Cross-layer congestion control for wireless sensor networks

Congestion in wireless sensor networks (WSNs) can lead to longer delay, higher packet loss ratio, and higher energy waste due to a large number of packet retransmissions and packet drops after several retransmission failures. To detect congestion precisely and regulate it fairly, a congestion control protocol based on cross-layer design, i. e. upstream congestion control (UCC) protocol, is proposed. In the protocol, each node takes advantage of unoccupied buffer size and predicted traffic flow at medium access control (MAC) layer as congestion level indication, and combines node priority to assign the upstream traffic rates of its last-hop nodes. Based on this congestion detection and priority-based rate adjustment schemes, the UCC protocol utilizes a cross-layer optimization and mitigates congestion with the help of hop-by-hop rate adjustment. Finally, simulation results show that the proposed protocol achieves higher throughput, better priority-based fairness and lower packet loss ratio than both congestion control and fairness (CCF) protocol and priority-based congestion control protocol (PCCP).