Downlink resource allocation under time-varying interference: Fairness and throughput optimality

We address the problem of downlink resource allocation in the presence of time-varying interference. We consider a scenario where users served by a base station face interference from a neighbouring base station that uses the same channels. We model the interference from the neighbouring base station as an ON/OFF renewal process, that arises due to its idle and busy cycles. The users feedback their downlink SINR values to their base station, but these values are outdated. In this setting, we characterize how Layer 2 can optimally exploit the reported SINR values, which could be unreliable due to time-varying interference. In particular, we propose resource allocation policies in two well-known paradigms. First, we address the problem of α-fair scheduling, and propose a policy that ensures asymptotic convergence to the optimal α-fair throughput. Second, we propose a throughput optimal resource allocation policy, i.e., a policy that can stably support the largest possible set of traffic rates under the interference scenario considered. Estimating the outage probability from the outdated SINR values plays an important role in both scheduling paradigms, and we accomplish this using tools from renewal theory.