Spatio-temporal searcher structure for 3G W-CDMA smart antenna systems

Smart antenna systems have been considered for base station (BS) and mobile station (MS) to improve spectral efficiency and link quality. The newly emerging 3rd generation mobile (W-CDMA and cdma2000) systems are required to support high bit rate services. This type of high bit rate traffic inevitably consumes a significant amount of capacity and causes considerable interference to low data rate users. Under these circumstances, the smart antenna system is a good candidate to mitigate this interference and keep link quality at adequate levels. One of the crucial components, which can be very complex, is the searcher whose functionality is to continuously search for new multipath signals for combining. A spatio-temporal searcher structure is proposed to enhance the detection capability of the multipath traffic channel searcher. This structure basically employs a spatio-temporal signal structure to search for a new signal. The detection and false alarm probabilities of the new and conventional schemes are calculated and numerical examples of mean acquisition time are given.