共享码本随机接入有限块长信息理论极限分析

Fundamental Limits of Massive Random Access with A Common Codebook and Finite Blocklength

超大规模机器通信(umMTC)是6G移动通信网络的典型应用场景。针对umMTC场景中的共享码本随机接入问题展开信息理论研究,在给定基站天线数、码长、用户载荷和发送功率的情况下,推导了平均每用户误差概率的非渐近可达界和逆定理。仿真结果证实了可达界和逆定理的紧致性,并且证明了当用户数低于某一门限时存在多用户干扰消除效应。基站配置多天线能够显著降低平均每用户误差概率,这对支持大量用户可靠接入具有重要意义。此外,与独立码本随机接入相比,共享码本随机接入在能效性方面更具优势。

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.