Research On Geographic Routing Protocol In Wireless Sensor Network

Under the development of chip technology, man can produce powerful processor in small area, these processors are cheap, energy-conserving, and enough for daily use, wireless sensor network is born. Wireless sensor network is usually used for monitoring environment and doing simple calculation on these data.We propose a geographic routing protocol in this dissertation, it is composed of localization algorithm and routing algorithm. This localization algorithm takes advantage of the measured distance between neighbors and the coordinates of two-hop nodes, it performs well even when the measured distance error is high. The main idea of this algorithm is to localize the node constrained by many conditions first, so the coordinates calculated are very accurate, after that, some constraints will be incorporated, and so on. It is verified in experiment that this technique can greatly enhance the localization accuracy. The weak point of this algorithm is that localizing sensor node from sink node, if the coordinates of the nodes near sink are wrong, then the whole network will be turned a little angle, and this error will be more severe when nodes are far from sink. The routing algorithm uses the coordinates of node to route, it cares less about the absolute coordinates error than local relative coordinates error. First, it greedily chooses next-hop node to transfer packet, when its neighbor are all father from destination than it, the routing mode of this packet is changed to search mode. This algorithm is more effective than former ones, because it greedily chooses node from two-hop neighbors which result in bypassing some little voids in sensor network, and the incorporation of responsible region can help to find the destination easily. The support for geographic hash table is a good help for data-centric storage and data backup.