Performance Analysis of Decode-and-Forward Protocols in Unidirectional and Bidirectional Cooperative Diversity Networks PDF Download

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Languages : en
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Cooperative communications have the ability to induce spatial diversity, increase channel capacity, and attain broader cell coverage with single-antenna terminals. This thesis focuses on the performance study of both unidirectional and bidirectional cooperative diversity networks employing the decode-and-forward (DF) protocol. For the unidirectional cooperative diversity network, we study the average bit-error rate (BER) performance of a DF protocol with maximum-likelihood (ML) detection. Closed-form approximate average BER expressions involving only elementary functions are presented for a cooperative diversity network with one or two relays. The proposed BER expressions are valid for both coherent and non-coherent binary signallings. With Monte-Carlo simulations, it is verified that the proposed BER expressions are extremely accurate for the whole signal-to-noise ratio (SNR) range. For the bidirectional cooperative diversity network, we study and compare the performance of three very typical bidirectional communication protocols based on the decode-and-forward relaying: time division broadcast (TDBC), physical-layer network coding (PNC), and opportunistic source selection (OSS). Specifically, we derive an exact outage probability in a one-integral form for the TDBC protocol, and exact closed-form outage probabilities for the PNC and OSS protocols. For the TDBC protocol, we also derive extremely tight upper and lower bounds on the outage probability in closed-form. Moreover, asymptotic outage probability performance of each protocol is studied. Finally, we study the diversity-multiplexing tradeoff (DMT) performance of each protocol both in the finite and infinite SNR regimes. The performance analysis presented in this thesis can be used as a useful tool to guide practical system designs for both unidirectional and bidirectional cooperative diversity networks.

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Languages : en
Pages : 121

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Space-time coding and spatial diversity schemes enhance the performance of energy constrained multihop clustered relay networks. The purpose of this thesis is to evaluate the performance of techniques such as the decode-and-forward with cooperative diversity and the Alamouti space-time coding, which were primarily used in relay multiple-input multiple-output communications, in distributed clustered two-hop and multihop relaying networks consisting of single-antenna terminals. Simulation results, in single carrier Rayleigh and Stanford University Interim channels for phase shift keyed and quadrature amplitude modulation, show that the use of the decode-and-forward with cooperative diversity and the Alamouti cooperative space-time coding schemes improve the error probability performance in a power constrained, clustered multihop relaying network operating in a multipath fading environment.

Author: Xilin Bai
Publisher:
ISBN:
Category :
Languages : en
Pages : 43

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In conventional point-to-point wireless communication, wireless channels may suffer from multipath fading, in which signal attenuation can vary significantly over the course of a given transmission, and thus communication between transmitter and receiver is vulnerable. In recent years, a new paradigm of cooperative communication was proposed and had become a heated topic in the design of wireless networks, such as cellular networks and wireless ad hoc networks. The basic idea lies in cooperative communication is that individual mobile users in wireless networks help each other to send signals to the destination cooperatively. The destination jointly detects multiple copies of the received signals from different cooperative users. Due to the cooperative diversity, the joint detection of the combined signals can be more reliable, and system performance as well as robustness can be significantly improved. The user who helps others forward the information is called a relay. According to the functions of the relay, there are two kinds of cooperative protocols: the relay may first decode the received information and then forward it to the destination as called decode-and-forward (DF) cooperative protocol, or the relay may simply amplify the received signal and forward it as called amplify-and-forward (AF) cooperation protocol. The aim of this thesis research is to implement the DF cooperative communication system based on GNU Radio and Universal Software Radio Peripheral (USRP). Specifically, we focus on a two-user cooperation scheme, one serves as the source node, while the other can be the relay node. The experiments of this model are carried out on GNU Radio, an open-source software development toolkit, and USRPs, computer-hosted software radios. To measure the experiments results, the packet-error-rate (PER) performance analysis is provided for cooperative communications in wireless networks with different configurations, such as various relay positioning, power allocation, payload length and experiment environment. From the simulation results, we can see that the location of the relay plays a critical role in the performance of cooperative communication. The closer the relay to the source, the more transmitter power is preserved; while the closer the relay to the destination, the more receiver power is kept. It is observed that laying the relay near around midpoint of the source and destination will achieve the best cooperative performance. Regarding various power allocation, in a certain low power range, the larger the power is, the better the transmission performance is. However, beyond this power range, different as expected, the less the power is, the better result there will be. This could possibly be caused by the limitation of the amplifier in the USRP boards. Furthermore, with regard to different payload length, the longer the packet is, the more possibilities that the packet is decoded wrong. Finally, tests in different environment show that no matter inside a room, in the narrow hall way, or in open space, the above transmission trend turns out to be the same. The main contribution of the thesis lies in: First, the implementation of the channel estimation based on GNU Radio and USRPs; Second, the design of packet format in order to implement the DF cooperation systems; Third, the implementation of the maximum ratio combing (MRC) and joint decode at the destination. In this research project, we achieve the goal of implementing the DF cooperative communication protocols on the platform of GNU Radio and USRPs, verifying the theoretical performance in books, and learning from experiment results under different scenarios and contributing to the design of DF cooperative communication systems.

Author: MinChul Ju
Publisher:
ISBN:
Category :
Languages : en
Pages : 290

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Relay communication has been shown to be effective to extend service coverage and mitigate channel impairments. This thesis focuses on relay selection (RS) of both unidirectional and bidirectional relay networks employing the amplify-and-forward (AF) and decode-and-forward (DF) protocols. This thesis presents four works on RS in two-hop relay networks. In the first work, we study opportunistic relaying (OR) and selection cooperation (SC) in DF-based unidirectional multi-antennas relay networks. We first propose two joint relay-and-antenna selection schemes which combine OR and SC, respectively, with transmit antenna selection. For each joint selection scheme, a single best transmit antenna at the source, a single best relay, and a single best transmit antenna at this selected relay are jointly determined. Then we derive the outage probabilities, and show that the two schemes achieve the same outage performance. In the second work, we study RS with the physical-layer network coding (PNC) in DF-based bidirectional relay networks. By modifying the well-known SC and OR, we first propose two RS schemes for the PNC network: SC-PNC and OR-PNC. Then we derive the outage probability and diversity order of the SC-PNC. Finally, we show that the OR-PNC achieves the same outage performance as the SC-PNC. In the third work, we study RS with the analog network coding (ANC) and time division broadcast (TDBC), in AF-based bidirectional relay networks. We first consider RS schemes for the ANC and TDBC protocols based on a max-min criterion. Then we derive outage probabilities for the ANC and TDBC protocols. In the fourth work, we study joint relay-and-source selection in an AF-based bidirectional relay network. Since RS and opportunistic source selection (OSS) could individually improve performance of relay networks, we propose a joint RS-OSS protocol. In this network, a best source is selected to transmit data to the other source with the help of a selected best relay. Then, we derive the outage probability and average bit-error rate. The considered RS schemes and obtained outage probability expressions will help the design of two-hop wireless communications in determining the system parameters such as relay location and the transmission power at each terminal.

Author: Salama Said Ikki
Publisher:
ISBN:
Category : Data transmission systems
Languages : en
Pages : 0

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Author: Larry L. Peterson
Publisher: Elsevier
ISBN: 0123850606
Category : Computers
Languages : en
Pages : 921

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Book Description
Computer Networks: A Systems Approach, Fifth Edition, explores the key principles of computer networking, with examples drawn from the real world of network and protocol design. Using the Internet as the primary example, this best-selling and classic textbook explains various protocols and networking technologies. The systems-oriented approach encourages students to think about how individual network components fit into a larger, complex system of interactions. This book has a completely updated content with expanded coverage of the topics of utmost importance to networking professionals and students, including P2P, wireless, network security, and network applications such as e-mail and the Web, IP telephony and video streaming, and peer-to-peer file sharing. There is now increased focus on application layer issues where innovative and exciting research and design is currently the center of attention. Other topics include network design and architecture; the ways users can connect to a network; the concepts of switching, routing, and internetworking; end-to-end protocols; congestion control and resource allocation; and end-to-end data. Each chapter includes a problem statement, which introduces issues to be examined; shaded sidebars that elaborate on a topic or introduce a related advanced topic; What's Next? discussions that deal with emerging issues in research, the commercial world, or society; and exercises. This book is written for graduate or upper-division undergraduate classes in computer networking. It will also be useful for industry professionals retraining for network-related assignments, as well as for network practitioners seeking to understand the workings of network protocols and the big picture of networking. - Completely updated content with expanded coverage of the topics of utmost importance to networking professionals and students, including P2P, wireless, security, and applications - Increased focus on application layer issues where innovative and exciting research and design is currently the center of attention - Free downloadable network simulation software and lab experiments manual available

Author: Andrew S. Tanenbaum
Publisher: Prentice Hall
ISBN: 9780135408001
Category :
Languages : en
Pages : 30

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Author: Andrew S. Tanenbaum
Publisher:
ISBN: 9789332518742
Category : Computer networks
Languages : en
Pages : 0

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This edition reflects the latest networking technologies with a special emphasis on wireless networking, including 802.11, 802.16, Bluetooth, and 3G cellular, paired with fixed-network coverage of ADSL, Internet over cable, gigabit Ethernet, MPLS, and peer-to-peer networks. It incorporates new coverage on 3G mobile phone networks, Fiber to the Home, RFID, delay-tolerant networks, and 802.11 security, in addition to expanded material on Internet routing, multicasting, congestion control, quality of service, real-time transport, and content distribution.

Author: National Research Council
Publisher: National Academies Press
ISBN: 0309324882
Category : Social Science
Languages : en
Pages : 587

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Children are already learning at birth, and they develop and learn at a rapid pace in their early years. This provides a critical foundation for lifelong progress, and the adults who provide for the care and the education of young children bear a great responsibility for their health, development, and learning. Despite the fact that they share the same objective - to nurture young children and secure their future success - the various practitioners who contribute to the care and the education of children from birth through age 8 are not acknowledged as a workforce unified by the common knowledge and competencies needed to do their jobs well. Transforming the Workforce for Children Birth Through Age 8 explores the science of child development, particularly looking at implications for the professionals who work with children. This report examines the current capacities and practices of the workforce, the settings in which they work, the policies and infrastructure that set qualifications and provide professional learning, and the government agencies and other funders who support and oversee these systems. This book then makes recommendations to improve the quality of professional practice and the practice environment for care and education professionals. These detailed recommendations create a blueprint for action that builds on a unifying foundation of child development and early learning, shared knowledge and competencies for care and education professionals, and principles for effective professional learning. Young children thrive and learn best when they have secure, positive relationships with adults who are knowledgeable about how to support their development and learning and are responsive to their individual progress. Transforming the Workforce for Children Birth Through Age 8 offers guidance on system changes to improve the quality of professional practice, specific actions to improve professional learning systems and workforce development, and research to continue to build the knowledge base in ways that will directly advance and inform future actions. The recommendations of this book provide an opportunity to improve the quality of the care and the education that children receive, and ultimately improve outcomes for children.

Author: David Tse
Publisher: Cambridge University Press
ISBN: 9780521845274
Category : Computers
Languages : en
Pages : 598

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Book Description
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.