Energy Efficient Scheduling for Delay-Constrained Spectrum Aggregation

In this paper, we construct an analytical design framework for energy efficient scheduling for delay-constrained spectrum aggregation (ESSA), where the practical hardware limitations on SA capability bring various technical challenges. Specifically, the conventional water-filling power control cannot be adopted over all the channels, and the delay-aware scheduling solution should interact with the channel allocation. To overcome these challenges, we design the ESSA scheduling scheme in two steps. First, with given rate vector and channel allocation, we minimize the total power consumption for SA, including both the transmit power as well as the circuit power. Due to the properties of delay-constrained SA, we divide the scheduled users into conforming and nonconforming user sets, and design their water-filling power allocation strategies differentially. Second, based on the differentiated water-filling power control, we optimize the channel allocation and rate control iteratively via Lyapunov optimization to minimize the power consumption with the average delay constraint. The proposed ESSA scheme is finally evaluated by simulation results.