Layered graph-merged detection and decoding of non-binary LDPC coded massive MIMO systems

Abstract

In order to improve the spectral efficiency and reliability of communication systems, both the multiple-input multiple-output (MIMO) technique and non-binary low-density parity-check (NB-LDPC) codes are considered as powerful tools to meet the requirements. In order to further optimize the MIMO NB-LDPC systems and adapt to massive MIMO scenarios, a new joint detection and decoding (JDD) method of massive MIMO with NB-LDPC codes, called layered graph-merged detection and decoding (GMDD), is proposed. In this paper, factor graphs associated to symbol-based belief propagation (BP) MIMO detection and NB-LDPC decoding are merged into a single graph. For massive MIMO condition, a MIMO detection graph is attached to several NB-LDPC decoding graphs, which makes the methods unique to existed ones. Compared with separated detection and decoding (SDD), for BER less than 5 × 10-2 the proposed method can achieve nearly 7 dB gain with same or even fewer iterations. Corresponding hardware architecture and complexity analysis are also given in this paper.