Frequency shift estimation device and method
A frequency offset estimation and frequency offset technology, which can be used in carrier regulation, transmission systems, electrical components, etc., to solve problems such as co-channel interference, failure to work properly, and reduced terminal receiving performance, and achieve the effect of improving the accuracy of frequency offset estimation.
Active Publication Date: 2010-12-01
SANECHIPS TECH CO LTD
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[0005] When the TD-SCDMA system uses multiple Midamble code offsets to transmit services at the same time, the Midamble codes with multiple offsets interfere with each other, especially the Midamble codes have cyclic correlation characteristics; in addition, in order to improve the spectrum utilization of the TD-SCDMA system rate, co-frequency networking can be used, but while co-frequency networking improves spectrum utilization, it will bring co-channel interference, and there is also co-frequency interference in some data of Midamble codes
[0006] Due to the above reasons, if the received Midamble code part of the data is directly calculated with the local Midamble code through correlation operations to calculate the frequency offset, there will be a large error, which will greatly reduce the receiving performance of the terminal, and even fail to work normally.
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[0046] Various preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0047] The present invention proposes a frequency offset estimation method based on Midamble codes for TD-SCDMA system terminals. Firstly, through multi-cell channel estimation processing, the channel estimation of each cell is calculated and the Midamble code offset currently used by each cell is detected, and then according to the channel estimation results Reconstruct each Midamble code offset signal with the Midamble code offset detection result, eliminate the interference between each Midamble code, and then use the Midamble code part data after interference cancellation to calculate the corresponding frequency offset estimation value of each activated Midamble code offset, Finally, the final frequency offset estimation value is obtained by combining the frequency offset estimation values corresponding to the active Midamble code ...
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The invention provides a frequency shift estimation method, which comprises the following steps of: performing channel estimation of multiple cells to acquire a channel estimation value of each cell; detecting activated training sequence shifts according to the channel estimation value of each cell; aiming at one activated training sequence shift, removing the interference of other training sequence shifts from received training sequence data to acquire a clean signal corresponding to the activated training sequence shift; acquiring a frequency shift estimation value of the activated training sequence shift by using the clean signal corresponding to the activated training sequence shift; acquiring frequency shift estimation values of a plurality of activated training sequence shifts; and acquiring a final frequency shift estimation value according to the frequency shift estimation values of the plurality of activated training sequence shifts. The invention also provides a frequency shift estimation device. In the method, by removing the interference among Midamble codes, the frequency shift estimation is performed by using the clean signal, so the accuracy of frequency shift estimation is improved.
Description
technical field [0001] The present invention relates to a wireless communication system, in particular to a frequency offset estimation device and method. Background technique [0002] In the TD-SCDMA (Time Division Synchronous Code Division Multiple Access, Time Division Synchronous Code Division Multiple Access) system, the base station and the terminal both transmit and receive at the nominal carrier frequency. Due to device level limitations, there will be a certain deviation between the actual transmitted and received frequencies. The TD-SCDMA system requires the base station's carrier frequency error to be less than 0.05PPM, and the user's carrier frequency error to be less than 0.1PPM. On the base station side, due to relatively small restrictions on temperature, volume, power consumption, and cost, the frequency accuracy of the oscillator can meet the requirements. On the user side, however, limited by the aforementioned various reasons, the frequency accuracy of t...
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Login to View More IPC IPC(8): H04B1/707
CPCH04B1/7103H04L27/0014
Inventor 梁立宏
Owner SANECHIPS TECH CO LTD