Oriental Journal of Computer Science and Technology

Open Access Open Access  Restricted Access Subscription Access

Improving WLAN Quality of Services (Qos) Using Opnet


Affiliations
1 Karnatak University of Dharwad-03, India
2 Central University of Karnataka-67, India
 

Wireless local area networks (WLANs) are in a period of great expansion and there is a strong need for them to support multimedia applications. With the increasing demand and penetration of wireless services, users of wireless networks now expect Quality of Service (QoS) and performance comparable to what is available from fixed networks. Providing QoS requirements like good throughput and minimum access delay are challenging tasks with regard to 802.11 WLAN protocols and Medium Access Control (MAC) functions. This research is done to study, the presently implemented schemes (the Point Coordination Function (PCF) of IEEE 802.11, the Enhanced Distributed Coordination Function (EDCF) of the proposed IEEE 802.11e extension to IEEE 802.11), solves these issues and what can be done to improve them further. The metrics used were Throughput, Data Drop, Retransmission and Medium Access Delay, to analyze the performance of various MAC protocols in providing QoS to users of WLAN. Two scenarios, with same Physical and MAC parameters, one implementing the DCF and other EDCF, were created in the network simulation tool (OPNET MODELER) to obtain the results. The results showed that the performance of EDCF was better in providing QoS for real-time interactive services (like video conferencing) as compared to DCF, because of its ability to differentiate and prioritize various services. Index Terms - Wireless local area networks (WLANs).

Keywords

Expect Quality of Service (QoS), Point Co-ordination Function (PCF), Enhanced Distributed Coordination Function (EDCF), OPNET.
User
Notifications
Font Size

  • Choi Sunghyun, Del, Sai, Mangold S. “IEEE 802.11 e contention-based channel access (EDCF) performance evaluation”, IEEE International Conference on In Communications, 2, pp. 1151-1156, (2003).

  • Choi S. and Shin K. G., “A cellular local area network with QoS guarantees for heterogeneous traffic”, Proceedings IEEE Infocom’97, pp. 1032-1039, Kobe, Japan, (1997).

  • Crow Brian P., WidjajaIndra, Kim JeongGeun, Prescott T. Sakai,”IEEE 802.11 Wireless Local Area Networks”, IEEE Communications Magazine, (1997).

  • Draft Standard IEEE 802.11, “Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications”, (1999).

  • Grilo A. and Nunes M., “Performance Evaluation of IEEE 802.11e”, In Proc. IEEE Personal, Indoor and Mobile Radio Communications (PIMRC), vol. 1, pp. 511 -517, (2002).

  • Gu D. and Zhang J., “QoS enhancement in IEEE 802.11 wireless local area networks”, IEEE Communications Magazine, vol. 41, no. 6, pp. 120 -124, (2003).

  • Hannikainen Marko, LavikkoTommi, Kukkala Petri And HamalainenTimo D., QoS Supporting Wireless Network”, published in Kluwer Academic Publishers., (2003).

  • Kim Andrew, “OPNET Tutorial”, TECOMM LAB, (2003).

  • Lindgren Anders, Almquist Andreas, and SchelenOlov,”Quality of Service Schemes for IEEE 802.11" (2001).

  • Liu X., Chong E. K. P., and Shroff N. B., “Opportunistic Scheduling with QoS Requirements in Time-varying Wireless Channels”, Computer Networks, 4(41): pp. 451-474 (2003).


Abstract Views: 218

PDF Views: 2




  • Improving WLAN Quality of Services (Qos) Using Opnet

Abstract Views: 218  |  PDF Views: 2

Authors

Ishwar Baidari
Karnatak University of Dharwad-03, India
S. P. Sajjan
Central University of Karnataka-67, India
Ajeet Kumar Singh
Central University of Karnataka-67, India

Abstract


Wireless local area networks (WLANs) are in a period of great expansion and there is a strong need for them to support multimedia applications. With the increasing demand and penetration of wireless services, users of wireless networks now expect Quality of Service (QoS) and performance comparable to what is available from fixed networks. Providing QoS requirements like good throughput and minimum access delay are challenging tasks with regard to 802.11 WLAN protocols and Medium Access Control (MAC) functions. This research is done to study, the presently implemented schemes (the Point Coordination Function (PCF) of IEEE 802.11, the Enhanced Distributed Coordination Function (EDCF) of the proposed IEEE 802.11e extension to IEEE 802.11), solves these issues and what can be done to improve them further. The metrics used were Throughput, Data Drop, Retransmission and Medium Access Delay, to analyze the performance of various MAC protocols in providing QoS to users of WLAN. Two scenarios, with same Physical and MAC parameters, one implementing the DCF and other EDCF, were created in the network simulation tool (OPNET MODELER) to obtain the results. The results showed that the performance of EDCF was better in providing QoS for real-time interactive services (like video conferencing) as compared to DCF, because of its ability to differentiate and prioritize various services. Index Terms - Wireless local area networks (WLANs).

Keywords


Expect Quality of Service (QoS), Point Co-ordination Function (PCF), Enhanced Distributed Coordination Function (EDCF), OPNET.

References