Fundamental Limits of Massive Random Access with A Common Codebook and Finite Blocklength
Ultra-massive Machine Type Communication(umMTC)is expected to be a key use case in the 6th Generation wireless networks.The information-theoretical analysis for unsourced random access in umMTC scenarios is conducted.Thenon-asymptotic achievability and converse bounds are established on the per-user probability of error for given number of receive antennas,blocklength,payload size,and transmitting power.Simulation results verify the tightness of our bounds and demonstrate that when the number of users is below a thresh-old,the multi-user interference can be almost perfectly canceled.The per-user probability of error decreases as the number of receive an-tennas increases,highlighting the crucial role of MIMO in supporting reliable access for a large number of users.Moreover,it is shown that in contrast to random access with individual codebooks,random access with a common codebook achieves higher energy efficiency.
common codebookmassive random accessfinite blocklengthachievability and converse bounds