Ds/cdma reverse link structure for high data rate transmission

Abstract

Increased data rate transmission in the reverse traffic channel is obtained by modifying a core reverse CDMA traffic channel signal generator and modulator by creating a plurality of parallel pathways, each of which includes a Walsh modulator and a modulo-2 adder which direct-sequence spreads the modulated data using one of a plurality of modified long codes. The DS-spread data signals from each of the parallel pathways are summed and split to the I and Q channels for PN code spreading. The long code variations are obtained by varying one or more bits of the IS-95 standard public long code mask or private long code mask, specifically, one or more bits of the most significant bit (MSB) string of the public long code mask (bits M through M ). Generally, each variable bit provides two possible code channels—one Fundamental Code Channel and 2 −1 Supplemental Code Channels, where b is the number of bits that can be varied within the long code mask. In another embodiment, a multiplexer may be inserted into a core reverse channel sequence prior the PN spreading function to provide dual channel OQPSK that is consistent with existing IS-95 single channel OQPSK. Different levels of service can be selected using different codes and a plurality of multiplexers located in the error detection and encoding front end of the core reverse channel process sequence.