A comparison of CDMA, TDMA and slotted Aloha multiple access schemes in cellular mobile radio systems

The increasing demand for mobile radio services and the scarce bandwidth available suggest to devote considerable research efforts to find more efficient multiple access techniques in order to improve the system capacity. We compare the system performance of three mobile radio systems: the well known TDMA system, which is the basis of the European GSM, the recent CDMA system (a standard introduced by Qualcomm) and the proposed slotted Aloha packet system. Performance comparisons are made for these systems when the radio propagation is impaired by Rice fading and log-normal shadowing. The results show that the performance of slotted Aloha is comparable or better than CDMA, while exhibiting a virtual insensitivity to propagation conditions.