Admission control for VSG-CDMA systems supporting integrated services

Variable spreading gain CDMA (VSG-CDMA) with transmitting power control has been proposed by Sabnani et al. (see Proc. ICC'95, p.725-30, 1995) to provide integrated services in a wireless packet network. System capacities of VSG-CDMA systems with and without considering user activity factors were derived based on some intuitive arguments. The analysis is imprecise because a user's transmitted power is considered part of the interference to its own signal. In this paper, we present a more precise analysis. An optimal power vector assignment and a simple criterion for all users to achieve simultaneously their quality of service requirements (in terms of bit energy-to-interference density ratios) are derived. We found from numerical examples that, compared with the rough analysis given by Sabnani et al., significant improvement can be obtained. An access control scheme is also studied to guarantee delay bound requirements. Simulation results reveal that more connections can be further accommodated with access control.