Study On Non-orthogonal Multiple Access And Orthogonal Time Frequency Space Modulation With Spatial Modulation

Spatial Modulation(SM)is a novel modulation technology.Compared with traditional modulation methods such as the use of signal amplitude and phase to transfer information,Spatial modulation activates a single antenna,and then maps another part of the information into the traditional amplitude phase modulation signal sent on the activated antenna.Therefore,there is only a single radio frequency(RF)unit in the spatial modulation system,which has many excellent performances,such as more flexible spectrum efficiency(SE)and higher energy efficiency(EE).Therefore,spatial modulation has been extensively studied in5 G and B5 G wireless communications.In addition,non-orthogonal multiple access(NOMA)can support 5G massive access,and orthogonal time frequency space(OTFS)modulation can support 5G high mobile communications,so they have become the key technology of5 G.This article mainly studies the application of SM in NOMA and OTFS.Firstly,the recently proposed spatial modulation assisted NOMA based on bit allocation(BA)is extended to the cooperative NOMA system,and the cooperative NOMA structure called SM-C-NOMA-BA is proposed.At the same time,the system considers two working modes of half-duplex cooperation and full-duplex cooperation.Furthermore,the achievable rate of the proposed SM-C-NOMA-BA structure is analyzed and deduced under the constraint of finite alphabet inputs.Finally,the numerical results verify the validity of the structure.Secondly,the thesis studied the MIMO-OTFS system and proposed the GSM-OTFS structure.Considering that the traditional message passing(MP)detection algorithm cannot make good use of the activation mode and its sparse characteristics in the GSM-OTFS system to detect information,the MP detection algorithm is appropriately improved to improve its detection performance.Finally,the simulation analysis compares the bit error rate performance of MIMO-OTFS and GSM-OTFS under multipath fading channels.The results show that the GSM-OTFS system has better BER performance than the MIMO-OTFS system under certain conditions.The results show that the GSM-OTFS system has better BER performance than the MIMO-OTFS system in the case of a larger number of antennas.