Two-dimensional demodulator in spread spectrum code division multiple access system with antenna array
AssigneesElectronics and Telecommunications Research Institute, SK Telecom Co., Ltd.
InventorsKyung Hi Chang, Eung Soon Shin, Youn Ok Park, Mun Geon Kyeong
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Abstract
The present invention relates to structures of the spread CDMA system of band diffusion with antenna array. The present invention, structures of 2-D demodulator are provided, for spread spectrum CDMA systems with antenna array which can increase coverage area of base station and system capacity, by extracting and combining all information needed in time and space domains, using only the information which shall be calculated in a CDMA system inherently.
Claims10
A two-dimensional demodulator for a Code Division Multiple Access system with antenna array, comprising:
- a multipath detector which receives sampled digital baseband signals and outputs time information concerning where multipath signals and phase information of transmitting codes are located, and outputs correlation values after comparing a correlation value of a snapshot signal and an estimated code sequence with a threshold value established in advance when the correlation value is larger than the threshold value;
- multiple beamformers which receive the correlation values output from said multipath detector and sampled digital baseband signals, and create multiple scalar signals in linear combination, using space information associated with an incoming direction of said sampled digital baseband signals;
- multiple multipath trackers which execute code tracking for phase conformity with transmitting codes and create multiple scalar signals and frequency error components for each path after passing through a time alignment process for each path, using the phase information of transmitting codes output from said multipath detector, and scalar signals from said multiple beamformers;
- and
- a multipath combiner which combines multiple scalar signals and frequency error components created from said multiple multipath trackers for the time domain respectively.
A two-dimensional demodulator for a Code Division Multiple Access system with antenna array, comprising:
- a multipath detector which receives sampled digital baseband signals and outputs time information concerning where multipath signals, and phase information of transmitting codes, are located;
- multiple multipath trackers which execute code tracking for each path by input of the phase information of transmitting codes output from said multipath detector, and create time information for multipaths, corresponding to time information for space signals, and correlation values of snapshot signals in each time and tracked code sequence;
- multiple beamformers which create scalar signals for each path by input of the time information for space signals created from said multiple multipath trackers and of despreaded snapshot signals of inverse diffusion;
- and
- a multipath combiner which combines scalar signals of each path, created from said multiple beamformers.
Dependencies are inferred from the claim text.