Distributed QC-LDPC Coded Spatial Modulation for Half-Duplex Wireless Communications

Abstract

The bit error rate (BER) performance of spatial modulation (SM) can be further improved by applying quasi-cyclic low-density parity-check (QC-LDPC) codes recommended in 5G to SM. It motivates us to propose a QC-LDPC coded SM (QC-LDPCC-SM) scheme, where SM signals are protected by QC-LDPC codes. To estimate the channel state information at the receiver, a novel iterative joint channel estimation and data detection based on variable block length (IJCEDD-VBL) for SM is presented. In standard 5G LDPC codes, the parity-check matrix contains multiple submatrices, and then we can construct two different QC-LDPC codes by suitably selecting the submatrices. Thus, the QC-LDPCC-SM scheme can be effectively extended to cooperative scenarios when deploying the generated LDPC codes at the source and relay, respectively. We develop an analytical approach for the BER performance of the proposed schemes. The simulation and theoretical results are in good agreement at high signal-to-noise ratio (SNR). Furthermore, the proposed coded cooperative scheme outperforms its corresponding non-cooperative counterpart and the existing scheme. The numerical results also validate the effectiveness of the proposed channel estimation scheme.

Optimized distributed Goppa codes based on spatial modulation

“…In addition, Figures 8 and 9 compare the performance of the proposed DGC-SM scheme (𝛾 S ,R = ∞) and the non-cooperative system. Note that FIGURE 9 Performance comparison of the cooperative and non-cooperative systems using C S (32, 17, 7) and C R (32,12,9).…”

“…Finally, we compare the proposed DGC-SM (𝛾 S ,R = ∞) using C S (32, 17, 7) and C R (32,12,9) with the traditional systems such as conventional SM (CSM) [3], conventional QSM (CQSM) [24], Euclidean distance optimized antenna selection scheme for CSM (EDAS-CSM) [26], and capacity optimized antenna selection scheme for CSM (COAS-CSM) [26]. During the simulations, the MLD, smart decoding algorithm and optimized information selection algorithm are used in the proposed system.…”

“…Another interesting point is that the antennas of the source and relay are shared to give a virtual MIMO concept, which can reap the benefits of multiple antenna systems [10]. Various distributed channel codes such as [11][12][13] have been investigated since coded cooperation was proposed.…”

“…FIGURE12 Effect of the number of receiving antennas on the performance of the DGC-SM (N T = 4, 4-QAM) using C S (64,16,17) and C R (64, 10, 22).…”