Research On Inter-Cluster Routing Protocol Based On HEED

With the rapid development of semiconductor technology, micro-system technology, communication technology and computer technology, the applications of wireless sensor network has become more and more widespread. The study on it has become an important topic in wireless network field. Wireless sensor network (WSN) has its own characteristics. First, the energy of this network is limited, so the most important goal of WSN is to save nodes' energy. Second, it is based on data centric routing, so it is necessary to aggregate data locally. For WSN has many differences from traditional wireless network, it is necessary to design specific communication protocol for it.At present, routing protocols of WSN are divided into flat routing protocols and hierarchical routing protocols. This paper analyzes characteristics of a number of typical protocols and identifies their deficiencies. On the basis, the paper proposes two new routing protocols—ICRPG (Inter-Cluster Routing Protocol by Gateway Based on HEED) and ICRPR (Inter-Cluster Routing Protocol of Relative Data Based on HEED).ICRPG aims at solving the problem of fast energy depletion caused by all cluster heads communicating with base station in the HEED. The protocol introduces the concepts of gateway, middle cluster head and center cluster head. Middle cluster head communicates with center cluster head through gateway, so the number of cluster heads which communicate with base station directly is decreased. As a result, it balances the energy of nodes and prolongs the life of network. The protocol has three improvements. First, considering of the distance between node and base station and the residual energy of node, it proposes an algorithm for selecting center cluster head and middle cluster head to ensure nodes choose routing path following the principle of "distance first, energy second". Second, it builds a routing information table, which involves middle cluster head, gateway and center cluster head. Third, it updates routing information table after each round of data transmission to guarantee to choose the gateway and center cluster head with the maximum residual energy in next round of data transmission.ICRPR is a kind of inter-cluster routing protocol merging data aggregation and routing technology. Ordinary hierarchical routing protocol only aggregates inner-cluster data; however, the data in a certain area is often relative in practical application. Aggregating these relative data can efficiently save the energy of nodes. By getting the set of cluster head with relative data, ICRPR aggregates the data from the cluster heads with relative data in neighbor areas. So the efficiency of whole wireless sensor network is enhanced.