Class and Channel Condition Based Scheduler for EDGE/GPRS

The efficient management of the radio resource of a 3-G system is important from an operator’s perspective. This, however, cannot be the only concern when quality of service (QoS) negotiations have been made for various users and the operator has to uphold these. This leads to a fairness objective that the operator has to keep in mind. In this paper we outline a scheme to perform packet-level scheduling and resource allocation at the wireless node that takes into account the notions of both efficiency and fairness and presents a means to explore the trade-off between these two notions. As a part of this scheme we see the scheduling problem as deciding not just the packet transmission schedule but also the power allocation, the modulation and coding scheme allocation and the spreading code determination since the latter three directly influence the radio resources consumed. Using a utility maximization formulation based on the data-rates that the mobiles can transmit at, we decide on the weights for a weighted proportionally fair allocation based scheduling algorithm. We also show how one can adapt the weights and the algorithm for a time-varying channel. We conclude with a simulation based performance analysis for infinitelybacklogged sources and TCP sources on an EDGE system.