An improved 802.15.4 unslotted CSMA/CA algorithm for reducing collision probability and delay in wireless sensor networks

A smaller backoff exponent (BE) can lead to higher collision probability in high-density wireless sensor networks. Consequently, this gives rise to reduced throughput and increased delay. This article improves the unslotted CSMA/CA algorithm, including: firstly, by reducing the basic unit value of backoff period (BP) and increasing the contention window (CW), the collision probability can be significantly reduced when multiple nodes simultaneously backoff, and the delay can also be reduced; Secondly, in response to the lack of a dynamic mechanism to reduce BE in the original unslotted CSMA/CA algorithm, this article proposes an adaptive adjustment algorithm for BE. It can reasonably reduce BE to further reduce delay when network status allows. This article establishes two mathematical models for the improved algorithm for analysis. Compared with the original algorithm, the simulation results show that the collision probability and network delay are improved by at least 43.45% and 52.72%, respectively.