Industrial Technology Research Institute

Huei-Jin Lin

Pang-An Ting

Jiun-Yo Lai

Wei Ping Chuang

Jen-Yuan Hsu

Yung-Yih Jian

An apparatus and method for cell acquisition and downlink synchronization acquisition in an OFDMA wireless communication system are provided. In an SS apparatus in a broadband wireless communication system, a preamble subcarrier acquirer extracts subcarrier values having a preamble code from an FFT signal. A multiplier code-demodulates the subcarrier values by multiplying the subcarrier values by a preamble code. A correlator calculates a plurality of differential correlations in the code-demodulated signal. An IFFT processor IFFT-processes the differential correlations by mapping the differential correlations to subcarriers. A maximum value detector detects a maximum value from the IFFT signal and calculates a timing offset using an IFFT output index having the maximum value.

FFT-size detection and cell search for a cellular communication system

A DC offset estimation system is disclosed. A DC offset estimation system includes a carrier frequency offset estimator receiving an input signal and estimating a carrier frequency offset value, a symbol timing recovery unit providing a symbol boundary of the input signal, and a DC offset estimator estimating a DC offset value to compensate the input signal based on the input signal, the carrier frequency offset value, and the symbol boundary.

DC offset estimation system and method

The invention provides an FFT-size detection method and system and a cell search method and system based on FFT-size detection, and more particularly to a cell search method based on FFT-size detection in cellular system. The cell search method utilizes two frames to correctly detect the actual cell ID. The cell search method uses the first frame to detect the actual FFT size of a received signal. When the FFT size is determined, the cell search method use the second frame to detect the cell ID of a base station outputting the received signal based on the FFT size.

FFT-size detector and FFT-size detection method and cell search apparatus and cell search method in cellular system

The method disclosed in the invention comprises setting a plurality of subcarrier position hypotheses for a received preamble according to a plurality of ideal subcarrier positions and the maximum amount of integer carrier frequency offset (ICFO), generating a plurality of preamble pattern hypotheses by retrieving the received preamble according to the subcarrier position hypotheses, calculating the correlation between the preamble pattern hypotheses and a plurality of specified preamble patterns, determining to which sector the received preamble belongs according to a correct preamble pattern, the specified preamble pattern having the highest correlation with the preamble pattern hypotheses, obtaining a correct subcarrier position according to the sector to which the received preamble belongs; and estimating the ICFO by calculating the offset between the correct subcarrier position and the subcarrier position hypothesis of the preamble pattern hypothesis having the highest correlation with the correct preamble pattern.

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Taichung, Taiwan

Huei-Jin Lin