An enhanced carrier sensing algorithm for IEEE 802.15.4 low-rate wireless sensor networks

Wireless sensor networks based on the IEEE 802.15.4 standard is able to achieve low-power transmissions in low-rate and short-distance wireless personal area networks (WPANs). It employs the slotted carrier sense multiple access with collision avoidance (CSMA/CA) for the contention mechanism. The blind backoff process in the slotted CSMA/CA will cause lower channel utilization. Sensor node performs backoff process immediately when the clear channel assessment (CCA) detecting busy channel. It may neglect the implicit information of CCA failed detection and further cause the redundant senses. This paper proposes an additional carrier sensing (ACS) algorithm based on IEEE 802.15.4 to enhance the carrier sensing mechanisms in original slotted CSMA/CA. An analytic model is developed to evaluate the performance of ACS algorithm. The analytical and simulation results demonstrate that the proposed scheme significantly improves the throughput, average medium access control (MAC) delay and power consumption of CCA detecting.