Performance of the joint CDMA/PRMA protocol for voice transmission in a cellular environment
Alex Brand, A.H. Aghvami · 2002
Joint CDMA/PRMA, a candidate for an uplink protocol for third generation mobile communication systems, controls the radio channel access such that the interference variance is reduced and the throughput increased, compared to random access CDMA. Joint CDMA/PRMA can either be viewed as an evolution of conventional PRMA, such that it can operate under direct-sequence (DS) CDMA conditions, or as an evolution of packet CDMA. Simulation results are presented for voice-only traffic in an isolated cell and in a cellular environment with path loss coefficients /spl gamma/=4 and 3. The system under consideration employs random direct sequences with code length 7 and (511,229,38) BCH-coding. The voice coding rate is 8 kb/s, and a voice activity factor of 0.43 is assumed. In a no-fading/perfect power control environment, depending on the quality of service (QoS) requirements, for /spl gamma/=3 an increase of 47 to 88 per cent in capacity can be achieved over random access CDMA.