Method and device for realizing automatic frequency control

Abstract

This invention discloses a method for realizing AFC including: carrying out multi-path search by the precursor part and the message part of a channel to get multi-path information to be used to de-spread the control part and the data part to get information of the control part and the data part then to carry out frequency deviation estimation to the de-spread information of the control part to get the deviation information, then carrying out frequency deviation correction to the de-spread information of the control part and the data part by the deviation frequency to realize AFC, a device for realizing automatic frequency control is also disclosed.

Description

technical field [0001] The present invention relates to automatic frequency control (AFC, Automatic Frequency Control) technology, especially a method and device for realizing automatic frequency control. Background technique [0002] In a wireless communication system, affected by the stability and accuracy of the local crystal oscillator of the user equipment (UE) and the Doppler frequency shift phenomenon caused by the movement of the UE, there is a carrier frequency difference between the base station and the UE, namely frequency offset. Due to the existence of frequency offset, the coherent detection performance of the uplink and downlink is greatly reduced, and even the UE cannot access normally. Therefore, the frequency offset must be controlled to eliminate the negative impact of the frequency offset. At present, the method of effectively controlling the frequency offset is called AFC. The principle of AFC is to estimate the frequency offset of the signal, and then ...

AI Technical Summary

Problems solved by technology

[0006] From the description of Method 1, it can be seen that Method 1 has the following disadvantages: First, because the frequency offset estimation is realized by using the data in the preamble, and limited by the inherent length of the preamble data, the accuracy of the frequency offset estimation is poor, and the fixed The length is 2 time slots with a total of 4096 chips; second, in the preamble, due to the introduction of the frequency offset estimation process before the frequency offset correction, a large amount of interpolation and filtered data needs to be stored, which increases the complexity of AFC and hardware storage overhead , wasting hardware resources

[0009] From the description of Method 2, Method 2 has the following disadvantages: First, due to the need for multi-channel parallel processing, the signal process after deviation correction requires multiple channels of support, which inevitably requires multiple sets of hardware resources, which increases hardware overhead; It is necessary to make a decision between multiple channels, resulting in an increase in complexity, thereby increasing the complexity of implementation; second, the selection of the preset frequency offset value is more difficult

From the above analysis, it can be seen that the main disadvantages of the existing technology are: high hardware resource overhead, which wastes hardware resources; either the implementation is complicated, or the accuracy of frequency offset control is reduced due to low accuracy of deviation correction

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