Quality-of-Service degradation strategies in multimedia wireless networks

We propose new strategies for call degradation and call admission in a third generation multimedia wireless network. Our approach is based on modeling the quality-of-service (QoS) degradation of real-time and non-real-time traffic. To increase the carried traffic in an overloaded system, some of the ongoing calls are forced to operate under a degraded mode, thereby releasing channels that they are using. Two orthogonal QoS parameters, called carried traffic and bandwidth degradation, are characterized and a cost function describing the total revenue earned by the system from a bandwidth degradation policy is formulated. This cost function model is then extended to incorporate a call admission policy. Detailed simulation experiments are conducted to validate the proposed model. When there is a mixture of real-time and non-real-time calls in the system, the real-time traffic generally has preemptive priority over the other, which are buffered for future admission in case of preemption. A channel sharing scheme is proposed for non-real-time traffic and analyzed using a Markov modulated Poisson process (MMPP) based queueing model and by simulation experiments.