Flow Control of Wireless Mesh Networks Using LQR and Factor Graphs.

This paper presents two novel factor graph formulations for performing flow control on radio transceivers forming a large Wireless Mesh Network (WMN). Both factor graph formulations are abstractions of a discrete-time finite-horizon Linear Quadratic Regulator (LQR) used to solve an Optimal Control Problem (OCP). The first formulation, WMNLQR, is a centralized controller which demonstrates the superiority of inference-based, graphical solvers over more traditional least-squares and Dynamic Programming (DP) approaches. Specifically, we see linear runtime complexity with respect to both state dimension and trajectory length by leveraging the sparsity inherent to the problem. The second formulation, DWMNLQR, is a decentralized implementation which leverages the physical RF message passing capabilities of the radio transceivers to assist in the factor graph solver. The decentralized algorithm supplements the capabilities of WMNLQR, as it aids in robustness and real-time solving of WMN flow control without compromising global optimality.