A HIERARCHICAL CONGESTION AVOIDANCE ALGORITHM IN WIRELESS SENSOR NETWORKS

In most wireless sensor networks (WSNs), all data converge to the sink. A node needs to forward data from its downstream nodes that are farther to the sink. Thus the nodes closer to the sink have relatively heavier traffic load, which easily results in congestion at these nodes. To deal with this problem, this paper presents a novel hierarchical congestion avoidance algorithm, HCA, and HCA provides different channel access opportunities to different nodes based on the distribution of traffic loads. In another word, HCA gives the nodes with heavier loads more chance to transmit data to avoid and mitigate congestion occurrence. For each node, its traffic load is estimated via the hierarchical level it locates and the number of children it has. Simulation results show that HCA algorithm reduces packet loss ratio, improves throughput and gains energy saving in single-path WSNs, which highlights the property of mitigating congestion of HCA.