—This paper evaluates the performance of a variant of IEEE 802.11 DCF (we call it the delayed-DCF scheme). In the delayed-DCF scheme, before transmitting a packet, each node first waits for a deterministic delay, and then enters the normal procedure of the legacy DCF. The delayed-DCF scheme adopts a mixed-type contention resolution method: the deterministic delay postpones the time that nodes contend for channel and its counter counts down without the influence of the channel status, while the legacy backoff time resolves collision when nodes contends for channel and its counter can be adaptively adjusted by the contention intensity of the channel. We find via simulation that there exists an optimal deterministic delay, which can minimize the mean and standard deviation of the MAC access delay while maximizing the system throughput. This good feature enables the delayed-DCF scheme to be very applicable to the delay-variance-sensitive applications such as voice over WLANs.
—Wireless LAN, delayed channel access, DCF, performance.
The authors are with Faculty of Information Technology, Macau University of Science and Technology, Taipa, Macau (e-mail: zqlict@ hotmail.com, email@example.com, hndai@ ieee.org).
Cite: Qing Lin Zhao, Zhi Jie Ma, and Hong Ning Dai, "Performance Evaluation of the Delayed-DCF Scheme in Wireless LANs," International Journal of Future Computer and Communication vol. 2, no. 5, pp. 391-394, 2013.