Overview of Wideband CDMA

Abstract

The use of direct sequence (DS) code division multiple access (CDMA) is of interest to both the military and the commercial communities. In this paper, we present an overview of what has come to be known as wideband CDMA (WCDMA). While no precise definition of such a waveform exists, the concepts behind a WCDMA design are simple to state. Minimally, one would want to be able to efficiently support high data rate multimedia traffic, as well as make effective use of the multipath which is inherent on any wireless channel. The former condition suggests the need for a large rf bandwidth, and the latter condition requires that that bandwidth be, at the least, larger than the coherence bandwidth of the channel. In the following sections, we will illustrate how the use of a properly designed DS WCDMA system can enhance performance. We consider first the obvious issue of capacity, but then we also look at considerations such as coarse acquisition and power control.