The Research On Routing Algorithm Based On The Tree And AODVjr In ZigBee Networks

ZigBee technology has the advantages of low cost, low power consumption, low complexity and high reliability. At present, it has become the mainstream technology of wireless sensor networks. With the constant improvement of ZigBee protocol, the wireless sensor networks based on ZigBee technology will be used in a wider range of applications, such as home automation, industrial controlling, intelligent medical, military, agricultural production, wireless positioning, and so on. ZigBee networks routing algorithm has significant effects on the performance of the entire network. It is significant to design a high performance routing algorithm for ZigBee network according to different requirements. ZigBee routing algorithms can be divided into three types, Tree routing, AODVjr algorithm and the hybrid algorithm of them. In order to solve the problems existed in ZigBee routing algorithms, the paper proposes ZigBee network tree routing algorithm based on the two-hop neighbor table and ZigBee hybrid routing algorithm based on uneven clustering mechanism, according to the research of existing routing algorithm for ZigBee networks.For the problem that ZigBee network tree routing algorithm and the existing routing algorithm based on the neighbor table have unbalanced traffic load and a long data transmission path, the ZigBee network tree routing algorithm based on the two-hop neighbor table is proposed. Using two-hop neighbor table, the algorithm excludes the descendants of the current node, descendants of one-hop neighbor node and leaf nodes in set of two-hop neighbor nodes. The algorithm calculates tree routing hops of all the remaining nodes in the two-hop neighbor set to the destination node, selects the two-hop neighbor node which has the smallest tree routing hops to the destination node as the target node, and selects the one-hop neighbor node which can reach the target node which has the smallest tree routing hops to the destination node as the next forwarding node. When the one-hop neighbor nodes have the tree routing hops, the node which has less neighbors nodes is chosen as the next hop forwarding node. Theoretical analysis shows the algorithm can find a shorter transmission path than tree routing algorithm based on one-hop neighbor table. The simulation results show that the algorithm is effective in shortening routing hops, reducing end-to-end delay and improving packet delivery ratio.For the problem that nodes have unbalanced energy consumption in ZigBee network hybrid routing algorithm, based on the tree routing algorithm and AODVjr algorithm, the ZigBee hybrid routing algorithm based on uneven clustering mechanism is proposed. With uneven clustering mechanism, the algorithm divides the network into several uneven logical clusters, the scale of clusters which closed to the coordinator is smaller, reducing the packets cluster head forwarded, and the energy consumption is balanced. Based on the clustering, the transmission is divided into transmission within the clusters and between the clusters. Transmission within the clusters uses tree routing algorithm based on the neighbor table. While the transmission between the clusters uses the AODVjr algorithm when the tree routing algorithm based on the neighbor table is invalid, which can find out a shorter path between two cluster head nodes by initiate a route discovery, in the same time, only the cluster head nodes and gateway nodes can broadcast control packets, to reduce the redundant control packets. The Theoretical analysis shows that the algorithm can find a shorter route in a limited time. The simulation results show that the proposed algorithm can effectively shorten transmission path, balance energy consumption, prolong the network lifetime and achieve the purpose of improving the network performance.