2022/11/28 by Göttsch, Fabian, Osawa, Noboru, Ohseki, Takeo +4
#FOS: Computer and information sciences #Information Theory (cs.IT)
paper · doi:10.48550/arxiv.2211.15294
We consider a user-centric scalable cell-free massive MIMO network with a total of LM distributed remote radio unit antennas serving K user equipments (UEs). Many works in the current literature assume LM≫ K, enabling high UE data rates but also leading to a system not operating at its maximum performance in terms of sum throughput. We provide a new perspective on cell-free massive MIMO networks, investigating rate allocation and the UE density regime in which the network makes use of its full capability. The UE density K approximately equal to (LM)/(2) is the range in which the system reaches the largest sum throughput. In addition, there is a significant fraction of UEs with relatively low throughput, when serving K>(LM)/(2) UEs simultaneously. We propose to reduce the number of active UEs per time slot, such that the system does not operate at ``full load'', and impose throughput fairness among all users via a scheduler designed to maximize a suitably defined concave componentwise non-decreasing network utility function. Our numerical simulations show that we can tune the system such that a desired distribution of the UE throughput, depending on the utility function, is achieved.