Impact of high-speed packet transmissions on voice user in the reverse link of CDMA systems

Abstract

We study the impact of high-speed packet transmissions on voice users with various radio resource management (RRM) mechanisms in the reverse link of CDMA wireless systems. Two RRM mechanisms, the time-scheduled (TS) scheme and rate-controlled (RC) scheme, are compared and evaluated in terms of voice user impact. In the TS scheme, transmissions from data users are scheduled in time, so that only a limited number of them are transmitting data at any given time instant. On the other hand, in the RC scheme, multiple users simultaneously transmit data under base station control while the rate change of each user is limited to one step at a time. First of all, we study the different characteristics of inter-cell interference with the two RRM schemes. We then investigate the impact on a voice user by simulations of a cdma2000 reverse link with the two RRM schemes. It is shown that a voice user transmitting together with data users controlled by the TS scheme needs more transmit power and higher SNR to keep the voice quality at the desired level since the voice user suffers from the higher interference level and much variation of it.