Coherent slot detection under frequency offset for W-CDMA

Typically a local oscillator at a mobile station receiver, which is used to generate a carrier frequency, cannot generate an accurate carrier frequency for the down-conversion processing. The effects of the frequency offset can significantly degrade the performance of the system if they are not compensated. In this paper, a coherent slot detection scheme under frequency offset for a code division multiple access (CDMA) wireless communications system, e.g., 3^rd generation (3G) W-CDMA system, is proposed. The proposed method coherently detects and then cancels the frequency error in the baseband signal after frequency down-conversion. We also investigate the effects of frequency offset in the first step of the cell search procedure, i.e., slot time detection, for the downlink of the W-CDMA system. Detection probabilities under the different frequency offset values are analyzed and simulated