PERFORMANCE EVALUATION OF RESERVATION BASED MAC LAYER PROTOCOLS FOR LOCAL WIRELESS DATA NETWORKS

Abstract

Wireless is one of the fastest growing segment of the communications industry. Although the concept is decades old, its cost and technical limitations for .years restricted it to a relatively few, specialized applications. With the recent advances in hardware and communication technologies and growing popularity of lap-top computers, the wireless environment, is being used for more and more diverse applications. These applications will have very high data rates. But the available bandwidth in the wireless media is limited. Existing MAC layer protocols including Packet Reservation Multiple Access Protocol (PRMA) adopts a fixed length frame structure. So they are not best suited for Data traffic. In the light of these facts it is required to have a new MAC layer Protocol to utilize the limited available bandwidth efficiently. In the present dissertation, two MAC layer Protocols, Packet Reservation Multiple Access(PRMA) protocol and Reservation based Multiple Access with Variable length frame(RMAV) protocol have been studied. PRMA is an old protocol based on fixed length frame structure. RMAV was designed under the consideration that the population of wireless terminals and the system load frequently change and are almost unpredictable in wireless data communications. RMAV is based on the slot reservation scheme and adopts a frame structure with variable length. The Frame length increases as the number of active terminals and/or the system load increases. This dissertation work also proposes some simple modifications to the Protocols, to improve the system Performance considerably. Simulation studies were carried out to compare their Performance. The effects of system load on channel utilization and mean message delay was also studied. Findings suggest that the RMAV Protocol has an edge over PRMA Protocol in most of the situations.