A channel assignment and handoff strategy for mobile multimedia cellular communication systems with variable bandwidth support

We propose an efficient channel allocation and handoff strategy to guarantee continuous services with QoS guarantees to mobile multimedia users, known as the Variable Bandwidth Channel Allocation Scheme (VBCAS). In order to minimize the forced termination probabilities of ongoing calls, the bandwidth for different types of calls varies in a dynamic way. If there are not sufficient channel resources for a new arriving handoff call, the system adjusts the bandwidth of calls in service and reallocates enough channel resources for the arriving handoff call to avoid interrupting its session. The adjustment of the bandwidth of calls is done so that the basic quality of service for a call with particular service type is guaranteed. The strategy is modelled and analyzed by using a multi-dimensional Markov chain. Performance measures, such as blocking probabilities of new calls, forced termination probabilities of calls, average bandwidth allocated to a call are obtained. Numerical results show that significant improvements on QoS can be obtained by using the channel allocation and handoff strategy proposed in this paper.