Improving the resource utilization in Wireless Mesh Networks based on Spatial -TDMA
Oriol Gras Granyó · 2009
Wireless Mesh Networks are expected to gain significant importance in the telecommunication market in the near future. Nevertheless, some critical factors menace them not to achieve their expected features. In this thesis we focus our research on the improvement of their performance. To face the multiple access issue we consider the utilization of Spatial Time Division Multiple Access (STDMA). STDMA benefits from the spatial distribution of nodes allowing the reuse of timeslots by users sufficiently far apart. This feature permits a better utilization of the spectrum, but arises an NP-complete optimization problem consisting in distributing efficiently links into timeslots. In the first part of the thesis, we will address the link scheduling problem and we will propose two heuristics to try to improve the overall performance of the system. In the second part of the thesis, we will deal with directional antennas, and in particular, with switched beam antennas. Several works have demonstrated the significant benefits of switched beam antennas applied to WMNs. This kind of antennas are formed by several fixed beam patterns that are switched according to the communications requirements. Switching among patterns cause, though, a consumption of energy and a lose of time to stabilize the patterns. A set of algorithms to reduce the switchings without deteriorating the frame length achieved with the scheduling algorithms will be presented.