Performance Analysis of Cooperative Communication Systems with Hierarchical Modulation Over AWGN Channel and Rayleigh Fading Channels PDF Download

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Languages : en
Pages : 0

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Author: Essam Saleh Altubaishi
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ISBN:
Category :
Languages : en
Pages : 123

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Cooperative communication has recently become a key technology for modern wireless networks such as 3GPP long-term evolution and WiMAX, because in such networks the transmission rate, the communication reliability, and coverage problems could be improved in a cost-effective manner. This, however, faces many design challenges. First, cooperative transmission typically involves a relaying phase which requires extra resources. This may cause a reduction in the spectral efficiency. Second, extra control signaling increases the complexity of operation, which may limit practical implementation. In addition, a wireless channel is time-varying, mainly due to the multipath propagation. As a result, a careful design of efficient cooperative communication systems is required, not only to enhance the spectral efficiency and maintain the quality-of-service (QoS), but also to be practical. In this dissertation, we aim to address the challenges imposed by cooperative communication and wireless transmission, and design the efficient and distributed systems which can be practically implemented in existing wireless systems. The research work is divided into two main topics: 1) adaptive cooperative wireless systems with variable-rate transmission, and 2) cooperative wireless systems with a power consumption constraint. The first topic investigates how the spectral efficiency of cooperative wireless communication systems can be improved while maintaining the QoS in terms of bit error rate and outage probability. The spectral efficiency enhancement is achieved by using three techniques: adaptivity over the relay node (i.e., relay node is active or not), adaptivity over the modulation mode, and relay selection. Based on that, we propose several adaptive cooperative schemes for both the decode-and-forward (DF) and amplify-and-forward (AF) protocols. To evaluate these schemes, we provide performance analysis in terms of average spectral efficiency, average bit error rate (ABER), and outage probability over Rayleigh fading channels. We start with the single-relay cooperative system using DF protocol, in which two adaptive cooperative schemes with variable-rate transmission are proposed. The first scheme, called the minimum error rate scheme (MERS), aims to exploit the transmit diversity to improve the bit error rate. By trading the multiplexing gain against the diversity gain, we propose the second scheme, called the maximum spectral efficiency scheme (MSES), in which cooperative transmission is avoided whenever it is not beneficial. The MERS improves the ABER significantly and achieves equal or better average spectral efficiency compared to the fixed (i.e., non-adaptive) relaying scheme. In contrast, the MSES provides the best average spectral efficiency due to its ability to not only adapt to the channel variation but also to switch between cooperative and non-cooperative transmissions. To further increase the spectral efficiency, we then propose the third scheme, called variable-rate based relay selection (VRRS) scheme, in which a relay node is selected from among the available relay nodes, based on a predefined criterion. Furthermore, we propose two AF adaptive cooperative schemes, mainly to enhance the spectral efficiency. In the first scheme, we introduce a generalized switching policy (GSP) for a single-relay cooperative wireless system that exploits the variable-rate transmission and useful cooperative regions. The second scheme, called the AF efficient relay selection (AFERS) scheme, extends the GSP to also consider the relay selection technique. Analytical and simulation results verify that the AFERS scheme not only outperforms conventional direct transmission in terms of the average spectral efficiency, but also the AF fixed relaying and the outage-based AF adaptive cooperative scheme. The second topic investigates the fair power consumption of the relay nodes for AF cooperative wireless communication systems. The fairness is defined as to achieve equal power consumption over the relay nodes. We focus on how the relay selection process can be controlled in a distributed manner so that the power consumption of the relay nodes can be included in relay selection. We first introduce a simple closed-form expression for the weight coefficient used in order to achieve the considered fairness that depends only on the local average channel conditions of the relay path. We then derive closed-form expressions of the weighted outage probability and ABER and show that our proposed strategy not only has less complexity than the conventional centralized one but also provides better accuracy in distributing the total consumed power equally among the relay nodes without affecting the performance.

Author: Ali Zarei Ghanavati
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ISBN:
Category :
Languages : en
Pages : 113

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One of the main issues of wireless communication systems is to cope with random variationof their channel conditions. In many wireless communication systems, the receiver estimatesthe channel for symbol detection. It is usually assumed that channel estimation is perfect,but in practice, channel estimation error (CEE) can become signicant and can degrade theperformance of wireless communication systems. This thesis addresses the eects of channelestimation error in two contexts: CEE in cooperative communication systems and CEE inlink layer performance.Cooperative diversity, which has been recently presented as an eective way of mitigatingthe eect of deep fades in wireless channels and improving spectral and power eciencyof the wireless networks, is considered in the rst part of this dissertation. Taking intoconsideration the presence of CEE, part I of this thesis analyzes a few cooperative communicationsystem models, which display dierent levels of practicality and represent largeclasses of cooperative systems in the literature. This thesis spells out delineating aspectsof these models and rigorously compares their error probabilities. Furthermore, a novelsignal detection scheme in the presence of CEE is presented for large classes of cooperativecommunication systems.Part II of this dissertation focuses on cross layer issues between the physical and linklayers of wireless communication systems. In particular, the frame error probability (FEP)is derived for a wireless communication system over fading channels in the presence ofCEE. Part II also explores the issue of optimizing bit transmission power for minimizing theexpected energy required to reliably deliver a frame to the destination node through an ARQmechanism over a fading channel. Also, an optimization algorithm is designed to minimizethe expected energy for reliable delivery of a frame for the systems under consideration.

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Publisher: Academic Press
ISBN: 012397223X
Category : Technology & Engineering
Languages : en
Pages : 687

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This book gives a review of the principles, methods and techniques of important and emerging research topics and technologies in Channel Coding, including theory, algorithms, and applications. Edited by leading people in the field who, through their reputation, have been able to commission experts to write on a particular topic. With this reference source you will: - Quickly grasp a new area of research - Understand the underlying principles of a topic and its applications - 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 Channel Coding - Presents core principles in Channel Coding theory and shows their applications - 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

Author: Andrea Jo Goldsmith
Publisher:
ISBN:
Category : Wireless communication systems
Languages : en
Pages : 432

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Author: Hemanta Kumar Sahu
Publisher:
ISBN: 9789999315715
Category : Technology & Engineering
Languages : en
Pages : 0

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Diving into the cutting-edge realm of wireless communication, "Harvesting Signals" offers a meticulous exploration of the synergistic potential between cooperative communication, Space Shift Keying (SSK) modulation, and Radio Frequency (RF) energy harvesting. In a landscape where the demand for efficient wireless networks is ever-growing, this book presents a groundbreaking investigation into the fusion of cooperative strategies with advanced modulation techniques, promising not only enhanced spectral efficiency but also sustainable energy utilization through RF energy harvesting. Authored by leading experts in the field, this comprehensive analysis delves into the theoretical foundations, practical implementations, and performance evaluations of cooperative communication systems employing SSK modulation and RF energy harvesting. Through a blend of rigorous mathematical frameworks and practical insights, readers are guided through the intricacies of system design, resource allocation, and optimization strategies. From theoretical derivations to real-world experimentation, "Harvesting Signals" offers a roadmap for researchers, engineers, and students alike to navigate the complexities of next-generation wireless networks. Whether seeking to optimize spectral efficiency, extend network lifetime, or minimize energy consumption, this book serves as an indispensable resource in unlocking the full potential of cooperative communication combined with SSK modulation and RF energy harvesting. Prepare to embark on a journey into the forefront of wireless communication research, where innovation meets sustainability, and where the pursuit of performance leads to the harvesting of signals.

Author: Uysal, Murat
Publisher: IGI Global
ISBN: 1605666661
Category : Computers
Languages : en
Pages : 632

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Offers practitioners, researchers, and academicians with fundamental principles of cooperative communication. This book provides readers diverse findings and exposes underlying issues in the analysis, design, and optimization of wireless systems.

Author: Ibrahim Y. Abualhaol
Publisher:
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Category :
Languages : en
Pages : 332

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Author: Jie Yang
Publisher:
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Category : Antenna arrays
Languages : en
Pages : 332

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Abstract: This dissertation studies several problems centered around developing a better understanding of the energy efficiency of cooperative wireless communication systems. Cooperative communication is a technique where two or more nodes in a wireless network pool their antenna resources to form a "virtual antenna array". Over the last decade, researchers have shown that many of the benefits of real antenna arrays, e.g. spatial diversity, increased range, and/or decreased transmission energy, can be achieved by nodes using cooperative transmission. This dissertation extends the current body of knowledge by providing a comprehensive study of the energy efficiency of two-source cooperative transmission under differing assumptions about channel state knowledge, cooperative protocol, and node selfishness. The first part of this dissertation analyzes the effect of channel state information on the optimum energy allocation and energy efficiency of a simple cooperative transmission protocol called "orthogonal amplify-and-forward" (OAF). The source nodes are required to achieve a quality-of service (QoS) constraint, e.g. signal to noise ratio or outage probability, at the destination. Since a QoS constraint does not specify a unique transmit energy allocation when the nodes use OAF cooperative transmission, minimum total energy strategies are provided for both short-term and long-term QoS constraints. For independent Rayleigh fading channels, full knowledge of the channel state at both of the sources and at the destination is shown to significantly improve the energy efficiency of OAF cooperative transmission as well as direct (non-cooperative) transmission. The results also demonstrate how channel state knowledge affects the minimum total energy allocation strategy. Under identical channel state knowledge assumptions, the results demonstrate that OAF cooperative transmission tends to have better energy efficiency than direct transmission over a wide range of channel conditions. The second part of this dissertation focuses on the development of an opportunistic hybrid cooperative transmission protocol that achieves increased energy efficiency by not only optimizing the resource allocation but also by selecting the most energy efficient cooperative transmission protocol from a set of available protocols according to the current channel state. The protocols considered in the development of the hybrid cooperative transmission protocol include compress-and-forward (CF), estimate-and-forward (EF), non-orthogonal amplify-and-forward (NAF), and decode-and-forward (DF). Instantaneous capacity results are analyzed under the assumption of full channel state knowledge at both of the sources and the destination node. Numerical results are presented showing that the delay limited capacity and outage probability of the hybrid cooperative transmission protocol are superior to that of any single protocol and are also close to the cut-set bound over a wide range of channel conditions. The final part of this dissertation focuses on the issue of node selfishness in cooperative transmission. It is common to assume in networks with a central authority, e.g. military networks, that nodes will always be willing to offer help to other nodes when requested to do so. This assumption may not be valid in ad hoc networks operating without a central authority. This section of the dissertation considers the effect selfish behavior on the energy efficiency of cooperative communication systems. Using tools from non-cooperative game theory, a two-player relaying game is formulated and analyzed in non-fading and fading channel scenarios. In non-fading channels, it is shown that a cooperative equilibrium can exist between two self-interested sources given that the end of the cooperative interaction is uncertain, that the sources can achieve mutual benefit through cooperation, and that the sources are sufficiently patient in the sense that they value future payoffs. In fading channels, a cooperative conditional trigger strategy is proposed and shown to be an equilibrium of the two-player game. Sources following this strategy are shown to achieve an energy efficiency very close to that of a centrally-controlled system when they are sufficiently patient. The results in this section show that cooperation can often be established between two purely self-interested sources without the development of extrinsic incentive mechanisms like virtual currency.

Author: Mohammad Jafar Taghiyar Renani
Publisher:
ISBN:
Category : Wireless communication systems
Languages : en
Pages : 0

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Space-time coding has demonstrated that the deployment of multiple antennas at the transmitter allows for simultaneous increase in throughput and reliability. However, the use of antenna arrays is impractical for deployment in some practical scenarios. Therefore, cooperative diversity has been recently introduced for realizing transmit diversity. Most of the literature in cooperative diversity assume perfect channel state information (CSI). However, in practice, imperfect CSI should be considered. In this thesis, we first investigate the performance of cooperative communications with imperfect CSI, where the channel estimates are obtained by pilot symbols. We present an exact bit error probability expression in the presence of channel estimation errors. We also study the effect of imperfect CSI in two-way multi-relay cooperative networks when the max-min relay selection is used. We derive an exact expression for the outage probability based on which a novel optimum power allocation scheme is proposed.