Adaptive chip equalizers for synchronous DS-CDMA systems with pilot sequences

摘要

A system and method for communicating over a single communication channel in a Direct Sequence-Code Division Multiplex (DS-CDMA) communication system. A pilot signal normally used for synchronization and channel estimation is now used as a training sequence for a chip-equalizer implemented in a mobile handset receiver device. The pilot sequence is always present in the data stream and may be continually used for equalizer adaptation at the mobile handset receiver. The method of using a pilot sequence(s) in order to adapt the taps of a chip equalizer occurs prior to despreading the user data. Additionally, a plurality of pilot sequences each having a known chipping sequence are generated and transmitted for continuous equalizer adaptation at the mobile handset receiver. The plurality of pilots received enables greater adaptation speed, thus enabling efficient tracking of fast varying channels. The method implements a least squares algorithm for enabling fast adaptation in rapidly fading channels using multiple pilot sequences.