The Research On Frequency Index Modulation Techniques

As an original modulation,index modulation(IM)techniques has attracted wide interestsfor it achieves higher spectral and energy efficiency compared with traditional systems by index carrying part information.Therefore,it is a potential technique and is expected to become one of the key techniques of the 5th generation(5G)mobile communication technology.So far index modulation techniques includes two parts: spatial modulation(SM)and index modulation orthogonal frequency division multiplexing(OFDM).In index modulation OFDM,the idea of sub-carrier index modulation is inspired by SM.Compared with conventional OFDM system,index modulation OFDM attains bit error rate(BER)performance gain and peak to average power ratio(PAPR)gain,and contributes to the reducing of inter-carrier interference(ICI).The paper focuses on the researches of frequency index modulation techniques,and the main work of the thesis is as follows:Firstly,we research the system model of OFDM and the basic principles of two kinds of index modulation OFDM systems.Moreover,we discuss the influence of index modulation OFDM to PAPR.It is shown via computer simulations that index modulation OFDM has great superiority on BER performance and PAPR performance.Then,we deeply discuss the basic principles of the generalized space and frequency index modulation(GSFIM).In order to overcome the disadvantage of high system complexity,we propose a kind of simple space and frequency index modulation technique,i.e.SM based on frequency and quadrature amplitude modulation(FQAM)/frequency and phase shift keying(FPSK),which greatly simplifies the system structure.Simulation results show that the proposed scheme(i.e.FQAM/FPSK-SM)achieves significantly better BER performance than traditional SM system with sacrificing little spectral efficiency,and it can assign information flexibly among the constellation modulation,the index of the active antenna and the index of the active frequency.Therefore,FQAM/FPSK-SM can make a good tradeoff between effectiveness and reliability.Finally,we propose FQAM/FPSK-SM combining non-orthogonal sub-carrier to improve the spectral efficiency of FQAM/FPSK-SM.The proposed scheme avoids non orthogonal interference on the usual sense,because there is only one active sub-carrier at each time.It is also the superiority of the presented system.Simulation results show that under the different parameter configuration,non orthogonal FQAM/FPSK-SM not only enhances thespectral efficiency,but also achieves the nearly same performance as FQAM/FPSK-SM with the same transmit rate and improves throughput of unit bandwidth by adjusting the compression coefficient.