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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: 2004-11-03
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 embodiment 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 forms a vector with a length of N (N is the number of subcarriers) after a certain encoding process and constellation mapping: i=0, 1, ΛN-1, this vector produces time-domain data vector by serial-to-parallel transform part 101 and IFFT (inverse Fourier transform) part 102, parallel-to-serial transform part 103: m=0, 1, ΛN-1, and then obtain the time-domain data vector after adding L cyclic prefixes by adding the cyclic prefix part 104: l=0, 1, ΛN+L-1, then digital-to-analog conversion is performed by the digital-to-analog conversion part 105, and finally sent to the channel transmission part 106 for transmission to the receiving end after transmission filtering and up-conversion. At the receiving end, after the received signal is processed by down-conver...

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Abstract

This invention relates to a new OFDM frequency-offset estimation and tracing scheme. The carrier frequency acquire stage in the scheme applies the insert of total '1' pilot frequency in the transmitting end time-domain signals and utilizes FFT module in the system at the receiving end to estimate the frequency offset to make the orthonormal one in the estimation sphere of (-N / 2, N / 2), the error bit rate of corrected OFDM system based on the offset estimate value is close to that without frequency offset. At the same time, the orthonormal frequency offset tracing sphere can reach to (-0.5,0.5) to the frequency offset of the tracing stage based on the circulation prefix meeting the tracing requirement very well. This invention uses the existing FFT module and a circulating prefix structure for related offset estimation to get an accurate computing result.

Description

technical field [0001] The present invention relates to the field of communication technology, in particular to a frequency shift suitable for carrier frequency acquisition phase and tracking phase in OFDM (Orthogonal Frequency Division Multiplexing) system and modulation system containing FFT (Fast Fourier Transform) module and band cyclic prefix Estimation methods and their systems. Background technique [0002] At present, in the field of wireless communication technology, OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing) system is gradually being popularized and applied due to its simple structure and good transmission effect. Parallel transmission of data on the carrier, the system can reduce the adverse effects of frequency selective fading to a certain extent compared with the single-carrier system, and also has the advantages of simple structure, high frequency band utilization, anti-multipath fading and burst resistance co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/76H04J1/00H04J11/00H04L27/32
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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