Optimal call admission control and bandwidth adaptation in multimedia cellular mobile networks

Third and future generations of cellular mobile networks are designed to provide adaptive multimedia services with QoS guarantees. In this scenario call admission control and bandwidth adaptation work together in order to improve the system's performance by reducing blocking probability of multimedia calls. However, this improvement is done at cost of the QoS degradation of ongoing multimedia calls, which may be unacceptable to the users of real time services as videoconference, videophone, so on. Another problem concerns with the bandwidth adaptation is that it may consume a lot of wireless and wireline resources due to extra signalling overhead as well as battery power in the mobile station. In addition, frequent bandwidth switching among different bandwidth levels may be worse than a large degradation ratio. Thus, an important aspect to be considered in the design of Radio Resource Management is how to optimize the system's performance by minimizing blocking probability, controlling bandwidth adaptation, and maximizing user's satisfaction. In this paper we address this subject by proposing a Semi-Markov Decision Model that seeks an optimal stationary policy that match this goal. Results show that the optimal policy outperforms the performance of a non-optimal adaptive resource allocation scheme that seeks only to improve blocking probability.