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Combined synchronization process and its receiving terminal based on two-dimension short time slippage self-correlation

A two-dimensional correlation and receiving-end technology, applied in the field of digital information transmission, can solve the problems that the pilot frequency reduces the system spectrum utilization rate, the correlation peak of the differential calculation differential correlation result is difficult to distinguish, and affects the frame synchronization, etc., so as to avoid the system spectrum utilization rate. Reduce, guarantee the estimation range and estimation accuracy, and the effect of strong ability

Inactive Publication Date: 2008-12-10
TSINGHUA UNIV
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Problems solved by technology

The disadvantage of this method is that in the case of frequency selective channels or large timing deviations, the non-linearity of the differential operation will cause the correlation peaks of the differential correlation results to be difficult to distinguish, which will affect the frame synchronization.
For OFDM systems where the cyclic prefix fills the guard interval, the cyclic characteristics of the cyclic prefix can be used for frame synchronization and small-scale carrier frequency offset estimation (see the paper: J.J.van de Beek, et al., "MLestimation of time and frequency offset in OFDM systems" , IEEETransactions on Signal Processing, vol.45, no.7, pp.1800-1805, Jul.1997.), while the traditional timing offset estimation and large-scale carrier frequency offset estimation methods generally need to use pilot frequency to complete, but the pilot The addition of frequency will reduce the spectrum utilization of the system

Method used

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  • Combined synchronization process and its receiving terminal based on two-dimension short time slippage self-correlation
  • Combined synchronization process and its receiving terminal based on two-dimension short time slippage self-correlation
  • Combined synchronization process and its receiving terminal based on two-dimension short time slippage self-correlation

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Embodiment 2

[0085] The signal frame structure adopted by the transmission system of the second embodiment of the method of the present invention is as follows: figure 2 shown. The length of the signal frame is 1728 symbols, which consists of a frame header and a frame body. The frame header is a training sequence of 192 symbols, using a PN sequence with a fixed phase, consisting of an m-sequence of 127 symbols and a cyclic prefix of 65 symbols, such as image 3 shown. The frame body is a data block with 1536 symbols, which can be an independent data block modulated by single carrier or multi-carrier, or can be obtained together with the frame header by cyclic suffix OFDM. Because the frame headers of the signal frames are all the same, there is a partial cycle between the signal frames. The frame headers form a loop body, and two adjacent frame headers and the data between them form a loop frame; and because the frame headers are composed of m sequences and their The cyclic extension ...

Embodiment 3

[0141] The signal frame of the transmission system in the third embodiment of the present invention adopts the signal frame structure 1 of the Chinese terrestrial digital television transmission standard (GB 20600-2006), corresponding to the frame header mode 1. The length of the signal frame is 4200 symbols, which consists of a frame header and a frame body. The frame header is a PN sequence of 420 symbols. The PN sequence is composed of an m sequence of 255 symbols and its cyclic extension. Different cyclic shifts of the m sequence correspond to PN sequences of different phases. The phase difference between two PN sequences is the number of bits of relative cyclic shift of their m sequences, Figure 13 Shown are two PN sequences with a phase difference of 10. A superframe of the system is composed of 225 signal frames, and the PN sequences of adjacent frame headers have different phase differences, and the value range of the PN sequence phase difference is -112 to 112. Bec...

Embodiment 4

[0188] The signal frame adopted by the transmission system of Embodiment 4 of the present invention is as follows: Figure 15 shown. The signal frame consists of a 128-symbol cyclic prefix and a 1024-symbol OFDM data body. The cyclic prefix is ​​obtained by duplicating the 128 symbols at the end of each OFDM data body to form a cyclic body in the transmission sequence, and each signal frame constitutes a cyclic frame. The number of sub-carriers in the OFDM data body is 1024, of which the number of effective sub-carriers is 628, and the rest of the sub-carriers are virtual sub-carriers. The signal frame does not contain any known information such as pilots, and only has a part of the cyclic characteristics formed by the cyclic prefix. The symbol rate of the signal frame is assumed to be 1.536Msymbol / s. The received sequence is a sequence obtained by sampling the received signal using 4 times the symbol rate.

[0189] For this kind of block transmission system that uses a cy...

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Abstract

The invention relates to a united synchronized method based on the two-dimensional short sliding self correlation, comprising: firstly, the receiving end processes the two-dimensional short sliding self correlation for the receiving serial; secondly processing the circulated frame synchronization by using the result of the self correlation operation; then, processing the timing frequency synchronization and the carrier frequency synchronization by using the frequency bias estimation and the carrier frequency bias estimation. The invention also relates to a corresponding receiving end of the united synchronized method. The technical solution of the invention provides the united synchronized method and the receiving end thereof, which can offer reliable and precise synchronization under the bad transmitting condition; the invention is suitable for the transmitting system having the part circulated characteristic for all the transmitting serials.

Description

technical field [0001] The present invention relates to the technical field of digital information transmission, in particular to a transmission system applied to a transmission sequence with partial cyclic characteristics, including cyclic frame synchronization, timing frequency synchronization and carrier frequency synchronization, and based on a combined two-dimensional short-term sliding autocorrelation Synchronous methods and their receivers. Background technique [0002] Synchronization is the primary task of digital communication system receiver design and implementation. Without accurate and reliable synchronization, the transmitted data cannot be effectively and reliably received. Under the harsh broadband wireless mobile transmission conditions, there are many unideal factors in the received signal, such as frequency selective fading caused by channel delay spread, time selective fading caused by channel Doppler spread, receiver noise and receiver carrier deviatio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L7/00
Inventor 彭克武许奥林杨知行宋健符剑
Owner TSINGHUA UNIV
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