Research On Broadcast Algorithm Based On Wireless Network

With the maturity of wireless communications technology and sensor technology, wireless sensor networks(WSN) have developed rapidly in the past ten years. With the multi- function, low cost, low power consumption and other advantages, wireless sensor networks attract people’s main concern.Broadcast is an important content in wireless sensor network research. Broadcast is a process that a node sends a message from a source to all other nodes in the network. Because the range of the wireless network area is much larger than the transmission range of a single node, it is necessary to rebroadcast broadcast messages by the intermediate nodes. Multiple messages sent by many intermediate nodes are transmitted simultaneously will interfere with each other and result in conflict. Thus the receiving node cannot receive messages correctly so as to prolong the broadcast latency. Although the study of minimum- latency broadcast problem has made good result. Unfortunately, the problem is NP-hard, so designing an efficient algorithm is still meaningful.In order to avoid conflict in the broadcast and reduce broadcast latency, this thesis purposes a conflict-aware broadcast scheduling algorithm(C BS) based Unit Disk Graph(UDG) under protocol interference model. CBS algorithm generates scheduling timetable based on the node distribution for each node during broadcast, and schedules the node broadcast message s in accordance with the scheduling timetable avoiding conflict in the broadcast. And then the node can complete broadcast successfully. CBS algorithm takes into account the case that the conditions of the sending node sent messages successfully and the receiving node receive messages successfully are different when a plurality of different nodes broadcast message simultaneously. It sets different conditions to ensure that nodes can send or receive messages successfully during broadcast. CBS algorithm prior schedules the node with greater impact on others to broadcast, and reduce the inference with other nodes during the broadcast. When CBS algorithm schedule the node broadcast, two conditions should be meeting. The node will not interfere with other receiving nodes when send messages, and the node receives the messages will not be interfered by other sending nodes, to ensure that the node in the process of broadcast won’t conflict, reducing the broadcast latency. Furthermore, C BS algorithm allows the nodes in different layers of broadcast tree to transmit simultaneously, which effectively improves the utilization of network channels.Studies show that CBS algorithm can avoid conflict among nodes during broadcast and succeed broadcasting. Compared with other algorithms, CBS algorithm can finish network broadcast by virtue of fewer messages within a short time and reduce broadcast latency.