METHOD AND APPARATUS FOR ENHANCING DATA RATES IN SPREAD SPECTRUM COMMUNICATION SYSTEMS

摘要

This invention relates to a spread spectrum communication system which enhances the data rate. In accordance with the invention, a high data rate spread spectrum transmitter (100) comprises an encoder (110) for encoding an input bit stream of R bits/second to produce an output bit stream of Rs bits/second, an interleaver (120) for scrambling the bits of the output bit straem of the encoder to produce an interleaved bit stream, a M-ary modulator (130) for modulating the interleaved bit stream, a serial-to-parallel converter (140) to convert the modulated bit stream to a plurality of parallel bit streams, a generator for generating a set of quasi orthogonal functions of a set of Walsh codes, an array of multipliers (150), each multiplier receiving one of the parallel bit streams and multiplying it with a Walsh code or quasi orthogonal function of a Walsh code to produce a spread spectrum bit stream, and a combiner (160) for combining the spread spectrum bit streams from the array of multipliers. Further, in accordance with the invention a high data rate receiver comprises a front end receiver for receiving the spread spectrum signal, a despreader for despreading the signal using a set of Walsh codes or quasi orthogonal function, a multi-user detection block for subtracting interference in the despread signal to form a corrected signal, and a combiner for combining the corrected signals.