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Automatic frequency control method

An automatic frequency control, automatic frequency technology, applied in the direction of automatic tone/bandwidth control, transmission control/equalization, radio/induction link selection and arrangement, etc., can solve large system errors, cannot quickly achieve frequency recovery, lose effectiveness and other problems to achieve the effect of occupying less resources

Active Publication Date: 2005-05-04
RDA CHONGQING MICROELECTRONICS TECH CO LTD +1
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  • Claims
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Problems solved by technology

[0005] The purpose of the present invention is to provide an automatic frequency control method for the above-mentioned problems in the prior art that use FOE to estimate the frequency offset. Due to the large system error, the validity of the estimation is lost, and the frequency cannot be recovered quickly.

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Embodiment Construction

[0018] see figure 1 The system model shown, where s(t) is the transmitted signal, c(t) is the channel fading process, n(t) is thermal noise and multi-user interference inside and outside the cell, r(t) is the received signal, which can be expressed as :

[0019] r ( t ) = Σ m a m g ( t - τ - mT ) e j ( 2 π F d t + θ 0 ) + Noise - - - - ( 1 ) ...

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Abstract

The method includes following steps: determining accurate position and code pattern of sequence of pilot frequency from data received; multiplying conjugate point of sequence of pilot frequency in this sub zone by data segment in the sequence of pilot frequency in data frame received so as to obtain actual data; calculating estimated frequency deviation by using numeric algorithm for automatic frequency adjustment; calculating adjusted value of frequency deviation by using adjustment strategy so as to complete one time of adjustment for center frequency of local carrier wave; after completing N time of adjustment, frequency adjustment for one phase is ended. Under same method, accurate frequency adjustment and tracking procedure for next phase is carried out. Through numeric algorithm, the invention calculates maximum likelihood estimation value of frequency deviation value. Advantages are: quick recovering frequency of carrier wave, quick speed and high efficiency etc.

Description

1. Technical field [0001] The present invention belongs to automatic frequency control (English abbreviation is AFC in this field) method in mobile communication system, particularly relates to a kind of fast, high-efficiency automatic frequency control method without any approximate processing. 2. Background technology [0002] In TDMA systems, reliable data detection is strictly dependent on the accurate estimation of the synchronization parameters of the received signal, that is, carrier frequency, phase and symbol timing information obtained from pilot bursts. Carrier frequency synchronization is the premise of realizing phase and symbol timing synchronization. Therefore, correct estimation of carrier frequency is the premise of receiving data correctly and the key to determine the success of initial cell search. [0003] The optimal decision for the detection of the received signal symbol sequence corrupted by noise is based on the Maximum A Posteriori Probability (MAP)...

Claims

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Application Information

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IPC IPC(8): H04B7/005H03G5/16
Inventor 陈发堂郑建宏申敏杨明洪刘树军周渝陇
Owner RDA CHONGQING MICROELECTRONICS TECH CO LTD
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