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Estimation method based on broadband OFDM system frequency-dependent Doppler shift

A Doppler frequency shift and wideband technology, which is applied in the field of estimation of frequency-variant Doppler frequency shift based on wideband OFDM system, can solve problems such as system performance impact

Inactive Publication Date: 2015-12-02
SYSU CMU SHUNDE INT JOINT RES INST +1
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Problems solved by technology

Therefore, the Doppler shift can have a serious impact on system performance

Method used

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  • Estimation method based on broadband OFDM system frequency-dependent Doppler shift
  • Estimation method based on broadband OFDM system frequency-dependent Doppler shift
  • Estimation method based on broadband OFDM system frequency-dependent Doppler shift

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Embodiment Construction

[0063] The present invention will be further described below in conjunction with the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0064] The idea of ​​the present invention is: use two pilot clusters to estimate the Doppler frequency shifts of the positions of the two pilot clusters, and then use the linear fitting method to estimate the Doppler frequency shifts on all subcarriers according to the estimated Doppler frequency shifts. Doppler frequency shift, the overall flow chart is as follows figure 1 shown.

[0065] Concrete realization process of the present invention is as follows:

[0066] First, design the sender as figure 2 The distribution of pilot symbols containing two pilot clusters is shown. According to the minimum mean square error MMSE criterion, the pilot sequence can be designed as follows:

[0067] s ( k ) = ...

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Abstract

The present invention discloses an estimation method based on broadband OFDM system frequency-dependent Doppler shift. Signals are transmitted by the wireless channels, when a reception end and a transmission end exist the relative movement, frequency deviation is generated between a reception signal and a sending signal, namely a Doppler effect occurs, and the more drastic is the relative movement, the severer is the Doppler effect. In a broadband OFDM system, the Doppler shift of the system changes along with the change of the frequency. In order to estimate the frequency-dependent Doppler shift of the broadband OFDM system, the method of the present invention firstly adopts two pilot frequency clusters to estimate the Doppler shift on two different subcarriers of the system respectively, and then adopts a linear fitting mode in a frequency domain to estimate to obtain the Doppler shift of the whole frequency domain, namely, the Doppler shift of all subcarriers. In addition, in order to improve a Doppler shift estimation effect, the present invention also adopts a method of adding a Kaiser window in a time domain to improve. The estimation method of the present invention has the advantage of good error performance.

Description

technical field [0001] The present invention relates to the technical field of communication, and more specifically, relates to a method for estimating frequency-varying Doppler frequency shift based on a wideband OFDM system. Background technique [0002] With the rapid development of mobile communication technology and Internet technology, many kinds of broadband wireless communication technologies have emerged, and the advent of these broadband wireless communication technologies makes it possible for users to have high demand for broadband services. As a core technology in broadband wireless communication technology, OFDM technology can not only effectively resist multipath interference, but also has the advantages of high spectrum utilization rate and strong data transmission capability. OFDM technology is widely used in practical applications. [0003] The OFDM system is a multi-carrier communication system in which subcarriers maintain mutual orthogonality. The system...

Claims

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Application Information

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IPC IPC(8): H04L25/02H04L27/26
CPCH04L25/0222H04L27/2628H04L27/2646H04L27/2675
Inventor 戴宪华刘平
Owner SYSU CMU SHUNDE INT JOINT RES INST
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