Patent ID: 6954483
Filing Date: 2005-10-11
Classification: H04B

Abstract:
1. A method of synchronizing mobile CDMA radio receivers in a cellular CDMA mobile radio system, wherein a first synchronization channel with a first frequency is provided for transmitting a synchronization signal with a code that is known to the mobile radio receivers and to base stations of the mobile radio system, and wherein a transmission from a base station to a mobile radio receiver delays the synchronization signal by an unknown time period and the first frequency is shifted by the transmission to a second frequency, the method which comprises the following steps: splitting the received synchronization signal into a real part signal and an imaginary part signal; sampling the real part signal and the imaginary part signal to form sampled signals; digitally filtering each sampled signal to correlate the sampled signal to the known code and to form filtered signals; squaring each filtered signal to form squared signals; determining a maximum signal level from the squared signals; estimating the unknown time period with the maximum signal level determined in the determining step; despreading the received synchronization signal with the known code and taking into account the time period estimated in the estimating step; determining a frequency deviation between the first frequency and the second frequency based on the despread received synchronization signal; and fine-tuning the second frequency to the first frequency based in part on the despread received synchronization signal.