URLLC with Coded Massive MIMO via Random Linear Codes and GRAND

Abstract

A present challenge in wireless communications is the assurance of ultra-reliable and low-latency communication (URLLC). While the reliability aspect is well known to be improved by channel coding with long codewords, this usually implies using interleavers, which introduce undesirable delay. Using short codewords is a needed change to minimizing the decoding delay. This work proposes the combination of a coding and decoding scheme to be used along with spatial signal processing as a means to provide URLLC over a fading channel. The paper advocates the use of random linear codes (RLCs) over a massive MIMO (mMIMO) channel with standard zeroforcing detection and guessing random additive noise decoding (GRAND). The performance of several schemes is assessed over a mMIMO flat fading channel. The proposed scheme greatly outperforms the equivalent scheme using 5G's polar encoding and decoding for signal-to-noise ratios (SNR) of interest. While the complexity of the polar code is constant at all SNRs, using RLCs with GRAND achieves much faster decoding times for most of the SNR range, further reducing latency.

面向超可靠低时延通信的有限块长mimo传输理论与技术

“…在此基础上, 文献 [89] 提出了步进 GRAND 算法, 在保证较低平均时延的同时有效降低了最差情 况下的时延. 另外, 文献 [90] 考虑 MIMO URLLC 系统, 将用于高阶调制的符号级 GRAND 算法推广 至空分复用场景, 接收端采用迫零检测并引入天线排序步骤, 相较比特级 GRAND 算法大幅降低了译 码复杂度. MIMO 系统半盲信道估计 [95] .…”