The Research Of New Protocol In Cooperative Communication

Multiple input multiple output (multiple-input multiple-out, MIMO) technology is one of the key technology of the fourth generation mobile communication technology. MIMO technology is installed several antennas in the transmitter and receiver, then the receiver can obtain different copies of the same signal, then the receiver can obtain space diversity. Space diversity can efficiently against signal decline in the environment to improve the channel capacity. However, as the limited of volume, cost and power consumption, it isn’t realized to install many antennas in one device, the cooperative communication solve the problems. Cooperative communication that the node have one antenna shares its antenna with other nodes by some ways to improve spatial diversity gain and channel capacity.The research achievements of this paper includes three parts:1)The SER is researched in three nodes cooperative communication system when the relay use HDAF protocol. First, the SER expression of the system is deduced. Second, as the exact expression is complex, the approximate expression is deduced. The simulation result shows that the approximate expression can replace exact expression when the total power is higher than 1 Odb.2)The power allocation is researched based on the approximate SER expression. The result shows that, the optimum power allocation factor in HDAF protocol is not only related to the channel which are source-to-relay and relay-to-destination, but also related to the total power of system. The optimum power allocation factor will be tend to 1/2 with the increase of total power.3)The SER performance and outage probability performance is researched when the incremental relay system has two relays. The SER expression and outage probability expression are deduced based on incremental two relays, then compare the performance of incremental two relays with incremental relay. The result shows that, on the one hand, the outage probability of incremental two relays is inferior to incremental relay in low SNR area, but superior to incremental relay in high SNR area. on the other hand, the SER performance of incremental two relays is better than incremental relay.At last, the article conclude the research achievement and summarize the hot topics about cooperative communication, and predict the probable problems that will be researched in the future.