The Research On Local Congestion Control Algorithm In Wireless Sensor Networks

WSN(Wireless Sensor Network) is a distributed ad-hoc network which is dependent from fixed equipment and facilities. The mobile nodes in WSN have the feature of data acquisition and wireless communication. However, the nodes in WNS have low computation capacity, constrained energy and weak communication ability. WSN often experiences congestion due to these constraints on resources, the loss of wireless transmission, the limitation of exclusive channel, the communication with the many-to-one and multi-hop pattern.How to share wireless channel efficiently is significant for data collection in wireless sensor network. With the requirement of multimedia sensing, local congestion, such as Sink and cluster head congestion, has becoming more common and more serious. Therefore, a local congestion control algorithm with fair channel allocation(FCA) was presented to mitigate local congestion as well as to improve the fairness of channel utilization. In order to decrease the extra communication overhead for obtaining the real-time buffer length of neighbors and improve the accuracy of congestion detection model based on buffer occupancy of single node, FCA presents a new model considers the total buffer length of neighbors with predict-based mechanism for real-time buffer occupancy and the average transmission time of packet. To avoid deteriorating congestion with an explicit notified package, FCA embeds an additional node address to the ACK control frame to carry congestion information. During the congestion alleviation stage, FCA presents a fair channel allocation mechanism based on real-time buffer occupancy and queue priority with the purpose of preventing package loss from buffer overflow. Simulations with burst data flow and step data flow show that the proposed protocol has comparative advantages compare with 802.11, CODA and PCCP in terms of collision, package delivery ratio, throughput and fairness.