Abstract
IEEE 802.11 is a widely used standard for MAC and PHY layers of WLANs. Unfortunately, the access methods offered in this standard cannot support QoS (Quality of Service) for real-time traffics. Using multimedia applications over WLANs is increasing and, on the other hand, it seems that the access methods employed in this standard causes high variations in delay or jitter and wastes bandwidth due to collisions. There are many methods to enable DCF—basic access method in 802.11—with service differentiation and QoS. The difficulty in majority of these methods is unfair bandwidth allocation among low and high priority traffics at high loads resulting starvation for low priority traffics. In this paper, we modify the way that the CW (Contention Window) size is calculated after a successful transmission and study the effect of the CW size on performance and fairness. Results of our simulations show that the performance of DCF with this modification is better, specially, for traffics in which throughput is the most important parameter. Besides, this method provides better fairness among low and high priority traffics. We also employ a scheme to enable 802.11 with service differentiation which grants dynamic priority to low priority traffics to prevent starvation, specially, in high loads.
References
IEEE Std. 802.11-1999 (1999). Information technology – Telecommunications and information exchange between systems – Local and metropolitan area networks – Specific requirement – Part II: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification.
Ni Q., Romdhani L., et al. (2004). A survey of QoS enhancements for IEEE 802.11 wireless LAN. Journal of Wireless Communications and Mobile Computing 4(5): 547–566
Zhu, H., Li, M., Chlamtac, I., & Prabhakaran, B. (2004). A survey of quality of service in IEEE 802.11 networks. IEEE Wireless Communications, pp. 6–14.
Hua Z., Ming L., Chlamtac I., Prabhakaran B. A survey of quality of service in IEEE 802.11 networks. Wireless Communications, IEEE 11(4): 6–14
Pattara-Atikom W., Krishnamurthy P., Banerjee S. (2003). Distributed mechanisms for quality of service in wireless LANs. 10(3): 26–34
Xiao Y. (2003). Backoff-based priority schemes for IEEE 802.11. IEEE International Conference on Communication 3: 1568–1572
Peng Y., Cheng S. (2003). Design of a fine tuned self-adapt DCF-based protocol. Communication Technology Proceedings, 2003. ICCT 2003. International Conference 2: 1220–1225
Lindgern, A., Almquist, A., & Schelen, O. (2001). Evaluation of quality of service schemes for IEEE 802.11 wireless LANs. Local Computer Networks, Proceedings. LCN 2001. 26th Annual IEEE Conference, pp. 348–351.
Deng, D.-J., & Chang, R.-S. (1999). A priority scheme for IEEE 802.11 DCF access method. IEICE Transaction on Communications, 82(1).
Vaidya, N. H., Bahl, P., & Gupta, S. (2000). Distributed fair scheduling in a wireless LAN. In Sixth annual international conference on mobile computing and networking, Boston.
Seongkwan, K., Youngsoo, K., & Sunghyun, C. et al. (2005). A high-throughput MAC strategy for next-generation WLANs. World of Wireless Mobile and Multimedia Networks, 2005. WoWMoM 2005. Sixth IEEE International Symposium, pp. 278–285.
Pau, G., Maniezzo, D., Das, S., et al. (2003). A cross-layer framework for wireless LAN QoS support. Information Technology: Research and Education, 2003. Proceedings. ITRE2003. International Conference on Publication, pp. 331–334.
Kanghee K., Ahmad A., Kim K. (2003). A wireless multimedia LAN architecture using DCF with shortened contention window for QoS provisioning. Wireless Communications and Networking 2: 1308–1311
Vergados D.J., Vergados D.D., Sgora A. (2005). Jitter analysis of the IEEE 802.11 DCF access mode. Vehicular Technology Conference 2: 1342–1345
Ksentini A., Nafaa A., Gueroui A., Naimi M. (2005). Determinist contention window algorithm for IEEE 802.11. Personal, Indoor and Mobile Radio Communications, IEEE 16th International Symposium 4: 2712–2716
Nafaa A., Ksentini A., et al. (2005). Sliding contention window (SCW): towards backoff range-based service differentiation over IEEE 802.11 wireless LAN networks. Network, IEEE 19(4): 45–51
Takahashi, K., & Tsuboi, T. (2005). A backoff algorithm for improving saturation throughput in IEEE 802.11 DCF. 14th IST Mobile & Wireless Communications Summit, June 2005.
Song, N. O., Kwak, B. J., Song, J., et al. (2003). Enhancement of IEEE 802.11 distributed coordination function with exponential increase exponential decrease backoff algorithm. Proc. VTC Spring 2003.
Jacob, L., Li, X., & Zhou, L. (2003). A MAC protocol with QoS guarantees for real-time traffics in wireless LANs. Information, Communications and Signal Processing, 2003 and the Fourth Pacific Rim Conference on Multimedia, 3, pp. 1962–1966.
Yang X., Yi P. (2005). Differentiation, QoS guarantee, and optimization for real-time traffic over one-hop ad hoc networks. Parallel and Distributed Systems, IEEE Transactions 16(6): 538–549
Burbank, J. L., & Kasch, W. T. (2005). Enhanced efficiency and flexibility while supporting QoS concepts: An adaptive MAC framework for 802.11 WLANs. Electrical and Computer Engineering, 2005. Canadian Conference, pp. 37–43.
Benveniste M. (2002). ‘Tiered contention multiple access’ (TCMA), a QoS-based distributed MAC protocol. Personal, Indoor and Mobile Radio Communications, 2002. The 13th IEEE International Symposium 2: 598–604
Deyun G., Jianfei C., King N. (2005). Admission control in IEEE 802.11e wireless LANs. Network, IEEE 19(4): 6–13
Tzu-Chieh T., Ming-Ju W. (2005). An analytical model for IEEE 802.11e EDCA. Communications, 2005. ICC 2005. 2005 IEEE International Conference 5: 3474–3478
Powell, C., Alnuweiri, H., & Nasiopoulos, P. (2005). An enhanced distributed channel access deficit round-robin (EDRR) access scheme for IEEE 802.11 wireless networks. Wireless and Optical Communications Networks, 2005. WOCN 2005. Second IFIP International Conference, pp. 45–50.
Davcevski M., Janevski T. (2005). Analysis of IEEE 802.11e QoS in multimedia environment. Telecommunications in Modern Satellite, Cable and Broadcasting Services, 2005. 7th International Conference 1: 45–48
Jie H., Devetsikiotis M. (2003). Designing improved MAC packet schedulers for 802.11e WLAN. Global Telecommunications Conference, 2003. GLOBECOM ’03. IEEE 1: 184–189
Tiantong, Y., Chi-Hsiang, Y., & Hassanein, H. (2005). DRCE: A high throughput QoS MAC protocol for wireless ad hoc networks. Computers and Communications, 2005. ISCC 2005. Proceedings. 10th IEEE Symposium, pp. 671–676.
Salhotra A., Narasimhan R., Kopikare R. (2005). Evaluation of contention free bursting in IEEE 802.11e wireless LANs. Wireless Communications and Networking Conference, 2005 IEEE 1: 107–112
Yang X. (2004). IEEE 802.11e: QoS provisioning at the MAC layer. Wireless Communications, IEEE 11(3): 72–79
da Silva, M. P., & Westphall, C. B. (2005). Performance analysis and service differentiation in the MAC sublayer of IEEE 802.11e ad hoc networks. Advanced Industrial Conference on Telecommunications/Service Assurance with Partial and Intermittent Resources Conference/E-Learning on Telecommunications Workshop. AICT/SAPIR/ELETE 2005. Proceedings, pp. 434–440.
Hua Z., Chlamtac I. (2005). Performance analysis for IEEE 802.11e EDCF service differentiation. Wireless Communications. IEEE Transactions 4(4): 1779–1788
Hyunmin K., Sangho S., Sin-Chong P. (2005). Performance evaluation of enhanced distributed contention control (EDCC) mechanism in IEEE 802.11e. Communications, 2005. ICC 2005. 2005 IEEE International Conference 5: 3461–3466
Jun Z., Zihua G., Qian Z. et al. (2002). Performance study of MAC for service differentiation in IEEE 802.11. Global Telecommunications Conference, 2002. GLOBECOM ’02. IEEE 1: 778–782
Dongyan, C., Daqing, G., & Jinyun, Z. (2004). Supporting real-time traffic with QoS in IEEE 802.11e based home networks. Consumer Communications and Networking Conference, 2004. First IEEE, pp. 205–209.
Malli, M., Ni, Q., Turletti, T., & Barakat, C. (2004). Adaptive fair channel allocation for QoS enhancement in IEEE 802.11 wireless LANs. IEEE International Conference on Communications (ICC 2004), Paris.
Pattara-Aukom W., Banerjee S., Krishnamurthy P. (2002). Starvation prevention and quality of service in wireless LANs. Wireless Personal Multimedia Communications, 2002. The 5th International Symposium 3: 1078–1082
Kwon Y., Fang Y., Latchman H. (2004). Design of MAC protocols with fast collision resolution for wireless local area networks. Wireless Communications, IEEE Transactions 3(3): 793–807
Zuyuan F., Bensaou B., Jin Y. (2004). Collision-free MAC scheduling algorithms for wireless ad hoc networks. Global Telecommunications Conference, 2004. GLOBECOM ’04. IEEE 5: 2770–2774
Shreedhar M., Varghese G. (1996). Efficient fair queuing using deficit round-robin. Journal of IEEE/ACM Transaction on Networking 4: 375–385
IEEE Std 802.11e/D3.3. (October 2002). Draft supplement to IEEE standard for telecommunications and information exchange between systems - LANMAN specific requirements. Pan 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY).
Liu, W., Lou, W., Chen, X., & Fang, Y. (2003). A QoS-enabled MAC architecture for prioritized services in IEEE 802.11 WLANs. IEEE GLOBECOM 2003, San Francisco, CA.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Khalaj, A., Yazdani, N. & Rahgozar, M. Effect of the contention window size on performance and fairness of the IEEE 802.11 standard. Wireless Pers Commun 43, 1267–1278 (2007). https://doi.org/10.1007/s11277-007-9300-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11277-007-9300-5