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WO2003007565A1 - Systele de traitement prealable pour l'egalisation de canal de communication - Google Patents

Systele de traitement prealable pour l'egalisation de canal de communication Download PDF

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Publication number
WO2003007565A1
WO2003007565A1 PCT/KR2001/001334 KR0101334W WO03007565A1 WO 2003007565 A1 WO2003007565 A1 WO 2003007565A1 KR 0101334 W KR0101334 W KR 0101334W WO 03007565 A1 WO03007565 A1 WO 03007565A1
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WO
WIPO (PCT)
Prior art keywords
response
output
difference
channel
subtraction unit
Prior art date
Application number
PCT/KR2001/001334
Other languages
English (en)
Inventor
Chang-Bok Joo
Ki-Yeul Han
Original Assignee
Chang-Bok Joo
Ki-Yeul Han
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chang-Bok Joo, Ki-Yeul Han filed Critical Chang-Bok Joo
Publication of WO2003007565A1 publication Critical patent/WO2003007565A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/01—Equalisers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/005—Control of transmission; Equalising
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference

Definitions

  • the present invention relates to a preprocessing system for a communication channel equalization, and in particular to a preprocessing system for a communication channel equalization which is capable of forming symmetric upper and lower bridge circuits based on an absolute value circuit and a low pass filter(LPF) in a channel equalization of a wire/wireless communication, emphasizing a magnitude of a direct wave response portion and suppressing a magnitude of a multi-pass response portion in a channel equalization pre-stage for thereby implementing a channel equalization with respect to a wire or wireless communication channel in which a channel equalization is not available because an impulse response characteristic exceeds an equalization range of a channel equalizer.
  • LPF low pass filter
  • a wire or wireless communication system includes a transmitter 10, a communication channel 20 which is a signal transmission path and a receiver 30.
  • the receiver 30 includes a channel equalizer 40 for compensating an impulse response characteristic of the communication channel 20 and a signal detector 50 for detecting and recovering a transmitted signal.
  • the receiving signal when a transmitted signal of the transmitter 10 is received into the receiver 30 throughout the communication channel 20 without any interference, the receiving signal has a stable transmission signal shape.
  • the receiver 30 since the receiver 30 receives a direct wave as well as a time delayed multipass wave, namely, a multi-path signal due to a reflection signal effect by various objects, the receiving signal shape may be largely changed. In this case, it is impossible to detect and recover the transmission signal in the receiver 30.
  • the above-described channel equalizers are designed for the communication channel having a limited characteristic of a certain range.
  • the channel equalization is performed with respect to a wire or wireless communication channel in which an impulse response characteristic which represents a signal transmission characteristic of a communication channel is included in an equalization range of a channel equalizer, and the channel equalization is not performed with respect to the wire or wireless communication channel which exceeds the equalization range of the channel equalizer due to a bad communication channel environment.
  • the wire/wireless communication system in order to perform a reliable, high quality and high speed communication, it is needed to effectively control the multi-pass wave.
  • the multi-pass wave which causes a long time delay spread phenomenon due to various reflections of objects and a reflection effect by a load operation or termination based on various electric or electronic equipments makes the communication unavailable in the case of the communication channel like a mobile communication or a power line communication.
  • an object of the present invention to provide a preprocessing system for a communication channel equalization which overcomes the problems encountered in the conventional art. It is another object of the present invention to provide a preprocessing system for a communication channel equalization which is capable of implementing a channel equalization by forming an absolute value circuit , a LPF and symmetric upper and lower bridge circuits based on the features that an impulse response of a communication channel is represented as a direct wave response portion and a time delayed multi-pass wave response portion in a wire/wireless communication system, decreasing a delay spread due to a multipass in a channel equalization pre-stage, largely generating a response speed between the LPF having different frequency bandwidths, namely, an gradient difference of a response function, emphasizing a magnitude of a first response portion corresponding to a direct wave response portion among the impulse responses of the communication channel and suppressing the magnitude of the multi-pass wave response portion for a wire or wireless communication channel in which the impulse response characteristic exceeds an equalization range of the channel equalizer
  • a preprocessing system for a entire communication channel equalization which is characterized in that the direct wave response portion in an impulse response characteristic of a channel is enhanced using a difference between filter outputs of different response speeds which represents an gradient of a response function, after removing a negative time portion or a positive time portion for suppressing a magnitude of a multi-pass wave response portion and reducing a range of a multipass wave response time portion in an impulse response of a channel.
  • Figure 1 is a block diagram illustrating the construction of a transmission system of a communication
  • Figure 2 is a view illustrating a channel equalizer which includes a channel equalization preprocessing system
  • Figure 3 is a view illustrating the construction of a channel equalization preprocessing system according to the present invention.
  • Figure 4 is a view illustrating an impulse response characteristic of a channel equalization preprocessing system according to the present invention
  • Figure 5 is a view illustrating an impulse response of each element of Figure 3 in a communication channel in which a receiving signal detection is impossible;
  • Figure 6 is a view illustrating an impulse response of each element of Figure 3 in a communication channel in which there is an error when detecting a receiving signal
  • Figure 7 is a view illustrating an impulse response of each element of Figure 3 in a communication channel which has a better impulse response characteristic.
  • Figure 2 is a view illustrating a channel equalizer having a channel equalization preprocessing system according to the present invention.
  • a channel equalization preprocessing system 400 according to the present invention is installed in the channel equalizer 40 for thereby implementing a channel equalization with respect to a wire or wireless communication channel in which a channel equalization is impossible.
  • FIG. 3 is a block diagram illustrating a channel equalization preprocessing system according to the present invention.
  • an absolute value circuit 401 for removing a negative time portion or a positive time portion with respect to an input for limiting a multi-pass response portion among the impulse responses of the communication channel 20
  • a summing unit 404 for summing a response output by a LPF1 402 of a frequency bandwidth f ⁇ Hz] and a response output by a LPF2 403 of the same pass bandwidth
  • an upper bridge circuit 410 for obtaining a difference between an output from the summing unit 404 and a lower bridge circuit which feeds back through a first feedback gain unit 416, passing a response output based on the response output through the LPF having different pass bandwidths
  • a lower bridge circuit 420 for obtaining a difference between the output from the summing unit 404 and a response output of the upper bridge circuit 410, passing the response output based on the difference through the LPF having different pass bandwidths, obtaining a difference of
  • the upper bridge circuit 410 includes a first subtraction unit 411 for obtaining a difference between an output from the summing unit 404 and a response output of the lower bridge circuit 420 fed back through a first feedback gain unit, a second subtraction unit 414 for inputting an output of the first subtraction unit 411 into a third LPF 412 of the pass bandwidth f ⁇ Hz] and the fourth LPF 413 of the pass bandwidth f 2 Hz] of the parallel structure and obtaining a difference between a response output of the third LPF 412 and a response output of the fourth LPF 413, a first bridge gain unit 415 for providing an output
  • the lower bridge circuit 420 which is symmetric with respect to the upper bridge circuit 410 includes a third subtraction unit 421 for obtaining a difference between an output from the summing unit 404 and a response output of the upper bridge circuit 410 which is fed back through the second feedback gain unit, a fourth subtraction unit 424 for inputting an output from the third subtraction unit 421 into a fifth LPF 422 of the pass bandwidth f ⁇ Hz] and a sixth LPF 423 of the pass bandwidth f 3 [Hz] of the parallel structure, a second bridge gain unit 425
  • the relationship of f ⁇ Hz], f 2 [Hz] and f 3 [Hz] is f 2 ⁇ f, ⁇ f 3
  • the magnitude of the gain of the first and second feedback gain units 416 and 426 is
  • the channel equalization preprocessing system removes a negative time portion or a positive time portion from the impulse response of the communication channel and reduce the range of the multi-pass response time portion for thereby decreasing a delay spread due to the multi-pass.
  • the magnitude of the first response portion corresponding to a response portion of the direct wave from the impulse response of the communication channel by largely generating a response speed difference of the upper and lower bridge circuits 410 and 420, namely, an gradient difference of the impulse response function through the symmetric upper and lower bridge circuits 410 and 420 formed of the third LPF 412 and the fourth LPF 413 having the different pass bandwidths f ⁇ Hz] and f 2 [Hz] and the fifth LPF 422 and sixth LPF 423 having different pass bandwidths f ⁇ Hz] and f 3 [Hz].
  • the channel equalization preprocessing system according to the present invention formed using the absolute value circuit and the LPF for reducing the range of response time portion of the multi-pass wave and the magnitude thereof using a response speed difference between the filters having different pass bandwidths implements a channel equalization in the channel equalizer with respect to the communication channel in which the range of the channel equalization is exceeded by the impulse response characteristic.
  • the band pass filter(BPF) may be used instead of the first through sixth LPF 402 through 423.
  • the absolute value circuit 401 for reducing the range of the multi-pass wave response portion among the impulse responses of the communication channel inputted through the communication channel 20 of the wire/wireless communication system removes a negative time portion or a positive time portion.
  • a sum value of a response output based on the first LPF 402 having a pass bandwidth of f ⁇ Hz] which passes an output of the absolute value circuit 401 through the first summing unit 404 and a response output based on the second LPF 403 having the same pass bandwidth f ⁇ Hz] as the first LPF 402 which passes an impulse response of the communication channel is obtained.
  • the upper and lower bridge circuits 410, 420 are operated.
  • the first subtraction unit 411 obtains a difference between an output from the summing unit 404 and an output of the fourth subtraction unit 424 of the lower bridge circuit 420 fed back through the first feedback gain unit 416.
  • the first feedback gain unit 416 provides an output from the fourth
  • the first bridge gain unit 415 provides an output from the second
  • the lower bridge circuit 420 having the structure symmetrical to the upper bridge circuit 410 operates in the same method as the upper bridge circuit 410. Namely, a difference between an output from the summing unit 404 and an output of the second subtraction unit 414 of the upper bridge circuit 410 fed back through the second feedback gain unit 426.
  • the second feedback gain unit 426 provides an output from the
  • a difference between a response output based on the fifth LPF 422 having a frequency bandwidth of a f ⁇ Hz] which passes through an output of the third subtraction unit 421 through the fourth subtraction unit 424 and a response output based on the sixth LPF 423 having a pass bandwidth of a f 3 [Hz] of the parallel structure which passes through an output of the third subtraction unit 421 is obtained.
  • An output based on the difference is outputted to the second bridge gain unit 425.
  • the fifth subtraction unit 430 obtains a difference between a response output outputted through the first bridge gain unit 415 of the upper bridge circuit 410 and a response output outputted through the second bridge gain unit 425 of the lower bridge circuit 420 and largely emphasize a magnitude of the response output corresponding to a direct wave response portion in the impulse response of the communication channel and outputs an impulse response of the communication channel which suppressed the magnitude of a multi-pass wave response portion and reduced the range of a multi-pass wave response time portion in an impulse response of a channel to the channel equalizer 40.
  • Figure 5 is a view illustrating a response output of each element of Figure 3 in the case that the communication channel which can not detect a receiving signal since the equalization range of the channel equalizer is largely deviated
  • Figure 6 is a view illustrating an impulse response of each element of Figure 3 in a communication channel in which there is an error when detecting a receiving signal
  • Figure 7 is a view illustrating an impulse response of each element of Figure 3 in a communication channel which has a better impulse response characteristic.
  • each of Figures 5, 6 and 7 represents an impulse response of a corresponding communication channel
  • (b) of each of the same represents a response output of the first LPF 402
  • (c) of each of the same represents a response output of the second LPF 403
  • (d) of each of the same represents an output of the summing unit 404
  • (e) of each of the same represents an output of the second subtraction unit 414 of the upper bridge circuit 410
  • (f) of each of the same represents an output of the fourth subtraction unit 424 of the lower bridge circuit 420
  • (g) of each of the same represents a last impulse response outputted from the fifth subtraction unit 430.
  • a negative time delay portion is removed as a result of the check of the impulse response outputted from the summing unit 404, and as shown in (g) of Figure 5, the direct wave response portion among the impulse response of the communication channel is clear as a result of the check of the last impulse response outputted from the fifth subtraction unit 430 and the magnitude of the same is emphasized, and the magnitude of the multi-pass response portion is largely suppressed.
  • a negative time delay portion is removed as a result of the check of the impulse response outputted from the summing unit 404 like the embodiment of Figure 5, and the direct wave response portion among the impulse response of the communication channel is clear as a result of the check of the last impulse response outputted from the fifth subtraction unit 430 as shown in (g) of Figure 6, and the magnitude of the same is emphasized, and the magnitude of the multi-pass response portion is largely reduced.
  • the direct wave response portion among the impulse response of the communication channel is more clear as a result of the check of the last impulse response outputted from the fifth subtraction unit 430 like the embodiments of Figures 5 and 6 for thereby obtaining a typical impulse response characteristic of the communication channel.
  • the channel equalization preprocessing system it is possible to implement a channel equalization with respect to the wire/wireless communication channel in which the channel equalization is impossible since the impulse response characteristic largely exceeds the equalization range of the channel equalizer by forming the absolute value circuit and upper and lower symmetric bridge circuits with LPF having different frequency bandwidth, emphasizing the magnitude of the direct wave response portion in the channel equalization pre-stage and suppressing the multi-pass wave response portion and reducing the range of the multi-pass wave response time portion.
  • the channel equalization preprocessing system it is possible to perform a reliable and high quality high speed power line communication and mobile communication in which the impulse response characteristic of the communication channel is bad due to the multi-pass wave by improving the impulse response characteristic of the communication channel having the multi-pass wave.
  • the present invention may be well adapted to various wire/wireless transmission apparatus and system, a high speed power line transmission apparatus, a home network system, etc.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)

Abstract

La présente invention concerne un système de traitement préalable pour l'égalisation d'un canal de communication qui se caractérise en ce qu'une caractéristique de réponse en impulsion d'un canal est renforcée par utilisation d'une différence entre les sorties de filtre de différentes vitesses de réponse représentant un gradient d'une fonction de réponse en impulsion, par enlèvement d'une partie de temps négative ou d'une partie de temps positive pour donner de l'importance à une grandeur d'une partie de réponse d'onde directe et pour supprimer une grandeur d'une partie de réponse d'onde plusieurs passages dans une réponse en impulsion d'un canal de façon à mettre en oeuvre une égalisation de canal en formant un circuit à valeur absolue, un filtre passe-bas et des circuits ponts supérieurs et inférieurs symétriques reposant sur des caractéristiques faisant qu'une réponse en impulsion est représentée sous forme d'une partie de réponse d'onde directe et d'une partie de réponse plusieurs passage retardée d'une période dans une égalisation de canal d'un système de communication filaire ou radio.
PCT/KR2001/001334 2001-07-10 2001-08-06 Systele de traitement prealable pour l'egalisation de canal de communication WO2003007565A1 (fr)

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Application Number Priority Date Filing Date Title
KR1020010041097A KR20030005700A (ko) 2001-07-10 2001-07-10 채널등화 전처리 시스템
KR2001/41097 2001-07-10

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CN113131899A (zh) * 2019-12-31 2021-07-16 深圳市大富科技股份有限公司 一种用于拓展耦合器带宽的电路以及一种移动通信设备

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KR100826919B1 (ko) * 2006-12-08 2008-05-06 한국전자통신연구원 무선통신 시스템에서 등화 장치 및 그 방법

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113131899A (zh) * 2019-12-31 2021-07-16 深圳市大富科技股份有限公司 一种用于拓展耦合器带宽的电路以及一种移动通信设备

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