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Synchronizing method for quadrature frequency division multiple access system

An orthogonal frequency division multiple access, coarse synchronization technology, applied in the multi-frequency code system, signal channel and other directions, can solve the problem of limitation, sacrifice spectrum utilization, high complexity, achieve low complexity, high spectrum utilization, The effect of accurate carrier frequency offset estimation

Inactive Publication Date: 2006-10-25
BEIJING UNIV OF POSTS & TELECOMM +1
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Problems solved by technology

However, since the length of the training sequence is given, the length of the frame and the accuracy of carrier frequency offset estimation are limited, and a certain spectrum utilization is also sacrificed.
In addition, some scholars have proposed to use methods based on cyclic prefix, virtual subcarrier or subspace for multi-user carrier frequency offset estimation, but most of these algorithms have high complexity

Method used

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  • Synchronizing method for quadrature frequency division multiple access system
  • Synchronizing method for quadrature frequency division multiple access system
  • Synchronizing method for quadrature frequency division multiple access system

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Embodiment Construction

[0044] In a preferred embodiment of the invention, the synchronization sequence is described in the form of an Additive Time Domain Training Sequence (ATTS). figure 1A schematic diagram of the generation of the ATTS sequence according to the present invention is shown. When the number of subcarriers available in the OFDMA system is not equal to the length of IDFT, a Gold code is inserted at a specific frequency point in the frequency domain. A suggested method is to first generate a Gold code with half the order of the IDFT modulator , and then insert these Gold codes into the symmetrical frequency points on both sides of the IDFT center frequency point in turn, where the zero frequency point and other frequency points that have not been inserted into the Gold code value are zero-inserted, and the sequence is converted into a time-domain signal by IDFT , as the ATTS sequence after weighting, and when the number of available subcarriers of the OFDM system is equal to the length...

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Abstract

The method includes steps: in orthogonal frequency division multiple access (OFDMA) system, when number of usable sub carrier wave is equal to length of inverse discrete Fourier transform (IDFT), Gold code is adapted as synch sequence directly; when the said number is not equal to the said length, Gold code equal to half length of IDFT is inserted to symmetrical frequency points with, and zeros are inserted to zero frequency points and other frequency points without inserting Gold codes; after being converted to time domain, the sequence is in use as synch sequence; sending the synch sequence to receiving end from the sending end to establish synch; sending superposed data in OFDMA and synch sequence to the receiving end, or sending data in OFDMA to receiving end directly; using dichotomy at receiving end , the receiving end searches relevant peak value of synch sequence, using estimated carrier deviation compensates phase of received signal so as to obtain data of OFDMA system.

Description

technical field [0001] The invention relates to a synchronization method suitable for Orthogonal Frequency Division Multiple Access (OFDMA) system. Background technique [0002] It can be predicted that multimedia services such as audio, video, image, and Internet will become the dominant services of mobile communications in the future, and these services have significantly increased requirements for wireless link transmission capabilities (peak service rate is greater than 20Mbps), in this case, the orthogonal frequency Multiplexing (OFDM) technology is gradually emerging. OFDM technology modulates high-speed data streams into multiple parallel low-speed data streams with overlapping frequency spectrums. Since the period of the OFDM symbol is significantly increased, the ability of the OFDM symbol to resist multipath delay is improved. Further, by adding a guard interval (GI) greater than the maximum multipath delay at the front end of the OFDM symbol, the multipath delay ...

Claims

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Application Information

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IPC IPC(8): H04L27/26H04L5/02
Inventor 陶小峰谢文飞姬翔李霜李立华张平
Owner BEIJING UNIV OF POSTS & TELECOMM
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