Research On Spatial Modulation Based Uplink Multiple Access Theory

Spatial Modulation is a novel modulation technique which can map information bits into space domain.Due to advantages of high rate,flexible structure,low energy consumption,and anti inter-channel interference characteristic,spatial modulation can adapt to the development requirements of future optical communication networks and the new generation of wireless communication systems.Besides,in spatial modulation systems,different antennas carry extra spatial information,which will lead to the reduction of complexity and improve the performance if spatial modulation is combined with multiple access schemes.In this thesis,the application of spatial modulation technology in uplink multiple access schemes is studied.Firstly,this paper studies the basic theory of spatial modulation,and gives the model and signal structure of the spatial modulation system.Meanwhile,this paper also studies the basic theory of generalized spatial modulation and gives the model of the generalized spatial modulation system.In addition,the system performance of space modulation and generalized space modulation is compared with that of traditional MIMO.Then,a model of the uplink spatial-modulation based SCMA system based on authorized access mechanism is proposed,and a Joint Spatial SM-MPA(JSM-MPA)detection Algorithm that can perform Joint detection on spatial-modulated SCMA system is given.The simulation results show that compared with the traditional M-order QAM-SCMA system,the spatial modulation SCMA system can greatly improve the bit error rate performance in the high-order modulation situation.After that,this paper makes an in-depth study of the spatial modulation based uplink grant-free system.Firstly,the model and signal transmission form of the spatial modulation based uplink grant-free system are presented,and the joint active user detection-channel estimation algorithm based on Maximum a Posteriori(MAP)is presented.The optimal threshold of the algorithm is derived by solving the threshold which minimizes the sum of the false alarm probability and the missing alarm probability.In addition,the time complexity of the system is analyzed.Finally,in order to use fewer pilot resource while carrying more users,at the same time reduce the complexity of the system,this paper proposes a spatial modulation uplink grant free system based on resource allocation,the signal model of the system is given.The thesis put forward the pilot resource,time slot,antenna joint distribution rule.Based on the above criteria two joint resource allocation scheme is designed.On this basis,two active user detection algorithms are presented and their time complexity is analyzed in detail.In addition,the channel estimation mechanism that can solve Channel State Information(CSI)aliasing of users is presented,and the probability of Channel estimation failure is analyzed theoretically.