TD(98)008

Abstract
CDMA schemes appear to be very promising access techniques for coping with the requirements of third-generation mobile systems, mainly because of their flexibility. This paper proposes an Adaptive S-ALOHA DS-CDMA access scheme as a method for integrating non-real time (i.e. Internet applications) and real-time (i.e. voice) services in a multicell scenario, by exploiting the potentials of CDMA under time-varying channel load conditions. The Adaptive component makes data terminals autonomously change their transmission rate according to the total (voice+data) channel occupancy, so that the minimum possible data delay is almost always achieved. The proposed scheme is then compared to a reservation TDMA-based protocol (PRMA++), showing the benefits of ALOHA-CDMA in terms of complexity, flexibility and data delay performance.