CDMA system using a spreading code divided into quadrature components and interference cancellation by substracting respread data from received signal.

摘要

A code-division multiple-access system has a downstream channel for transmission from a base station to a number of mobile stations, and an upstream channel for transmission from the mobile stations to the base station. On the downstream channel, each mobile station's spreading code is divided into two parts, which modulate data transmitted on in-phase and quadrature carriers, respectively, thereby enabling the length of the spreading code to be doubled without increasing the chip rate. On the upstream channel, as soon as a symbol is received from one mobile station, it is despread to estimate its value, then respread and canceled as interference with respect to the other mobile stations, these processes being iterated in a cyclic order of the mobile stations.