Joint Back-Pressure Power Control and Interference Cancellation in Wireless Multi-Hop Networks

Back-Pressure Power Control (BPPC) is a cross-layer network optimization policy that uses power control at the physical layer to facilitate efficient routing of packets at the network layer. The starting point of this paper is that interference cancellation can be judiciously employed together with power control to further enhance network throughput. Effective cancellation requires that the interfering signal can be reliably decoded, implying that power control and interference cancellation are tightly coupled. This leads to a joint Back-Pressure Power Control and Interference Cancellation (BPPC-IC) problem formulation, with the pragmatic constraint that each receiver can cancel at most one interfering signal. This problem is shown to be NP-hard, and two approximate solutions are proposed based on successive geometric programming approximation, and an extended weighted minimum mean squared error (WMMSE) reformulation, respectively. A simpler approximation based on stochastic exploration of the control space is also considered. Simulation results demonstrate that joint optimization of power control and interference cancellation pays off, enabling considerably higher network throughput, and lower average delay due to reduced backlogs.