A DYNAMIC RATE-BASED BORROWING SCHEME FOR MULTIMEDIA WIRELESS NETWORKS

Abstract

With the recent advances in wireless communications, cellular networks are supposed to support the real-time multimedia traffic such as data, video tele-conferencing etc. To carry the multimedia traffic these networks must be able to provide quality-of-service (QoS) guarantees to the users. Various schemes have been proposed for QoS provisioning in the multimedia wireless networks. These schemes include call admission control and resource reservation schemes. Call Admission Control schemes are used to decide whether an incoming call should be admitted for network service or not. Channel reservation strategies are designed by either reserving a fixed number of channels or adjusting the reservations dynamically. The scheme presented in this dissertation attempts to allocate the desired bandwidth to every multimedia connection originating in a cell or being handed off to the cell. In case of insufficient bandwidth, bandwidth is borrowed on a temporary basis from the existing connections. It is guaranteed that no connection gives up more than its fair share of bandwidth, i.e., the amount of bandwidth borrowed from a connection is proportional to its tolerance to bandwidth loss. It is also made sure that if bandwidth has to be borrowed, it is borrowed from all the existing connections. At the time of admitting the connection, some bandwidth is also reserved dynamically in all the six neighboring cells to take care of the possible handoff. A cap is also implemented on the reserved pool of bandwidth in each cell. The borrowed bandwidth is promptly returned back to the degraded connections as soon as the bandwidth becomes available. The scheme presented in this dissertation is then compared with two previous schemes on the basis of some specified QoS parameters. The implementation of the scheme is done in C language on a Pentium IV system under Windows-98 environment.