Interference in Large Wireless Networks

Download Interference in Large Wireless Networks PDF Online Free

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

DOWNLOAD NOW!


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.

Capacity Results for Interference Networks and Nested Cut-set Bound

Download Capacity Results for Interference Networks and Nested Cut-set Bound PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 107 pages
Book Rating : 4.:/5 (988 download)

DOWNLOAD NOW!


Book Synopsis Capacity Results for Interference Networks and Nested Cut-set Bound by : Reza Khosravi Farsani

Download or read book Capacity Results for Interference Networks and Nested Cut-set Bound written by Reza Khosravi Farsani and published by . This book was released on 2016 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, a full characterization of the sum-rate capacity for degraded interference networks with any number of transmitters, any number of receivers, and any possible distribution of messages among transmitters and receivers is established. It is proved that a successive decoding scheme is sum-rate optimal for these networks. Moreover, it is shown that the transmission of only a certain subset of messages is sufficient to achieve the sum-rate capacity for such networks. Algorithms are presented to determine this subset of messages explicitly. The sum-rate expression for the degraded networks is then used to derive a unified outer bound on the sum-rate capacity of arbitrary (non-degraded) interference networks. Several variations of degraded networks are identified for which the derived outer bound is sum-rate optimal. Specifically, noisy interference regimes are derived for certain classes of multi-user/multi-message large interference networks. Also, network scenarios are identified where the incorporation of both successive decoding and treating interference as noise achieves their sum-rate capacity. Next, by taking insight from the results for degraded networks, an extension to the standard cut-set bound for general communication networks is presented which is referred to as nested cut-set bound. This bound is derived by applying a series of cuts in a nested configuration to the network first and then bounding the information rate that flows through the cuts. The key idea for bounding step is indeed to impose a degraded arrangement among the receivers corresponding to the cuts. Therefore, the bound is in fact a generalization of the outer bound for interference networks: here cooperative relaying nodes are introduced into the problem as well but the proof style for the derivation of the outer bound remains the same. The nested cut-set bound, which uniformly holds for all general communication networks of arbitrary large sizes where any subset of nodes may cooperatively communicate to any other subset of them, is indeed tighter than the cut-set bound for networks with more than one receiver. Moreover, it includes the generalized cut-set bound for deterministic networks reported by Shomorony and Avestimehr which was originally a special case of the outer bound established for the interference networks by the author (2012). Finally, capacity bounds for the two-user interference channel with cooperative receivers via conferencing links of finite capacities are investigated. The capacity results known for this communication scenario are limited to a very few special cases of the one-sided channel. One of the major challenges in analyzing such cooperative networks is how to establish efficient capacity outer iv bounds for them. In this thesis, by applying new techniques, novel capacity outer bounds are presented for the interference channels with conferencing users. Using the outer bounds, several new capacity results are proved for interesting channels with unidirectional cooperation in strong and mixed interference regimes. A fact is that the conferencing link (between receivers) may be utilized to provide one receiver with information about its corresponding signal or its non-corresponding signal (interference signal). As an interesting consequence, it is demonstrated that both strategies can be helpful to achieve the capacity of the channel. Lastly, for the case of Gaussian interference channel with conferencing receivers, it is argued that our outer bound is strictly tighter than the previous one derived by Wang and Tse.

Interference Alignment

Download Interference Alignment PDF Online Free

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

DOWNLOAD NOW!


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.

Capacity of Interference Networks

Download Capacity of Interference Networks PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 366 pages
Book Rating : 4.:/5 (893 download)

DOWNLOAD NOW!


Book Synopsis Capacity of Interference Networks by : Sriram Sridharan

Download or read book Capacity of Interference Networks written by Sriram Sridharan and published by . This book was released on 2010 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an interference network, multiple transmitters communicate with multiple receivers using the same communication channel. The capacity region of an interference network is defined as the set of data rates that can be simultaneously achieved by the users of the network. One of the most important example of an interference network is the wireless network, where the communication channel is the wireless channel. Wireless interference networks are known to be interference limited rather than noise limited since the interference power level at the receivers (caused by other user's transmissions) is much higher than the noise power level. Most wireless communication systems deployed today employ transmission strategies where the interfering signals are treated in the same manner as thermal noise. Such strategies are known to be suboptimal (in terms of achieving higher data rates), because the interfering signals generated by other transmitters have a structure to them that is very different from that of random thermal noise. Hence, there is a need to design transmission strategies that exploit this structure of the interfering signals to achieve higher data rates. However, determining optimal strategies for mitigating interference has been a long standing open problem. In fact, even for the simplest interference network with just two users, the capacity region is unknown. In this dissertation, we will investigate the capacity region of several models of interference channels. We will derive limits on achievable data rates and design effective transmission strategies that come close to achieving the limits. We will investigate two kinds of networks - "small" (usually characterized by two transmitters and two receivers) and "large" where the number of users is large.

On the Capacity of Multi-terminal Systems

Download On the Capacity of Multi-terminal Systems PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 130 pages
Book Rating : 4.:/5 (812 download)

DOWNLOAD NOW!


Book Synopsis On the Capacity of Multi-terminal Systems by : Amin Jafarian

Download or read book On the Capacity of Multi-terminal Systems written by Amin Jafarian and published by . This book was released on 2012 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: A central feature of wireless networks is multiple users sharing a common medium. Cellular systems are among the most common examples of such networks. The main phenomenon resulting from this inter-user interaction is interference, and thus analyzing interference networks is critical to determine the capacity of wireless networks. The capacity region of an interference network is defined as the set of rates that the users can simultaneously achieve while ensuring arbitrarily small probability of decoding error. It is an inherently hard problem to find the capacity region of interference networks. Even the capacity region of a general 2-user interference channel is a prominent open problem in information theory. This work's goal is to derive achievable regions that are improved over known results, and when possible, capacity theorems, for K user interference networks. Another multiuser channel that is commonly found in wireless systems is a broadcast channel. Broadcast channels stand side by side with Interference channels as the two of the most important channels for which capacity results are still not completely known. In this work we develop inner and outer bounds on the capacity region of fading broadcast channels, using which we find a part of the capacity region under some conditions. In summary, this work first presents coding arguments for new achievable rate regions and, where possible, capacity results for K-user interference networks. Second, it provides inner and outer-bounds for a class of fading broadcast channels.

Interference Management in Wireless Networks

Download Interference Management in Wireless Networks PDF Online Free

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

DOWNLOAD NOW!


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.

Communications in Interference Limited Networks

Download Communications in Interference Limited Networks PDF Online Free

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

DOWNLOAD NOW!


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.

Practical Interference Management Strategies in Gaussian Networks

Download Practical Interference Management Strategies in Gaussian Networks PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 137 pages
Book Rating : 4.:/5 (973 download)

DOWNLOAD NOW!


Book Synopsis Practical Interference Management Strategies in Gaussian Networks by : Seyed Ali Hesammohseni

Download or read book Practical Interference Management Strategies in Gaussian Networks written by Seyed Ali Hesammohseni and published by . This book was released on 2016 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing demand for bandwidth intensive activities on high-penetration wireless hand-held personal devices, combined with their processing power and advanced radio features, has necessitated a new look at the problems of resource provisioning and distributed management of coexistence in wireless networks. Information theory, as the science of studying the ultimate limits of communication e ciency, plays an important role in outlining guiding principles in the design and analysis of such communication schemes. Network information theory, the branch of information theory that investigates problems of multiuser and distributed nature in information transmission is ideally poised to answer questions about the design and analysis of multiuser communication systems. In the past few years, there have been major advances in network information theory, in particular in the generalized degrees of freedom framework for asymptotic analysis and interference alignment which have led to constant gap to capacity results for Gaussian interference channels. Unfortunately, practical adoption of these results has been slowed by their reliance on unrealistic assumptions like perfect channel state information at the transmitter and intricate constructions based on alignment over transcendental dimensions of real numbers. It is therefore necessary to devise transmission methods and coexistence schemes that fall under the umbrella of existing interference management and cognitive radio toolbox and deliver close to optimal performance. In this thesis we work on the theme of designing and characterizing the performance of conceptually simple transmission schemes that are robust and achieve performance that is close to optimal. In particular, our work is broadly divided into two parts. In the rst part, looking at cognitive radio networks, we seek to relax the assumption of non-causal knowledge of primary user's message at the secondary user's transmitter. We study a cognitive channel model based on Gaussian interference channel that does not assume anything about users other than primary user's priority over secondary user in reaching its desired quality of service. We characterize this quality of service requirement as a minimum rate that the primary user should be able to achieve. Studying the achievable performance of simple encoding and decoding schemes in this scenario, we propose a few di erent simple encoding schemes and explore di erent decoder designs. We show that surprisingly, all these schemes achieve the same rate region. Next, we study the problem of rate maximization faced by the secondary user subject to primary's QoS constraint. We show that this problem is not convex or smooth in general. We then use the symmetry properties of the problem to reduce its solution to a feasibly implementable line search. We also provide numerical results to demonstrate the performance of the scheme. Continuing on the theme of simple yet well-performing schemes for wireless networks, in the second part of the thesis, we direct our attention from two-user cognitive networks to the problem of smart interference management in large wireless networks. Here, we study the problem of interference-aware wireless link scheduling. Link scheduling is the problem of allocating a set of transmission requests into as small a set of time slots as possible such that all transmissions satisfy some condition of feasibility. The feasibility criterion has traditionally been lack of pair of links that interfere too much. This makes the problem amenable to solution using graph theoretical tools. Inspired by the recent results that the simple approach of treating interference as noise achieves maximal Generalized Degrees of Freedom (which is a measure that roughly captures how many equivalent single-user channels are contained in a given multi-user channel) and the generalization that it can attain rates within a constant gap of the capacity for a large class of Gaussian interference networks, we study the problem of scheduling links under a set Signal to Interference plus Noise Ratio (SINR) constraint. We show that for nodes distributed in a metric space and obeying path loss channel model, a re ned framework based on combining geometric and graph theoretic results can be devised to analyze the problem of nding the feasible sets of transmissions for a given level of desired SINR. We use this general framework to give a link scheduling algorithm that is provably within a logarithmic factor of the best possible schedule. Numerical simulations con rm that this approach outperforms other recently proposed SINR-based approaches. Finally, we conclude by identifying open problems and possible directions for extending these results.

Interference Management for Wireless Networks

Download Interference Management for Wireless Networks PDF Online Free

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

DOWNLOAD NOW!


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.

On the Capacity of Multiple-terminal Communication Networks

Download On the Capacity of Multiple-terminal Communication Networks PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 206 pages
Book Rating : 4.F/5 ( download)

DOWNLOAD NOW!


Book Synopsis On the Capacity of Multiple-terminal Communication Networks by : Stanford University. Stanford Electronics Laboratories

Download or read book On the Capacity of Multiple-terminal Communication Networks written by Stanford University. Stanford Electronics Laboratories and published by . This book was released on 1975 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Interference Management with Limited Channel State Information in Wireless Networks

Download Interference Management with Limited Channel State Information in Wireless Networks PDF Online Free

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

DOWNLOAD NOW!


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.

Feedback and Interference Alignment in Networks

Download Feedback and Interference Alignment in Networks PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 272 pages
Book Rating : 4.:/5 (785 download)

DOWNLOAD NOW!


Book Synopsis Feedback and Interference Alignment in Networks by : Changho Suh

Download or read book Feedback and Interference Alignment in Networks written by Changho Suh and published by . This book was released on 2011 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increasing complexity of communication networks in size and density provides us enormous opportunities to exploit interaction among multiple nodes, thus enabling higher date rate of data streams. On the flip side, however, this complexity comes with challenges in managing interference that multiple source-destination pairs in the network may cause to each other. In this dissertation, we make progress on how we exploit the opportunities, as well as how we overcome the challenges. In the first part, we find that feedback - one of the common ways to enable interaction in networks - has a promising role in improving the capacity performance of networks. Earlier results on feedback capacity were somewhat discouraging. This is mainly due to Shannon's original result on feedback capacity where he showed that in point-to-point communication, feedback does not increase capacity. Hence, traditionally it is believed that feedback has had little impact on increasing capacity of communication links. Therefore, the use of feedback has been limited to improving the reliability of communications, usually in the form of ARQ. In this dissertation, we show that in stark contrast to the point-to-point case, feedback can improve the capacity of interference-limited network. In fact, the improvement can be unbounded. This result shows that feedback can have a potentially significant role to play in mitigating interference. Also in the process of deriving this conclusion, we characterize the feedback capacity of the two-user Gaussian interference channel to within 2 bits, one of the longstanding open problems in network information theory. In the second part, we propose a new interference management technique for widely deployed cellular networks. Inspired by a recent breakthrough, the concept of interference alignment, we develop an interference alignment technique for cellular networks. Our technique promises almost interference-free communication with the increase of the number of clients in cellular networks. It shows substantial gain (around 30% to 60%) as compared to one of the interference management techniques in current cellular systems. In addition, it comes with implementation benefits: it can actually be implemented with small changes to emerging 4G cellular standards and architectures at the base-stations and clients. In particular, the required signal-processing circuitry, software control, and channel-state feedback mechanisms are extensions of existing implementations and standards. Lastly, we extend the interference alignment principle, developed in the context of wireless networks, into other fields of network research such as storage networks. In an effort to protect information against node failures, storage networks employ coding techniques, such as maximum distance separable (MDS) erasure codes, known as optimal codes in reliability with respect to redundancy. However, these MDS codes come with prohibitive maintenance cost when it comes to repairing failed storage nodes. While only partial information stored in the failed node needs to be recovered, the conventional MDS codes focus on the complete data recovery (including unwanted data, corresponding to interference) by downloading too much information from survivor storage encoded nodes, thus causing the high repair cost. Building on the connection between wireless and wireline networks, we leverage the interference alignment principle to develop a new class of MDS codes that significantly reduces the repair cost over the conventional MDS codes and also achieves information-theoretic optimal bound on the repair cost for all admissible code parameters.

Capacity Results for Wireless Networks

Download Capacity Results for Wireless Networks PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (191 download)

DOWNLOAD NOW!


Book Synopsis Capacity Results for Wireless Networks by :

Download or read book Capacity Results for Wireless Networks written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Interference Alignment

Download Interference Alignment PDF Online Free

Author :
Publisher :
ISBN 13 : 9781321367560
Total Pages : 161 pages
Book Rating : 4.3/5 (675 download)

DOWNLOAD NOW!


Book Synopsis Interference Alignment by : Sundar Rajan Krishnamurthy

Download or read book Interference Alignment written by Sundar Rajan Krishnamurthy and published by . This book was released on 2014 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Capacity characterization of communication networks is the most fundamental problem in Information Theory, that underlies the design of various wireless and wired networks. The radical idea of "Interference alignment" has enabled Capacity or Degrees of Freedom characterization (DoF, a first order approximation) for many interference networks. Various alignment schemes developed have provided new and fundamental insights into the number of accessible signal dimensions in communication networks where the output signals are linear functions of the input signals. Most of the prior art deal with generic channels wherein the channel coefficients are assumed to be independent and drawn from a continuous distribution, continuous alphabet with infinite diversity, and the network is often single-hop. These assumptions are challenged due to the following reasons : 1) In MIMO systems, poor scattering environment and network topology lead to spatial dependencies that are manifested as rank deficient channels, 2) Multi-hop dependencies arise due to the presence of relays, and 3) Linear network coding applications (as in wired networks) act as finite field counterparts of wireless networks, with limited diversity. In this thesis, Capacity / DoF of linear communication networks are characterized for "Non-generic channels". One of the significant problems considered is the DoF of the K-user MIMO rank deficient interference channel, with different ranks for the direct and the cross channels. For this rank deficient interference channel, it is shown that the rank deficiency of direct channels does not help DoF and the rank-deficiency of cross-channels does not hurt DoF. The main challenge is to account for the spatial dependencies introduced by rank deficiencies in the interference alignment schemes that typically rely on the independence of channel coefficients. Another interesting problem is the DoF of Two-hop MIMO rank deficient interference channel with different channel ranks in the first and the second hops, for which a rank-matching principle is identified reminiscent of impedance matching in circuit theory. For this channel, the DoF loss is shown to be the rank-mismatch between the two hops. Finally, capacity results for the finite field counterparts of wireless networks are presented, exploring the implications of channels being from a finite alphabet with limited diversity. By characterizing the capacity of constant finite field channels over F[subscript pn] channel and 3-user interference channel, interesting parallels are drawn between p and SNR, and n and Channel Diversity.

Interference Management Via Interference Alignment in Wireless Networks

Download Interference Management Via Interference Alignment in Wireless Networks PDF Online Free

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

DOWNLOAD NOW!


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.

On Deterministic Models for Capacity Approximations in Interference Networks and Information Theoretic Security

Download On Deterministic Models for Capacity Approximations in Interference Networks and Information Theoretic Security PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (14 download)

DOWNLOAD NOW!


Book Synopsis On Deterministic Models for Capacity Approximations in Interference Networks and Information Theoretic Security by : Rick Fritschek

Download or read book On Deterministic Models for Capacity Approximations in Interference Networks and Information Theoretic Security written by Rick Fritschek and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

A Wireless Metropolitan Area Network Case

Download A Wireless Metropolitan Area Network Case PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 67 pages
Book Rating : 4.:/5 (713 download)

DOWNLOAD NOW!


Book Synopsis A Wireless Metropolitan Area Network Case by : Stela Llusha

Download or read book A Wireless Metropolitan Area Network Case written by Stela Llusha and published by . This book was released on 2007 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: