JOINT POWER CONTROL, LINK SCHEDULING AND ROUTING IN WIRELESS MULTI-HOP NETWORKS

Abstract

The interactions among different layers in wireless networks call for a new design paradigm that moves beyond conventional layering concept. A cross layer design with the consideration of physical, MAC and network layer has been shown significant importance in literature. In this dissertation, we first study the problem of joint power control and link scheduling with the objective of minimizing the schedule-length, subject to a given traffic demand of each link and SINR constraints. Then, we include aspects of routing problem to satisfy a given end-to-end traffic demand of each source-destination pair in the network. The resulting optimization problem becomes joint power control, link scheduling and routing with the objective of minimizing the schedule-length. A column generation based solution procedure is implemented to solve the optimization problem, which gives us three important decisions-optimal route, minimized schedule, and minimum power vector. We also discuss the influence of power control, spatial reuse, variable transmission rates, SINR variations and availability of multiple paths between a source-destination pain The column generation method decomposes the linear optimization problem into a master problem and a sub-problem. It is observed that the complexity of the overall solution procedure lies in solving the sub-problem, which is mixed-integer in nature, and finding an optimal solution is NP-hard in general. Therefore, a new formulation of the sub-problem using Perron-Frobenius eigenvalue condition is presented [25]. The new formulation reduces the complexity of the sub-problem and thus improves the efficiency of the overall solution procedure. Our numerical analysis shows that the average computation time is reduced by 99.54% for a 13-link network.