A method for frequency deviation estimation

Abstract

The invention relates to digital wireless communication field, especially relates to signal processing field, and discloses a projection method for frequency deviation, which includes: first step, the emitter sends the communication signal; second step, the receiver receives the communication signal emitted by emitter; third step, the receiver can obtain the reference signal by the method of relative demodulation; fourth step, the receiver obtains the reference signal and the rotation angle of constellation of presume signal, and the rotation angle contains the frequency offset information; fifth step, the rotation angle is converted into projection value of frequency offset by the receiver according to the fixed relationship between the rotation angle and the frequency offset. Using the method provided by the invention, it does not need the given known signal, and does not search in frequency extension comparing with present method, at the same time it can limit the effect of noise partly in signal processing, and be realized easily, and high accuracy.

Description

technical field [0001] The invention relates to the field of digital wireless communication, in particular to the field of signal processing, in particular to a method for frequency offset estimation. Background technique [0002] In the field of digital wireless communication, frequency offset estimation is one of the commonly used signal processing methods. [0003] Since the base station and the mobile station, or the carrier frequency between the mobile station and the mobile station cannot be absolutely equal, there is a relatively fixed frequency offset between the actual received signal and the expected received signal of the receiver. This frequency offset is harmful in the field of digital wireless communication, and it can reduce the accuracy of channel estimation and cause an increase in bit error rate. Therefore, in a digital wireless communication system, the receiver usually needs to estimate the frequency offset according to the uplink received signal, and th...

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Problems solved by technology

[0005] But the disadvantage of this method is: this method needs to use a known signal, and in the mobile communication system, in order to improve the communication efficiency of the system, such a known signal Usually it is very short or does not exist. For example, in the PCS system, the known signal length available in the TCH frame structure is only 12 symbols, and the estimation result obtained by using this patented method has poor precision; if there is no known signal, the method failure

[0006] At the same time, when this method is applied in actual engineering, it is necessary to first estimate the position of the known signal in the received signal, which increases the complexity of the method and also increases the probability of abnormal situations, that is, when the position of the known signal is incorrectly estimated, The frequency offset estimation result of this method is wrong

[0007] In addition, this method uses search for frequency offset estimation, which requires a lot of calculation. For example, in a preferred embodiment of this method, the Within the frequency offset estimation range, the search process is implemented at an interval of 16 Hz. According to the conventional search method, 513 search operations are required. Even if the number of searches is reduced by some implementation techniques, the amount of calculation is still large, which brings a lot to the practical application of the method. inconvenient

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