Energy-delay tradeoffs for multi-user multi-antenna downlink communication systems

In this paper, we study the energy-delay tradeoff issue in multi-user multi-antenna downlink communication systems. We formulate this problem as a stochastic optimization model subjected to stability and users´ rate requirements to minimize the base station (BS) long-term energy consumption. The proposed algorithm works without requiring any knowledge of traffic arrival rates and channel statistics. However, it yields an average power expenditure arbitrarily approaching the theoretically minimum value achieved by an algorithm optimized with complete knowledge of future events. Further, we mathematically depict the tradeoff between BS long-term energy consumption and uses delay by a control parameter. Simulation results demonstrate the adaptivity and robustness of the proposed algorithm to channel conditions and traffic arrivals.