Frequency shift estimation device and method

Abstract

A method for frequency offset estimation includes: performing a multi-cell channel estimation to obtain the channel estimation value of each cell; detecting active training sequence offsets according to the channel estimation value of each cell; obtaining frequency offset estimation values of multiple active training sequence offsets. To obtain the frequency offset estimation value of an active training sequence offset includes: removing the interferences of other active training sequence offsets in the received training sequence data, thus obtaining a clean signal corresponding to said active training sequence offset; using said clean signal to obtain the frequency offset estimation value of said active training sequence offset; obtaining the final frequency offset estimation value on the basis of the frequency offset estimation values of multiple active training sequence offsets. A device for frequency offset estimation is also provided by the invention. By removing the interferences among midamble codes and using clean signals to estimate frequency offset, the method of the invention improves the accuracy of frequency offset estimation.

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...

AI Technical Summary

Problems solved by technology

[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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