An Enhanced Mac Scheme for 802.11 with Constant Time Contention using Sequencing Technique

Abstract

Wireless networks offer a vast variety of uses by both business and home users. Now, the industry accepts a handful of different wireless technologies. Each wireless technology is defined by a standard that describes unique functions at both the Physical and the Data Link layers of the OSI Model. These standards differ in their specified signaling methods, geographic ranges, and frequency usages, among other things. Stations using the IEEE 802.11 Standard contend for the channel using the Distributed Coordination Function (DCF) because it’s performance degrades especially with the large number of stations. IEEE 802.11 standard specifies a MAC scheme called CONTI that resolve the contention (collision) in constant number of time slots. The main aim is to have only one station remaining in contention that will transmit the data. CONTI shows better performance when compared to other scheme like DCF based on the parameters like throughput, collision rate, delay etc. The performance can be further improved by introducing a sequencing technique via VBA algorithm. Simulation is done using NS2 (version 2.34).