Research Of Spatial Modulation Based On Differential Code

With the vigorous development of mobile communication technology,people are becoming more and more need high-speed transmission rate,large capacity,super reliability,anytime and anywhere access.In the face of growing demand,communication resources are scarce.So,a new wireless transmission technology is further needed.Spatial modulation(SM)is a new concept of multiple input multiple output(MIMO)transmission technology.It likely to be the wireless transmission technology in the fifth generation of mobile communication system.SM is a multiplexing technology of multiple antenna,was presented in recent years.The structure of single antenna working in the transmitter successfully avoid some problems,such as inter-channel interference(ICI)and inter-antenna synchronization(IAS).The input information bits are divided into two parts in SM.One is mapped to constellation diagram of the space antenna,the other one is mapped to the signal constellation diagram.SM effectively improves the utilization of frequency band without increasing the system bandwidth and transmission power.It overcomes the defects of traditional MIMO.The ideas of the SM have attracted wide attention of scholars both at home and abroad.In this paper,a new differential spatial modulation(DSM)scheme was put forward based on differential coding in the SM system.In DSM,the transmitter integrating the differential coding selects antenna to transmit modulation information.The receiver based on the characteristics of the difference,proposes a new demodulation method,the differential detection directly.The demodulation algorithm is different from the existing algorithm.It is according to the modulus value of the difference of received signal in adjacent time.The DSM can be demodulated with the channel state information unknown.This is also the biggest advantages.Based on the research background and current situation of the development,the paper simply introduces the basic principle and system model of SM,deeply analyzes the implementation scheme of DSM.First of all,the scheme of two antennas in transmitter is detailed,including the antenna encoded in transmitter,demodulation steps at the receiver with different modulation modes.The paper theoretically analyzes the feasibility,gives performance simulation and the curve.Then,the paper gives two kinds of implementation plan for four antennas in transmitter.The feasibility of the proposed method is verified by matlab simulation.Results show that the DSM can implement demodulation in the channel parameters unknown,also has good ability to resist the change of channel parameters.