Optimal bandwidth allocation for bandwidth adaptation in wireless multimedia networks

Abstract

The concept of bandwidth adaptation which additionally allocates the terminated bandwidth to ongoing calls is one of the promising methods to reduce the new call blocking and handoff call dropping probabilities. In this paper, we formulate the bandwidth allocation problem for the bandwidth adaptation as a binary linear integer program which maximizes the satisfaction degree of customers. Since this optimization should be performed in real time, we presented a computationally efficient heuristic algorithm for the problem based on the Lagrangean relaxation procedure. Our simulation test shows that the algorithm finds a sub-optimal solution within 0.5% in average from the true optimal solution. The solutions of our scheme show better performance than other scheme in both handoff call dropping and new call blocking probabilities. Scope and purpose With the emergence of various multimedia applications, it becomes more important that wireless networks satisfy quality of service (QoS) requirements. Each base station has a specific amount of bandwidth to be used within a small geographical area called cell. As the number of users increases, the amount of bandwidth assigned to a cell becomes insufficient to support the required number of users. Therefore, wireless networks will employ smaller cells to perform channel reuse in the cells at specific distance and to accommodate the overall increase in system capacity. Since employing smaller cells implies higher rate of handoff, the continuous support of QoS guarantees of multimedia calls poses a major challenge in the wireless networks. Such a support requires the development of an adaptable network resource management framework. In this paper, we deal with the multimedia adaptive service where the bandwidth of an ongoing call can be varied during its lifetime. When an ongoing call is completed or is handed off from a current cell to another, its bandwidth can be reallocated to other ongoing calls. The concept of this bandwidth adaptation is one of the promising methods to reduce the new call blocking and handoff call dropping probabilities. If the bandwidth is optimally allocated among all ongoing calls which need more bandwidth, then the satisfaction grade of the customers can be increased. We formulate the bandwidth allocation problem for this bandwidth adaptation as a binary linear integer program which maximizes the satisfaction degree of customers.