Optimal MIMO Broadcasting for Energy Harvesting Transmitter With non-Ideal Circuit Power Consumption

This paper develops a novel approach to optimal broadcast scheduling for an energy-harvesting powered transmitter with non-ideal circuit power consumption. Relying on the uplink-downlink duality and convex optimization tools, the proposed approach provides low-complexity algorithms to obtain the optimal transmission policies that maximize the weighted sum-throughput for multi-input multi-output (MIMO) broadcast channels. For both time-invariant and time-varying channels, it is revealed that the optimal transmission between any two consecutive channel or energy state changing instants, termed epoch, can only take one of the three strategies: 1) no transmission; 2) transmission with an energy-efficiency (EE) maximizing sum-power over part of the epoch; or 3) transmission with a sum-power greater than the EE-maximizing power over the whole epoch. The proposed approach can provide the optimal benchmarks for practical schemes in energy-harvesting MIMO broadcast transmissions, and can be employed to develop efficient online scheduling schemes which require only causal knowledge of energy arrival realizations.