Recouping Opportunistic Gain in Dense Base Station Layouts Through Energy-Aware User Cooperation

Abstract

To meet the increasing demand for wireless capacity, future networks are likely to consist of dense layouts of small cells. Thus, the number of concurrent users served by each base station is likely to be small resulting in diminished gains from opportunistic scheduling, particularly under dynamic traffic loads. We propose user-initiated traffic spreading, that is transparent to base stations, in order to extract higher opportunistic gain and improve downlink performance. For a specified tradeoff between energy consumption and performance, we characterize the optimal policy by modelling the system as a Markov decision process and also present a tractable heuristic that yields significant performance gains even in multi-user scenarios. Our simulations show that, in the performance-centric case, average delays can be lowered by up to 25% even in homogeneous scenarios where users have identical channel distribution, and up to 51% with heterogeneous users. Further, we show that the bulk of the performance improvement can be achieved with very small increase in energy consumption, e.g., in an energy-sensitive scenario, up to 73% of the performance improvement can typically be achieved at 14% of the energy cost of the performance-centric case.