QoS-Ring: A token ring approach for QoS provisioning in Ad-hoc Networks

摘要

Ad-hoc wireless networks have gained much popularity due to their easy deployment and dynamic reconfiguration. Ad-hoc networks, as any other network need to support both real time traffic and normal data traffic. Multimedia applications demand stringent guarantees on bandwidth, delay and jitter. In a best effort network, all users obtain the same level of service which depends on the network load. In other words, it cannot support the sophisticated requirements of multimedia applications. Therefore, new mechanisms have to be developed to support the desired QoS (Quality of Service) levels for the modern applications. QoS provision at the medium access level is particularly important because it has direct effect on how and when data is transmitted. A lot of works have been reported that try to render the desired QoS to the application. Some of them are based on dividing traffic into various traffic classes and assigning different back off related values for each class. Some others are based on transmitting multiple frames at a time to reduce the number of contention attempts and some others discard frames with expired deadlines. But many of these dictate strict procedures for assuring the desired QoS of the application. The proposed method is a simpler one based on the application of token rings to wireless domain. It uses election algorithm to find who should transmit data next. Unlike token ring, the proposed system uses a distributed procedure for maintaining the logical structure of the ring. Experiments show that, with the proposed system, the response time of stations that need to send real time data is reduced.