Open loop carrier synchronization algorithm under MPSK modulation based on FFT
A technology of Fourier transform and carrier synchronization, which is applied in the direction of phase modulation carrier system, baseband system components, etc., can solve problems such as carrier frequency offset estimation, and achieve the effect of improving estimation accuracy.
Active Publication Date: 2014-06-11
PLA UNIV OF SCI & TECH
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[0020] The purpose of the present invention is to provide an open-loop carrier synchronization algorithm based on fast Fourier transform MPSK modulation, which solves the problem of carrier frequency offset estimation in burst communication
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[0043] The present invention will be described in further detail below in conjunction with the accompanying drawings.
[0044] combine figure 1, the entire flow chart is carried out according to the following steps, down-convert the received MPSK signal, sample and remove the modulation information to obtain a discrete sampling sequence with a length of L, complement and discrete signal sequence x(n) (0≤n≤L-1 ) zeros of the same length to form a new sequence; for x′(n): {x(0),x(1),x(2),...,x(L-1),0,. ..,0} perform FFT transformation of 2L points to obtain the corresponding discrete Fourier transformed spectral sequence Ω'(k); find the peak and the position k of the peak in the spectral sequence Ω'(k) p , according to the position of the spectral peak and the position of the left and right spectral lines of the peak, calculate the corresponding amplitude |Ω′(k p -1)|, |Ω′(k p )| and |Ω′(k p +1)|, calculate the fractional part of the frequency offset estimation according to ...
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The invention discloses an open loop carrier synchronization algorithm under MPSK modulation based on FFT. According to the technical scheme, the open loop carrier synchronization algorithm under MPSK modulation based on FFT mainly comprises two steps that down-conversation is carried out on received MPSK signals, data auxiliary information is used for removing modulation information, FFT is carried out on the signals to obtain a signal frequency spectrum, and a rough estimation value of carrier frequency offset is determined by utilizing the position where a peak value occurs in the frequency spectrum; a peak value spectral line and two spectral lines at the left and the right of the peak value in the signal frequency spectrum are used, and the estimated fractional part of the frequency offset, namely a fine estimation value of the carrier frequency offset is obtained through the method of spectral line interpolation; the final estimation value of the carrier frequency offset is obtained according to the obtained rough estimation value of the carrier frequency offset and the fine estimation value of the carrier frequency offset. Compared with an existing carrier frequency offset estimation method, the open loop carrier synchronization algorithm under MPSK modulation based on FFT can effectively improve the estimation accuracy of the carrier frequency offset and does not increase the difficulty of calculation, thereby having broad application prospects in an MPSK open loop carrier synchronization system.
Description
technical field [0001] The invention belongs to carrier synchronization technology, and in particular relates to an open-loop carrier synchronization algorithm based on fast Fourier transform MPSK modulation, and accurately estimates carrier frequency deviation through a newly proposed carrier fine estimation formula. Background technique [0002] In the communication system, the carrier synchronization of the burst signal is a very important issue, which directly affects whether the signal can be received correctly and the communication quality is good or bad. For example, in time-division multiple access, bursty data communication is usually used, and a fast and high-precision carrier frequency estimation algorithm is required to realize carrier synchronization. Since the acquisition performance and tracking performance of the traditional phase-locked loop synchronization are determined by the loop filter, and there is a "hanging" phenomenon, that is, when the initial phas...
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IPC IPC(8): H04L27/20H04L25/02
Inventor 刘爱军张邦宁梁小虎潘小飞郭道省潘克刚童新海方华杨思祥叶展龚超刘贤王桁赵兵续欣陆溪平晋军张应宪
Owner PLA UNIV OF SCI & TECH