Patent ID: 6181732
Filing Date: 2001-01-30
Classification: H04B

Abstract:
A receiving apparatus for spectrum spreading communication for receiving a spectrum-spread signal as a receiving signal, which is created by applying spectrum-spreading with spreading codes on a transmitting side by means of direct spreading to an information signal including a known transmitting symbol sequence, said apparatus comprising:a synchronizing circuit for synchronizing spreading codes on a receiving side same as said spreading codes on said transmitting side with said spreading codes on said transmitting side of said receiving signal to be synchronized spreading codes;a spectrum inverse spreading section for applying spectrum-inverse-spreading to said receiving signal with said synchronized spreading codes and outputting a spectrum-inverse-spread signal; anda demodulating section for demodulating said information signal from said spectrum-inverse-spread signal,said synchronizing circuit having:a correlator for correlating said receiving signal with said spreading codes on said receiving side and outputting correlation values of a receiving symbol sequence;a symbolic integration section for inversely modulating correlation values of said receiving symbol sequence with theoretical values of said known transmitting symbol sequence, performing symbolic integration for a predetermined number of symbols, and outputting symbolically integrated correlation values;a pseudo correlation removing section in which symbolically integrated theoretical correlation values are previously obtained by taking account of said known transmitting symbol sequence and said spreading codes on said transmitting side, for removing pseudo correlation values from said symbolically integrated correlation values by subtracting parts from which a maximum amplitude part of said symbolically integrated theoretical correlation values is removed, from said symbolically integrated correlation values; anda synchronization detecting section for detecting a maximum part of an amplitude of an output signal output from said pseudo correlation removing section, and at time when detecting said maximum part, sending said spectrum inverse spreading section said spreading codes on said receiving side as said synchronized spreading codes.