Low-Complexity Implementation of CDMA Downlink Equalization

It has recently been recognized by several authors that the CDMA downlink capacity can be increased via traditional equalization techniques, see Klien, Frank and Visotski, Ghauri and Slock, Zoltowski and Krauss, Lenardi and Slock, Lenardi and Slock. The downlink physical channels (except for the SCH channel) are orthogonal in all 3G CDMA modes, hence most intra-cell interference is due to the multipath channel. It therefore appears that a type of multiuser detection can be achieved in the mobile terminal by a low complexity equalizer-receiver without requiring additional side-information such as the in-cell users' activity states, codes, powers, etc.,. Such a receiver would maintain compatibility with 3G standards while providing two kinds of system benefits: increased capacity due to reduction of multiple access interference, and higher data transfer speeds due to reduction of inter-symbol interference.