Jointly-Layered Iterative Detection and Decoding for Massive MIMO: An EP-SU Based Framework

Expectation propagation with successive updating (EP-SU) offers a symbol-wise, layering-like update, enhancing the detection performance for massive MIMO. Nevertheless, this layered potential has not yet been exploited in iterative detection and decoding (IDD). To address this gap, we propose a jointly-layered IDD algorithm for LDPC-coded massive MIMO systems, termed EP-SU-JL. By restructuring EP-SU in a layered manner and embedding it within a jointly-layered IDD framework, the proposed approach facilitates more frequent and efficient iterative information exchange between the detector and decoder, accelerating convergence and enhancing performance. Additionally, a sorting and grouping scheme is introduced to optimize the symbol update process. Numerical simulations demonstrate that the proposed EP-SU-JL consistently outperforms state-of-the-art (SOA) EP-based IDD algorithms across various MIMO scenarios while maintaining comparable complexity.