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Method and apparatus for compensating for phase noise of symbols spread with a long spreading code

A technology of phase noise and spreading codes, which is applied in the field of code division multiple access wireless communication systems, and can solve problems such as unreflective channel quality

Inactive Publication Date: 2008-03-12
INTERDIGITAL TECH CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, phase noise can affect signal-to-interference ratio measurements made for signals with different spreading factors by different amounts
Therefore, channel quality indicator measurements based on shared pilot channels may not reflect the channel quality seen by high-speed physical downlink shared channels

Method used

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  • Method and apparatus for compensating for phase noise of symbols spread with a long spreading code
  • Method and apparatus for compensating for phase noise of symbols spread with a long spreading code

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Embodiment Construction

[0011] The inventive features may be incorporated into an integrated circuit (IC) or configured in a circuit comprising a plurality of interconnected components.

[0012] The present invention can be applied to any wireless communication system, including but not limited to 3rd Generation Partnership Project (3GPP) system. Hereinafter, the present invention will be described with reference to the shared pilot channel and the high-speed physical downlink shared channel. However, it should be noted that the reference of the shared pilot channel SIR and the high-speed physical downlink shared channel is used to illustrate the present invention, and the present invention can be applied to any other channel using any spreading factor.

[0013] 1 is a block diagram of a receiver 100 that compensates for phase noise associated with spread data with long spreading codes in accordance with the present invention. The receiver 100 includes a first despreader 102, a constellation correct...

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Abstract

A method and apparatus for compensating for phase noise of symbols spread with a long spreading code are disclosed. To compensate for the phase noise, a phase error estimate is generated from despread symbols with a short spreading code. A phase correcting phasor is applied to chip rate data before despreading the data with a long spreading code. A signal-to-interference ratio (SIR) on a common pilot channel (CPICH) may be calculated by spreading the data with a parent spreading code in an orthogonal variable spreading factor (OVSF) code tree and by combining symbols. Alternatively, a magnitude of the symbols may be used in estimating the SIR. The SIR of a channel using a short spreading code and an SIR of a channel using a long spreading code are measured. The SIR of the channel with the long spreading code may be compensated in accordance with a difference between degradation of the SIRs.

Description

technical field [0001] The present invention relates to a Code Division Multiple Access (CDMA) wireless communication system. More particularly, the present invention relates to a method and apparatus for compensating symbol phase noise with long spreading codes. Background technique [0002] In CDMA systems using different spreading code lengths, if receiver imperfections such as phase noise are characterized as varying over time, such as phase noise on the scale of spreading code lengths, the imperfections are likely when long spreading codes are used Degrades more transmissions than when short spreading codes are used. For example, in a Universal Mobile Telecommunications System (UMTS) Frequency Division Duplex (FDD) system, the spreading code may change from 4 to 512 chips. [0003] In third generation (3G) High Speed ​​Downlink Packet Access (HSDPA) systems, Adaptive Coding and Modulation (AMC) is based on Channel Quality Indicator (CQI) estimated by Wireless Transmit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B7/216
Inventor P·J·佩特拉斯基M·贝露里R.杨A·V·俊巧利K·P·凯尔内
Owner INTERDIGITAL TECH CORP