Joint routing, gateway selection, scheduling and power management optimization in wireless mesh networks

Abstract

The third generation (3G) wireless communications technology delivers user traffic in a single step to the wired network via base station; therefore it requires all base stations to be connected to the wired network. On the other hand, in the fourth generation (4G) communication systems, it is planned to have the base stations set up so that they can deliver each other’s traffic to a small number of base stations equipped with wired connections. In order to improve system resiliency against failures, a mesh structure is preferred. The most important issue in Wireless Mesh Networks (WMN) is that the signals that are simultaneously transmitted on the same frequency channel can interfere with each other to become incomprehensible at the receiver end. It is possible to operate the links at different times or at different frequencies, but this also lowers capacity usage. In this thesis, we tackle the planning problems of WMN, using 802.16 (Wi-MAX) protocol, such as deploying a given number of gateway nodes along with operational problems such as routing, management of power used by nodes and scheduling while maximizing the minimum service level provided. The WMN under consideration has identical routers with fixed locations and the demand of each router is known. In order to be able to apply our results to real systems, we work with optimization models based on realistic assumptions such as physical interference and single path routing. We propose heuristic methods to obtain optimal or near optimal solutions in reasonable time. The models are applied to some cities in Istanbul and Ankara provinces.