Coordination gains in the cellular uplink with noisy interference

This paper studies the performance gains of coordination in an elemental cellular network consisting of a multiple-access channel (MAC) and a point-to-point channel (P2P) interfering with each other. It is assumed that this network, denoted as PIMAC, is operating in the noisy (very-weak) interference regime. Three schemes, denoted as naive-TIN, TDMA-TIN, and IA-TIN, each with different coordination requirements among the transmitters (and receivers), are compared with each other in terms of achievable sum rates. It is shown that, although the PIMAC is in the noisy interference regime, allowing more coordination between the users might increase the performance, depending on the channel parameters. Consequently, this proves the sub-optimality of TDMA-TIN and naive-TIN in those regimes, which is in contrast to existing results for K-user interference and X channels. The analytical finding are verified by numerical evaluations.