Clustering-Based Activity Detection Algorithms for Grant-Free Random Access in Cell-Free Massive MIMO

Future wireless networks need to support massive machine type communication (mMTC) where a number of devices accesses the network and MIMO is promising enabling technology. Massive access schemes have been studied for co-located arrays. In this paper, we investigate activity detection in grant-free random mMTC cell-free using distributed Each active device transmits non-orthogonal pilot sequence points (APs) APs send received signals central processing unit (CPU) joint detection. The maximum likelihood problem formulated algorithms are provided solve it. simulation results show that macro-diversity gain by architecture improves performance compared when coverage area large.