Industrial Technology Research Institute

Ho-Chi Hwang

Muh-Rong Yang

Yun-Yen Chen

Po-Tsun Chen

The present invention provides an apparatus and method for code group identification and frame synchronization for cell searching used in wide-band DS-CDMA cellular systems. This method characterizes each secondary synchronization code sequence (SSCS) with a corresponding theoretical frequency sequence, which represents the occurrence times of CS to CS in a corresponding SSCS. Thus, 64 secondary synchronization code sequences corresponding to 64 code groups defined in DS-CDMA systems also corresponds to 64 theoretical frequency sequences. By characterizing the SSCS transmitted by a base station, a real frequency sequence can be generated. Comparing the real frequency sequence with the 64 theoretical frequency sequences, one can determine one or two candidate code groups, which may be employed by the base station. Finally, one can compare the SSCS transmitted by the base station with all the possible SSCSs corresponding to the candidate code groups to determine a specific code group and a frame boundary for the base station.

Method and apparatus for code group identification and frame synchronization in DS/CDMA systems

An MMSE linear detector is implemented using a variable step-size Griffiths' algorithm. The received signal is sampled and stored. The stored samples are multiplied with components of a spreading sequence to provide products that are summed to provide a first output. The stored samples are also multiplied with components of a weight vector to provide products that are summed to provide a second output. A computing unit uses the Griffiths' algorithm to iteratively compute the weight vector. Another computing unit computes the step-size for each successive iteration of the Griffiths' algorithm based on the first and second outputs.

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Hsinchu Hsien, Taiwan

Ho-Chi Hwang