Design And Simulation Of Index Modulation MIMO-OFDM System

With the continuous evolution of communication networks,Multiple Input Multiple Output(MIMO)technology and Orthogonal Frequency Division Multiplexing(OFDM)technology have become the basic transmission mechanism for the upstream and downstream links of the 5th Generation(5G)mobile communication networks.MIMO-OFDM technology not only has a high spectrum utilization and transmission rate,but also has a strong resistance to noise,interference and multipath effects.However,the high radio frequency(RF)overhead,complex signal processing and high Peak-to-Average Power(PAPR)inherent defects of multiantenna and multi-carrier structures pose important challenges to the further promotion and application of MIMO-OFDM technology.Index Modulation(IM)technology,as a new modulation technique,is expected to provide a more efficient MIMO-OFDM solution by using antennas,subcarriers,time slots and other communication resources to carry information and thus build sparse signals in multiple dimensions.In this paper,the optimal design and performance analysis of existing index modulation MIMO-OFDM systems are studied to explore index modulation MIMO-OFDM transmission schemes that further reduce the number of RF chains and PAPR fluctuations.In order to reduce the RF overhead of the multicarrier spatial modulation OFDM(SM-OFDM)system,an improved SM-OFDM scheme based on Offset Spatial Modulation(OSM)is proposed in Chapter 2 of the thesis,and two system models,single-RF structure and multi-RF structure,are given based on different antenna selection methods,and the mapped antenna dimension of the modulated data is adjusted by precoding at the transmitter side to achieve the requirement of effective control of the number of RF chains.In addition,the reachable capacity of the proposed system and the bit error ratio(BER)upper bound are derived theoretically,and the effects of frequency offset interference and clipping noise on the BER performance of the system are theoretically analyzed.In order to better weigh the RF overhead,spectral efficiency and system performance indexes in the space-frequency joint index modulation system,the OSM technique is extended to the space-frequency joint index modulation system in Chapter 3 of the thesis,and two improvement schemes,single-RF structure and double-layer spectrum multiplexing,are proposed from the perspectives of reducing RF overhead and improving spectral efficiency,respectively.For the generalized space-frequency joint index modulation system with high spectral efficiency,an improvement scheme with flexible reduction of the number of RF chains is proposed,and two antenna set selection methods are given to provide a compromise between RF cost and system BER performance.In order to further reduce the PAPR of the index modulatuon MIMO-OFDM sys-tem and improve the efficiency of the amplifier,the constantenvelope phase modulation MIMO-OFDM transmission technique is investigated in Chapter 4 of the thesis.The paper first simulates and analyzes the parameter selection and BER performance of constant-envelope MIMO-OFDM.Based on this,the paper proposes a constant-envelope index modulation MIMO-OFDM system model that integrates constant-envelope phase modulation and index modulation techniques,and investigates the transceiver design and parameter selection of each system for space-domain,frequency-domain and space-frequency-domain modulation methods to explore the application potential of constant-envelope index modulation MIMO-OFDM system.