A MAC protocol based on a S-ALOHA/overlapped CDMA system supporting multirate applications

Abstract

In this paper, we propose a new multirate network based on a hybrid Slotted-ALOHA/Overlapped CDMA (SALOHA/O-CDMA) system as an effective way of integrating multirate traffic. The key issue in this proposal is to exploit the potential of the overlapped CDMA (O-CDMA) when jointly used with the S-ALOHA protocol in a link layer. The newly proposed system is modeled using general Markov chain from which both the system throughput and the average delay are derived. Our system is then compared to the classical S-ALOHA/variable processing gain (VPG) CDMA (S-ALOHA/VPG-CDMA) system. Finally, system stability passing through general finite user model is also envisaged. Numerical results show that our system outperforms the latter.