Interference Management With Limited Channel State Information In Wireless Networks

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Interference Management with Limited Channel State Information in Wireless Networks

Author : Namyoon Lee
Publisher :
ISBN 13 :
Total Pages : 582 pages
Book Rating : 4.:/5 (93 download)

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Book Synopsis Interference Management with Limited Channel State Information in Wireless Networks by : Namyoon Lee

Download or read book Interference Management with Limited Channel State Information in Wireless Networks written by Namyoon Lee and published by . This book was released on 2014 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interference creates a fundamental barrier in attempting to improve throughput in wireless networks, especially when multiple concurrent transmissions share the wireless medium. In recent years, significant progress has been made on characterizing the capacity limits of wireless networks under the premise of global and instantaneous channel state information at transmitter (CSIT). In practice, however, the acquisition of such instantaneous and global CSIT as a means toward cooperation is highly challenging due to the distributed nature of transmitters and dynamic wireless propagation environments. In many limited CSIT scenarios, the promising gains from interference management strategies using instantaneous and global CSIT disappear, often providing the same result as cases where there is no CSIT. Is it possible to obtain substantial performance gains with limited CSIT in wireless networks, given previous evidence that there is marginal or no gain over the case with no CSIT? To shed light on the answer to this question, in this dissertation, I present several achievable sum of degrees of freedom (sum-DoF) characterizations of wireless networks. The sum-DoF is a coarse sum-capacity approximation of the networks, deemphasizing noise effects. These characterizations rely on a set of proposed and existing interference management strategies that exploit limited CSIT. I begin with the classical multi-user multiple-input-single-output (MISO) broadcast channel with delayed CSIT and show how CSI feedback delays change sum-capacity scaling law by proposing an innovative interference alignment technique called space-time interference alignment. Next, I consider interference networks with distributed and delayed CSIT and show how to optimally use distributed and moderately-delayed CSIT to yield the same sum-DoF as instantaneous and global CSIT using the idea of distributed space-time interference alignment. I also consider a two-hop layered multiple-input-multiple-output (MIMO) interference channel, where I show that two cascaded interfering links can be decomposed into two independent parallel relay channels without using CSIT at source nodes through the proposed interference-free relaying technique. Then I go beyond one-way and layered to multi-way and fully-connected wireless networks where I characterize the achievable sum-DoF of networks where no CSIT is available at source nodes using the proposed space-time physical-layer network coding. Lastly, I characterize analytical expressions for the sum spectral efficiency in a large-scale single-input-multiple- output (SIMO) interference network where the spatial locations of nodes are modeled by means of stochastic geometry. I derive analytical expressions for the ergodic sum spectral efficiency and the scaling laws as functions of relevant system parameters depending on different channel knowledge assumptions at receivers.

Interference Management for Wireless Networks

Author : Chia-Chi Huang
Publisher :
ISBN 13 : 9781109246001
Total Pages : 108 pages
Book Rating : 4.2/5 (46 download)

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Book Synopsis Interference Management for Wireless Networks by : Chia-Chi Huang

Download or read book Interference Management for Wireless Networks written by Chia-Chi Huang and published by . This book was released on 2009 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interference is a key property of wireless communications due to the broadcasting nature of wireless links. The design of wireless networks needs to put interference management into consideration. Traditionally, interference management is done by partitioning the whole network into orthogonal non-interfering channels via time- or frequency-division multiplexing. While orthogonalization significantly reduces the complexity of the design and implementation of wireless networks, it also introduces artificial restriction and leads to suboptimal performance. This thesis is devoted to the design and analysis of interference management from a cross-layer perspective. The key to increase spectrum efficiency of a wireless network is to treat the entire network as a channel rather than viewing them as a set of separate links. Based on this idea, we propose three interference management schemes and evaluate the fundamental limits associated with them. We use the notions of both conventional and generalized degrees of freedom (DOF), which are two widely-used approximations of channel capacity, as merits to evaluate and compare the performance improvement brought by the interference management schemes. The thesis consists of four main results. First, we consider a multiple-input-multiple-output (MIMO) 2-suer cognitive radio system in an information theoretic setting where some messages are made available, by a genie, to some nodes (other than the intended nodes) non-causally, noiselessly, and for free. We find the DOF region of this system and show that this region is larger than the one without cognitive message sharing. Our results also show that in general it may be more beneficial, in terms of sum DOF, for a user to have a cognitive transmitter than to have cognitive receiver. Second, we consider a MIMO Gaussian interference channel with user cooperation, including cooperation at transmitters only, at receivers only, and at transmitters as well as receivers. We find the DOF region of this system and obtain a negative result that allowing users to cooperate does not enlarge the DOF region of this channel. Third, we explore the capacity and generalized degrees of freedom (GDOF) of a 2-user Gaussian X channel, i.e. a generalization of the 2-user interference channel where there is an independent message from each transmitter to each receiver. We provide the GDOF characterization of the channel under a symmetric setting. We also identify the regime where interference alignment is helpful so that the X channel has a higher capacity than the underlying symmetric interference channel. We further extend the noisy interference capacity characterization previously obtained for the interference channel to the X channel. Lastly, we study the effect of the absence of channel knowledge for MIMO networks. In particular, we assume perfect channel state information at the receivers and no channel state information at the transmitter(s). We provide the characterization of the DOF region for a 2-user MIMO broadcast channel. We then use the result of the broadcast channel to find the DOF region for some special cases of a 2-user MIMO interference channel.

Interference Management for Multiuser Mimo Wireless Networks

Author : Tiangao Gou
Publisher :
ISBN 13 : 9781267420978
Total Pages : 180 pages
Book Rating : 4.4/5 (29 download)

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Book Synopsis Interference Management for Multiuser Mimo Wireless Networks by : Tiangao Gou

Download or read book Interference Management for Multiuser Mimo Wireless Networks written by Tiangao Gou and published by . This book was released on 2012 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the primary goals of designing communication systems is to achieve high data rates. Due to limited spectrum, users need to share the common resource, which causes interference with each other. Interference in turn creates a bottleneck on the communication rate. Recently two breakthroughs have been made to relieve this bottleneck. One is using multiple antennas known as multiple input multiple output (MIMO) technology and the other is an interference management technique called interference alignment. While much progress has been made on understanding of each individually, relatively little is known about how to use both techniques together to deal with interference. This thesis presents the progress we have made towards determining the capacity benefits of multiple antennas and interference alignment in different network settings and under various assumptions about the channel state information known at the transmitters. The thesis consists of five main results. First, we characterize the optimal degrees of freedom (DoF) of the K user MIMO Gaussian interference channel with M transmit and N receive antennas for each user when the ratio of the maximum to the minimum of M and N is equal to an integer. Second, we study the N+1 user single input multiple output (SIMO) Gaussian interference channel with one transmit and N receive antennas for each user. We characterize the generalized degrees of freedom (GDoF) of the network, which directly leads to a capacity approximation within a bounded gap which is independent of the signal strength. We also derive outer bounds which identify a strong interference regime where the capacity region is established. Third, we characterize the optimal DoF of two classes of finite state compound wireless networks including the multiple-input single-output (MISO) finite state compound broadcast channel (BC) with arbitrary number of users and antennas at the transmitter and the finite state scalar (single antenna nodes) compound X networks with arbitrary number of users. Fourth, we propose a blind interference alignment scheme through staggered antenna switching, i.e., we seek to align interference without any knowledge of the channel coefficient values at the transmitters. This scheme achieves the optimal DoF of the vector broadcast channel where the transmitter is equipped with M antennas and there are K receivers, each equipped with a reconfigurable antenna capable of switching among M preset modes. Fifth, we go beyond the single hop wireless networks to multihop interference networks and characterize the DoF of the 2-source 2-destination 2-hop interference network formed by concatenation of two 2-user interference channels. The key to this result is a new idea, called aligned interference neutralization, that provides a way to align interference terms over each hop in a manner that allows them to be cancelled over the air at the last hop.

Interference Management in Wireless Networks

Author : Venugopal V. Veeravalli
Publisher : Cambridge University Press
ISBN 13 : 1316730794
Total Pages : 228 pages
Book Rating : 4.3/5 (167 download)

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Book Synopsis Interference Management in Wireless Networks by : Venugopal V. Veeravalli

Download or read book Interference Management in Wireless Networks written by Venugopal V. Veeravalli and published by Cambridge University Press. This book was released on 2018-02-22 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Learn about an information-theoretic approach to managing interference in future generation wireless networks. Focusing on cooperative schemes motivated by Coordinated Multi-Point (CoMP) technology, the book develops a robust theoretical framework for interference management that uses recent advancements in backhaul design, and practical pre-coding schemes based on local cooperation, to deliver the increased speed and reliability promised by interference alignment. Gain insight into how simple, zero-forcing pre-coding schemes are optimal in locally connected interference networks, and discover how significant rate gains can be obtained by making cell association decisions and allocating backhaul resources based on centralized (cloud) processing and knowledge of network topology. Providing a link between information-theoretic analyses and interference management schemes that are easy to implement, this is an invaluable resource for researchers, graduate students and practicing engineers in wireless communications.

Interference Alignment

Author : Syed A. Jafar
Publisher : Now Publishers Inc
ISBN 13 : 160198474X
Total Pages : 147 pages
Book Rating : 4.6/5 (19 download)

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Book Synopsis Interference Alignment by : Syed A. Jafar

Download or read book Interference Alignment written by Syed A. Jafar and published by Now Publishers Inc. This book was released on 2011 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interference Alignment: A New Look at Signal Dimensions in a Communication Network provides both a tutorial and a survey of the state-of-art on the topic.

Interference Management Via Interference Alignment in Wireless Networks

Author : Chenwei Wang
Publisher :
ISBN 13 : 9781267836403
Total Pages : 237 pages
Book Rating : 4.8/5 (364 download)

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Book Synopsis Interference Management Via Interference Alignment in Wireless Networks by : Chenwei Wang

Download or read book Interference Management Via Interference Alignment in Wireless Networks written by Chenwei Wang and published by . This book was released on 2012 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: In wireless communication networks, competition among users for channel resources can result in severe mutual interference. This is a bottleneck for obtaining higher communication rates. Recent advances in the network information theory, such as the idea of interference alignment, have greatly facilitated our understanding of signal dimensions or even exact capacity of wireless networks and produced a number of new transmission schemes to achieve higher rates. Usually, we are interested in the fundamental questions -- what is the channel capacity of multiuser networks, and how to achieve higher communication rates, attractive for both theoretical researchers and engineers. Since finding the exact capacity of multiuser wireless networks is quite challenging, if not impossible, we are interested in the degrees of freedom (DoF) characterization, i.e., a coarse capacity approximation, of wireless networks. The number of DoF of a communication network is a metric of great significance as it provides a lens into the most essential aspects of the communication problem. DoF investigations have motivated many fundamental ideas such as interference alignment. In this dissertation, we investigate the DoF of a number of multiuser wireless networks using the idea of interference alignment. In particular, we start from the classical interference channels with global channel knowledge at each node. A number of scenarios will be studied, including networks with single antenna or multiple antennas at each node. Next, we consider the interference channel with local cooperation and local connectivity. Then we go beyond one-hop to multihop wireless networks where we find the DoF of multiple unicast for 2-source 2-sink layered networks with arbitrary topologies. Finally, we weaken the global channel knowledge assumption, to study broadcast channels with no channel state information at the transmitter. Several interesting tools, insights and surprising results are obtained in this work -- including phase alignment, asymmetric complex signaling, subspace alignment chains, genie chains, the observation that removing interference-carrying links can reduce the channel capacity, and blind interference alignment.

Communications in Interference Limited Networks

Author : Wolfgang Utschick
Publisher : Springer
ISBN 13 : 3319224409
Total Pages : 519 pages
Book Rating : 4.3/5 (192 download)

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Book Synopsis Communications in Interference Limited Networks by : Wolfgang Utschick

Download or read book Communications in Interference Limited Networks written by Wolfgang Utschick and published by Springer. This book was released on 2016-02-04 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers means to handle interference as a central problem of operating wireless networks. It investigates centralized and decentralized methods to avoid and handle interference as well as approaches that resolve interference constructively. The latter type of approach tries to solve the joint detection and estimation problem of several data streams that share a common medium. In fact, an exciting insight into the operation of networks is that it may be beneficial, in terms of an overall throughput, to actively create and manage interference. Thus, when handled properly, "mixing" of data in networks becomes a useful tool of operation rather than the nuisance as which it has been treated traditionally. With the development of mobile, robust, ubiquitous, reliable and instantaneous communication being a driving and enabling factor of an information centric economy, the understanding, mitigation and exploitation of interference in networks must be seen as a centrally important task.

Interference in Large Wireless Networks

Author : Martin Haenggi
Publisher : Now Publishers Inc
ISBN 13 : 1601982984
Total Pages : 136 pages
Book Rating : 4.6/5 (19 download)

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Book Synopsis Interference in Large Wireless Networks by : Martin Haenggi

Download or read book Interference in Large Wireless Networks written by Martin Haenggi and published by Now Publishers Inc. This book was released on 2009 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since interference is the main performance-limiting factor in most wireless networks, it is crucial to characterize the interference statistics. The main two determinants of the interference are the network geometry (spatial distribution of concurrently transmitting nodes) and the path loss law (signal attenuation with distance). For certain classes of node distributions, most notably Poisson point processes, and attenuation laws, closed-form results are available, for both the interference itself as well as the signal-to-interference ratios, which determine the network performance. This monograph presents an overview of these results and gives an introduction to the analytical techniques used in their derivation. The node distribution models range from lattices to homogeneous and clustered Poisson models to general motion-invariant ones. The analysis of the more general models requires the use of Palm theory, in particular conditional probability generating functionals, which are briefly introduced in the appendix.

Massive MIMO

Author : Hien Quoc Ngo
Publisher : Linköping University Electronic Press
ISBN 13 : 9175191474
Total Pages : 69 pages
Book Rating : 4.1/5 (751 download)

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Book Synopsis Massive MIMO by : Hien Quoc Ngo

Download or read book Massive MIMO written by Hien Quoc Ngo and published by Linköping University Electronic Press. This book was released on 2015-01-16 with total page 69 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last ten years have seen a massive growth in the number of connected wireless devices. Billions of devices are connected and managed by wireless networks. At the same time, each device needs a high throughput to support applications such as voice, real-time video, movies, and games. Demands for wireless throughput and the number of wireless devices will always increase. In addition, there is a growing concern about energy consumption of wireless communication systems. Thus, future wireless systems have to satisfy three main requirements: i) having a high throughput; ii) simultaneously serving many users; and iii) having less energy consumption. Massive multiple-input multiple-output (MIMO) technology, where a base station (BS) equipped with very large number of antennas (collocated or distributed) serves many users in the same time-frequency resource, can meet the above requirements, and hence, it is a promising candidate technology for next generations of wireless systems. With massive antenna arrays at the BS, for most propagation environments, the channels become favorable, i.e., the channel vectors between the users and the BS are (nearly) pairwisely orthogonal, and hence, linear processing is nearly optimal. A huge throughput and energy efficiency can be achieved due to the multiplexing gain and the array gain. In particular, with a simple power control scheme, Massive MIMO can offer uniformly good service for all users. In this dissertation, we focus on the performance of Massive MIMO. The dissertation consists of two main parts: fundamentals and system designs of Massive MIMO. In the first part, we focus on fundamental limits of the system performance under practical constraints such as low complexity processing, limited length of each coherence interval, intercell interference, and finite-dimensional channels. We first study the potential for power savings of the Massive MIMO uplink with maximum-ratio combining (MRC), zero-forcing, and minimum mean-square error receivers, under perfect and imperfect channels. The energy and spectral efficiency tradeoff is investigated. Secondly, we consider a physical channel model where the angular domain is divided into a finite number of distinct directions. A lower bound on the capacity is derived, and the effect of pilot contamination in this finite-dimensional channel model is analyzed. Finally, some aspects of favorable propagation in Massive MIMO under Rayleigh fading and line-of-sight (LoS) channels are investigated. We show that both Rayleigh fading and LoS environments offer favorable propagation. In the second part, based on the fundamental analysis in the first part, we propose some system designs for Massive MIMO. The acquisition of channel state information (CSI) is very importantin Massive MIMO. Typically, the channels are estimated at the BS through uplink training. Owing to the limited length of the coherence interval, the system performance is limited by pilot contamination. To reduce the pilot contamination effect, we propose an eigenvalue-decomposition-based scheme to estimate the channel directly from the received data. The proposed scheme results in better performance compared with the conventional training schemes due to the reduced pilot contamination. Another important issue of CSI acquisition in Massive MIMO is how to acquire CSI at the users. To address this issue, we propose two channel estimation schemes at the users: i) a downlink "beamforming training" scheme, and ii) a method for blind estimation of the effective downlink channel gains. In both schemes, the channel estimation overhead is independent of the number of BS antennas. We also derive the optimal pilot and data powers as well as the training duration allocation to maximize the sum spectral efficiency of the Massive MIMO uplink with MRC receivers, for a given total energy budget spent in a coherence interval. Finally, applications of Massive MIMO in relay channels are proposed and analyzed. Specifically, we consider multipair relaying systems where many sources simultaneously communicate with many destinations in the same time-frequency resource with the help of a massive MIMO relay. A massive MIMO relay is equipped with many collocated or distributed antennas. We consider different duplexing modes (full-duplex and half-duplex) and different relaying protocols (amplify-and-forward, decode-and-forward, two-way relaying, and one-way relaying) at the relay. The potential benefits of massive MIMO technology in these relaying systems are explored in terms of spectral efficiency and power efficiency.

System-level Performance Analysis of Multiple-antenna Wireless Networks with Limited Channel State Information

Author : Jeonghun Park
Publisher :
ISBN 13 :
Total Pages : 492 pages
Book Rating : 4.:/5 (12 download)

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Book Synopsis System-level Performance Analysis of Multiple-antenna Wireless Networks with Limited Channel State Information by : Jeonghun Park

Download or read book System-level Performance Analysis of Multiple-antenna Wireless Networks with Limited Channel State Information written by Jeonghun Park and published by . This book was released on 2017 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cellular communication systems are interference limited because of frequency reuse. To manage the interference, information about the channel state can be used. Specifically, under the premise of perfect and global channel state information at transmitters (CSIT), prior work showed significant spectral efficiency improvement in many cases of wireless networks by using advanced interference management techniques. Unfortunately, obtaining perfect and global CSIT is infeasible in practice due to finite capacity feedback links and associated overheads. For this reason, characterizing the performance of wireless networks with limited CSIT is important to understand the performance achievable in practical wireless networks. Motivated by this, in this dissertation, I analyze the spectral efficiency of wireless networks with various scenarios of limited CSIT. Leveraging the analytical results, I propose strategies to obtain spectral efficiency gains under limited CSIT. First, I determine appropriate feedback rate used in a multi-antenna cellular network. Specifically, I analyze the net spectral efficiency, which is defined as the downlink spectral efficiency normalized by the uplink overheads caused by using limited feedback. Subsequently, I obtain the optimal feedback rate to maximize the net spectral efficiency. In addition, I extend this result to a multiple-antenna device-to-device network, where I derive the optimal feedback rate to maximize the net spectral efficiency. Next, I consider a cooperative cellular network and propose a semi-static base station (BS) clustering strategy by exploiting the graph theory. By using the proposed strategy, I show that the same spectral efficiency gain with dynamic BS clustering is achieved while avoiding the associated complexity. I also study the spectral efficiency of K-tier heterogeneous networks with limited feedback. Considering non-cooperative and cooperative heterogeneous networks, I formulate and solve adaptive feedback partition problems to maximize the ergodic spectral efficiency in each case. Last, I assume a spectrum-shared millimeter wave (mmWave) downlink cellular network. I characterize the rate coverage performance assuming that inter-operator BS coordination is used. By using the analytical results, I show that inter-operator BS coordination is valuable when sharing the spectrum with a dense operator in a mmWave cellular network.

Interference Management in Multiple-antenna Wireless Networks

Author : Ioannis Spyropoulos
Publisher :
ISBN 13 :
Total Pages : 86 pages
Book Rating : 4.:/5 (476 download)

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Book Synopsis Interference Management in Multiple-antenna Wireless Networks by : Ioannis Spyropoulos

Download or read book Interference Management in Multiple-antenna Wireless Networks written by Ioannis Spyropoulos and published by . This book was released on 2009 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation focuses on the topic of interference management in wireless networks with multiple-antenna nodes. Two network paradigms are considered, namely, time-division duplexing (TDD)/code-division multiple-access (CDMA) cellular and ad hoc. In TDD/CDMA cellular networks with asymmetric data traffic, dynamic channel allocation (DCA) enhances resource utilization compared to fixed channel allocation (FCA); however, it induces base-to-base and mobile-to-mobile crossed-slot intercell interference that can severely degrade network performance. To deal with this problem, a decentralized scheme is proposed, which combines an interference-aware DCA algorithm with space-time linear minimum-mean-square-error (LMMSE) joint detection at the base and mobile stations. The former assigns active links to timeslots in a way that crossed-slot interference is mitigated, while the latter suppresses the remaining intercell interference (along with intersymbol and intracell interference) by exploiting its spatio-temporal autocorrelation statistics. The performance of this scheme is evaluated in terms of SINR outage and average throughput via analytical approximations and Monte Carlo simulations, and it is compared with that of benchmark random DCA (RDCA) and FCA schemes. The cases of single- and dual-antenna reception with perfect and imperfect channel state information are examined. It is shown that the proposed scheme achieves higher average throughput than FCA (particularly for dual-antenna reception) as well as RDCA (for heavy traffic loads). These throughput gains are more significant in uplink than in downlink. In ad hoc networks, interference management via collision-avoidance medium access schemes results in poor spatial reuse and, thus, restricts network throughput. To address this shortcoming, two physical-medium-access-control cross-layer protocols are proposed. The first increases spatial reuse by integrating medium access, power control, and optimum receive beamforming in a distributed manner, and it is named progressive back-off algorithm with optimum receive beamforming (PBOA-ORB). The second additionally incorporates transmit beamforming, on the premise of centralized control, and it is named progressive back-off algorithm with transmit and optimum receive beamforming (PBOA-TORB). The performance of both protocols is evaluated in terms of aggregate throughput and energy efficiency via simulations over a single-hop network. It is shown that the throughput of PBOA-ORB increases linearly with the number of antennas per node thanks to interference suppression provided by optimum receive beamforming. PBOA-TORB achieves only an incremental throughput gain over PBOA-ORB despite its centralized nature. However, it is significantly more energy efficient than PBOA-ORB thanks to extra array gain provided by transmit beamforming. The research for this dissertation was conducted at the UCSD Center for Wireless Communication, under the "MIMO Wireless Communication Systems" project (CoRe research grant com04-10176) and the ``Multiuser MIMO Systems'' project (CoRe research grant com07-10241).

Fundamentals of Wireless Communication

Author : David Tse
Publisher : Cambridge University Press
ISBN 13 : 9780521845274
Total Pages : 598 pages
Book Rating : 4.8/5 (452 download)

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Book Synopsis Fundamentals of Wireless Communication by : David Tse

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.

Designing MIMO Interference Alignment Networks

Author : Behrang Nosrat Makouei
Publisher :
ISBN 13 :
Total Pages : 304 pages
Book Rating : 4.:/5 (815 download)

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Book Synopsis Designing MIMO Interference Alignment Networks by : Behrang Nosrat Makouei

Download or read book Designing MIMO Interference Alignment Networks written by Behrang Nosrat Makouei and published by . This book was released on 2012 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wireless networks are increasingly interference-limited, which motivates the development of sophisticated interference management techniques. One recently discovered approach is interference alignment, which attains the maximum sum rate scaling (with signal-to-noise ratio) in many network configurations. Interference alignment is not yet well understood from an engineering perspective. Such design considerations include (i) partial rather than complete knowledge of channel state information, (ii) correlated channels, (iii) bursty packet-based network traffic that requires the frequent setup and tear down of sessions, and (iv) the spatial distribution and interaction of transmit/receive pairs. This dissertation aims to establish the benefits and limitations of interference alignment under these four considerations. The first contribution of this dissertation considers an isolated group of transmit/receiver pairs (a cluster) cooperating through interference alignment and derives the signal-to-interference-plus-noise ratio distribution at each receiver for each stream. This distribution is used to compare interference alignment to beamforming and spatial multiplexing (as examples of common transmission techniques) in terms of sum rate to identify potential switching points between them. This dissertation identifies such switching points and provides design recommendations based on severity of the correlation or the channel state information uncertainty. The second contribution considers transmitters that are not associated with any interference alignment cooperating group but want to use the channel. The goal is to retain the benefits of interference alignment amid interference from the out-of-cluster transmitters. This dissertation shows that when the out-of-cluster transmitters have enough antennas, they can access the channel without changing the performance of the interference alignment receivers. Furthermore, optimum transmit filters maximizing the sum rate of the out-of-cluster transmit/receive pairs are derived. When insufficient antennas exist at the out-of-cluster transmitters, several transmit filters that trade off complexity and sum rate performance are presented. The last contribution, in contrast to the first two, takes into account the impact of large scale fading and the spatial distribution of the transmit/receive pairs on interference alignment by deriving the transmission capacity in a decentralized clustered interference alignment network. Channel state information uncertainty and feedback overhead are considered and the optimum training period is derived. Transmission capacity of interference alignment is compared to spatial multiplexing to highlight the tradeoff between channel estimation accuracy and the inter-cluster interference; the closer the nodes to each other, the higher the channel estimation accuracy and the inter-cluster interference.

Interference Management in Non-cooperative Networks

Author : Abolfazl Sayed Motahari
Publisher :
ISBN 13 :
Total Pages : 146 pages
Book Rating : 4.:/5 (613 download)

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Book Synopsis Interference Management in Non-cooperative Networks by : Abolfazl Sayed Motahari

Download or read book Interference Management in Non-cooperative Networks written by Abolfazl Sayed Motahari and published by . This book was released on 2009 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectrum sharing is known as a key solution to accommodate the increasing number of users and the growing demand for throughput in wireless networks. While spectrum sharing improves the data rate in sparse networks, it suffers from interference of concurrent links in dense networks. In fact, interference is the primary barrier to enhance the overall throughput of the network, especially in the medium and high signal-to-noise ratios (SNR's). Managing interference to overcome this barrier has emerged as a crucial step in developing efficient wireless networks. This thesis deals with optimum and sub-optimum interference management-cancelation in non-cooperative networks. Several techniques for interference management including novel strategies such as interference alignment and structural coding are investigated. These methods are applied to obtain optimum and sub-optimum coding strategies in such networks. It is shown that a single strategy is not able to achieve the maximum throughput in all possible scenarios and in fact a careful design is required to fully exploit all available resources in each realization of the system.

Topological Interference Management for Multi-user Wireless Networks

Author : Hassan Kallam
Publisher :
ISBN 13 :
Total Pages : 94 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Topological Interference Management for Multi-user Wireless Networks by : Hassan Kallam

Download or read book Topological Interference Management for Multi-user Wireless Networks written by Hassan Kallam and published by . This book was released on 2021 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: Topological Interference Management (TIM) allows studying the Degrees of Freedom (DoF) of partially connected linear interference communication networks, where the Channel State Information at the Transmitter (CSIT) is restricted to the topology of the network, i.e., a knowledge of which interference links are weak and which are strong. In this thesis, we consider TIM for infinite downlink cellular networks in the one-dimensional (1D) linear and the two-dimensional (2D) hexagonal models. We consider uniformly distributed users in each cellular cell, effectively creating a continuous distribution of users, aiming to study user classes based on different interference profiles rather than on actual individual users' positions. We also consider the construction of the TIM network topology by analyzing different interference thresholds. Unlike previous works, we use TIM at the user class level to find the system's DoF independent of the actual user position. Then, after proposing a fractional coloring scheme that can achieve the optimal DoF solution, a trade-off between DoF and Signal to Interference Ratio (SIR) is given. This thesis also presents a new approach to construct an interference topology for the unicast TIM problem of multi-user wireless networks. Based on our interference topology construction approach, we are able to evaluate the achievable rate's theoretical limit, in the asymptotic Signal to Noise Ratio (SNR) regime, for the underlying wireless network and not just for its topological interference representation. This new approach allows us to cope with the finite SNR regime and not just with the asymptotic SNR regime with the DoF analysis. A new SNR independent interference threshold parameter is proposed and we evaluate the achievable symmetric rates of the wireless network in both the finite SNR regime and the asymptotic SNR regime. Then, we present outer bound solutions on the new normalized interference threshold parameter for interference topologies with half-DoF-feasibility, considering both an orthogonal resource allocation and Interference Alignment (IA). These bounds specify if a given half-DoF-feasible interference topology can be, in terms of the achievable rate, the best topology or not. Using this result, we limit the search space in the normalized interference threshold parameter range, to find half-DoF-feasible interference topologies having the possibility to be the best topologies in terms of the achievable rate. Finally, this thesis considers a case study on TIM for small-scale wireless networks, in which, we consider the TIM problem for four users wireless networks using our proposed interference topology construction approach. Then, we apply the achievable rates analysis, proposed under the new interference topology construction approach, for all interference topologies with half-DoF-feasibility, through both orthogonal sharing and IA, in the TIM problem of four users wireless networks.

Full-Duplex Wireless Communications Systems

Author : Tho Le-Ngoc
Publisher : Springer
ISBN 13 : 3319576909
Total Pages : 170 pages
Book Rating : 4.3/5 (195 download)

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Book Synopsis Full-Duplex Wireless Communications Systems by : Tho Le-Ngoc

Download or read book Full-Duplex Wireless Communications Systems written by Tho Le-Ngoc and published by Springer. This book was released on 2017-07-02 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the development of self-interference (SI)-cancellation techniques for full-duplex wireless communication systems. The authors rely on estimation theory and signal processing to develop SI-cancellation algorithms by generating an estimate of the received SI and subtracting it from the received signal. The authors also cover two new SI-cancellation methods using the new concept of active signal injection (ASI) for full-duplex MIMO-OFDM systems. The ASI approach adds an appropriate cancelling signal to each transmitted signal such that the combined signals from transmit antennas attenuate the SI at the receive antennas. The authors illustrate that the SI-pre-cancelling signal does not affect the data-bearing signal. This book is for researchers and professionals working in wireless communications and engineers willing to understand the challenges of deploying full-duplex and practical solutions to implement a full-duplex system. Advanced-level students in electrical engineering and computer science studying wireless communications will also find this book useful as a secondary textbook.

On Efficiency and Intelligence of Next-generation Wireless Networks

Author : Pedram Kheirkhah Sangdeh
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.3/5 (795 download)

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Book Synopsis On Efficiency and Intelligence of Next-generation Wireless Networks by : Pedram Kheirkhah Sangdeh

Download or read book On Efficiency and Intelligence of Next-generation Wireless Networks written by Pedram Kheirkhah Sangdeh and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ever-increasing demand for data-hungry wireless services and rapid proliferation of wireless devices in sub-6 GHz band have pushed the current wireless technologies to a breaking point, necessitating efficient and intelligent strategies to utilize scarce communication resources. This thesis aims at leveraging novel communication frameworks, artificial intelligence techniques, and synergies between them in bringing efficiency and intelligence to the next generation of wireless networks.In the first chapter of this thesis, we propose a novel spectrum sharing scheme to address spectrum shortage, a fundamental issue in current and future wireless networks. Our proposed scheme enables transparent spectrum utilization for a small cognitive radio network by leveraging two interference management techniques that are not reliant on inter-network coordination, fine-grained synchronization, and knowledge about other occupants of the spectrum. We further extend this idea in the second chapter of this thesis and enable concurrent device-to-device and cellular communications in cellular networks where the base station and wireless devices exploit interference management techniques to avoid causing interference to each other, making concurrent spectrum utilization possible for both cellular and device-to-device communications. In the third chapter, to enhance spectral efficiency, connectivity, and throughput of Wireless Local Area Networks (WLAN), we propose a non-orthogonal multiplexing scheme (NOMA). In our proposed scheme, the access point (AP) is equipped with a novel precoder design and user grouping which are tailored based on the requirements of power-domain NOMA. Also, a novel successive interference cancellation technique is designed for users which does not require channel estimation to decode the signals and is more resilient to interference compared to the existing techniques. The second part of this thesis focuses on taking advantage of artificial intelligence for solving communication and networking challenges and also taking advantage of novel communication frameworks to let future wireless networks indulge intelligence-oriented networking and resource management. In the fourth chapter, we propose a new solution to solve a long-standing issue ahead of multi-user multiple-input multiple-output (MU-MIMO) communications in WLANs, which is the large sounding overhead for acquiring the channel state information (CSI). Our learning-based solution includes an automated mechanism that enables access points to collect, clear, and balance dataset, and also deep neural networks to compress CSI and reduce the airtime overhead for channel acquisition. However, with provisioning concurrent MU-MIMO and orthogonal frequency division multiple access (OFDMA) in the new generation of WLANs, not only the sounding overhead problem becomes more acute, but it also marries with a complex resource allocation problem which makes designing a practical enabler of MU-MIMO-OFDMA transmissions necessary for WLANs. In the fifth chapter of this thesis, we propose DeepMux, which comprises a deep-learning-based channel sounding and a deep-learning-based resource allocation both of which reside in access points and impose no computational/communication burden on users, enabling efficient downlink MU-MIMO-OFDMA transmissions in WLANs. We finally design a communication framework for accelerating federated learning in future intelligent transportation systems, where heterogeneous capabilities and mobility of users along with limited available bandwidth for communications are huge obstacles toward making the network intelligent in a distributed manner. With the aid of a deadline-driven scheduler and asynchronous uplink multi-user MIMO, our proposed solution reduces data loss at vehicles in a dynamic vehicular environment, making a concrete step toward the practical adoption of federated learning in future transportation systems.