Coherent DS-CDMA: promising multiple access for wireless multimedia mobile communications

This paper describes a design concept and the features of coherent DS-CDMA access which supports multimedia services and also flexible system deployment. The testbed implemented for a series of field experiments near Tokyo and some measurement results are reported. In the proposed system, two-layer code assignment and transmit power control based on signal-to-interference (SIR) measurements are used. Pilot symbol-assisted coherent RAKE reception in the reverse link is employed to enhance the transmission quality. This paper also reports on the cell search algorithm used to accomplish rapid cell search under asynchronous cell site operation and low power consuming matched filter implementation. Finally, as an evolutionary step in future technology, an application of an interference canceling scheme and an adaptive beamforming scheme are presented in order to further increase the link capacity