Improved backoff algorithm for IEEE 802.15.4 wireless sensor networks

Abstract

In wireless sensor networks (WSN) the medium access control CSMA/CA uses binary exponential backoff (BEB) algorithm to minimize collision among the contending nodes. The range of backoff exponent is limited to very small values. This causes channel access collision among the nodes resulting in degradation of quality of service. In this paper improved binary exponential backoff (IBEB) algorithm is proposed using interim backoff (IB) and unit interim period (IP) to minimize channel access collision by randomly waking up within the backoff time to sense the channel. The result shows that IBEB outperforms significantly the existing BEB algorithm employed in the IEEE 802.15.4 MAC standard as well as Linear/Multiplicative Increase and Linear Decrease (LMILD) and Multiplicative Increase Linear Decrease (MILD) schemes on variable network load and size.