A Novel Transmitter-Based Selective-Precoding Technique for DS/CDMA Systems

A new transmitter precoding technique is presented that selectively pre-decorrelates users to destructive multiple access interference while allowing interference when it is expected to contribute to the useful signal. This enhances the effective signal to interference-plus-noise ratio at the receiver. The resulting benefit comes by making use of energy that is already in the system so performance improvement is attained with no additional power-per-user investment. The proposed technique applies to the downlink of cellular CDMA systems employing phase-shift-keying modulation.