Spatial Modulation In Cooperative MISO Systems And Performance Analysis

By adding relay nodes to assist with information transmission from source to destination,cooperative communication can improve spectral efficiency and network coverage for wireless communication systems effectively.Spatial modulation(SM)scheme can overcome the inter-channel interference and synchronization problems,as well as reducing the implementation complexity and cost of multi-antenna system.Also,SM is able to obtain high data transmission rate by using the antenna index to transmit information invisibly.By combing the cooperative communication and SM technology,the performance analysis of cooperative spatial modulation system over Rayleigh fading channels and Nakagami fading channels is investigated in this paper.In order to improving system performance,the asymptotic performance analysis and corresponding adaptive power allocation schemes are given,which provide good theoretical basis for performance evaluation and optimization of cooperative spatial modulation system.The main work of this paper is as follows:1.Performance analysis of cooperative spatial modulation MISO system is investigated.Firstly,the system model of cooperative spatial modulation MISO system using amplify-and-forward relaying is introduced.Secondly,the bit error probability of symbol estimation(P_d)and bit error probability of transmit antenna index estimation(P_a)are obtained by using the probability density function(PDF)and the moment generating function(MGF)of the signal-to-noise-ratio(SNR)at the source-relay-destination link and source-destination link,respectively.Finally,based on the above-mentionedP_d andP_a,the theoretical expressions of the average bit error rate(BER)of the system can be derived.The simulation results verify the effectiveness of the theoretical analysis.2.The adaptive power allocation scheme of cooperative spatial modulation MISO system is investigated.The power allocation technology is introduced in the cooperative spatial modulation MISO system to allocate the transmit power at source node and relay node reasonably.Firstly,the asymptotic approximation formulas of P_d,P_a and average BER are derived respectively.Then an optimal power allocation scheme and two sub-optimal power allocation schemes are given,which based on the accurate BER formula and above-mentioned asymptotic approximation BER expression.The simulation results show that the cooperative spatial modulation MISO system with adaptive power allocation can achieve better BER performance.3.Performance analysis of cooperative spatial modulation MISO system over Nakagami fading channels is studied.The system model of cooperative spatial modulation MISO system over Nakagami fading channels is given firstly.Then the corresponding theoretical expressions of P_d and P_a are derived,which contribute the average BER.In high SNRs,the asymptotic approximation formulas ofP_d,P_a and average BER are obtained.Based on the asymptotic approximation formulas,we also analysis the diversity orders of the system.Simulation results verify the correctness of the theoretical analysis.