Research And Simulation On Link Adaptation In OFDM With Index Modulation System

With the rapid development of wireless communication technologies,people have put forward higher and higher requirements on the next generation mobile communication system.Under such background of the era,OFDM with index modulation(OFDM-IM)gradually receives the researchers' concern because of its low peak-to-average power ratio,strong ability to resisit against offset and high energy efficiency.To further improve the transmission performance of OFDM-IM system,bit error rate and achievable rate of the OFDM-IM system are studied firstly.Furthermore,based on these studies,adaptive modulation algorithms and adaptive power allocation algorithms are proposed,which aim at optimizing the bit error rate and achievable rate by applying link adaptation technology to OFDM-IM system.Specific work of this thesis can be summarized as follows.In the first chapter,development process,rationale and relative merits first are introduced.Then current research situation about OFDM-IM and the main research contents and innovation points of this article are described.The second chapter presents the basic model of OFDM-IM system and the bit error rate and achievable rate with perfect channel estimation are analyzed by theoretical derivation and numerical simulation.Then the bit error rate and its effect factors under the circumstance of perfect channel estimation are further analyzed.Finally,based on the achievable rate with perfect channel estimation,we research the impacts of channel estimation error on achievable rate and present theoretic demonstratation and simulation comparison.In the third chapter,adaptive modulation technology in OFDM-IM system are discussed.Firstly,we explain its basic principle and optimization criterion.Furthermore,a design principle in constellation about adaptive modulation scheme in OFDM-IM is proposed by researching the impacts of constellation of digital modulated signals on its bit error rate.Based on the designed constellation,a modulation mode selection algorithm about adaptive constellation modulation and corresponding detection algorithm are proposed.Moreover,a transceiver design for adaptive constellation modulation between multiple subblocks is further proposed.Finally,Simulation demonstrate that the proposed algorithms can improve the bit error rate of OFDM-IM system.In the forth chapter,adaptive power allocation algorithms in OFDM-IM system are discussed.With the goal of improving bit error rate,a power allocation algorithm based on the minimum Euclidean distance and a power allocation algorithm based on normalized Euclidean distance are proposed separately at first.The two proposed algorithms can improve bit error rate of OFDM-IM by adjusting power between every activated subcarrier in each subblock.Then,from the perspective of the achievable rate,an adaptive power allocation algorithm based on lower bounds of achievable are proposed to optimize achievable rate of OFDM-IM.The proposed algorithm accomplishes system performance improvement through the balance of system resource between subblocks.The finally chapter summarizes the main contiabution and points out the possible prospects in the future studies.