Research On Performance Of Communication Systems Based On Quadrature Spatial Modulation

With the rapid development of wireless communication technology,large-scale MIMO technology has become one of the key solutions to the high data rate,ultra-low latency and massive data requirements of the Fifth Generation Mobile Communication Network(5G).However,multiple active radio frequency(RF)chains consume a large proportion of power,which results in a lower energy efficiency(EE)for large-scale MIMO.Moreover,the disadvantages such as inter-channel interference(ICI)and precise inter-antenna synchronization(IAS)also limit the development and application of large-scale MIMO technology.Quadrature spatial modulation(QSM)is a novel MIMO transmission technology which not only uses traditional constellation symbols to carry information bits,but also uses the active transmit antenna index to transmit additional information bits.As QSM technology activates only one quadrature antenna subset in each transmission time slot,it overcomes the shortcomings of MIMO technology in terms of spectral efficiency,energy efficiency and hardware complexity,and becomes the key technology that is expected to replace the traditional MIMO.Based on this,the main contributions of this dissertation are outlined as follows:1.The performance of QSM MIMO system under two communication scenarios is studied:(1)Direct communication under the Rayleigh channels and the Nakagami-m channels;(2)Communication using transmit antenna selection(TAS)technology under the Rayleigh channels.The closed expressions for outage probability of the considered system in two scenarios are derived and the bit error rate of the QSM MIMO system under TAS is analyzed.In addition,the results of the analysis are verified by Monte Carlo simulations.The results show that the QSM MIMO system has significant improvement in the outage performance compared to SM MIMO system at the same transmission rate.Moreover,the outage probability of the considered system under TAS decreases with the increase of the transmitting antennas.2.Considering the QSM amplify and forward(AF)cooperative communication system with multiple receiving antennas in the destination node.The performance of the system in two scenarios is studied:(1)the source node and the destination node communicate with a single relay;(2)the source node and the destination node communicate with multiple relays,and relay selection is used based on the maximum signal-to-noise ratio(SNR)principle.The exact closed expressions of the outage probability in two scenarios are derived respectively.And the outage performance and bit error performance of the considered system are analyzed by Monte Carlo simulation.The simulation results show that,the relay selection scheme can improve the outage performance of the considered system.From the analysis of numerical results,we can find that as the number of relays increases,the outage probability of the system decreases.3.The communication system combining QSM with multi-relay cognitive cooperative technology is studied.The relay nodes and the destination node of the system were decoded by the maximum likelihood detection(ML)algorithm.In addition,the mean power allocation algorithm was used to analyze the outage performance of the system.The exact outage probabilities of three relay selection strategies were analyzed and derived respectively:(1)random relay selection(RRS);(2)suboptimal relay selection(SRS);(3)optimal relay selection(ORS).To more intuitively evaluate system performance,the approximate outage performance and the diversity gains of three relay selection strategies were studied,and the above performance is simulated by Monte Carlo.The theoretical analysis and simulation results show that,ORS can obviously reduce the outage probability and effectively improve the gain of the system comparing with RRS and SRS.