A framework for analysis of VBR traffic over CDMA

With emerging multi-media wireless applications, there is a need for next-generation W-CDMA to be designed to support variable rate traffic. Several schemes have previously been proposed to support variable rate transmission, namely, variable spreading gain (VSG), multicode transmissions and fixed spreading gain (FSG). In this paper, a universal framework to evaluate and compare the various variable rate transmission schemes in terms of bit error rate (BER), power and required bandwidth is proposed. The framework also provides for the synthesis of the power assignment that delivers a specified BER to heterogeneous variable rate sources under each scheme.