Performance evaluation of a joint CDMA/NC-PRMA protocol forwireless multimedia communications

摘要

A joint code division multiple access and noncollision packetnreservation multiple access (CDMA/NC-PRMA) technique is proposed andninvestigated as an uplink protocol for the third-generation (3G) mobilensystems. Being the underlying time division multiple access (TDMA)narchitecture of the CDMA transmissions, NC-PRMA enables the base stationn(BS) to have a centralized control over the slot allocation policy. Innorder to reduce the multiple access interference (MAI) variation in anCDMA transmission, two different slot assignment schemes, referred to asnload-balancing (LB) and power-grouping (PG) schemes, are proposed andnevaluated. Simulation results show that considerable improvement can benachieved over the joint CDMA/PRMA scheme, in which the MAI variation isnreduced by way of a dynamic permission probability for contendingnterminals. Especially when an imperfect power control mechanism isnconsidered, the proposed PG assignment scheme achieves significantnperformance advantages