The Research Of OFDM With Index Modulation In Wireless Transmission Technology

Orthogonal frequency division multiplexing with index modulation(OFDM-IM)is a novel multi-carrier transmission technology in recent years.It shows the same characteristics as traditional multi-carrier technology,which contains high spectral efficiency,the strong ability of anti-multipath,and so on.Moreover,compared with the conventional multi-carrier technology,OFDM-IM system has the following advantages,such as it is more easier to construct a low-peak ratio transmission signal;it has a stronger system robustness under the scheme of high-speed wireless transmission;and it can do a well tradeoff between the system spectrum efficiency and transmission performance.These advantages may give OFDM-IM an important role in the future's mobile communication as a novel physical layer transmission technology.This thesis does the research based on the characteristics of OFDM-IM,which transmit subblocks as the basic transmission unit and contains a lot of silence subcarriers.Then,three different aspects around OFDM-IM are further discussed,which are adaptive algorithms,interference suppression,and OFDM-IM-based cognitive radio transmission strategy.The specific works of this thesis are summarized as follows.Firstly,based on the modeling of OFDM-IM,the bit error rate expressions and the achivable rate expressions of OFDM-IM are deduced theoretically.Two analytical ideas for calculating the tight bound of bit error rate of OFDM-IM are given in order to laid a theoretical foundation for the follow-up research works.This content is mainly reflected in the second chapter of this paper.Secondly,in order to obtain the further gain and better system performance,this thesis explores the adaptive allocation algorithms for OFDM-IM under the assumption of the channel state information known at the transmit side.According to the transmission mode of subblock-based transmission unit,this thesis discusses the three different modes of adaptive methods to achieve the optimal bit error rate performance.At the same time,taking account of the complexity of these restrictions,suboptimal algorithms with low complexity are proposed.The simulation results show that the adaptive allocation algorithms can achieve obvious bit error rate performance improvements.Furthermore,these methods can be combined and achieve a higher improvement.This content is mainly reflected in the third chapter of this thesis.Thirdly,the main two shortcomings of the multi-carrier system,namely intercarrier interference and high peak-to-average power ratio value also exist in the OFDM-IM system.In this thesis,combined with the structural characteristics of OFDM-IM,the corresponding solution are proposed.To start with,we discuss the different performances of OFDM-IM and OFDM system suffering the same frequency-offset interference environment,and propose a frequency offset interference cancellation algorithm for OFDM-IM.Then,for solving the peak-to-average power ratio problem,we use the silent subcarriers to carry the noise signal which can restrain the peak-to-average power ratio value.In addition,this paper presents a method of carrying side information to deal with the impact of the transmission error of phase information which will lead to high influence on bit error rate in the transmission process.This content is mainly reflected in the fourth chapter of this thesis.Finally,this thesis designs a cognitive radio transmission strategy for OFDM-IM system.In this thesis,it propose a strategy to use OFDM-IM system at the transmittion side of secondary user(cognitive user),and use the index information of OFDM-IM to transmit the secondary bits without introducing interference.Then,it deduces the bit error rate expression of primary user and secondary user seperately,and gives the expression of achivable rate for the system.Theoretically,it is proved that the mentioned transmission strategy outperforms the traditional transmission strategy.In addition,it discusses the impact of location of the secondary user to the bit error performance.This content is mainly reflected in the fifth chapter of this thesis.