Filtering method for channel estimation in CDMA timing tracking system

A channel estimation and timing tracking technology, applied in baseband system components and other directions, can solve the problems of broadening the time delay spectrum, reducing the accuracy of timing adjustment, affecting the accuracy of path search, etc., to achieve accurate timing adjustment, overcome accuracy, and improve reception. The effect of system performance

Inactive Publication Date: 2006-04-19
XUANPU INDUSTRY CO LTD
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Problems solved by technology

Using a conventional filter whose filtering algorithm is aligned at the corresponding position, it is prone to delay spectrum broadening when the timing is adjusted, which will affect the accuracy of the path search and cause the timing adjustment accuracy to decrease.

Method used

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  • Filtering method for channel estimation in CDMA timing tracking system
  • Filtering method for channel estimation in CDMA timing tracking system
  • Filtering method for channel estimation in CDMA timing tracking system

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Embodiment Construction

[0017] Combine below figure 1 , figure 2 A specific embodiment of the present invention is described to further understand the content of the present invention.

[0018] The invention provides a filtering method for channel estimation in a timing tracking system of code division multiple access, which comprises the following steps:

[0019] Step 1. Calculate the channel estimate according to the training sequence of the received signal, and simultaneously obtain the channel estimation delay spectrum;

[0020] Step 2. Determine whether a timing adjustment has occurred in this frame. If there is no timing adjustment, skip to step 5. When a timing adjustment occurs, it is necessary to calculate the shift value Δ of the average sequence, and calculate the cumulative adjustment amount as Δ 0 , let the shift value Δ of the average sequence, Δ=mod(Δ 0 , K), where K is the length of the channel estimate of the receiving system. When the receiving timing is adjusted, output a new ...

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Abstract

After accomplishing channel estimation and obtaining power of time delay of channel from calculation, the method filters out high frequency segment, which is corresponding to fast fading part of channel, so as to obtain relative accurate estimation. Being adopted in the invention, averaging method of cyclic shift carried out shift alignment for time delay spectrum of route of channel in order to prevent spread of the spectrum caused by change of channel estimation from change of channel so as to ensure correctness for searching following routes. Since flip of time delay spectrum caused by operation of shift filter or, especially caused by position change of effective route may be occur, the system modifies channel estimation to prevent error command for adjusting timing based on condition of shift of time delay in system.

Description

technical field [0001] The present invention relates to a channel estimation filtering method of a timing tracking system in a code division multiple access (CDMA) communication system, specifically, it relates to a channel estimation filtering method of a timing tracking system in a TD-SCDMA system. Background technique [0002] In a CDMA receiving device, in order to obtain a good receiving effect, it is necessary to obtain accurate chip timing and symbol timing. Since the receiving device is in the process of constant movement, channel conditions will continue to change, and it is necessary for the timing tracking system of the receiving device to continuously track changes in system delay. The timing tracking system will detect the changes of the wireless channel, and constantly track the channel changes, and provide accurate timing adjustment instructions for the receiver to meet the requirements of the receiving device. [0003] In the process of timing tracking and a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/02
Inventor 王炳立李兴伟叶远谢一宁
Owner XUANPU INDUSTRY CO LTD
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