Based On Relay Selection Scheme And ARQ Joint Optimization Research Of Cooperative Communication

Wireless wideband technology let people remove the limitation of traditional wire communication and enter the mobile communication age. Being confronted with great research and appliance market, wireless mobile communication obtain rapid development and cause the fast evolution from the first generation mobile communication to the third generation mobile communication, which make the requirement of wireless services stand out. Especially the next generation mobile communication, ask stationary terminal to achieve lGbps information transmission rate while mobile terminal to obtain 100Mbps information transmission rate. But, limited spectral resources will become the development bottleneck of wireless communication in the future. Fortunately, multiple antennas technology enables to raise the information transmission rate and spectral efficiency, so, it has been hot point in wireless communication area. However, owing to the practical limitations, some terminals cannot be arranged with multiple antennas, then, there is a new class of methods called cooperative communication had been proposed.Cooperative communication enables single-antenna terminals in a multiple users networks to share their unique antenna with each other and generate a virtual multiple antennas transmitter that make them obtain transmit diversity. So, it has been widely investigated in this decade within wireless cellular network, ad-hoc and wireless sensor network and so on. Recently, there mainly are three cooperative protocols being acknowledged: AF, DF and CC. For cooperative communication, without question, relay selection scheme is the most important and hot point. Through large numbers of research and practical consideration, there mainly are also three relay selection schemes, that is, FPLRS, ORS and ITRS. Unfortunately, there still exist some difficult questions needed be urgently resolved, such as, how to decide the number of cooperative relays, which relay selection scheme and cooperative protocol will be adopted, how to achieve power allocation and network joint optimization.In this paper, we improve some methods and propose some innovative technologies, not only display theoretical analyses in detail, but also list a large number of performance simulations and corresponding result analyses.Firstly, single-antenna terminal network combing with space time block code was taken into consideration. According to Shannon formula and Ford-Fulkerson theorem (MFML), we calculate channel capacity and obtain the outage probability of the whole cooperative system. Alamouti scheme being used by the'best' and 'sub-best' relays listed by fixed priority table was investigated. Subsequently, we assume multiple relay terminals use DF, while, we also deduce an optimal power allocation scheme. Finally, whether the distance and antennas' correlation between cooperative relays can influence the outage probability of whole cooperative system also had been investigated.Secondly, we apply ORS to cooperative MIMO system, which every relay was arranged with multiple antennas. Relays can automatically detect the CSI and use MRRC and Beamforming technology. In order to minimizing the outage probability of whole cooperative system, based on ORS and practical situation we proposed a new relay selection scheme and provided a statistical optimal power allocation scheme. Close-form expression of outage probability and diversity order were also displayed. In the interests of fairness, there are two situation used to simulation, that is, same number relay terminals with different number antennas and different number relay terminals with same number antennas.Lastly, we focus our research point on how to use ARQ technology to jointly optimize the whole cooperative system so as to decrease the collision probability which is not be avoided in distributed wireless network. The new scheme'A Joint Optimization Scheme based Relay Selection and Adaptive Cooperative Protocol Switch' was not only obtain better outage probability than ORS and ITRS and decrease the collision probability comparing to ORS, but also own the powerful robustness to different network topologies.