Research On Spatial Modulation Systems Based On Antenna Offset

Multiple input and multiple output(MIMO)has been a key technology in current wireless communication systems.Compared to conventional MIMO,spatial modulation(SM)has the unique advantage of its single radio frequency(RF)structure.Because of this feature,SM is considered as a low-cost,low-complexity MIMO implementation.However,the transmission rate of SM-MIMO is limited by the switching frequency between the RF chain and transmit antennas,which has been a bottleneck for its application in future broadband wireless communications.For alleviating this problem,this thesis proposes a novel spatial modulation scheme.With the aid of channel state information(CSI)at the transmitter,the novel scheme will introduce an offset between the RF chain and a specific transmit antenna to reduce the switching frequency and improve the transmission performance.Firstly,the thesis gives a thorough research about the key technologies of traditional spatial modulation systems,include spatial modulation and space shift keying(SSK)modulation.Then,the SM-MIMO systems based on transmit antenna selection(TAS)technology and precoding technology are also studied.The simulation verification and performance analysis are also presented.Secondly,a novel scheme termed as offset spatial modulation(OSM)is proposed in the thesis.The proposed OSM system includes two working modes,static and dynamic.The upper bound of the theoretical bit error rate(BER)of the two operating modes is derived.The thereotical BER upper bound of OSM is also verified by simulation.Subsequently,this thesis analyzes the RF switching frequency of the OSM system in detail,and proves that OSM can effectively solve the RF switching problem of SM-MIMO systems.In addition,the BER performance of the proposed OSM and its counterparts are compared.The simulation results verify that the proposed OSM scheme provides significant performance gain than conventional SM.The computational complexity of the proposed OSM and its counterparts is also analyzed,which demonstrates that the proposed OSM also has superioity in computational complexity.Finally,the proposed OSM principle is extended to some existing SM-MIMO systems to further improve their performance.For example,the OSM system could be combined with some TAS based and precoding based SM-MIMO systems to further enhance the transmission performance.Furthermore,the proposed OSM with single RF chain is extended to multiple RF chains,termed as mutiple radio frequency OSM(MRF-OSM).Simulation results verify its superiority than conventional SM.