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A time synchronization method for TD-SCDMA system

A TD-SCDMA, time synchronization technology, applied in the direction of communication between multiple stations, which can solve the problems of inter-symbol interference, channels running into other channel windows, and false users.

Active Publication Date: 2007-06-06
XIAMEN UNISOC TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] As mentioned above, the TD-SCDMA system divides the estimated channel into K channel windows and allocates them to different code channels. Each channel window can only have W multipaths at most. When there is a synchronization error, the original path Expand the split into multiple paths. At this time, the expanded channel may run into other channel windows, causing great interference and even the appearance of false users, which greatly reduces the performance of the system; even after the expansion The multi-channel is still in the channel window, which will also bring a large inter-symbol interference at this time

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  • A time synchronization method for TD-SCDMA system
  • A time synchronization method for TD-SCDMA system
  • A time synchronization method for TD-SCDMA system

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Embodiment Construction

[0029] Please refer to Fig. 6, which is a schematic flow chart of the method of the present invention. As shown in the figure: The time synchronization method of the TD-SCDMA system uses the 128-chip channel estimation sample diagram to obtain the correlation value of each odd tap of the channel response with its previous tap and the next tap through a two-correlator ; Use the correlation value to judge whether the system is a positive time synchronization error or a negative time synchronization error through the decision-making unit, and decide whether the sampling time advances, lags behind or remains unchanged; before using the correlator to obtain the correlation value, perform noise reduction processing.

[0030] Figure 7 is a special case of the correlator, where real(x) means taking out the real part of x.

[0031] At the same time, we give the pseudo-code of the decision-making unit as follows:

[0032] Entry parameter r 1 and r 2 , the export action is lead or lag...

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Abstract

The invention relates to a time synchronizing method for TD-SCDMA system, particularly a new time synchronizing method using 128-chip channel estimated master drawing in the TD-SCDMA system, obtaining the related values of each odd-order tapping of the channel response with its previous tapping and next tapping; using these related values to judge whether the system has a positive time synchronization error or a negative one by an policy making unit and determining the sampling time to lead, lag or be invariant. The method mainly solves the problem of time synchronization error caused by timing error of receiving-end matching filter (root rising cosine (RRC) filter) of the TD-SCDMA system, avoids the appearance of a false target and reduces the interference between symbols.

Description

Technical field: [0001] The invention relates to a time synchronization method in a communication system, in particular to a new time synchronization method realized by using a 128-chip channel estimation pattern in a TD-SCDMA system. Background technique: [0002] We know that the TD-SCDMA system is classified into the 1.28Mcps protocol of UMTS TDD, and the frame structure and time slot structure of TD-SCDMA are shown in Figure 1 and Figure 2. Let's take the following example to illustrate the midamble data formation process. [0003] assuming m P =(m 1 , m 2 ,...,m P ) is the basic Midamble code, P=128, m P =( m 1 , m 2 ,..., m P ) is the basic Midamble code after QPSK modulation, then there are: m i =(j) i m i For all i=1,...,P, j = - 1 . make i max =L m +(K-1)W, here L m =144, K can take {2, 4, 6, 8, 10, 12, 14, 16}, generally K takes 8, [0004] we construct ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B7/26
Inventor 程健林敬东
Owner XIAMEN UNISOC TECH CO LTD