Research Of Node Scheduling Algorithm In Wireless Sensor Networks

In Wireless Sensor Networks (WSN), it is a crucial problem that how to prolong the network lifetime using the nodes reasonably in programming sensor networks. Node scheduling algorithm is a feasible method to resolve above-mentioned question, which refers to make the nodes work in turns to save energy. At present, many scheduling algorithms need geographic information with the help of GPS positioning system, which is not conducive to build a low-cost sensor networks; at the same time, all the existing random scheduling algorithms which have better applications are on a basis of Boolean sensing model, and it doesn't accord with the actual case. In view of the above- mentioned problems, based on the existing random scheduling algorithm , we have accomplished the following work.First of all, the existing random scheduling algorithm is described briefly, and the strengths and weaknesses are analyzed. The random scheduling algorithm is on local coverage of network and without the help of geographic information, and has a good fault tolerance. In addition, using local coverage control strategy can not only simplify the protocol design of network, but also configure nodes more flexibly. But the Boolean sensing model used doesn't accord with the actual sensing case, so based on probabilistic sensing model more close to the practical applications, we have analyzed the relationship between coverage intensity and the number of nodes and given the expression by which we can get the nodes needed to deploy. So configuring nodes in random scheduling algorithm has been resolved.Secondly, to resolve another question in random scheduling algorithm, that is, how to make the nodes evenly distributed in every subset composed of some sensor nodes, a new method - a random scheduling algorithm based on the average degree of nodes is presented, which is on the basis of probabilistic sensing model. Taking advantage of information transmission between neighbor nodes and average degree of nodes, it makes every node's neighbor nodes distributed in different subsets evenly. The simulation results show that the nodes in every subset brought by the new algorithm are uniformly distributed, and analysis shows that the new algorithm can work with a very low time complexity and message complexity, so it has a great practicability.