An adaptive collision resolution scheme for energy efficient communication in IEEE 802.15.4 networks

IEEE 802.15.4 provides a widely accepted solution for low-cost and low-power wireless communications, and it is known to be applicable to many types of WSN application scenarios. To enhance energy efficiency and throughput of sensor nodes, many CSMA/CA schemes based on IEEE 802.15.4 have been proposed. However, they still suffer from unnecessary waste of energy and bandwidth due to inefficient backoff management. In order to overcome these problems, we propose an enhancement to existing schemes, called adaptive collision resolution (ACR). ACR appropriately adapts backoff exponent (BE) to the current network contention level based on physical and link-layer measurements. In addition, it adjusts backoff periods (BP) to avoid meaningless backoffs and additional clear channel assessments (CCAs) by using the estimated time remaining until the channel becomes idle. To verify the feasibility and applicability of our scheme, we studied mathematical analysis and tested it on the Matlab and USRP/GNU Radio testbed. We also performed simulation study using OPNET, and our simulation results indicate that ACR shows improved energy efficiency and throughput performance over existing schemes.