Uplink Throughput Scaling in Dense Wireless Networks with Limited Collaboration

We consider multiaccess in cell-based dense wireless networks (e.g., cellular and WiFi with access points) when the communications are interference-limited. The purpose is to understand, in a dense network, how MIMO, user diversity, network topology and limited cooperation influence the uplink cell throughput. Each cell has n N_t-antenna users and K neighboring N_r -antenna cells, and the channels are i.i.d. Rayleigh. Multi-users are allowed to transmit in one cell simultaneously, and each cell decodes by treating signals coming from other cells as noise. We assume that only the receivers have channel state information (CSI), and every cell has a common number of active users. It is shown that N_r/1+KN_tN_r log n bit/s/Hz is achievable for every cell by selecting exp{ 1/1+KN_tN_r log n} users per cell according to a simple threshold rule, and decoding using successive interference cancelation. On the other hand, this is also shown to be an upper bound on the per cell throughput, no matter how users are chosen. Furthermore, simulations are provided to verify the results.