Cross-Layer Scheduling and Adaptive Modulation for QoS Support on Wireless Multimedia Networks

In this paper we present a cross-layer scheduling algorithm based on a priority function that combines information from the channel quality (SINR), the quality of service (QoS) and the modulation scheme allowed, intended for usage in the process of packet scheduling transmission between a base station and mobile terminals. The objective is to jointly exploit the temporal variation in users channel conditions and select users which can use the channel in a more efficient way, while also ensuring that resource allocation fairness and QoS constraints are satisfied. The algorithm is evaluated and compared against the best SIR (signal to interference ratio) and FIFO (first in first out) algorithms, for the case where the environment is the downlink of a MC-CDMA/TDD wireless communications system. Two classes of service are considered: real-time and non-real-time. The results show significant improvements in terms of user satisfaction can be achieved by considering adaptive modulation jointly with channel and QoS aware scheduling