Enhanced backoff scheme in CSMA/CA for IEEE 802.11

An enhanced CSMA/CA (carrier sense multiple access with collision avoidance) protocol to be used in the medium access control (MAC) layer of the IEEE 802.11 standard for wireless local area networks (wireless LANs) is proposed in this work. In wireless LANs, the CSMA/CA protocol supports asynchronous data transfer, and adopts an acknowledgment mechanism to confirm successful transmissions and a handshaking mechanism to reduce collisions. In both cases, a binary exponential backoff mechanism is used. The enhanced protocol improves the exponential backoff scheme by dynamically adjusting the contention window (CW) around the optimal value. Moreover, an analytical model based on the Markov chain is developed to analyze the system performance in terms of throughput and delay. Numerical results are presented to show the effect of the proposed backoff mechanism.

[1]  Melody Moh,et al.  Analyzing the hidden-terminal effects and multimedia support for wireless LAN , 2000, Comput. Commun..

[2]  A. Girotra,et al.  Performance Analysis of the IEEE 802 . 11 Distributed Coordination Function , 2005 .

[3]  Kwang-Cheng Chen,et al.  Interference analysis of nonpersistent CSMA with hidden terminals in multicell wireless data networks , 1995, Proceedings of 6th International Symposium on Personal, Indoor and Mobile Radio Communications.

[4]  Yang Xiao,et al.  Throughput and delay limits of IEEE 802.11 , 2002, IEEE Communications Letters.

[5]  Vasileios Vitsas,et al.  Performance analysis of the collision avoidance procedure of the advanced infrared (AIr) CSMA/CA protocol for wireless LANs , 2002, Vehicular Technology Conference. IEEE 55th Vehicular Technology Conference. VTC Spring 2002 (Cat. No.02CH37367).

[6]  Xiaowen Wang,et al.  Performance enhancement of 802.11 wireless LAN for asymmetric traffic using an adaptive MAC layer protocol , 2002, Proceedings IEEE 56th Vehicular Technology Conference.

[7]  Ramiro Jordan,et al.  Wireless communications and networking: an overview , 2002 .

[8]  Theodore Antonakopoulos,et al.  CSMA/CA performance under high traffic conditions: throughput and delay analysis , 2002, Comput. Commun..

[9]  Wha Sook Jeon,et al.  Performance of an exponential backoff scheme for slotted-ALOHA protocol in local wireless environment , 1995 .

[10]  Marco Conti,et al.  Dynamic tuning of the IEEE 802.11 protocol to achieve a theoretical throughput limit , 2000, TNET.

[11]  Adam Wolisz,et al.  Performance study of access control in wireless LANs – IEEE 802.11 DFWMAC and ETSI RES 10 Hiperlan , 1997, Mob. Networks Appl..