Forward link performance of multiple access schemes in cellular systems

The actual trend towards personal communication systems suggests to devote considerable research efforts to find more efficient multiple access techniques in order to improve the system capacity. The authors compare the system performance of three multiple access techniques used in mobile radio systems: TDMA, CDMA, and the slotted Aloha packet system. The performance of the three protocols has been evaluated in the presence or absence of both antenna diversity and power control, with a focus on the base-to-mobile link. The results obtained show that CDMA and slotted Aloha work much better than TDMA; moreover the performance of slotted Aloha is comparable to CDMA, while exhibiting a virtual insensitivity to propagation conditions