Resource allocation for CDMA networks based on real-time source rate adaptation

In CDMA, resource allocation is a task critical to the performance of this inherently interference limited multiple access technique. In this paper we introduce a new technique aimed at increasing the number of real-time calls supported in a CDMA network at the cost of a smooth controllable degradation of reconstructed source quality while channel-induced distortion remains bounded by fixing a maximum target FER. This paradigm is based on real-time source codecs with externally adaptable output rate. This work also includes a study of the relation between interference, the number of users in the network and the reconstructed source quality at the output of the source decoder for the case of a single-state real-time coder. We present mathematical analysis and simulations to show that it is possible to achieve a 30% relative increase in the number of users for a 10% relative increase in distortion and to significantly outperform an equivalent CDMA system in the relative increase in the number of users that can be achieved for a given increase in source distortion.