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Unsupervised adaptive chip separation filter for CDMA terminal

An adaptive, splitter technology used in the field of communication systems

Inactive Publication Date: 2002-05-08
NOKIA MOBILE PHONES LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Unfortunately, this precludes their application to systems employing long pseudonoise (PN) scrambling codes, which change the correlation properties of the signal from one symbol interval to another

Method used

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  • Unsupervised adaptive chip separation filter for CDMA terminal
  • Unsupervised adaptive chip separation filter for CDMA terminal
  • Unsupervised adaptive chip separation filter for CDMA terminal

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Embodiment Construction

[0027] As mentioned above, in a synchronous CDMA downlink using orthogonal codes, multiple access interference (MAI) is basically generated by multipath channels, therefore, MAI can be suppressed by linear channel equalization, a channel equalizer algorithm The receiver of is disclosed, which implements linear inter-chip interference cancellation through adaptive chip separation. This method is suitable for systems using long code scrambling, such as the proposed third generation wideband CDMA system. The results are shown below, providing a considerable performance gain when compared to a conventional RAKE receiver.

[0028] In one aspect of the present invention, a CDMA terminal space-time adaptive receiver structure is disclosed for the downlink of a CDMA system using long code scrambling. The receiver's ability to suppress MAI is based on the equalization of multipath channel effects, which essentially restores the orthogonality between different users. The rules for ada...

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Abstract

A receiver for use in a CDMA telecommunications system is disclosed. The receiver includes at least one antenna for receiving signals from a CDMA channel, where the received signals include a desired user signal. The receiver also includes combining circuitry, for performing chip waveform filtering and maximal ratio combining, to produce mutually correlated chip estimates of the received signals. The receiver further includes an adaptive separator, for adaptively separating the mutually correlated chip estimates, and a correlator, for despreading the output of the adaptive separator to obtain an estimate for data symbols of the desired user signal. In addition, the receiver further includes estimating circuitry, coupled to the combining circuitry, for estimating a response of the channel, where the combining circuitry utilizes the channel response estimate as a reference.

Description

field of invention [0001] The present invention generally relates to communication systems, and in particular to a receiver for realizing adaptive channel equalization. Background of the invention [0002] The CDMA system is based on a digital, wideband, spread spectrum technique that transmits multiple independent user signals over allocated frequency bands of the radio spectrum. In CDMA, each user signal includes a different orthogonal code and a pseudo-random binary sequence, which modulate the carrier and expand the spectrum of the waveform, so that a large number of user signals can share the same frequency spectrum. The user signals are separated in the receiver using a correlator so that only the signal with the chosen orthogonal code can be despread. Other user signals whose codes do not match are not despread and therefore contribute to system noise. The signal-to-noise ratio of the system is determined by the ratio of the desired signal power enhanced by the syst...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B1/707H04B7/08H04L25/03
CPCH04L2025/03401H04B1/7097H04B7/0857H04B1/7093H04B1/7115H04L2025/03477H04B1/7103H04L2025/03617
Inventor P·科穆莱宁M·海基莱
Owner NOKIA MOBILE PHONES LTD