Method for calibrating smart antenna array systems in real time
First Claim
1. A method for calibrating smart antenna array systems in real time, comprising:
- pre-calibrating each antenna element of a smart antenna array to obtain a transmitting compensation coefficient ckTX and a receiving compensation coefficient ckRX of each antenna element relative to a calibration antenna element;
performing a transmitting calibration procedure comprised of transmitting calibration signals simultaneously over a plurality of transmitting links to form a combined signal such that a calibration link receives the combined signal;
performing a receiving calibration procedure comprised of transmitting a receiving calibration signal over the calibration link such that a plurality of receiving links receive the receiving calibration signal simultaneously; and
processing the combined signal received by the calibration link and the receiving calibration signal received by the receiving links, respectively, with a baseband signal processor to obtain compensation coefficients of each transmitting link and each receiving link of the smart antenna array, wherein;
A. the transmitting and receiving calibration signal for each antenna element is generated by a periodic cycling shift of a basic calibration sequence such that each calibration signal is a calibration sequence with good anti-white-noise characteristics;
B. in the transmitting calibration procedure, the baseband signal processor first computing an amplitude and phase response of each transmitting link on the basis of the combined signal received by the calibration link, then computing the compensation coefficient of each transmitting link on the basis of the amplitude and phase response of each transmitting link and the transmitting compensation coefficients ckTX obtained in the pre-calibration for compensating downlink data of the base station; and
C. in the receiving calibration procedure, the baseband signal processor first computing an amplitude and phase response of each receiving link on the basis of the received receiving calibration signal of each receiving link, then computing the compensation coefficient of each receiving link on the basis of the amplitude and phase response of each receiving link and the receiving compensation coefficients CkRX obtained in the pre-calibration for compensating uplink data of the base station.
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Accused Products
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. The calibration signal of each antenna element is generated by a periodic cycling shift of a basic calibration sequence.
41 Citations
13 Claims
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1. A method for calibrating smart antenna array systems in real time, comprising:
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pre-calibrating each antenna element of a smart antenna array to obtain a transmitting compensation coefficient ckTX and a receiving compensation coefficient ckRX of each antenna element relative to a calibration antenna element;
performing a transmitting calibration procedure comprised of transmitting calibration signals simultaneously over a plurality of transmitting links to form a combined signal such that a calibration link receives the combined signal;
performing a receiving calibration procedure comprised of transmitting a receiving calibration signal over the calibration link such that a plurality of receiving links receive the receiving calibration signal simultaneously; and
processing the combined signal received by the calibration link and the receiving calibration signal received by the receiving links, respectively, with a baseband signal processor to obtain compensation coefficients of each transmitting link and each receiving link of the smart antenna array, wherein;
A. the transmitting and receiving calibration signal for each antenna element is generated by a periodic cycling shift of a basic calibration sequence such that each calibration signal is a calibration sequence with good anti-white-noise characteristics;
B. in the transmitting calibration procedure, the baseband signal processor first computing an amplitude and phase response of each transmitting link on the basis of the combined signal received by the calibration link, then computing the compensation coefficient of each transmitting link on the basis of the amplitude and phase response of each transmitting link and the transmitting compensation coefficients ckTX obtained in the pre-calibration for compensating downlink data of the base station; and
C. in the receiving calibration procedure, the baseband signal processor first computing an amplitude and phase response of each receiving link on the basis of the received receiving calibration signal of each receiving link, then computing the compensation coefficient of each receiving link on the basis of the amplitude and phase response of each receiving link and the receiving compensation coefficients CkRX obtained in the pre-calibration for compensating uplink data of the base station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for generating a calibration sequence signal for the real-time calibration of a smart antenna array by a periodic cycling shift of a basic calibration sequence, comprising the steps of:
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a1. providing a binary sequence mp with the length P as the basic calibration sequence, mP=(m1, m2, . . . ,mP), where P=w×
N, N is the number of antenna elements of a smart antenna array, and w is the window length of channel estimation of each transmitting or receiving link;
a2. performing a phase equalization to the sequence mp, generating a complex vector of the calibration sequence mp, mP=(m1,m2, . . . ,P), where elements of the sequence mi=(j)i−
1·
mi, i=1, . . . P, and j is the square root of −
1;
a3. expanding mp periodically and obtaining a new periodical complex vector m, m=(m1,m2, . . . ,mi max )=(m2,m3, . . . ,mp,m1,m2, . . . ,mp);
a4. obtaining a calibration sequence vector with a length Lm=P+w−
1 for each antenna element from the periodical complex vector m, m(k)=(m1(k),m2(k), . . . ,mLm (k)), k=1, . . . N, an element of the calibration sequence vector mi(k)=mi+(N−
k)W, i=1, . . . . Lm and k=1, . . . N; and
a5. generating a calibration sequence signal with a fixed power from the calibration sequence vector on the basis of a calibration requirement.
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Specification