LIM-URA: A Less-is-More Strategy for Quasi-Static Fading Unsourced Random Access

This paper discusses the unsourced random access (URA) problem in quasi-static fading multi-input and multi-output (MIMO) channel. A novel less-is-more (LIM) strategy is firstly proposed where only a small portion of data with strong energy-per-unit is transmitted into channels while others are implicitly embedded into the transmission. The LIM encoder generates extreme transmission sparsity and strong denoising capability. Correspondingly, the proposed decoder is elaborated with complexity analyses. Numerical results demonstrate that the proposed LIM-URA design shows a capacity performance close to the recently established MIMO achievable bound compared with other state-of-the-arts under identical spectral efficiency.