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Method for synchronizing down going service code channel in CDMA system of using intelligent antenna

A code division multiple access and smart antenna technology, which is applied in the communication between multiple stations, can solve the problems of communication quality degradation, signal-to-noise ratio reduction, and bit error rate increase

Inactive Publication Date: 2008-01-09
BEIJING XINWEI TELECOM TECH
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  • Description
  • Claims
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Problems solved by technology

Therefore, under multipath conditions, this method of synchronizing downlink service code channels will lead to a decrease in signal-to-noise ratio, an increase in bit error rate, a decrease in communication quality, and an increase in call drop rate.

Method used

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  • Method for synchronizing down going service code channel in CDMA system of using intelligent antenna
  • Method for synchronizing down going service code channel in CDMA system of using intelligent antenna

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Embodiment Construction

[0016] Figure 1 illustrates the different transmission paths between the downlink service code channel and the synchronization head of the smart antenna system of time division duplex (TDD) code division multiple access (CDMA), where the dotted line represents the transmission path of the synchronization head, and the solid line is the smart antenna in the cell The propagation path of a transmitted user signal. It can be clearly seen that there is an obvious difference between the synchronization header and the path experienced by the user, and the difference in this path directly leads to the time delay between the synchronization header received by the user and the user signal. The present invention utilizes the feature that the correlation power is the largest when the CDMA user signal is synchronized with the corresponding orthogonal spread spectrum sequence generated locally to eliminate the influence of the time delay difference and improve the system performance.

[001...

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Abstract

Based on synchronization header, the disclosed method solves down going synchronization position primarily. Based on demodulated synchronous training sequence, using method for searching of maximal correlated power point modifies down going synchronization of service code channel so as to obtain higher synchronous accuracy, and raise SNR after system demodulation. Not need of adding training sequence, but using characteristic of signal itself, the method increases down going synchronous accuracy of system, and raises communication quality of system of service code channel in environment of multiple paths.

Description

technical field [0001] The present invention relates to a code division multiple access communication system, more precisely relates to a method for synchronizing downlink service code channels of a code division multiple access wireless communication system (CDMA) using smart antenna technology. Background technique [0002] No. 97118934.X Chinese patent titled "Method for Establishing and Maintaining a Synchronous Code Division Multiple Access Communication Link" discloses a method for establishing and maintaining a Synchronous Code Division Multiple Access Communication System (SCDMA) link, which includes In order to achieve synchronization, the terminal adopts a processing method for downlink signals. This method completely relies on the detection of the synchronization header to realize the synchronization of the downlink service code channel. In the electromagnetic propagation environment with sparse buildings, or in the application of fixed wireless access with line ...

Claims

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Application Information

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IPC IPC(8): H04B7/26
Inventor 李一鸣丁勇谢海燕
Owner BEIJING XINWEI TELECOM TECH
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