Adaptive clear channel assessment (A-CCA): Energy efficient method to improve wireless sensor networks (WSNs) operations

Clear Channel Assessment (CCA) is an integral component of CSMA based Medium Access Control (MAC) protocols employing channel sensing during transmission. The channel sensing mechanism is a cross-layer scheme where CCA operates at the PHY layer, used on the transmitter and receiver side, impacting the MAC layer, including the node's energy consumption and overall throughput. This paper evaluates IEEE 802.15.4 standard-based MAC protocols for various traffic conditions. It proposes an adaptive CCA (A-CCA) timing mechanism to improve node energy consumption by reducing node time in false wakeups and idle-listening modes. ACCA helps transmitters to adjust their radio powers in high traffic and interference environments above the noise floor, allowing the receiver to monitor the sender signal and adjust its wakeup period accordingly. The proposed scheme was evaluated using Cooja Simulator as well as CC2420 based platforms to report improved node lifetime and reduce false wakeups under heavy interference. The proposed scheme reported (1.10% and 1.18%) reduction in radio duty cycle for light and heavy traffic environments. The results of the study indicated that ACCA improved the network power consumption, where an overall 6% power reduction is achieved to improve the node lifetime.