Research On Relaying Protocols And Relay Selection Scheme In Wireless Cooperation Communication

Multi-antenna technology has large number of advantages，like improving thereliability of system transmission, enhancing system capacity, confront the wirelessfading channels effectively and so on. However, in actually, the system is limited bycommunication equipment volume, energy consumption computation ability and so on,it’s much more difficult to equip many antennas on communication ends in limited size.So, how to solve these problems as well as take the advantages of multi-antennatechnology is widely discussed in researchers. And then, the concept of cooperativecommunication is put forward. In cooperative communication, usually there are manypotential relay nodes in system, compared with the multiple relay nodes participate inthe cooperative communications, single relay selection technology is more simple, andit can not only make use of all the channel state information (CSI) to achieve fulldiversity, but also can improve the system performance.In this paper, we simply introduce the background and current situation ofdevelopment of cooperative communication, sum up diversity technology and diversitymerging technology, and at the same time, review the various typical relay protocols ofcooperative communication. This paper mostly focuses on the relay protocols and singlerelay selection strategy in cooperative communication system, so the main researchcontent of this paper is as follows:Base on the three-node system model, we researched the outage probabilityperformance of the incremental relaying protocol. In this paper, we introduce thecommon incremental relaying protocol--incremental amplify-and-forwardprotocol(IAF) and incremental selection amplify-and-forward (ISAF), and discuss and analyzetheir outage probability performance under the condition of high signal-to-noise. On thebasis of IAF and ISAF, this paper proposed a new incremental relaying protocol namedincremental amplify-and-forward protocol based on competitionscheme and ARQ. Thisprotocol base on the three-node cooperative communication system, added ARQmechanism in the cooperation, the destination node through feedback control frameACK/NACK to decide whether to adopt cooperative transmission. In this paper, theoutage probability performance and diversity-multiplexing trade-off (DMT)performance of new protocol is be derived, it proves that the proposed protocol can effectively improve the outage probability and the DMT performance with theincreasing the number of repeat sending times.Then considered the system with a path between the source and the destination, theoutage performance of the single relaying selection strategy including both selectioncooperation and opportunistic relaying are re-examined. Under different decodingforwarding protocols, these two relaying selection strategies are narrated and theirperformance is discussed in detail. Finally simulation shows that the outage probabilityperformance of selection cooperation is much better than that of opportunistic relayingscheme under the decoded-forward (DF) protocol and incremental decoded-forward(IDF) protocol. However, under the selective decoded-forward (SDF) protocol, theoutage performance of selection cooperation is may be worse than that of opportunisticrelaying scheme in the condition of existing less number of the relay, but in most of theconditions, the selection cooperation is better. Specially, in the case of with greaternumber of the relay case, the advantage is more obvious.