Activity Detection in Distributed MIMO: Distributed AMP via Likelihood Ratio Fusion

We develop a new algorithm for activity detection grant-free multiple access in distributed multiple-input multiple-output (MIMO). The is version of the approximate message passing (AMP) based on soft combination likelihood ratios computed independently at points. underpinning theoretical basis our observation that we made about state evolution AMP. Specifically, with minimum mean-square error denoiser, maintains block-diagonal structure whenever covariance matrices signals have such structure. show by numerical examples outperforms competing schemes from literature.