Fibonacci Backoff Algorithm for IEEE 802.15.4/ZigBee

Abstract

The IEEE 802.15.4 is a standard proposed for Wireless Personal Area Network (PAN) and supports low data rate, low cost, low complexity and low power consumption applications. In IEEE 802.15.4 MAC layer, the CSMA/CA algorithm follows the Binary Exponential Backoff (BEB) scheme in order to determine the backoff delay each node shall wait as they need to access the channel. This paper investigate a weakness concerning BEB scheme, that is, the possibility of more than two nodes choose the same backoff exponent value and consequently increasing collision and network contention level which will degrade the overall network performance. To overcome this problem, a new Fibonacci Backoff (FIB) scheme is proposed through which nodes shall wait for an incremental backoff periods as they need to access the channel. Performance of FIB algorithm will be compared to that of BEB after simulating both on two scenarios of a star topology.