Bicriteria Optimization in Multihop Wireless Networks: Characterizing the Throughput-Energy Envelope

Network throughput and energy consumption are two important performance metrics for a multihop wireless network. Current state-of-the-art research is limited to either maximizing throughput under some energy constraint or minimizing energy consumption while satisfying some throughput requirement. Although many of these prior efforts were able to offer some optimal solutions, there is still a critical need to have a systematic study on how to optimize both objectives simultaneously. In this paper, we take a multicriteria optimization approach to offer a systematic study on the relationship between the two performance objectives. To focus on throughput and energy performance, we simplify link layer scheduling by employing orthogonal channels among the links. We show that the solution to the multicriteria optimization problem characterizes the envelope of the entire throughput-energy region, i.e., the so-called optimal throughput-energy curve. We prove some important properties of the optimal throughput-energy curve. For case study, we consider both linear and nonlinear throughput functions. For the linear case, we characterize the optimal throughput-energy curve precisely through parametric analysis, while for the nonlinear case, we use a piecewise linear approximation to approximate the optimal throughput-energy curve with arbitrary accuracy. Our results offer important insights on exploiting the tradeoff between the two performance metrics.