Method for detecting precode sequence and precode detector

A preamble and detector technology, applied in the field of signal demodulation, can solve problems such as code sequence changes and no prior information of code sequence

Inactive Publication Date: 2005-04-06
LUCENT TECH INC
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  • Abstract
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Problems solved by technology

Additionally, the receiver has no a priori information about the code sequences used, and the possible code sequences change frequently
Thus, the ortho

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  • Method for detecting precode sequence and precode detector
  • Method for detecting precode sequence and precode detector
  • Method for detecting precode sequence and precode detector

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Embodiment Construction

[0041] According to the present invention, a Code Division Multiple Access (CDMA) preamble detector applies a Fast Orthogonal Gold Transform (FOGT) to a received spread spectrum signal for either of the despreading and preamble signature sequence detection processes. Implementations operating in accordance with the present invention allow for simpler detection circuitry. The detection of the preamble sequence enables fast detection and demodulation of data signals in a channel randomly accessed by multiple users in a CDMA telecommunication system, such a channel may be, for example, according to the Wideband-CDMA (W-CDMA) standard Random Access Channel (RACH) of the operating system.

[0042] For the exemplary implementation of the invention described below, a CDMA receiver detects the preamble portion of a Random Access Channel (RACH) burst, although the techniques described here are readily applicable to other CDMA applications. The RACH bursts may be as shown in Figures 1A...

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Abstract

The invention relates to a method of detecting a precode sequence of a group of precode sequence in a spread frequency signal, including following steps: (a) correlating the received spread frequency signal with the aggregate sequence of a first orthogona gold code (OGC) to provide precode signal; (b) according to the second quick switching method, correlating the precode signal with the precode sequences to generate a group index value; (c) according to this group index value, forming decisive statistic; (d) selecting the precode sequence corresponding to the decisive statistic as detecting precode sequence of the precode sequence in this group.

Description

technical field [0001] The present invention relates to signal demodulation in Code Division Multiple Access (CDMA) communication systems, and more particularly to code sequence despreading and preamble detection in CDMA receivers. Background technique [0002] In a wireless, cellular, or similar Code Division Multiple Access (CDMA) telecommunications system, a plurality of channels are defined for uplink (user to base station) and downlink (base station to user) communications. Typically, each channel includes a spread spectrum signal synchronized to a common timing reference. The pilot signal is an unmodulated code sequence that is transmitted throughout the system for the synchronization (in terms of time and code phase) of the various code sequences. The pilot signal is spread (modulated) and despread (demodulation) operation use. The channel signal may be spread in frequency by utilizing pseudorandom (PN) and / or orthogonal code sequences. [0003] The signal transmit...

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Application Information

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IPC IPC(8): H04B1/707H04B7/26
CPCH04B1/707H04J13/12H04B1/7075
Inventor 戴维·L·巴图劳尔潘特利斯·莫诺勾迪斯
Owner LUCENT TECH INC
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