Dynamic Rate Adjustment (DRA) Algorithm for WiMAX Systems Supporting Multicast Video Services

摘要

This paper presents a dynamic rate adjustment (DRA) algorithm for WiMAX systems supporting multicast services. A scalable video coder with layered coding capability is assumed to be used to encode the multicast video information as a single base layer and multiple enhancement layers. The DRA algorithm first determines the portion of the base layer according to the QoS requirement of the multicast video service. It then dynamically adjusts the remaining portions of the enhancement layers to maximize the average throughput of the cell. In this paper, an analytical solution is presented to determine the best portions of the enhancement layers based on the estimated users' signal-to-noise-ratio (SNR). The accuracy of the analysis is verified via simulations. Simulation results indicate that DRA always achieves a higher average throughput than that of either uniform allocation algorithm or location-based allocation algorithm.