Research On Space Modulation Technology Of Distributed High Altitude Platform

When the high-altitude platform communication system performs emergency communication in remote areas,it has high requirements for communication capacity and communication rate.Due to the inter-channel interference in traditional MIMO communication,the transmission rate can only be increased to a limited extent.This paper focuses on the spatial modulation(SM)technology under the high-altitude MIMO communication platform,and proposes a low-complexity antenna selection algorithm and detection algorithm,which can effectively avoid inter-channel interference,reduce system complexity,and improve spectrum efficiency and information transmission.rate.The main research contents of this paper are as follows:(1)In response to the need to simultaneously meet the high channel capacity and transmission rate of emergency communications,this paper establishes a distributed high-altitude platform polarization diversity traditional spatial modulation(SM),generalized spatial modulation(Generalized Spatial Modulation,GSM),enhanced Spatial Modulation(Enhanced Spatial Modulation,ESM)and Quadrature Spatial Modulation(QSM)systems,based on the theoretical research of the polarization diversity MIMO channel model of the high-altitude platform,established a spatial modulation system model composed of multiple distributed high-altitude platforms Analyzed the performance of SM,GSM,ESM and QSM in the distributed high-altitude platform communication system,and evaluated the error rate performance of traditional spatial modulation and new spatial modulation in three typical scenarios of urban,suburban and open areas when the spectrum efficiency is the same..The simulation results show that in the proposed distributed high-altitude platform polarization diversity spatial modulation communication system,when the spectrum efficiency is the same,the performance of the orthogonal spatial modulation is the best.In an open environment,when the target bit error rate is the 8×2 system Compared with the traditional SM,the signal-to-noise ratio of the medium QSM is improved by about 4.5d B.(2)Due to the increase in the number of transmitting antennas,the problem of high complexity and difficulty in implementation of the antenna selection at the transmitting end and the detection algorithm at the receiving end in the polarization diversity orthogonal spatial modulation(QSM)system of the distributed high-altitude platform is proposed in this paper.A low-complexity antenna selection algorithm at the transmitting end of the system.The algorithm is based on channel capacity,antenna correlation or a combination of these indicators,which reduces the complexity of the algorithm,has better system performance,and improves system reliability.On this basis,in order to solve the problem of high maximum likelihood(ML)detection complexity at the receiving end of the system caused by multiple antennas in the distributed high-altitude platform polarization diversity spatial modulation system,a signal vector detection(SVD)and order-based A low-complexity detection algorithm combined with block minimum mean square error(OB-MMSE).The complexity performance of the proposed algorithm is also evaluated.With the increase of the number of antennas at the transmitting end,the LCTAS-AC-QSM antenna selection algorithm has the lowest complexity and the best bit error rate performance.When the total number of antennas is 32,compared with the QSM system The traditional antenna selection algorithm is reduced by 55%;the SVD&OB-MMSE detection algorithm proposed by the receiving end sacrifices a small amount of bit error rate performance while reducing the complexity of the optimal detection algorithm by 45%.The distributed high-altitude platform polarization diversity spatial modulation system studied in this paper combines the advantages of the high-altitude platform communication system and spatial modulation technology,effectively improving the spectrum efficiency and transmission rate under the condition of limited platform size,through improved low complexity The antenna selection algorithm and detection method reduce the complexity while ensuring the reliability of the system's bit error rate,which can provide a theoretical basis for the design of emergency communication systems in remote areas of high-altitude platforms.