This paper considers the massive MIMO unsourced random access problem in a quasi-static Rayleigh fading setting. The proposed coding scheme is based on a concatenation of a "conventional" channel code (such as, e.g., LDPC) serving as an outer code, and a sparse regression code (SPARC) serving as an inner code. The scheme combines channel estimation, single-user decoding, and successive interference cancellation in a novel way. The receiver performs joint channel estimation and SPARC decoding via an instance of a bilinear generalized approximate message passing (BiGAMP) based algorithm, which leverages the intrinsic bilinear structure that arises in the considered communication regime. The detection step is followed by a per-user soft-input-soft-output (SISO) decoding of the outer channel code in combination with a successive interference cancellation (SIC) step. We show via numerical simulation that the resulting scheme achieves stat-of-the-art performance in the massive connectivity setting, while attaining comparatively low implementation complexity.

翻译：本文研究了准静态瑞利衰落环境下的大规模MIMO无源随机接入问题。所提出的编码方案基于“传统”信道码（如LDPC）作为外码与稀疏回归码（SPARC）作为内码的级联结构。该方案以创新方式融合了信道估计、单用户解码与连续干扰消除。接收端通过基于双线性广义近似消息传递（BiGAMP）的算法联合执行信道估计与SPARC解码，该算法充分利用了通信场景中固有的双线性结构。检测步骤后，采用每用户软输入软输出（SISO）解码外信道码，并结合连续干扰消除（SIC）步骤。数值仿真表明，所提方案在大规模连接场景下实现了当前最优的性能，同时保持了较低的实现复杂度。