Automatic frequency correcting method for timedivision wireless communication system
Automatic frequency correcting method for timedivision wireless communication system
 CN 1,607,787 A
 Filed: 07/28/2003
 Published: 04/20/2005
 Est. Priority Date: 07/28/2003
 Status: Active Grant
First Claim
1. , a kind of automatic frequency correcting method of receiver of timedivision wireless communication system comprises and obtains a training data sequence pattern and fine frequency correction;
 Described fine frequency is proofreaied and correct and is constantly carried out frame by frame based on plurality of continuous or discontinuous frame, begins up to lockout or once new automatic frequency correction, and it comprises the steps;
each timeExtraction is corresponding to the reception data of described training data sequence part;
Channel estimating and route searching obtain amplitude and phase information in corresponding each channel delay tap in a collection of present frame, and select some active paths according to the channel estimation results of present frame and former some frames;
According to described channel estimation value and Path selection result, the reception data corresponding to training data sequence part on some the described active paths are carried out maximum ratio merge, carry out relevant with the training data sequence then;
Output sequence according to described path merges and correlation step obtains carries out a Frequency offset estimation and obtains the Frequency offset estimation value;
Signal to Interference plus Noise Ratio is estimated, obtains the Signal to Interference plus Noise Ratio estimated result in the present frame;
According to described Signal to Interference plus Noise Ratio estimated result, the kalman gain factor of computing application Frequency offset estimation in present frame;
According to the described Frequency offset estimation value and the kalman gain factor, carry out firstorder loop filtering and obtain cumulative frequency skew estimated value;
Described cumulative frequency skew estimated value is controlled the output frequency of local oscillator.
Chinese PRB Reexamination
Abstract
This invention discloses an automatic calibration method for a timedivision wireless communication system receiver including fetching a train data sequence mode and fine frequency calibration which is based on continuously calibrating one by one to the continuous or discontinuous frames till dropping out of step or a new calibration begins, each includes the following steps: signal pickup, channel estimation and path search, path merge, frequency offset estimation, SINR estimation, kalman gain factor computation, onestep loop filter and frequency control to realize frequency synchronization in the timedivision system quickly and accurately under low SINR conditions and poor mobile communication environment of frequency diffusion and time diffusion.

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No References
9 Claims

1. , a kind of automatic frequency correcting method of receiver of timedivision wireless communication system comprises and obtains a training data sequence pattern and fine frequency correction;
 Described fine frequency is proofreaied and correct and is constantly carried out frame by frame based on plurality of continuous or discontinuous frame, begins up to lockout or once new automatic frequency correction, and it comprises the steps;
each timeExtraction is corresponding to the reception data of described training data sequence part; Channel estimating and route searching obtain amplitude and phase information in corresponding each channel delay tap in a collection of present frame, and select some active paths according to the channel estimation results of present frame and former some frames; According to described channel estimation value and Path selection result, the reception data corresponding to training data sequence part on some the described active paths are carried out maximum ratio merge, carry out relevant with the training data sequence then; Output sequence according to described path merges and correlation step obtains carries out a Frequency offset estimation and obtains the Frequency offset estimation value; Signal to Interference plus Noise Ratio is estimated, obtains the Signal to Interference plus Noise Ratio estimated result in the present frame; According to described Signal to Interference plus Noise Ratio estimated result, the kalman gain factor of computing application Frequency offset estimation in present frame; According to the described Frequency offset estimation value and the kalman gain factor, carry out firstorder loop filtering and obtain cumulative frequency skew estimated value; Described cumulative frequency skew estimated value is controlled the output frequency of local oscillator.
 Described fine frequency is proofreaied and correct and is constantly carried out frame by frame based on plurality of continuous or discontinuous frame, begins up to lockout or once new automatic frequency correction, and it comprises the steps;

2. the automatic frequency correcting method of receiver of timedivision wireless communication system as claimed in claim 1 is characterized in that, the gain factor step of described computing application Frequency offset estimation in present frame adopts kalman gain factor computational methods.

3. the automatic frequency correcting method of receiver of timedivision wireless communication system as claimed in claim 2 is characterized in that, described kalman gain factor computational methods comprise the steps:

A) determine to set initial value P according to the Signal to Interference plus Noise Ratio value of being surveyed at that time _{0} B) initial value with frame counter k is made as 1; C) the frequency offset estimating variance R of calculating present frame _{k};
D) R that calculates by present frame according to following formula _{k}P with former frame calculating _{K1}Try to achieve the kalman gain factor K _{k};
K _{k}＝
P _{k1}(P _{k1}+R _{k}) ^{1}E) judge the K that is calculated _{k}Whether value is less than a preset value K _{LOW}If, K _{k}＜
K _{LOW}, then change K _{k}Make it equal K _{LOW}, with seasonal P _{k}=P _{K1}Otherwise, if K _{k}＞
=K _{LOW},, calculate the K of gained by present frame then according to kalman filtering theory _{k}Value and former frame calculate P _{K1}Value is calculated P _{k}Value;
P _{k}＝
(1K _{k})P _{k1}F) the output kalman gain factor K that present frame calculated _{k}To loop filter;
G) frame counter k adds 1, prepares to carry out having in the next frame renewal of related parameter.


4. the automatic frequency correcting method of receiver of timedivision wireless communication system as claimed in claim 3 is characterized in that, described frequency offset estimating variance R _{k}Calculate as follows:

5. the automatic frequency correcting method of receiver of timedivision wireless communication system as claimed in claim 4 is characterized in that, in the TDSCDMA system, and K _{R}Be chosen for (288.8) ^{2}

6.
As the automatic frequency correcting method of the described receiver of timedivision wireless communication system of arbitrary claim in the claim 1 to 5, it is characterized in that 6, in described Frequency offset estimation, the phase place of phase deviation estimated value adopts following formula to calculate: 
$\mathrm{\θap;\left(\frac{{c}_{\mathrm{real}}}{{c}_{\mathrm{imag}}}\right),}$ If$\frac{{c}_{\mathrm{real}}}{{c}_{\mathrm{imag}}}\≤\mathrm{lambda;,}$ Wherein, c _{Real}Real part for the phase deviation estimated value;
c _{Imag}Be the imaginary part of phase deviation estimated value, and if the c of calculating gained _{Real}/ c _{Imag}Value then directly estimates that with output phase the value of θ
is changed to λ
during greater than λ
.


7. the automatic frequency correcting method of receiver of timedivision wireless communication system as claimed in claim 6 is characterized in that, described λ
 is 1 or 0.5.

8. the automatic frequency correcting method of receiver of timedivision wireless communication system as claimed in claim 1 is characterized in that, described training data sequence pattern can carry out Cell searching by receiver and obtain.

9. the automatic frequency correcting method of receiver of timedivision wireless communication system as claimed in claim 1 is characterized in that, described training data sequence pattern can obtain by the method for notifications.
Specification(s)