Research On Network Coding For Wireless Relaying System

Network coding, known as an information exchange technology which combining simple coding and routing, first proposed in the noiseless wired network. By taking advantage of the broadcast nature of wireless networks, the application of network coding can increase system throughput. The number of the packet transmission and the power of sending can be reduced. Network coding can also enhance Error correction and robustness of the network. Substantial research has been witnessed in the field of theory and application of network coding in recent years.As a result, this thesis presents the studies of network coding technology applied to relay-based cooperative communication. Through theoretical analysis and numerical results, the good performance of the network coding in different wireless transmission scenarios is investigated. We focus on the design of the system solutions and Reasonable use of network resource.The contents of this work are listed as follows:The development of wireless communications is introduced, together with the background of the network coding technology and some domestic and foreign research advances.A cooperative ARQ protocol with network coding is proposed for uplink transmission system. First, the benefit of cooperative ARQ for wireless communications is analyzed. Then implementations and algorithm flow are investigated. Through theoretical analysis and numerical evaluation, we show that our scheme can improve the network resource utilization and the reliability of data transmission, by allowing relay to forwarding XOR-code between the new source information and the required retransmission information.Network coding for successive relaying system is studied. The conception of successive relaying and its key points are introduced. Then three relay strategies are detailed described, which are repetition coding, superposition coding and network coding. Theoretical analysis and numerical evaluation illustrate the possibility to improve system performance by using network coding. The performance of the protocols under different scenarios is also given.Network coding for two-way relaying system is studied. Power allocation and relay selection with individual transmission power constraint are analyzed. Distributed solution and centralized solution for this problem are presented, which considered to be sub-optimal for OFDM system. These two algorithms can effectively improve system transmission rate, but also have relatively low complexity.