Virtual-FIFO Back-Off Algorithm for Collision Resolution in Wireless Networks

Chih-Peng LI  

IEICE TRANSACTIONS on Communications   Vol.E88-B    No.10    pp.4056-4063
Publication Date: 2005/10/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.10.4056
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
binary exponential back-off (BEB),  collision resolution,  capture effect,  medium access control (MAC),  QoS,  

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This investigation proposes a virtual-FIFO (VFIFO) back-off algorithm for wireless networks. The proposed scheme takes advantage of the central unit (CU) in a wireless network to broadcast a common back-off window size to all the users, significantly alleviating the unfairness of bandwidth utilization in conventional binary exponential back-off (BEB) algorithms. The proposed scheme exploits the CU's capability for collision detection to estimate the number of simultaneously competing users. Additionally, packets generated in a given cycle are split into groups according to their times of arrivals and are guaranteed to be serviced one after another within the next cycle. Although the proposed algorithm is not strictly first come fist served, the FIFO principle is virtually accomplished. Simulation results demonstrate that the standard deviation of delay can be improved by more than two orders and the throughput can be maintained at 0.42 when the number of users approaches infinity. The capture effect even further improves system performance.