Carrier recovery method based on high-order QAM

A carrier recovery and high-order technology, applied in the direction of carrier adjustment, multi-carrier system, modulated carrier system, etc., can solve the problems of low estimation accuracy and large amount of calculation, and achieve improved search efficiency, small phase jitter, and reduced computational complexity Effect

Inactive Publication Date: 2021-06-08
TIANJIN UNIVERSITY OF TECHNOLOGY
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Problems solved by technology

[0006] At present, for the frequency offset estimation of high-order QAM, the existing technology often adopts two methods of open-loop structure and closed-loop structure, but the open-loop structure method has a large amount of calculation, and the closed-loop structure method has the problem of low estimation accuracy

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  • Carrier recovery method based on high-order QAM
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  • Carrier recovery method based on high-order QAM

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Embodiment Construction

[0047] The following will refer to Figure 1-6 Specific embodiments of the present invention will be described.

[0048] A carrier recovery method based on high-order QAM, such as figure 1 As shown, the details of each step are as follows:

[0049] The first step is to set the threshold of the power detector to τ to filter the constellation points that interfere with the maximum likelihood estimation results, and the threshold cannot be set too large so that only the constellation points with the highest power can pass through the power detector. If it is too large, the selected The estimation accuracy of the algorithm cannot be effectively guaranteed because the number of constellation points is too small; that is, before the maximum likelihood estimation of the received signal r(n), a power detector module is added to detect the power of the received signal r(n) , and the threshold of the power detector is set to τ, when the power of the received signal r(n) is greater tha...

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Abstract

The invention discloses a carrier recovery method based on high-order QAM, which adopts a method of combining an open-loop structure and a closed-loop structure to achieve the purpose of increasing a frequency offset capture range during frequency offset estimation, and adopts maximum likelihood estimation to complete frequency offset estimation in the open-loop structure; a power detector is used for retaining constellation points with relatively high reliability to increase the estimation precision; multi-stage estimation is introduced to reduce the operation complexity; the closed-loop structure can eliminate residual frequency offset and phase offset; and, according to the method, the calculation complexity can be greatly reduced, and meanwhile, the frequency offset estimation precision is improved.

Description

[0001] (1) Technical field: [0002] The invention belongs to the technical field of communication, relates to the fields of wireless communication and digital communication, in particular to a carrier recovery method based on high-order QAM (Quadrature Amplitude Modulation, quadrature amplitude modulation). [0003] (two) background technology: [0004] With the development and progress of microelectronics technology, computer technology and digital signal processor in recent years, digital signal processing technology has been more and more widely used in the field of communication, which has greatly promoted the development of digital modulation and demodulation technology in modern communication. However, with the increasing demand for information transmission, bandwidth resources are now facing serious shortages. High-order QAM is a joint amplitude and phase keying, that is, both the phase and amplitude of the signal can be used to transmit data. Each symbol can carry log ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/00H04L27/38
CPCH04L27/0014H04L27/38H04L2027/0026H04L2027/0046H04L2027/0053
Inventor 孟鑫张骁博张炜林马社祥
Owner TIANJIN UNIVERSITY OF TECHNOLOGY
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