Soft Decision Detection Algorithm For Index Modulation

Index Modulation(IM)technology is a new digital modulation scheme in which the indices of transmission resources/carriers are used to convey additional information bits.It appears as competitive candidates for next generation wireless networks due to the attractive advantages in terms of spectral and energy efficiency as well as hardware simplicity.IM is termed spatial modulation(SM)in space domain and orthogonal frequency division multiplexing index modulation(OFDM-IM)in frequency domain.First,in this thesis,the soft output detection algorithm for OFDM-IM coded modulation system is studied.The soft input soft output detector is an important guarantee to realize the potential of the coding system.Note that,not all the symbol combinations in one signal block are legitimate,which is refer to as the activation pattern(AP)constraint.In the conventional symbol-wise detectors,a careful processing in the detection procedure to take into account the AP constraint is required.Therefore,symbol-wise detectors are not very suitable for OFDM-IM.The bit-wise detector can avoid the complex processing for the AP constraint,since all the bit combinations are legitimate.Specifically,the randomized bit-wise MCMC(R-b-MCMC)detector is proposed for the single-level coded OFDM-IM(SL-COFDM-IM)firstly.The randomized step can effectively avoid the "stalling" problem of MCMC detectors.Furthermore,for the two-level coded OFDM-IM(TL-COFDM-IM)which encodes active indices and constellation symbols with different LDPC codes,respectively,a low-complexity iterative multistage decoder(IMSD)is proposed.The low-complexity IMSD can process the multiplicative interference in both component detectors effectively and efficiently and can reduce the feedback cost between different stages.Second,low-complexity algorithms for uplink GSM-MIMO systems are studied.To be specific,by utilizing the sparsity property of GSM signals,three AMP-based algorithms are developed,vector-form AMP,scalar-form AMP and structured scalar-form AMP.The vector-form AMP is based on the vector signal of each user,whose complexity is the highest and performance is the best.Besides,the scalar-form AMP is based on the scalar-signal and has the lowest complexity and worst performance.Furthermore,based on the scalar-form AMP,the structured scalar-form AMP takes into account the constraint between signals of different antennas belonging to the same user.The structured scalar-form AMP approaches the performance of vector-form AMP with the same complexity as scalar-form AMP.Furthermore,a simple while effective damping strategy is introduced in AMP detector to guarantee convergence in correlated channel.