Spread spectrum PR-QMF transmultiplexer codes for CDMA communications

Abstract

Orthogonal transmultiplexers have been successfully utilized for multiple access communications. They are of FDMA type in their most common version. The frequency selective PR-QMFs were used in transmultiplexers for CDMA communications reported in the literature. This conflicts with the fundamentals of CDMA theory. We introduce novel spread spectrum PR-QMF codes. It is shown that the spread spectrum PR-QMF codes with minimized auto- and cross-correlation properties drastically outperform the conventional Gold (1967) codes in CDMA communication scenarios considered.