Forward-link capacity of a DS/CDMA system with mixed multirate sources

Abstract

Some studies have been done on capacity of a code division multiple access (CDMA) system with mixed multirate sources, However, a vast majority of these studies have concentrated on the reverse link. This trend comes from the fact that the capacity of a CDMA system is reverse-link limited. However, forward link can be a limiting link because emerging data services are likely to require higher data rates in the forward link than in the reverse link, In this paper, we analyze and simulate the forward-link capacity of a CDMA system with mixed multirate sources in a multipath fading channel, The outage probability of the forward link is derived for a CDMA system with mixed multirate sources. By introducing a forward-link power factor, the forward-link Erlang capacity is obtained in a closed form. The forward-link capacity is analyzed in terms of the number of multipaths, the number of rake fingers in a mobile station, closed-loop power control, and impact of soft handoff, The results in this paper can be applied to overall system design of a CDMA system with multimedia services in future mobile communication systems.