Coordinating Base Stations for Greater Uplink Spectral Efficiency in a Cellular Network

We propose an ambitious approach towards lifting the limits imposed by cochannel interference on the uplink spectral efficiency of a cellular network, viz., coordinating several base stations in the reception of users within their coverage area, and suppressing interference between users by means of coherent linear beamforming across the base stations. We evaluate by simulation the potential gain in spectral efficiency from such coordination, when there is 1 user per base station antenna in the network, and all users (but for a small fraction in outage) must be served at a constant and common data rate. We highlight the dependence of the spectral efficiency gain on the number of rings of neighbors with which each base station is coordinated, as well as the underlying signal-to-noise ratio (SNR) distribution in the network. Results from this study point to the possibility of doubling the uplink spectral efficiency with 1-ring coordination and nearly quadrupling it with 4-ring coordination, under high-SNR conditions.