Download or read book Modeling and Mitigation of Interference in Wireless Receivers with Multiple Antennae written by Aditya Chopra and published by . This book was released on 2011 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent wireless communication research faces the challenge of meeting a predicted 1000x increase in demand for wireless Internet data over the next decade. Among the key reasons for such explosive increase in demand include the evolution of Internet as a provider of high-definition video entertainment and two-way video communication, accessed via mobile wireless devices. One way to meet some of this demand is by using multiple antennae at the transmitter and receiver in a wireless device. For example, a system with 4 transmit and 4 receive antennae can provide up to a 4x increase in data throughput. Another key aspect of the overall solution would require sharing radio frequency spectral resources among users, causing severe amounts of interference to wireless systems. Consequently, wireless receivers with multiple antennae would be deployed in network environments that are rife with interference primarily due to wireless resource sharing among users. Other significant sources of interference include computational platform subsystems, signal leakage, and external electronics. Interference causes severe degradation in communication performance of wireless receivers. Having accurate statistical models of interference is a key requirement to designing, and analyzing the communication performance of, multi-antenna wireless receivers in the presence of interference. Prior work on statistical modeling of interference in multi-antenna receivers utilizes either the Gaussian distribution, or non-Gaussian distributions exhibiting either statistical independence or spherical isotropy. This dissertation proposes a framework, based on underlying statistical-physical mechanism of interference generation and propagation, for modeling multi-antenna interference in various network topologies. This framework can model interference which is spherically isotropic, or statistically independent, or somewhere on a continuum between these two extremes. The dissertation then utilizes the derived statistical models to analyze communication performance of multi-antenna receivers in interference-limited wireless networks. Accurate communication performance analysis can highlight the tradeoffs between communication performance and computational complexity of various multi-antenna receiver designs. Finally, using interference statistics, this dissertation proposes receiver algorithms that best mitigate the impact of interference on communication performance. The proposed algorithms include multi-antenna combining strategies, as well as, antenna selection algorithms for cooperative communications.

Download or read book Radio Frequency Interference Modeling and Mitigation in Wireless Receivers written by Kapil Gulati and published by . This book was released on 2011 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: In wireless communication systems, receivers have generally been designed under the assumption that the additive noise in system is Gaussian. Wireless receivers, however, are affected by radio frequency interference (RFI) generated from various sources such as other wireless users, switching electronics, and computational platforms. RFI is well modeled using non-Gaussian impulsive statistics and can severely degrade the communication performance of wireless receivers designed under the assumption of additive Gaussian noise. Methods to avoid, cancel, or reduce RFI have been an active area of research over the past three decades. In practice, RFI cannot be completely avoided or canceled at the receiver. This dissertation derives the statistics of the residual RFI and utilizes them to analyze and improve the communication performance of wireless receivers. The primary contributions of this dissertation are to (i) derive instantaneous statistics of co-channel interference in a field of Poisson and Poisson-Poisson clustered interferers, (ii) characterize throughput, delay, and reliability of decentralized wireless networks with temporal correlation, and (iii) design pre-filters to mitigate RFI in wireless receivers.

Download or read book Protocols for Multi antenna Ad hoc Wireless Networking in Interference Environments written by Danielle Ayodele Hinton and published by . This book was released on 2010 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental question for the design of future wireless networks concerns the nature of spectrum management and the protocols that govern use of the spectrum. In the oligopoly model, spectrum is owned and centrally managed, and the protocols tend to reflect this centralized nature. In the common's model, spectrum is a public good, and protocols must support ad hoc communication. This work presents the design, tradeoffs and parameter optimization for a new protocol (Simultaneous Transmissions in Interference (STI-MAC)) for ad hoc wireless networks. The key idea behind the STI-MAC protocol is 'channel stuffing, ' that is, allowing network nodes to more efficiently use spatial, time and frequency degrees of freedom. This is achieved in three key ways. First, 'channel stuffing' is achieved through multiple antennas that are used at the receiver to mitigate interference using Minimum-Mean-Squared-Error (MMSE) receivers, allowing network nodes to transmit simultaneously in interference limited environments. The protocol also supports the use of multiple transmit antennas to beamform to the target receiver. Secondly, 'channel stuffing' is achieved through the use of a control channel that is orthogonal in time to the data channel, where nodes contend in order to participate on the data channel. And thirdly, 'channel stuffing' is achieved through a protest scheme that prevents data channel overloading. The STI-MAC protocol is analyzed via Monte-Carlo simulations in which transmitter nodes are uniformly distributed in a plane, each at a fixed distance from their target receiver; and as a function of network parameters including the number of transmit and receive antennas, the distance between a transmitter-receiver pair (link-length), the average number of transmitters whose received signal is stronger at a given receiver than its target transmitter (link-rank), number of transmitter-receiver pairs, the distribution on the requested rate, the offered load, and the transmit scheme. The STI-MAC protocol is benchmarked relative to simulations of the 802.11(n) (Wi-Fi) protocol. The key results of this work show a 3X gain in throughput relative to 802.11(n) in typical multi-antenna wireless networks that have 20 transmitter-receiver pairs, a link-length of 10 meters, four receive antennas and a single transmit antenna. We also show a reduction in delay by a factor of two when the networks are heavily loaded. We find that the link-rank is a key parameter affecting STIMAC gains over Wi-Fi. In simulations of networks with 40 transmit-receiver pairs, link-rank of three, a link-length of 10 meters, and eight transmit and receive antennas in which the transmitter beamforms to its target receiver in its strongest target channel mode, we find gains in throughput of at least 5X over the 802.11(n) protocol.

Download or read book Cooperative Interference Mitigation in Wireless Cellular Networks written by Seyed Arvin Ayoughi and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, we explore potentials of cooperative communication at receivers' side in the downlink of wireless cellular networks for interference mitigation and signal enhancement. We investigate two regimes of latency and reliability of communication: one for providing high long-term average user rates for supporting a quality of service that is suitable for human visual and auditory perception, and the other for providing an ultrareliable low-latency machine-type wireless communication for streaming information in control applications. We consider three different models of cooperative communication. First, we study deploying a multi-antenna relay node that provides a nearby cell-edge user with extra dimensions over an out-of-band relaying link. We model this scenario by a Gaussian multiple-input multiple-output (MIMO) relay channel with correlated noise across relay and destination antennas, and analyze the capacity of this channel. This type of relay deployment is most effective when the number of receive antennas is small and the number of relay antennas is large enough. Second, we study deploying a multi-antenna half-duplex amplify-and-forward relay node that simultaneously provides multiple cell-edge users with extra dimensions. We show that the optimized relaying significantly improves the long-term average rates of cell-edge users, even after accounting for the extra bandwidth required for half-duplex relaying, provided that the relay is equipped with sufficiently many antennas. Third, we study cooperation among receivers for combating fading and mitigating interference for ultrareliable low-latency wireless communication. We consider multiple interfering broadcasts from controllers to their corresponding actuators. The recently-proposed Occupy CoW protocol efficiently exploits the spatial diversity of distributed receivers for combating deep fading. It consists of two consecutive phases: the broadcast phase and the cooperation phase. However, it avoids interference by orthogonalization; hence, its required bandwidth for achieving ultrareliability is not scalable in network size. We observe that full frequency reuse in the broadcast phase with successive interference cancellation notably improves the scalability of this protocol. We propose two schemes depending on whether interference cancellation or interference avoidance is implemented in the cooperation phase, and show that both outperform Occupy CoW, each in its own preference region.

Download or read book Interference Mitigation in Multi Hop Wireless Networks with Advanced Physical Layer Techniques written by Yantian Hou and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In my dissertation, we focus on the wireless network coexistence problem with advanced physical-layer techniques. For the first part, we study the problem of Wireless Body Area Networks (WBAN)s coexisting with cross-technology interference (CTI). WBANs face the RF cross-technology interference (CTI) from non-protocol-compliant wireless devices. Werst experimentally characterize the adverse effect on BAN caused by the CTI sources. Then we formulate a joint routing and power control (JRPC) problem, which aims at minimizing energy consumption while satisfying node reachability and delay constraints. We reformulate our problem into a mixed integer linear programing problem (MILP) and then derive the optimal results. A practical JRPC protocol is then proposed. For the second part, we study the coexistence of heterogeneous multi-hop networks with wireless MIMO. We propose a new paradigm, called cooperative interference mitigation (CIM), which makes it possible for disparate networks to cooperatively mitigate the interference to/from each other to enhance everyone's performance. We establish two tractable models to characterize the CIM behaviors of both networks by using full IC (FIC) and receiver-side IC (RIC) only. We propose two bi-criteria optimization problems aiming at maximizing both networks' throughput, while cooperatively canceling the interference between them based on our two models. In the third and fourth parts, we study the coexistence problem with MIMO from a different point of view: the incentive of cooperation. We propose a novel two-round game framework, based on which we derive two networks' equilibrium strategies and the corresponding closed-form utilities. We then extend our game-theoretical analysis to a general multi-hop case, specifically the coexistence problem between primary network and multi-hop secondary network in the cognitive radio networks domain. In the final part, we study the benefits brought by reconfigurable antennas (RA). We systematically exploit the pattern diversity and fast reconfigurability of RAs to enhance the throughput of MWNs. Werst propose a novel link-layer model that captures the dynamic relations between antenna pattern, link coverage and interference. Based on our model, a throughput optimization framework is proposed by jointly considering pattern selection and link scheduling, which is formulated as a mixed integer non-linear programming problem.

Download or read book Wireless Network Performance Enhancement via Directional Antennas Models Protocols and Systems written by John D. Matyjas and published by CRC Press. This book was released on 2015-11-18 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Directional antenna technologies have made significant advancements in the last decade. These advances have opened the door to many exciting new design opportunities for wireless networks to enhance quality of service (QoS), performance, and network capacity. In this book, experts from around the world present the latest research and development in

Download or read book Transmit Fading and Interference Mitigation for Multi antenna Wireless Communications written by Oghenekome Oteri and published by . This book was released on 2005 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Antennas in Wireless Communications written by Lal Chand Godara and published by CRC Press. This book was released on 2018-10-03 with total page 936 pages. Available in PDF, EPUB and Kindle. Book excerpt: The move toward worldwide wireless communications continues at a remarkable pace, and the antenna element of the technology is crucial to its success. With contributions from more than 30 international experts, the Handbook of Antennas in Wireless Communications brings together all of the latest research and results to provide engineering professionals and students with a one-stop reference on the theory, technologies, and applications for indoor, hand-held, mobile, and satellite systems. Beginning with an introduction to wireless communications systems, it offers an in-depth treatment of propagation prediction and fading channels. It then explores antenna technology with discussion of antenna design methods and the various antennas in current use or development for base stations, hand held devices, satellite communications, and shaping beams. The discussions then move to smart antennas and phased array technology, including details on array theory and beamforming techniques. Space diversity, direction-of-arrival estimation, source tracking, and blind source separation methods are addressed, as are the implementation of smart antennas and the results of field trials of systems using smart antennas implemented. Finally, the hot media topic of the safety of mobile phones receives due attention, including details of how the human body interacts with the electromagnetic fields of these devices. Its logical development and extensive range of diagrams, figures, and photographs make this handbook easy to follow and provide a clear understanding of design techniques and the performance of finished products. Its unique, comprehensive coverage written by top experts in their fields promises to make the Handbook of Antennas in Wireless Communications the standard reference for the field.

Download or read book Blind CSI Acquisition for Multi antenna Interference Mitigation in 5G Networks written by Ali Abdulmawgood Ali Ali Esswie and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Future wireless communication networks are required to satisfy the increasing demands of traffic and capacity. The upcoming fifth generation (5G) of the cellular technology is expected to meet 1000 times the capacity that of the current fourth generation (4G). These tight specifications introduce a new set of research challenges. However, interference has always been the bottleneck in cellular communications. Thus, towards the vision of the 5G, massive multi-input multi-output (mMIMO) and interference alignment (IA) are key transmission technologies to fulfil the future requirements, by controlling the residual interference. By equipping the base-station (BS) with a large number of transmit antennas, e.g, tens of hundreds of antennas, a mMIMO system can theoretically achieve significant capacity with limited interference, where many user equipment (UEs) can be served simultaneously at the same time and frequency resources. A mMIMO offers great spatial degrees of freedom (DoFs), which boost the total network capacity without increasing transmission power or bandwidth. However, the majority of the recent mMIMO investigations are based on theoretical channels with independent and identically distributed (i.i.d) Gaussian distribution, which facilitates the computation of closed-form rate expressions. Nonetheless, practical channels are not spatially uncorrelated, where the BS receives different power ratios across different spatial directions between the same transmitting and receiving antennas. Thus, it is important to understand the behavior of such new technology with practical channel modeling. Alternatively, IA is known to break the bottleneck between the capacity of the network and the overall spectral efficiency (SE), where a performance degradation is observed at a certain level of connected user capacity, due to the overwhelming inter-user interference. Theoretically, IA guarantees a linear relationship between half of the overall network SE and the online capacity by aligning interference from all transmitters inside one spatial signal subspace, leaving the other subspace for desired transmission. However, IA has tight feasibility conditions in practice including high precision channel state information at transmitter (CSIT), which leads to severe feedback overhead. In this thesis, high-precision blind CSIT algorithms are developed under different transmission technologies. We first consider the CSIT acquisition problem in MIMO IA systems. Proposed spatial channel estimation for MIMO-IA systems (SCEIA) shows great offered spatial degrees of freedom which contributes to approaching the performance of the perfect-CSIT case, without the requirements of channel quantization or user feedback overhead. In massive MIMO setups, proposed CSIT strategy offered scalable performance with the number of the transmit antennas. The effect of the non-stationary channel characteristics, which appears with very large antenna arrays, is minimized due to the effective scanning precision of the proposed strategy. Finally, we extend the system model to the full dimensional space, where users are distributed across the two dimensions of the cell space (azimuthal/elevation). Proposed directional spatial channel estimation (D-SCE) scans the 3D cell space and effectively attains additional CSIT and beamforming gains. In all cases, a list of comparisons with state-of-the-art schemes from academia and industry is performed to show the performance improvement of the proposed CSIT strategies.

Download or read book Fundamentals of Wireless Communication written by David Tse and published by Cambridge University Press. This book was released on 2005-05-26 with total page 598 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook takes a unified view of the fundamentals of wireless communication and explains cutting-edge concepts in a simple and intuitive way. An abundant supply of exercises make it ideal for graduate courses in electrical and computer engineering and it will also be of great interest to practising engineers.

Download or read book Limited Feedback MIMO for Interference Limited Networks written by Salam Walid Akoum and published by . This book was released on 2012 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Managing interference is the main technical challenge in wireless networks. Multiple input multiple output (MIMO) methods are key components to overcome the interference bottleneck and deliver higher data rates. The most efficient MIMO techniques require channel state information (CSI). In practice, this information is inaccurate due to errors in CSI acquisition, as well as mobility and delay. CSI inaccuracy reduces the performance gains provided by MIMO. When compounded with uncoordinated intercell interference, the degradation in MIMO performance is accentuated. This dissertation investigates the impact of CSI inaccuracy on the performance of increasingly complex interference limited networks, starting with a single interferer scenario, continuing to a heterogeneous network with a femtocell overlay, and finishing with a clustered multicell coordination model for randomly deployed transmitting nodes. First, this dissertation analyzes limited feedback beamforming and precoded spatial multiplexing over temporally correlated channels. Assuming uncoordinated interference from one dominant interferer, using Markov chain convergence theory, the gain in the average successful throughput at the mobile user is shown to decrease exponentially with the feedback delay. The decay rate is amplified when the user is interference limited. Interference cancellation methods at the receiver are shown to mitigate the effect of interference. This work motivates the need for practical MIMO designs to overcome the adverse effects of interference. Second, limited feedback beamforming is analyzed on the downlink of a more realistic heterogeneous cellular network. Future generation cellular networks are expected to be heterogeneous, consisting of a mixture of macro base stations and low power nodes, to support the increasing user traffic capacity and reliability demand. Interference in heterogeneous environments cannot be coordinated using traditional interference mitigation techniques due to the on demand and random deployment of low power nodes such as femtocells. Using tools from stochastic geometry, the outage and average achievable rate of limited feedback MIMO is computed with same-tier and cross-tier interference, and feedback delay. A hybrid fixed and random network deployment model is used to analyze the performance in a fixed cell of interest. The maximum density of transmitting femtocells is derived as a function of the feedback rate and delay. The detrimental effect of same-tier interference is quantified, as the mobile user moves from the cell-center to the cell-edge. The third part of this dissertation considers limited coordination between randomly deployed transmitters. Building on the established degrading effect of uncoordinated interference on practical MIMO methods, and the analytical tractability of random deployment models, interference coordination is analyzed. Using multiple antennas at the transmitter for interference nulling in ad hoc networks is first shown to achieve MIMO gains using single antenna receivers. Clustered coordination is then investigated for cellular systems with randomly deployed base stations. As full coordination in the network is not feasible, a random clustering model is proposed where base stations located in the same cluster coordinate. The average achievable rate can be optimized as a function of the number of antennas to maximize the coordination gains. For multicell limited feedback, adaptive partitioning of feedback bits as a function of the signal and interference strength is proposed to minimize the loss in rate due to finite rate feedback.

Download or read book MIMO Wireless Communications written by Ezio Biglieri and published by Cambridge University Press. This book was released on 2007-01-08 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple-output (MIMO) technology constitutes a breakthrough in the design of wireless communications systems, and is already at the core of several wireless standards. Exploiting multipath scattering, MIMO techniques deliver significant performance enhancements in terms of data transmission rate and interference reduction. This 2007 book is a detailed introduction to the analysis and design of MIMO wireless systems. Beginning with an overview of MIMO technology, the authors then examine the fundamental capacity limits of MIMO systems. Transmitter design, including precoding and space-time coding, is then treated in depth, and the book closes with two chapters devoted to receiver design. Written by a team of leading experts, the book blends theoretical analysis with physical insights, and highlights a range of key design challenges. It can be used as a textbook for advanced courses on wireless communications, and will also appeal to researchers and practitioners working on MIMO wireless systems.

Download or read book Academic Press Library in Signal Processing written by Fulvio Gini and published by Academic Press. This book was released on 2013-09-10 with total page 1389 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second volume, edited and authored by world leading experts, gives a review of the principles, methods and techniques of important and emerging research topics and technologies in communications and radar engineering. With this reference source you will: Quickly grasp a new area of research Understand the underlying principles of a topic and its application Ascertain how a topic relates to other areas and learn of the research issues yet to be resolved Quick tutorial reviews of important and emerging topics of research in array and statistical signal processing Presents core principles and shows their application Reference content on core principles, technologies, algorithms and applications Comprehensive references to journal articles and other literature on which to build further, more specific and detailed knowledge Edited by leading people in the field who, through their reputation, have been able to commission experts to write on a particular topic

Download or read book MIMO Communications Systems Antenna Selection and Interference Mitigation written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple-output (MIMO) techniques have evolved as one of the key enabling technologies to address the ever-increasing demand for high-speed wireless data access. In this dissertation, we explore some important problems in point-to-point and multiuser MIMO systems. Antenna selection provides a new form of diversity in MIMO systems with low cost and relatively small overhead increase. In the first part, we investigate this technique, concerning (1) associated diversity property analysis in MIMO spatial multiplexing systems with practical transmitter/receiver; (2) fast algorithm design, especially in correlated fading channels; (3) practical implementation. The first two problems above are addressed via novel geometric tools, which are also extended to analyze some open problems in MIMO study, in particular the diversity-multiplexing tradeoff in V-BLAST and SDMA systems employing ordered successive interference cancellation (SIC). Finally we focus on the study of interference mitigation in multiuser multicell MIMO downlink, and investigate the potential of cooperative transmission among adjacent base stations (BS) for effectively mitigating co-channel interference. Our study starts with a quasi-synchronous model to obtain performance upper bounds, by which we also explore some other advantages like channel rank/conditioning improvement and macro-diversity protection. When considering a more practical channel model, in which the inter-cell interfering signals from different BS?s in the downlink are by nature asynchronous at each MS, we propose some novel and effective pre-coding algorithms achieving different levels of tradeoffs between interference mitigation and computational complexity. In summary, we have tackled some open and interesting problems in MIMO study, in particular, the diversity analysis for MIMO spatial multiplexing systems with antenna selection and practical coding and decoding schemes, and the impact of ordering on the performance of S.

Download or read book Adaptive Wireless Communications written by Daniel W. Bliss and published by Cambridge University Press. This book was released on 2013-05-09 with total page 619 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adopting a balanced mix of theory, algorithms and practical design issues, this comprehensive volume explores cutting-edge applications in adaptive wireless communications and the implications these techniques have for future wireless network performance. Presenting practical concerns in the context of different strands from information theory, parameter estimation theory, array processing and wireless communication, the authors present a complete picture of the field. Topics covered include advanced multiple-antenna adaptive processing, ad hoc networking, MIMO, MAC protocols, space-time coding, cellular networks and cognitive radio, with the significance and effects of both internal and external interference a recurrent theme throughout. A broad, self-contained technical introduction to all the necessary mathematics, statistics, estimation theory and information theory is included, and topics are accompanied by a range of engaging end-of-chapter problems. With solutions available online, this is the perfect self-study resource for students of advanced wireless systems and wireless industry professionals.

Download or read book Advances in Multiuser Detection written by Michael L. Honig and published by John Wiley & Sons. This book was released on 2009-08-19 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Timely Exploration of Multiuser Detection in Wireless Networks During the past decade, the design and development of current and emerging wireless systems have motivated many important advances in multiuser detection. This book fills an important need by providing a comprehensive overview of crucial recent developments that have occurred in this active research area. Each chapter is contributed by noted experts and is meant to serve as a self-contained treatment of the topic. Coverage includes: Linear and decision feedback methods Iterative multiuser detection and decoding Multiuser detection in the presence of channel impairments Performance analysis with random signatures and channels Joint detection methods for MIMO channels Interference avoidance methods at the transmitter Transmitter precoding methods for the MIMO downlink This book is an ideal entry point for exploring ongoing research in multiuser detection and for learning about the field's existing unsolved problems and issues. It is a valuable resource for researchers, engineers, and graduate students who are involved in the area of digital communications.

Download or read book Interference Cancelling Receivers with Multiple Antennas for CDMA Systems written by Vafa Ghazi-Moghadam and published by . This book was released on 1997 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: