چكيده به لاتين
Wireless Mesh Networks are considered widely in many broadband applications. In most cases access to a permanent source of energy is not possible. Thus, nodes are equipped with batteries and energy-harvesting equipment such as solar panels. Energy sustainability, permanent activity of all network nodes, and quality of service are very important in most applications of these networks. The purpose of this thesis is to achieve energy sustainability as well as to ensure the quality of services in the solar powered wireless mesh networks. In this thesis for a general graph mode, a sleep synchronization and duty cycle control protocol is suggested. This protocol coordinates the nodes' activity times in a distributed manner, and at some fraction of each working period puts the node into sleep mode. In tree topology, which is a special case of general topology, time division protocol and energy-based division algorithm are proposed. In this protocol, each node divides its activity between the children. The proposed schemes need no modification to the IEEE 802.11 MAC and no knowledge of traffic demand and input energy pattern. By providing contiguous sleep intervals, these schemes put both the radio interface and the main-board into deep sleep mode to save more energy.
To ensure the quality of service and energy sustainability simultaneously, a joint sustainability and quality of service framework is proposed. Within the proposed framework, the connection’s needed energy is reserved using Virtual Battery concept. More importantly, the quality of service requirements are related to the characteristics of the virtual battery, resulting in compromises between the quality of service and the power profile of the connections. The simulation results show the required battery violation below acceptable value of 1%, and complete energy sustainability for a one-day interval. In the sleep coordination scheme for general graphs, the sleep intervals are at least an order of magnitude larger than perfect scheduler’s sleep intervals. The throughput of Time-Split is equivalent to 90% of the optimal algorithm, which according to 25% more energy saving compared to standard methods is an acceptable value. In addition, energy-based sleep coordination algorithms increase throughput more than about 60% in the imbalance energy and tree structure conditions, indicating a very good performance of the proposed algorithm.
