Unsourced Random Massive Access With Beam-Space Tree Decoding

The core requirement of massive Machine-Type Communication (mMTC) is to support reliable and fast access for an enormous number machine-type devices (MTDs). In many practical applications, the base station (BS) only concerns list received messages instead source information, introducing emerging concept unsourced random (URA). Although some multiple-input multiple-output (MIMO) URA schemes have been proposed recently, unique propagation properties millimeter-wave (mmWave) MIMO systems are not fully exploited in conventional schemes. grant-free access, BS cannot perform receive beamforming independently as identities active users unknown BS. Therefore, intrinsic beam division property can be improve decoding performance. this paper, a scheme based on beam-space tree mmWave system. Specifically, two decoders designed hard decision soft decision, respectively, utilize property. They both leverage assist discriminating sub-blocks transmitted from different users. Besides, first decoder reduce searching space, enjoying low complexity. second exploits advantage recover miss-detected packets. Simulation results verify superiority compared terms error probability.