Patent ID: 6574205
Filing Date: 2003-06-03
Classification: H04B

Abstract:
A CDMA cellular system comprising a plurality of mobile terminals and a plurality of base stations connected to said mobile terminals via radio links;each of said base stations comprising: first spreading means for spreading channel data with a first spreading code which is shared by all the base stations; first element code generating means for generating a first element code which is in synchronism in time with said first spreading code; second element code generating means for generating a second element code which differs from base station to base station; multiplying means for generating a second spreading code which differs from base station to base station, based on said first element code generated by said first element code generating means and said second element code generated by said second element code generating means; second spreading means for spreading the channel data based on said second spreading code generated by said multiplying means; adding means for adding the channel data spread by said first spreading means and the channel data spread by said second spreading means; and an antenna for transmitting sum channel data from said adding means; each of said mobile terminals comprising: detecting means for detecting said first spreading code; third element code generating means for generating said first element code of said second spreading code in synchronism with timing of said first spreading code; fourth element code generating means for generating said second element code out of synchronism with timing of said first spreading code; de-spreading means for de-spreading a signal transmitted from one of said base stations based on said first element code; and correlated value calculating means for calculating a correlated value between the signal de-spread by said de-spreading means and said second element code; said fourth element code generating means comprising means for generating said second element code based on timing where the correlated value calculated by said correlated value calculating means is maximum.