite system where the gateway station supports a two-way communication with several interactive user terminals equipped with a relatively small aperture antenna and transmitting low power. The RL implements an enhanced DVB-RCS standard operating with low-rate TDMA users (data rates up to few Mbit/s), as this scheme is currently the most popular for the considered scenario. The selected MUD technique is based on the adaption of iterative (turbo) interference cancellation strategies presented in literature for CDMA systems. Complete demodulator simulations were performed in general scenarios representative of real cases. The simulations have demonstrated the proposed interference mitigation algorithm reasonable complexity and an effective CCI reduction. Detailed guidelines have been finally reported in the thesis.
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Deric, Sanjin. "Increased Capacity for VDL Mode 2 Aeronautical Data Communication." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1376063529.
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Kumar, Sumit. "Architecture for simultaneous multi-standard software defined radio receiver." Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS160.
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Motivés par les capacités du SDR, nous théorisons dans ce travail un récepteur de définition radio multi-standard simultané (SMS-SDR). Un récepteur SMS-SDR sera capable de décoder "simultanément" les informations de plusieurs standards sans fil hétérogènes utilisant le même frontal RF. Nos réseaux cibles sont des réseaux à accès aléatoire fonctionnant dans des bandes sans licence. Ces normes fonctionnent sans coordination centralisée et sont soumises à de graves brouillage entre canaux du même type de technologie (CT-CCI) car leurs bandes de fréquences de fonctionnement se chevauchent. Nous développons plusieurs nouveaux algorithmes de traitement du signal en bande de base afin d'éliminer l'ICC des récepteurs à une et plusieurs antennes. Nous avons choisi le cas de l'utilisation de signaux à bande étroite et à large bande, en accordant une attention particulière aux systèmes basés sur OFDM, l'OFDM étant une technique de couche physique essentielle des normes sans fil modernes telles que les familles IEEE 802.11 et 4G. Au cours du développement, nous nous concentrons sur les méthodes pouvant fonctionner de manière autonome dans le récepteur, c'est-à-dire sans aucune coopération de la part de l'émetteur ou de la station de base. De cette manière, ce sont des réseaux à accès aléatoire appropriés fonctionnant dans des bandes sans licence. De plus, les algorithmes peuvent être intégrés à l'infrastructure existante sans aucun effort significatif. Enfin, nos méthodes d'atténuation des interférences sont utilisées pour développer des arbres de décision qui recommandent la séquence d'étapes permettant d'atténuer les interférences entre deux signaux hétérogènes. Enfin, nous avons validé nos algorithmes en les implémentant à l'aide de SDRMotivated by the capabilities of the SDR, we theorize in this work a simultaneous multi-standard radio definition receiver (SMS-SDR). An SMS-SDR receiver will be able to "simultaneously" decode the information of several heterogeneous wireless standards using the same RF front end. Our target networks are random access networks operating in unlicensed bands. These standards operate without centralized coordination and are subject to serious interference between channels of the same type of technology (CT-CCI) because their operating frequency bands overlap. We are developing several new baseband signal processing algorithms to eliminate ICC from single and multi-antenna receivers. We chose the case of the use of narrow-band and broadband signals, paying particular attention to OFDM-based systems, OFDM being an essential physical layer technique of modern wireless standards such as IEEE families 802.11 and 4G. During development, we focus on methods that can operate autonomously in the receiver, that is, without any cooperation from the transmitter or base station. In this way, they are appropriate random access networks operating in unlicensed bands. In addition, the algorithms can be integrated into the existing infrastructure without any significant effort. Finally, our interference mitigation methods are used to develop decision trees that recommend the sequence of steps to mitigate interference between two heterogeneous signals. Finally, we validated our algorithms by implementing them using SDR
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Silva, Carlos Filipe Moreira e. "Contemporary electromagnetic spectrum reuse techniques: tv white spaces and D2D communications." reponame:Repositório Institucional da UFC, 2015. http://www.repositorio.ufc.br/handle/riufc/15899.
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SILVA, C. F. M. Contemporary electromagnetic spectrum reuse techniques: tv white spaces and D2D communications. 128 f. 2015. Tese (Doutorado em Engenharia de Teleinformática) – Centro de Tecnologia, Universidade Federal do Ceará, Fortaleza, 2015.Submitted by Marlene Sousa (mmarlene@ufc.br) on 2016-03-29T12:13:57Z No. of bitstreams: 1 2015_tese_cfmsilva.pdf: 8667655 bytes, checksum: a7e392b18bd01de3be64a22b8ff9906b (MD5)
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Over the last years, the wireless broadband access has achieved a tremendous success. With that, the telecommunications industry has faced very important changes in terms of technology, heterogeneity, kind of applications, and massive usage (virtual data tsunami) derived from the introduction of smartphones and tablets; or even in terms of market structure and its main players/actors. Nonetheless, it is well-known that the electromagnetic spectrum is a scarce resource, being already fully occupied (or at least reserved for certain applications). Tra- ditional spectrum markets (where big monopolies dominate) and static spectrum management originated a paradoxal situation: the spectrum is occupied without actually being used! In one hand, with the global transition from analog to digital Television (TV), part of the spectrum previously licensed for TV is freed and geographically interleaved, originating the consequent Television White Spaces (TVWS); on the other hand, the direct communications between devices, commonly referred as Device-to-Device (D2D) communications, are attracting crescent attention by the scientific community and industry in order to overcome the scarcity problem and satisfy the increasing demand for extra capacity. As such, this thesis is divided in two main parts: (a) Spectrum market for TVWS: where a SWOT analysis for the use of TVWS is performed giving some highlights in the directions/actions that shall be followed so that its adoption becomes effective; and a tecno-economic evaluation study is done considering as a use-case a typical European city, showing the potential money savings that operators may reach if they adopt by the use of TVWS in a flexible market manner; (b) D2D communications: where a neighbor discovery technique for D2D communications is proposed in the single-cell scenario and further extended for the multi-cell case; and an interference mitigation algorithm based on the intelligent selection of Downlink (DL) or Uplink (UL) band for D2D communications underlaying cellular networks. A summary of the principal conclusions is as follows: (a) The TVWS defenders shall focus on the promotion of a real-time secondary spectrum market, where through the correct implementation of policies for protection ratios in the spectrum broker and geo-location database, incumbents are protected against interference; (b) It became evident that an operator would recover its investment around one year earlier if it chooses to deploy the network following a flexible spectrum market approach with an additional TVWS carrier, instead of the traditional market; (c) With the proposed neighbor discovery technique the time to detect all neighbors per Mobile Station (MS) is significantly reduced, letting more time for the actual data transmission; and the power of MS consumed during the discovery process is also reduced because the main processing is done at the Base Station (BS), while the MS needs to ensure that D2D communication is possible just before the session establishment; (d) Despite being a simple concept, band selection improves the gains of cellular communications and limits the gains of D2D communications, regardless the position within the cell where D2D communications happen, providing a trade-off between system performance and interference mitigation.
Nos últimos anos, o acesso de banda larga atingiu um grande sucesso. Com isso, a indústria das telecomunicações passou por importantes transformações em termos de tecnologia, heterogeneidade, tipo de aplicações e uso massivo (tsunami virtual de dados) em consequência da introdução dos smartphones e tablets; ou até mesmo na estrutura de mercado e os seus principais jogadores/atores. Porém, é sabido que o espectro electromagnético é um recurso limitado, estando já ocupado (ou pelo menos reservado para alguma aplicação). O mercado tradicional de espectro (onde os grandes monopólios dominam) e o seu gerenciamento estático contribuíram para essa situação paradoxal: o espectro está ocupado mas não está sendo usado! Por um lado, com a transição mundial da Televisão (TV) analógica para a digital, parte do espectro anteriormente licenciado para a TV é libertado e geograficamente multiplexado para evitar a interferência entre sinais de torres vizinhas, dando origem a «espaços em branco» na frequência da TV ou Television White Spaces (TVWS); por outro lado, as comunicações diretas entre usuários, designadas por comunicações diretas Dispositivo-a-Dispositivo (D2D), está gerando um crescente interesse da comunidade científica e indústria, com vista a ultrapassar o problema da escassez de espectro e satisfazer a crescente demanda por capacidade extra. Assim, a tese está dividida em duas partes principais: (a) Mercado de espectro eletromagnético para TVWS: onde é feita uma análise SWOT para o uso dos TVWS, dando direções/ações a serem seguidas para que o seu uso se torne efetivo; e um estudo tecno-econômico considerando como cenário uma típica cidade Europeia, onde se mostram as possíveis poupanças monetárias que os operadores conseguem obter ao optarem pelo uso dos TVWS num mercado flexível; (b) Comunicações D2D: onde uma técnica de descoberta de vizinhos para comunicações D2D é proposta, primeiro para uma única célula e mais tarde estendida para o cenário multi-celular; e um algoritmo de mitigação de interferência baseado na seleção inteligente da banda Ascendente (DL) ou Descendente (UL) a ser reusada pelas comunicações D2D que acontecem na rede celular. Um sumário das principais conclusões é o seguinte: (a) Os defensores dos TVWS devem-se focar na promoção do mercado secundário de espectro electromagnético, onde através da correta implementação de politicas de proteção contra a interferência no broker de espectro e na base de dados, os usuários primário são protegidos contra a interferência; (b) Um operador consegue recuperar o seu investimento aproximadamente um ano antes se ele optar pelo desenvolvimento da rede seguindo um mercado secundário de espectro com a banda adicional de TVWS, em vez do mercado tradicional; (c) Com a técnica proposta de descoberta de vizinhos, o tempo de descoberta por usuário é significativamente reduzido; e a potência consumida nesse processo é também ela reduzida porque o maior processamento é feito na Estação Rádio Base (BS), enquanto que o usuário só precisa de se certificar que a comunicação direta é possível; (d) A seleção de banda, embora seja um conceito simples, melhora os ganhos das comunicações celulares e limita os das comunicações D2D, providenciando um compromisso entre a performance do sistema e a mitigação de interferência.
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Gleissner, Filip. "Koexistence mobilních komunikačních systémů GSM-EDGE a UMTS." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-233470.
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The dissertation thesis deals with the investigation of the coexistence of GSM–EDGE and UMTS systems with focus on the physical layer of the systems. The aim is to provide a set of recommendations for practical cooperation while the systems operate in both the separated and the common radio bands. A detailed description of signal processing of both the systems on the physical layer is presented. On the basis of this description, models of both systems were created and implemented in the MATLAB environment. The simulations are focused on the physical layer quality parameters, especially the bit error ratio evaluation for various ratios of useful signal power to noise power during the transmission over the radio channel. Simulation is also used to examine the quality of received useful signal while it is interfered by signals from the same and adjacent channels. The purpose is to determine the isolation between these adjacent channels, when the bit error ratio of the useful signal does not exceed a certain reference value. The simulation results are subsequently subjected to comparison with the results of the experimental measurements in laboratory conditions. Before the measurements are carried out, a study of possible interference types is performed. Consequently, the crucial parameters of the measuring equipment used are verified. From the results of simulations and measurements, the proposal of a minimum and recommended carrier separation between both the systems is presented in order to efficiently utilize the assigned frequency spectrum. Furthermore, for the cooperation in both the separated and the common radio bands, the necessary precautions are given for reaching the required isolation and thereby inter-system interference minimization.
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Abadi, Tarla. "Design and performance analysis of cooperative relay systems." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/design-and-performance-analysis-of-cooperative-relay-systems(8edce5bc-1518-4df2-aa49-36bf5386036a).html.
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Cooperative relay systems have emerged as promising techniques to boost the performance of wireless systems. Recent studies have confirmed that interferences, co-channel interferences (CCIs) and self-interferences, have a huge impact on cooperative relay systems and can cause significant performance degradation. Two problems were observed in this research. Firstly, previous studies on performance analysis of Amplify-and-Forward (AF) relay systems in presence of CCIs have only focused on a specific interference channel model. However, in practical design scenarios, such an assumption is not a realistic proposition. Secondly, analyses of overheads introduced by a time-based relay selection protocol in distributed cooperative systems have been based on an over-pessimistic assumption where all packets involved in a collision are destroyed. Nevertheless, collisions due to the protocol overheads cause the system performance to be degraded but this does not mean that the failure of end-to-end transmission certainly occurs. The thesis aims to analyse the performance of practical cooperative relay systems in the presence of CCIs and self-interferences, by developing exact mathematical methods. A new unified mathematical method for AF relay systems in presence of a random number of arbitrary non-identical CCIs was developed. The obtained new approach derived in terms of a moment generating function of the aggregate interferences' power led to the derivation of new explicit expressions. The new results greatly simplify evaluation of average error rates over diverse practical interference scenarios. Moreover, a new exact mathematical analysis for distributed cooperative relay systems employing a time-based relay selection protocol based on an accurate interference model was presented. This approach led to the derivation of new exact expressions for the spectral efficiency which accounts for both self-interferences and the protocol overheads as well as for different fading scenarios and arbitrary relay locations. This approach provided several advantages over direct approaches, one of which is that it significantly simplified averaging-out the joint random variables involved.
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Han-ChunHsieh and 謝函君. "Analysis for IEEE 802.16e Uplink Co-channel Interference." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/41744874627718221539.
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Lin, Chun-Wei, and 林峻瑋. "STUDY ON CO-CHANNEL INTERFERENCE FOR WiMAX SYSTEM." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/07759569857332639599.
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碩士大同大學
通訊工程研究所
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The operator use's Cellular Network decrease Transmit power to increase the density of Base station and system capacity, but frequency reuse may cause the problem of co-channel interference more serious. The thesis focuses on investigating the distribution of base station in the area with serious interference to find the position of weak signal. By increasing the bandwidth to improve the problem of co-channel interference, and we can prove that it can decrease the problem of co-channel interference and increase the quality of signal via the actual measurement and the analytical data. In reality, it is difficult to increase the usable bandwidth so we use Multiple-Input/Multiple-Output(MIMO) to improve the influence of the co-channel interference. In the WiMAX campus experiment network, established in cooperation of Tatung University and Alcatel-Lucent(ALU) in 2009, we use the VoIP and FTP to estimate the influence of the co-channel interference. By the experiment, we know the MIMO Technology and the real performance. The result can be used by the manufacturers and students for network application and hardware development or the ISP vendor who using the ALU equipment for network maintenance.
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Yong-huang, Chang. "Equalization and Co-channel Interference Suppression without Spatial Diversity." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2607200615294900.
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