Performance of Adaptive Bandwidth Allocation for Multimedia Handover Services in UMTS mobile Cellular Networks

Abstract

With the ever growing multimedia services in the telecommunicationindustry, Quality of Service (QoS) provisioning in cellular networksis becoming more challenging. Studies have suggested that QoSrequirements can be met by increasing network capacity throughadopting micro/pico/femto-cellular architectures. A consequence ofusing small cell sizes is the increased rate of call handovers asmobile terminals move between cells. In a network supportingmultimedia services, the increased rate of call handovers not onlyincreases the signalling load on the network, but also adverselyaffects the QoS through sky rocketing handover failures. Forseamless connection, one of the solutions will be adequate provisionof resources like bandwidth. Moreover, bandwidth being a scarceresource, it should be used efficiently.As the world migrates fromAsynchronous Transfer Mode (ATM) transport to Internet Protocol (IP)in UMTS Radio Access Networks (UTRAN), it will introduce morechallenges in assigning bandwidth to multimedia services. This istrue as IP is of best effort nature. A better solution will be toallocate bandwidth discriminatingly, that is, high priority trafficgets better service while low priority traffic gets reduced service.This paper presents the design, implementation and performance of anAdaptive Bandwidth Allocation scheme for Multimedia HandoverServices on an IP-based Radio Access Network of a UMTS CellularNetworks. The methodology adopted is classifying multimedia trafficinto different classes using differentiated service (DiffServ)scheme. This is then tested and validated through simulation inNetwork Simulator 2(NS-2).From the simulation results it has beenproven that the adaptive bandwidth allocation minimizes packetlosses and give high throughput than non- adaptive bandwidthallocation. It has also been observed that non- adaptive bandwidthallocation does not guarantee service when the network experiencecongestion due to increased traffic in a cell during handover. Aftercomparing the simulated results, its clear that adaptive bandwidthallocation is found to yield better performance than non- adaptivebandwidth allocation.