A Priority Scheme for IEEE 802. 11 DCF Access Method

IEEE 802.11 is a standard for wireless LANs. The basic access method in its MAC layer protocol is the distributed coordination function (DCF) for the ad hoc networks. It is based on the mechanism of carrier sense multiple access with collision avoidance (CSMA/CA). DCF is used to support asynchronous data transmission. However, frames in DCF do not have priorities, making it unsuitable for real-time applications. With a little bad luck, a station might have to wait arbitrarily long to send a frame. In this paper, we propose a method to modify the CSMA/CA protocol such that station priorities can be supported. The method is simple, efficient and easy to implement in comparison to point coordination function (PCF), another access method in IEEE 802.11 based on access points (base stations). Simulations are conducted to analyze the proposed scheme. The results show that DCF is able to carry the prioritized traffic with the proposed scheme. key words: wireless LAN, CSMA/CA, multimedia applications,

[1]  D. Raychaudhuri,et al.  ATM-based transport architecture for multiservices wireless personal communication networks , 1994, IEEE J. Sel. Areas Commun..

[2]  Arvind Krishna,et al.  Wireless LANs and mobile networking: standards and future directions , 1996, IEEE Commun. Mag..

[3]  Zhao Liu,et al.  Distributed-queueing request update multiple access (DQRUMA) for wireless packet (ATM) networks , 1995, Proceedings IEEE International Conference on Communications ICC '95.

[4]  S. Hethuin,et al.  Digital wireless broadband corporate and private networks: RNET concepts and applications , 1997 .

[5]  Edward C. Prem,et al.  Wireless Local Area Networks , 2008, Industrial Communication Systems.

[6]  David J. Goodman,et al.  Efficiency of packet reservation multiple access , 1991 .

[7]  Luis M. Correia,et al.  An overview of wireless broadband communications , 1997 .

[8]  Reinaldo A. Valenzuela,et al.  BAHAMA: a broadband ad-hoc wireless ATM local-area network , 1995, Proceedings IEEE International Conference on Communications ICC '95.

[9]  A. S. Krishnakumar,et al.  Distributed multiple access procedures to provide voice communications over IEEE 802.11 wireless networks , 1996, Proceedings of GLOBECOM'96. 1996 IEEE Global Telecommunications Conference.

[10]  Gunnar Karlsson,et al.  Performance models of statistical multiplexing in packet video communications , 1988, IEEE Trans. Commun..

[11]  Jeong Geun Kim,et al.  PRMA/DA: a new media access control protocol for wireless ATM , 1996, Proceedings of ICC/SUPERCOMM '96 - International Conference on Communications.

[12]  D. Estrin,et al.  RSVP: a new resource reservation protocol , 1993, IEEE Communications Magazine.

[13]  Jim T. Geier.  Wireless Networking Handbook , 1996 .