Priority Collision Resolution - Distributed Coordination Function for Distributed Wireless Networks

Xiaohui Ye, Xin Liu, S. J. Ben Yoo, Zhi Ding

Abstract: In distributed wireless access networks, the short-term unfairness of IEEE 802.11 distributed coordination function (DCF) has been revealed by many works. In this paper, a modified DCF, based on the principle of priority collision resolution (PCR), is proposed to improve the short-term fairness in distributed access wireless networks. Our PCR-DCF achieves short-term fairness improvement without estimating behaviors of other users and the system contention level, such as the number of active users. Only the capability to identify collision is required. Theoretical analysis is carried out to validate the performance of PCR-DCF based on a slotted system model. Both simulations and analyses show that PCR-DCF has a much smaller packet transmission delay jitter than IEEE 802.11 DCF, with little degradation on the average packet transmission delay. Moreover, the analysis and simulation results indicate that PCR- DCF also experiences a much lower packet drop rate than IEEE 802.11 DCF in almost all load ranges with reasonable retransmission limit.