Research On Congestion Control In Wireless Sensor Network

With the rapid development of communication, embedded computing and sensortechnology, wireless sensor network gains people's great attention, which becomes animportant research focus. Wireless sensor networks are mainly used in environmentalmonitoring, military and transportation, etc. For large-scale and high-density networkapplications, it is more conducive to managing the entire network and saving the sensornodes' energy to use hierarchical structure of multi-hop clustering. However, characters ofthe wireless sensor network can lead to network congestion easily.Firstly, this paper elaborates the causes of network congestion, research status andchallenges on congestion control. At the same time, it induces and analyses the wirelesssensor network congestion control methods.Secondly, by analysis of the network structure of hierarchical clustering, this paperproposes detection methods based on combination of buffer occupancy rate and degree ofcongestion and congestion avoidance algorithm based on virtual cluster head CABVC.The algorithm gives congestion notification in advance to avoid the congestion. In thecongestion avoidance process, CABVC algorithm finds a virtual cluster head by thealgorithm of shortest path tree in the inner-cluster in order to share the data stream for thecluster head and structure multiple paths by using the virtual cluster head to reduce theoriginal path pressure of routing in extra-cluster. Structural adjustment mitigates networkcongestion effectively, so that the network will soon recover from the congestion trend andwork in the normal condition.Thirdly, this paper proposes congestion release algorithm CRBDP in wireless sensornetwork. The algorithm runs in the inevitable congestion network after the congestionavoidance, which can relieve congestion by rate control strategies and packets loss basedon the dynamic priority. CRBDP algorithm gives the specific methods in making dynamicpriority, rate measurement, adjustment and recovery process and the implementation ofpackets loss method.Finally, the paper studies and designs the experimental program, and then build experiment environment in NS2. By analysis and comparison with STCP and COMUTalgorithms, the experiments show that the proposed algorithm achieved good results onthe network throughput, data transmission delay and packet loss rate.