A novel OFDM frequency deviation evaluation and tracking scheme

A technology of frequency offset estimation and frequency offset estimation, which is applied in the field of communication, can solve the problems of increased complexity and difficulty of frequency offset calculation, and achieve the effect of meeting the requirements of frequency tracking

Inactive Publication Date: 2009-06-24
BEIJING UNIV OF POSTS & TELECOMM
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Problems solved by technology

[0005] In the previous frequency offset estimation algorithms, no matter it is the frequency offset estimation based on the pilot frequency or the frequency offset estimation based on the cyclic prefix, the method of correlation operation is basically used, which makes the calculation complexity of the frequency offset greatly increase, resulting in increased difficulty in the specific implementation process

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  • A novel OFDM frequency deviation evaluation and tracking scheme
  • A novel OFDM frequency deviation evaluation and tracking scheme
  • A novel OFDM frequency deviation evaluation and tracking scheme

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Embodiment Construction

[0036] Before describing the specific embodiments of the present invention, first combine figure 1 , Give a brief introduction to the existing OFDM system, such as figure 1 As shown, the data stream d(k) in the OFDM system undergoes certain encoding processing and constellation mapping to form a vector of length N (N is the number of subcarriers): This vector generates a time-domain data vector through a serial-parallel transform part 101, an IFFT (Inverse Fourier Transform) part 102, and a parallel-serial transform part 103: Then, the time domain data vector is obtained by adding L cyclic prefixes to the cyclic prefix part 104: Then the digital-to-analog conversion is performed by the digital-to-analog conversion section 105, and finally sent to the channel transmission section 106 after transmission filtering and up-conversion for transmission to the receiving end. At the receiving end, after the received signal is processed by down-conversion and receiving filtering, the a...

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Abstract

The invention relates to a new OFDM frequency offset estimation and tracking scheme. In the carrier frequency acquisition stage of this scheme, the main method is to insert all "1" pilots into the time domain signal at the transmitting end, and use the FFT module in the system at the receiving end to estimate the frequency offset in the wireless communication system, so that the normalized The frequency offset estimation range can be (-N / 2, N / 2), and the OFDM system bit error rate corrected by the frequency offset estimated value obtained according to the present invention is basically close to the bit error rate under the condition of no frequency offset Rate. At the same time, in the present invention, for the frequency offset estimation based on the cyclic prefix in the tracking stage, the normalized frequency offset tracking range can reach (-0.5, 0.5), which satisfies the requirement of frequency tracking well. In addition, because the present invention utilizes the existing FFT module and cyclic prefix structure in the system to perform corresponding frequency offset estimation, not only can the whole estimation process be relatively simple, the operation speed can be greatly improved, but also accurate frequency offset calculation results can be obtained.

Description

Technical field [0001] The present invention relates to the field of communication technology, in particular to a frequency shift suitable for the carrier frequency acquisition phase and the tracking phase in an OFDM (orthogonal frequency division multiplexing) system and a modulation system containing an FFT (fast Fourier transform) module and a cyclic prefix. Estimate method and its system. Background technique [0002] At present, in the field of wireless communication technology, the OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing) system is gradually being popularized and applied with its simple structure and good transmission effect. The OFDM system is based on several orthogonal sub-systems. Parallel transmission of data on the carrier, the system can reduce the adverse effects of frequency selective fading compared with the single carrier system to a certain extent, and also has a simpler structure, higher frequency band utiliz...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04J11/00H04J1/00H04L27/32H04B1/76
Inventor 秦升平尹长川郝建军罗涛纪红刘丹谱李剑峰乐光新
Owner BEIJING UNIV OF POSTS & TELECOMM
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