WO2004077713A1 - Procede et dispositif d'estimation d'une frequence porteuse - Google Patents

Procede et dispositif d'estimation d'une frequence porteuse Download PDF

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Publication number
WO2004077713A1
WO2004077713A1 PCT/CN2003/000145 CN0300145W WO2004077713A1 WO 2004077713 A1 WO2004077713 A1 WO 2004077713A1 CN 0300145 W CN0300145 W CN 0300145W WO 2004077713 A1 WO2004077713 A1 WO 2004077713A1
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WO
WIPO (PCT)
Prior art keywords
frequency
oscillator
calculate
subframe
control word
Prior art date
Application number
PCT/CN2003/000145
Other languages
English (en)
Chinese (zh)
Inventor
Chen Ji
Jingbo Liu
Original Assignee
Linkair Communications,Inc.
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 Linkair Communications,Inc. filed Critical Linkair Communications,Inc.
Priority to PCT/CN2003/000145 priority Critical patent/WO2004077713A1/fr
Priority to CN03807993.3A priority patent/CN1647430A/zh
Priority to AU2003211665A priority patent/AU2003211665A1/en
Publication of WO2004077713A1 publication Critical patent/WO2004077713A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L12/00—Data switching networks
    • H04L12/66—Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
    • 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
    • H04B1/7097—Interference-related aspects
    • H04B1/711—Interference-related aspects the interference being multi-path interference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0044—Control loops for carrier regulation
    • H04L2027/0063—Elements of loops
    • H04L2027/0065—Frequency error detectors

Definitions

  • the present invention belongs to the technical field of wireless communications, and particularly relates to the realization of carrier frequency estimation in a downlink synchronization subsystem of a CDMA system, and in particular, it relates to a carrier frequency estimation method and device.
  • phase synchronization can be accomplished with a channel estimator.
  • the mobile station must accurately control the frequency deviation between it and the base station within a certain range. Therefore, the mobile station must accurately estimate the frequency deviation between the mobile station and the base station.
  • the crystal in a mobile station is usually a few ppm, which produces a carrier frequency difference of a few KHz to a dozen KHz in the 2G band.
  • the initial synchronization process after the mobile station is powered on is:
  • Initial frame boundary detection A frame boundary of a cell may be detected
  • Initial carrier frequency acquisition Use the results of the first frame boundary detection to obtain the starting position of the downlink synchronization physical channel to achieve frequency acquisition and reduce the carrier frequency deviation from the range of ⁇ to less than 500Hz;
  • An object of the present invention is to provide a method and a device for estimating a carrier frequency, which are used to detect a frequency change of a crystal oscillator and a random Doppler frequency offset, and track VC0 or NC0 through correction The average offset is kept within an acceptable range.
  • a carrier frequency estimation method includes the following steps:
  • the despreading of the downlink continuous pilot channel symbol refers to: despreading the downlink continuous pilot channel symbol with a length of 128 chips.
  • the loop filter may include two configuration modes, and the two configuration modes may be referred to as configuration mode A and configuration mode B;
  • Configuration mode A is suitable for reducing the carrier frequency deviation from 500Hz to 100Hz; Configuration mode B is suitable for maintaining the carrier frequency deviation below 100Hz.
  • the use of the oscillator to read the frequency control word means that: a numerically controlled oscillator (NC0) can be used to read the frequency control word.
  • NC0 numerically controlled oscillator
  • a voltage-controlled oscillator such as a voltage-controlled crystal oscillator (VCX0) may be used to read the frequency control word.
  • the steps of the method according to the present invention may further include:
  • the loop filter may include a configuration mode A and a configuration mode B, where: the configuration mode A is suitable for reducing the carrier frequency deviation from 500 Hz to 100 Hz; the configuration mode B is suitable for maintaining the carrier frequency deviation below 100 Hz Happening.
  • a numerically controlled oscillator (NC0) can be used to read the frequency control word.
  • the steps of loop control include:
  • the configuration mode A includes the following steps:
  • Step 1 There are a total of 16 time slots in each subframe, and a total of 15 phase rotations can be obtained by the difference between the front and rear time slots, which is calculated as [, ⁇ 2 ,-.- ⁇ 5 ];
  • Step 6 Repeat step 1.
  • the configuration mode B includes the following steps:
  • Step 1 There are a total of 16 time slots in each sub-frame, and a total of 15 phase rotations can be obtained by the difference between the front and back time slots, which is calculated as ⁇ 2 , ...- ⁇ 15 ;
  • Step 2 Rotate the phase [through the loop filter to get:
  • 3 ⁇ 4, ⁇ -, + 3 ⁇ 4 ⁇ Vl ⁇ i ⁇ 15;.
  • K is the loop bandwidth parameter,. 16 representing the previous subframe
  • Step 3 Correspond to the 16 time slots of the next subframe, generate the NC0 frequency in each time slot
  • Step 4 Repeat step 1.
  • the invention also provides a carrier frequency estimation device, which includes: a Rake receiver, a loop filter, and an oscillator; wherein:
  • the oscillator may be: a numerically controlled oscillator.
  • the oscillator may be: a voltage controlled oscillator.
  • the voltage-controlled oscillator may be: a voltage-controlled crystal oscillator.
  • the beneficial effect of the present invention is that, by providing a carrier frequency estimation method and device, the method is used to detect a frequency change of a crystal oscillator and a random Doppler frequency offset, and track the average offset thereof by correcting VC0 or NC0, The frequency difference remains within an acceptable range.
  • Figure 1 shows the frame structure of the TD-LAS system (up-down transmission ratio 1: 1);
  • FIG. 2 is a structural diagram of a downlink continuous pilot channel subframe
  • FIG. 3 is a block diagram of carrier frequency tracking. detailed description
  • the present invention provides a method and a device for estimating carrier frequency, and a TD-IS system is taken as an example in the following to describe the embodiments of the present invention in detail with reference to the accompanying drawings:
  • ⁇ « ⁇ frame ⁇ is shown in Fig. 1, and the uplink-downlink transmission ratio is 1: 1.
  • the sub-frame structure of the downlink continuous pilot channel is shown in Figure 2.
  • the downlink continuous pilot channels in different cells use different combinations of LS + LA codes.
  • the length of the LS code is 136, including the C code of 64chips and the S code of 64chips, and the 8cliips interval. There are 16 symbols in each sub-frame. 21 ⁇ 2s contains
  • the TD-LAS machine coherent detection is used in both the uplink and the downlink, which requires accurate carrier and phase synchronization between the MS and the BS.
  • the simulation shows that in the TD-LAS machine, in order to correctly demodulate the 16QAM signal, the carrier frequency difference is required to be less than 100Hz.
  • the crystal in a mobile station is usually a few ppm, which produces a carrier frequency difference of a few KHz to a dozen KHz in the 2G band.
  • the initial synchronization process after the mobile station is powered on is,
  • Initial frame boundary detection A frame boundary of a cell may be detected
  • Initial carrier frequency acquisition Use the results of the first frame boundary detection to obtain the starting position of the downlink synchronization physical channel to achieve frequency acquisition and reduce the carrier frequency deviation from the KHz range to less than 500Hz;
  • the carrier acquisition unit reduces the initial frequency difference to less than 500Hz-IKZ, and the cell identification unit obtains the LA + LS combination used by the cell.
  • the mobile station can use the downlink continuous pilot channel for carrier frequency tracking, reduce the remaining frequency difference to less than 100Hz, and meet the demodulation requirements.
  • the function of carrier frequency tracking is to detect the frequency change of the crystal oscillator and random Doppler frequency offset.
  • the average offset can be tracked by correcting VC0 or NC0 to keep the frequency difference within an acceptable range.
  • NC0 or VCX0 reads the frequency control word and generates the corresponding frequency
  • Td represents the time of one time slot.
  • Configuration method A is suitable for reducing the carrier frequency deviation from 500Hz to 100Hz
  • configuration method B is suitable for keeping the carrier frequency deviation below 100Hz.
  • Step 1 There are a total of 16 time slots in each subframe, and a total of 15 phase rotations can be obtained by the difference between the front and back time slots, which is calculated as ⁇ ⁇ 3 ⁇ 4 , ⁇ . ⁇ 5 ];
  • Step 2 Calculate the average phase rotation of the first sub-frame ⁇ +) / 15;
  • Step 3 Calculate the average phase rotation of the M subframes.
  • Parameter M is the number of subframes used to calculate the average phase rotation.
  • Step 5 After the M * _ / subframes are completed, calculate the NC0 frequency ⁇ /, and after that, until M * + 1) the subframe time, NC0 — generates the frequency until the M * (+ 2) subframe, NC0 frequency: ⁇ .
  • the initial frequency / Q is determined by the specific configuration of the downconversion
  • Step 6 Repeat step 1.
  • Step 1 There are a total of 16 time slots in each subframe, and a total of 15 phase rotations can be obtained by the difference between the front and rear time slots, which is counted as [ ⁇ ⁇ n];
  • Step 2 Rotate the phase 15 ] through the loop filter to get [ ⁇ , ⁇ ,. ⁇ ⁇ , ⁇ , where: ⁇ PIA ',
  • K is the loop bandwidth parameter, where ⁇ 3 ⁇ 4. ⁇ 3 ⁇ 4 ⁇ representing the last subframe;
  • Step 4 Repeat step 1.
  • Input The RAKE receiver despreads the value of D-PIPCH for each arm on each time slot.
  • Output It is used to adjust the frequency control word of NC0 or VCX0.
  • a beneficial effect of the present invention is that, by providing a method and a device for carrier tracking, which are used to detect a frequency change of a crystal oscillator and a random Doppler frequency offset, and track the average offset thereof by correcting VC0 or NC0, The frequency difference remains within an acceptable range.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Stabilization Of Oscillater, Synchronisation, Frequency Synthesizers (AREA)

Abstract

Cette invention concerne un procédé et un dispositif permettant d'estimer une fréquence porteuse. Cette démarche consiste : à démoduler des symboles de canal pilote vers l'avant les uns après les autres au niveau de chaque bras du récepteur Rake ; à multiplier la valeur démodulée par la conjugaison des valeurs antérieures relevées sur chaque bras du récepteur Rake ; à additionner la valeur de multiplication au niveau de chaque bras du récepteur Rake et obtenir un complexe z = AeiΖ dans laquelle Ζ équivaut à la rotation de phase des symbole successifs estimés ; à calculer Ζ = arctan (Im[z]/Re[z]) et déterminer la rotation de phase entre les symboles successifs ; à calculer le décalage de fréquence porteuse résiduelle Δf = (Ζ2πTd) dans lequelle T est la durée du symbole ;à transmettre Δf à un filtre de boucle pour le traitement et l'estimation de mots de commande de fréquence correspondants ; à utiliser un oscillateur commandé par numéro dans les mots de commande de fréquence pour générer une fréquence correspondante. Ce procédé et ce dispositif, qui sont utilisés pour la variation de fréquence d'un oscillateur à cristal et un décalage Doppler aléatoire, permettent de maintenir le décalage de fréquence dans un plage acceptable par correction de VCO ou NCO et d'y suivre le décalage.
PCT/CN2003/000145 2003-02-25 2003-02-25 Procede et dispositif d'estimation d'une frequence porteuse WO2004077713A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/CN2003/000145 WO2004077713A1 (fr) 2003-02-25 2003-02-25 Procede et dispositif d'estimation d'une frequence porteuse
CN03807993.3A CN1647430A (zh) 2003-02-25 2003-02-25 一种载波频率估计方法及装置
AU2003211665A AU2003211665A1 (en) 2003-02-25 2003-02-25 A method and apparatus of estimating carrier frequency

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2003/000145 WO2004077713A1 (fr) 2003-02-25 2003-02-25 Procede et dispositif d'estimation d'une frequence porteuse

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WO2004077713A1 true WO2004077713A1 (fr) 2004-09-10

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AU (1) AU2003211665A1 (fr)
WO (1) WO2004077713A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101110807B (zh) * 2006-07-20 2012-01-04 财团法人工业技术研究院 估算发射器与接收器的小数频偏的装置与方法
US8184675B2 (en) 2006-07-12 2012-05-22 Telefonaktiebolaget L M Ericsson (Publ) Residual frequency offset exploitation
CN111585924A (zh) * 2020-03-25 2020-08-25 北京理工大学 频偏校正方法及接收器
CN113311225A (zh) * 2021-05-06 2021-08-27 武汉大学 一种估计lte残余载波频率偏差的方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1917499B (zh) * 2006-09-08 2012-05-16 清华大学 解决正交频分复用系统收发晶振存在偏差的方法
CN101179316B (zh) * 2007-11-30 2012-02-29 华为技术有限公司 时钟调整的方法、装置和接入点

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2354678A (en) * 1999-06-29 2001-03-28 Nec Corp CDMA receiver capable of estimating frequency offset from complex pilot symbols
CN1342004A (zh) * 2000-09-05 2002-03-27 华为技术有限公司 一种适用于码分多址接入系统的频偏估计方法
CN1358385A (zh) * 1999-04-23 2002-07-10 高通股份有限公司 频率偏移量校正的方法和装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1358385A (zh) * 1999-04-23 2002-07-10 高通股份有限公司 频率偏移量校正的方法和装置
GB2354678A (en) * 1999-06-29 2001-03-28 Nec Corp CDMA receiver capable of estimating frequency offset from complex pilot symbols
CN1342004A (zh) * 2000-09-05 2002-03-27 华为技术有限公司 一种适用于码分多址接入系统的频偏估计方法

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8184675B2 (en) 2006-07-12 2012-05-22 Telefonaktiebolaget L M Ericsson (Publ) Residual frequency offset exploitation
CN101110807B (zh) * 2006-07-20 2012-01-04 财团法人工业技术研究院 估算发射器与接收器的小数频偏的装置与方法
CN111585924A (zh) * 2020-03-25 2020-08-25 北京理工大学 频偏校正方法及接收器
CN111585924B (zh) * 2020-03-25 2021-07-16 北京理工大学 频偏校正方法及接收器
CN113311225A (zh) * 2021-05-06 2021-08-27 武汉大学 一种估计lte残余载波频率偏差的方法
CN113311225B (zh) * 2021-05-06 2022-03-04 武汉大学 一种估计lte残余载波频率偏差的方法

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AU2003211665A1 (en) 2004-09-17

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