WO2001035541A2 - Procede de decodage d'un signal code en etalement et dispositif de decodage correspondant - Google Patents

Procede de decodage d'un signal code en etalement et dispositif de decodage correspondant Download PDF

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Publication number
WO2001035541A2
WO2001035541A2 PCT/DE2000/003893 DE0003893W WO0135541A2 WO 2001035541 A2 WO2001035541 A2 WO 2001035541A2 DE 0003893 W DE0003893 W DE 0003893W WO 0135541 A2 WO0135541 A2 WO 0135541A2
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WO
WIPO (PCT)
Prior art keywords
transmission channel
sequence
spreading
spread
channel
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/DE2000/003893
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German (de)
English (en)
Other versions
WO2001035541A3 (fr
Inventor
Jürgen MICHEL
Bernhard Raaf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
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 Siemens AG, Siemens Corp filed Critical Siemens AG
Publication of WO2001035541A2 publication Critical patent/WO2001035541A2/fr
Publication of WO2001035541A3 publication Critical patent/WO2001035541A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/0007—Code type
    • H04J13/004—Orthogonal

Definitions

  • the present invention relates to a method for decoding a spread-coded signal according to the preamble of claim 1 and a corresponding decoding device, in particular for use in a mobile radio receiver, according to the preamble of claim 13.
  • T N - T C.
  • T denotes the duration of a data symbol to be transmitted
  • T c denotes the so-called chip duration of the spreading sequence.
  • the chip duration T c is significantly shorter than the symbol duration T, so that an ideally white broadband is used due to the spread coding
  • Transmitted signal is obtained, which is transmitted to a receiver via a multi-way channel and detected there.
  • orthogonal spreading sequences or spreading codes which are also referred to as channelization codes, are used for spreading the data symbols to be transmitted.
  • a specific spreading sequence is assigned to each participant.
  • the present invention has for its object to provide an improved method for decoding spread-coded signals and a corresponding decoding device, with the help of which the effort in despreading can be reduced by the effective use of shortened (de) spreading sequences.
  • a continuously transmitted transmission channel for example a pilot channel
  • a data sequence spread with a fixed spreading sequence or a fixed channelization code is transmitted, which is preferably known.
  • this transmission channel can be formed by the CPICH channel ("Common Pilot Indicator Channel").
  • the present invention is based on the fact that the data of a further transmission channel, for example a broadcast control channel (BCCH) or a paging channel, are spread with a spreading sequence which has the same spreading factor as the spreading sequence of the first-mentioned continuously transmitted transmission channel and about this spreading sequence is complementary.
  • This additional transmission channel can then be decoded in the receiver by multiplication or correlation with the corresponding shortened spreading sequence and subsequent integration.
  • a corresponding correction is carried out in the receiver using the previous knowledge via the first-mentioned transmission channel, with in particular knowledge of the known data sequence of the continuously transmitted transmission channel and the transmission power ratio between the two both transmission channels is used.
  • the use of the shortened (de) spreading sequence can significantly reduce the effort involved in despreading a received signal, so that in particular in the sleep mode of a mobile station when decoding one or more transmission channels with a preferably constant spreading factor, such as, for example, in UMTS, broadcast control - or the paging channel, the power consumption reduced and the efficiency can be increased.
  • the power saving is particularly important in the paging mode of a mobile station, since it contributes directly to the extension of the standby time of the mobile station.
  • the present invention is particularly suitable for decoding downlink channels, i.e. of transmission channels which are directed from a base station to a mobile station in DS-CDMA ("Direct Sequence Code Division Multiple Access") mobile radio systems, such as, for example, a UMTS mobile radio system.
  • DS-CDMA Direct Sequence Code Division Multiple Access
  • Fig. 1 shows a simplified block diagram of a transmitter and a receiver of a DS-CDMA mobile radio system according to the invention
  • FIG. 2 shows a code tree for DS-CDMA mobile radio systems, in which the usable orthogonal spreading sequences are given for different spreading factors.
  • 1 schematically shows the structure of the section of a section which contributes to the coding or spreading of transmission data
  • Transmitter 1 shown in a DS-CDMA mobile radio system which is in particular the transmitter of a base station.
  • the channel-specific spreading sequence d (t) is generated by a corresponding code generator 3.
  • Multiplication by the spreading sequence results in a band-spread, ie broadband, transmission signal S ⁇ (t) which is modulated onto a carrier signal cos ( ⁇ D t) by a modulator 4.
  • filtering is carried out with the aid of a bandpass filter 5 and the transmission power is adjusted with the aid of a power amplifier 6.
  • the transmission signal is then transmitted to a receiver 7.
  • 1 schematically shows the structure of the section of the receiver 7 of a DS-CDMA mobile station that contributes to decoding or despreading.
  • a bandpass filter 8 for selection and noise reduction is initially located at the receiver input.
  • the bandpass filter 8 is followed by a de odulator 9 which transforms the received signal s (t) back into the baseband.
  • this may require a synchronous regeneration of the carrier signal cos ( ⁇ D t), which is usually implemented with a phase locked loop 10 ("phase locked loop", PLL).
  • phase locked loop phase locked loop
  • the despreading is started as soon as a bit or symbol with the chip length M-T c (M ⁇ N) transmitted using the DS-CDMA band spreading technique has been received. If the signal-to-noise ratio is sufficient, the original transmission sequence d t () can be obtained in a unit 11 by correlation with the shortened channel-specific spreading sequence c'i (t) provided by a spreading code generator 12, which has the length M-T c. t) complete again ) c ⁇ r M t->P>
  • At least one continuously transmitted transmission channel B is present, for example the pilot channel of a base station transmitted via a downlink, the data sequence of which is known and which is spread with a fixed spreading sequence.
  • the data sequence of this transmission channel B can be transmitted, for example, with a transmitter 1 of the type shown in FIG. 1.
  • a spreading sequence c ⁇ (t) is used for a further transmission channel A for spreading, which is complementary to the spreading sequence used for the previously described transmission channel B
  • the de-spreading of this transmission channel A in a receiver 7 of the type shown in FIG. 1 can be effective through the correlation with the shortened spreading sequence c'i (t) and subsequent integration if the influence of the transmission channel B complementary and continuously transmitted to the transmission channel A is compensated in the receiver 7 with the aid of a compensation unit 14.
  • the compensation is particularly dependent on the Previous knowledge of the known data sequence transmitted via the transmission channel B and the known power ratio between the transmission channels A and B are carried out. Depending on this information, a corresponding value can be added to or subtracted from the output signal of the integrator 13 in the compensation unit 14.
  • Compensation unit 14 is always such that the influence of the complementary transmission channel B can be minimized or even completely eliminated.
  • the principle described above is advantageous, for example, for the despreading and decoding of transmission channels A which have a constant transmission power ratio to the continuously transmitted transmission channel B.
  • the invention is advantageously applicable for the despreading and decoding of broadcast and paging channels.
  • a signal from a base station is transmitted via these channels to several mobile stations located in one and the same radio cell. To ensure that this signal can be received by all mobile stations, it must be transmitted by the base station at a relatively high power. However, most mobile stations are in a more favorable position and can use the method described above. Power saving is particularly important in paging mode because it directly increases the standby time. The result of this is that an A / D converter on the receiving side (not shown in FIG. 1) and the correlators 11 required for despreading are intermittent in the receiver CO CO tr P 1 P 1 no Cn o cn ⁇ Cn

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Error Detection And Correction (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé permettant de décoder une séquence de bits de réception (s(t)) d'un premier canal de transmission (A), qui repose sur un codage d'étalement d'une séquence de données (di(t)) avec une première séquence d'étalement (ci(t)). Cette séquence de bits de réception est corrélée avec une séquence de désétalement (c'i(t)) raccourcie dérivée de la première séquence d'étalement et est ensuite intégrée. De plus, en fonction des informations connues sur au moins un deuxième canal de transmission (B) par l'intermédiaire duquel sont transmis des bits codés avec une seconde séquence d'étalement complémentaire de la première séquence d'étalement (ci(t)), une correction est effectuée afin de compenser l'influence du deuxième canal de transmission (B) sur le premier canal de transmission (A).
PCT/DE2000/003893 1999-11-11 2000-11-07 Procede de decodage d'un signal code en etalement et dispositif de decodage correspondant Ceased WO2001035541A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19954341 1999-11-11
DE19954341.0 1999-11-11

Publications (2)

Publication Number Publication Date
WO2001035541A2 true WO2001035541A2 (fr) 2001-05-17
WO2001035541A3 WO2001035541A3 (fr) 2002-05-10

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PCT/DE2000/003893 Ceased WO2001035541A2 (fr) 1999-11-11 2000-11-07 Procede de decodage d'un signal code en etalement et dispositif de decodage correspondant

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WO (1) WO2001035541A2 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1261144A1 (fr) * 2001-05-25 2002-11-27 Telefonaktiebolaget L M Ericsson (Publ) Méthode et système pour l'optimisation de la longueur d'une fenêtre de recherche
WO2002098009A1 (fr) * 2001-05-25 2002-12-05 Telefonaktiebolaget L M Ericsson (Publ) Procede et systeme permettant d'optimiser la longueur d'une fenetre de recherche
US7263119B1 (en) 2001-11-29 2007-08-28 Marvell International Ltd. Decoding method and apparatus
US7324433B1 (en) 2001-11-29 2008-01-29 Marvell International Ltd. Method and apparatus for determining signal quality

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09148980A (ja) * 1995-11-22 1997-06-06 Sony Corp パイロット信号検出方法、パイロット信号検出装置及び移動局受信装置
IL120538A (en) * 1997-03-26 2000-11-21 Dspc Tech Ltd Method and apparatus for reducing spread-spectrum noise
EP0930723A3 (fr) * 1998-01-14 2003-07-30 Yozan Inc. Système cellulaire à accès multiple par répartition de code à séquence directe

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1261144A1 (fr) * 2001-05-25 2002-11-27 Telefonaktiebolaget L M Ericsson (Publ) Méthode et système pour l'optimisation de la longueur d'une fenêtre de recherche
WO2002098009A1 (fr) * 2001-05-25 2002-12-05 Telefonaktiebolaget L M Ericsson (Publ) Procede et systeme permettant d'optimiser la longueur d'une fenetre de recherche
US7263119B1 (en) 2001-11-29 2007-08-28 Marvell International Ltd. Decoding method and apparatus
US7324433B1 (en) 2001-11-29 2008-01-29 Marvell International Ltd. Method and apparatus for determining signal quality
US7606296B1 (en) 2001-11-29 2009-10-20 Marvell International Ltd. Decoding method and apparatus
US7701871B1 (en) 2001-11-29 2010-04-20 Marvell International Ltd. Method and apparatus for determining signal quality
US7746925B1 (en) 2001-11-29 2010-06-29 Marvell International Ltd. Decoding method and apparatus
US8059707B1 (en) 2001-11-29 2011-11-15 Marvell International Ltd. Decoding method and apparatus

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WO2001035541A3 (fr) 2002-05-10

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