所属单位：北京航空航天大学电子信息工程学院

教研室：202 203 未来通信与网络推进组

发表刊物：IEEE globecom 2023

刊物所在地：美国

项目来源：国家重点研发6G灵活高效波形与多址技术

关键字：多址、格码、编码调制、多用户检测、MIMO

摘要：This paper studies a lattice-code based multiple-access (LCMA) framework, and develops a package of processing techniques that are essential to its practical implementation. In the uplink, K users encode their messages with the same ring coded modulation of 2m-PAM signaling. With it, the integer sum of multiple codewords belongs to the n-dimension lattice of the base code. Such property enables efficient algebraic binning for computing linear combinations of K users’ messages. For the receiver, we devise two new algorithms, based on linear physical-layer network coding and linear filtering, to calculate the symbol-wise a posteriori probabilities (APPs) w.r.t. the K streams of linear codeword combinations. The resultant APP streams are forwarded to the q-ary belief-propagation decoders, which parallelly compute K streams of linear message combinations. Finally, by multiplying the inverse of the coefficient matrix, all users’ messages are recovered. Even with single-stage parallel processing, LCMA is shown to support a remarkably larger number of users and exhibits improved frame error rate (FER) relative to existing NOMA systems such as IDMA and SCMA. Further, we propose a new multi-stage LCMA receiver relying on generalized matrix inversion. With it, a near-capacity performance is demonstrated for a wide range of system loads. Numerical results demonstrate that the number of users that LCMA can support is no less than 350% of the length of the spreading sequence or number of receive antennas. Since LCMA relaxes receiver iteration, off-the-shelf channel codes in standards can be directly utilized, avoiding the compatibility and convergence issue of channel code and detector in IDMA and SCMA.

论文类型：文章

一级学科：信息与通信工程

文献类型：期刊

是否译文：否

发表时间：2022-09-30

收录刊物：SCI