Research On Energy Efficiency Of Relay Antenna Selection In Cooperative MIMO System

Cooperative multi-input-multi-output (MIMO) system has the advantages of both the MIMO technique and the cooperative technique. Through making full use of spatial diversity gain, it can solve wireless multi-path fading problem, considerably improve the signal-to-noise ratio (SNR), need less transmit power than Single-input-single-output (SISO) system, and finally improve the spectral efficiency of the wireless communica-tion system significantly. However, since the circuitry consumption also increase with the number of nodes and antennas involved in the the communication process, total energy efficiency may not always be beneficial.First of all, this thesis introduces diversity properties of MIMO system, derives the system capacity and outage probability formula. Then this thesis describes some typi-cal collaborative communication model, which can effectively improve system outage probability caused by channel fading.Then this thesis focused on a single relay cooperation MIMO system, whose re-lay works under incremental decoding forward (IDF) protocol. The main problem is the energy efficiency of different relay antenna selection strategies. We use a better cooper-ative protocol and make a comprehensive analysis of antennas relay selection strategy, compare system outage probability, throughput and energy efficiency and other system metrics between SISO and MIMO relay system. In the transmit antenna selection (TAS) policy, the source node can be fed to select antenna from the destination node (TASD) or from the relay node (TASR). Simulation result shows that generally TASD has bet-ter performance. The relay, which works under half-duplex, can choose switch and stay (SSC) strategy or maximum ratio combining (MRC) strategy when listening from the source node, and can choose transmit antenna selection (TAS) strategy or beamforming (TBF) strategy when forward the information to the destination node. In this thesis, the source node works under TASD and the destination node works under SSC. We de-rived the outage probability and the energy efficiency formula of the system, the relay of which works under different strategies. Simulation results show that system with relay works under MRC+TBF has a maximum throughput, and has better performance when communication distance is large, and the system with relay works under SSC+TAS is more suitable when channel condition is better, such as the power of the source node is large or a short communication distance.Finally, this thesis studied another MIMO cooperative system, with the source node working under TBF and the destination node working under MRC. We reduced energy efficiency and outage probability expressions of the system with the relay in different working status. Simulation results show a similar conclusion.