Efficient access scheme using fuzzy controlled sliding backoff window for wireless networks

In this paper, a new backoff algorithm based on sliding the backoff interval is proposed to maximize the channel throughput and improve the fairness of random access channels. In the sliding backoff interval (SB) algorithm, every node that experiences packet collisions increase its SB range by a forward sliding factor (FSF) and in case of successful transmission decrease its SB range by a backward sliding factor (BSF). Forward and backward sliding factor (SF) is controlled according to the channel offered traffic using fuzzy controller to maximize the channel throughput. Furthermore, the operation of the proposed backoff algorithm does not depend on the knowledge of the number of active nodes. A computer simulation is developed using MATLAB to evaluate the performance of the proposed backoff algorithm and compare it with the binary exponential backoff (BEB) scheme which is widely used due to its high channel throughput while its fairness is relatively poor. It is shown that the proposed backoff algorithm achieves nearly the ideal performance of fairness at Bmin=2 and the ideal performance of fairness for all other values of Bmin. So, it significantly out-performs the BEB scheme in terms of improving the performance of fairness, while achieving high channel throughput.