The Performance Research Of Device-to-Device Communication System Based On Relay And Multi-antenna Technology

D2D(Device-to-Device) communication is a terminal direct communication technologies, which can effectively improve the spectrum utilization and reduce the pressure on the cellular network. However, due to the short communication distance, D2 D communication is not widely used in a cellular system, which can be effectively solved by the relay and multi-antenna assisted D2 D communication system. The main contributions are summarizes as follows:Firstly, the system performance of D2 D communication with the assistance of relay technology is studied in this thesis. The best relay is selected by using the opportunity relay algorithm to participate in the collaboration. The formula of the system outage probability, mutual information under the different modes is derived. Simulation results verify the theoretical analysis, also show that the application of relay technology can effectively improve the capacity of the D2 D system.Secondly, the D2 D relay communication system with the assistance of multi-antenna technology is studied. This paper considers two kinds of multi-antenna relay scenario: Only the receiving end of a multi-antenna system(SIMO), sending and receiving end are multi-antenna systems(MIMO). Under two scenarios, the formula of outage probability, error rates, and system capacity is derived. Simulation results verify the correctness of the formula, which also show that the use of multiple antennas and relay technology can effectively reduce the outage probability.Finally, D2 D relay communication system based on virtual MIMO technology is studied. Multi-antenna technology can bring huge performance gains but also brings a high price, which can be solved by the virtual MIMO technology. With the help of the communications technology of cluster collaboration, D2 D pairs use surrounding free devices to construct virtual antenna arrays and obtain MIMO capacity gains. According to the situation whether cooperation node can decode signal, two strategies of D2 D link based virtual MIMO communication is studied.