Abstract: Transmitting and receiving compensation coefficients of each antenna element relative to a calibration antenna element are obtained in the pre-calibration of a smart antenna. After the antenna array is installed, in transmitting calibration, amplitude and phase response of each transmitting link is computed according to the calibration signals received by the calibration link and, together with the transmitting compensation coefficient obtained in the pre-calibration, the compensation coefficient of each transmitting link is computed to compensate the downlink data of a base station. In receiving calibration, the amplitude and phase response of each receiving link is computed based on the signals received by the receiving links and, together with the receiving compensation coefficient obtained in pre-calibration, the compensation coefficient of each receiving link is computed to compensate the uplink data of the base station.
Type:
Grant
Filed:
June 23, 2005
Date of Patent:
September 5, 2006
Assignee:
Da Tang Mobile Communications Equipment Co., Ltd
Abstract: A real-time calibration method for a smart antenna array. The method includes: before installation, a smart antenna array is pre-calibrated to obtain transmission-coefficient matrix between antenna units; after installation at site, the pre-calibrated transmission-coefficient matrix is loaded in a base station to which the smart antenna array connects; during running, every transmission link of the base station transmits a unit calibration signal in sequence in a time-slot, and all other links, except the transmitting link, are in a reception state to receive the unit calibration signal, and the received unit calibration signals are recorded; with the received unit calibration signals and pre-calibrated transmission-coefficient matrix, the smart antenna array is calibrated. The method does not need beacon antenna, coupled structure of the antenna array and a special calibration link.
Type:
Grant
Filed:
March 11, 2005
Date of Patent:
August 29, 2006
Assignee:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: A channel estimation method for multiple code-sets in a time-slotted CDMA system. The method includes: A) performing a single code-set channel estimation of the received signal of each code-set, respectively, to obtain an original channel estimation, and deciding whether the desired number of iterations is reached; if yes, outputting each single code-set channel estimate; otherwise, going to Step B; B) performing limited time decision for the original channel estimates, retaining taps of channel estimation that meet a certain condition, recovering the interference caused by the response of each code-set using the tap values; canceling the interference caused by the response of other code-sets in the received signal of each code-set to obtain a clean signal of each code-set; taking the clean signal of each code-set as the said received signal of each code-set; and returning to Step A.
Type:
Application
Filed:
July 14, 2005
Publication date:
December 29, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: The invention discloses a method for estimating the space correlation characteristics of noise in a time slotted CDMA system. The method comprises primarily the steps of: making channel estimation for the received signal of each antenna of an antenna array, respectively, to obtain the original channel estimation result that includes values of taps, P in number, where P is the period of the basic code used for channel estimation; separating the signal response component and the noise response component from said original channel estimation result to obtain a noise response matrix of said antenna array; and making correlation operation with said noise response matrix to obtain a space correlation matrix of noise. By using the channel estimation characteristics of the time slotted CDMA system, the invention provides a method for estimating the space correlation characteristics of noise in a time slotted CDMA system.
Type:
Application
Filed:
July 5, 2005
Publication date:
December 29, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: A power-control method base on Downlink Piloting Time Slot (DwPTS) in a mobile communication system. While a terminal is being accessed randomly, the terminal determines the transmitting signal power at Uplink Piloting Time Slot (UpPTS) for open-loop power control by using broadcast information and the measured DwPTS power.
Type:
Application
Filed:
July 8, 2005
Publication date:
December 22, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: A correction method for time varying channels in a time slot division mobile communication system that includes: performing channel estimation and signal detection for a time-slot or burst signal received with a time invariant block processing method; estimating the channel deviation by using the detection result of some symbols that are near the channel estimation code; correcting the channel estimation with the estimated channel deviation; and demodulating the said detection result with the corrected channel estimation. The procedure can be carried out once or for a plurality of times.
Type:
Application
Filed:
June 24, 2005
Publication date:
December 15, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: A handover method in a mobile communication system, wherein, while maintaining communication with a certain base station before handover, a mobile terminal measures signals of adjacent cells and confirms the candidate handover target base stations; the mobile terminal sends measurement report to network; inserting the procedure of pre-synchronization between the mobile terminal and the target base station, including: while sending measurement report to the network, the mobile terminal sends training sequence to the target base station; after receiving the training sequence, the target base station sends training sequence response message to the mobile terminal; the mobile terminal maintains open-loop or closed-loop synchronization with the target base station; the network sends handover command to the mobile terminal; the mobile terminal directly switches to the target base station according the handover command; wireless link between the mobile terminal and the handover-forward base station is released.
Type:
Application
Filed:
June 9, 2005
Publication date:
December 8, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: The invention discloses a method of applying a long cell-code in a joint detection system. At transmitters, multiples of the spreading code (spreading factor) is taken as the length of the long cell-code to scramble the signal, and at receivers, the method still takes the multiuser detection to process the received signal.
Type:
Application
Filed:
May 5, 2005
Publication date:
November 3, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: A multiuser demodulation method for the variable spreading factor, and with this method the multiuser detection and variable spreading factor techniques can be used in the same system at the same time without increasing the demodulation computation volume and the system time-delay. When the transmitting side changes the physical code channel and uses variable spreading factor, at the receiving side the signal processing procedure is as follows: taking a low spreading factor to demodulate the received signals with the multiuser detection, intermediate demodulation result of the TFCI data and intermediate demodulation result of the user data are obtained; demodulate the intermediate demodulation result of the TFCI data with a fixed spreading factor or a variable spreading factor; from the demodulated intermediate demodulation result of TFCI data, a real spreading factor is obtained; process intermediate demodulation result of the user data with the real spreading factor to obtain the final received user data.
Type:
Application
Filed:
May 10, 2005
Publication date:
October 27, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.
Abstract: The invention discloses a real-time calibration method for a smart antenna array. Said method can calibrate a TDD CDMA system and a FDD CDMA system with separated transmission and reception antenna arrays.
Type:
Application
Filed:
March 11, 2005
Publication date:
October 27, 2005
Applicant:
Da Tang Mobile Communications Equipment Co., Ltd.