WO2008067721A1 - Procédé de processus de synchronisation, station de base, dispositif utilisateur et système de communication - Google Patents

Procédé de processus de synchronisation, station de base, dispositif utilisateur et système de communication Download PDF

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Publication number
WO2008067721A1
WO2008067721A1 PCT/CN2007/003382 CN2007003382W WO2008067721A1 WO 2008067721 A1 WO2008067721 A1 WO 2008067721A1 CN 2007003382 W CN2007003382 W CN 2007003382W WO 2008067721 A1 WO2008067721 A1 WO 2008067721A1
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WIPO (PCT)
Prior art keywords
sch
partial
psc
demodulated
ofdm symbol
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PCT/CN2007/003382
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English (en)
Chinese (zh)
Inventor
Zhenglei Hu
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Huawei Technologies Co., Ltd.
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Application filed by Huawei Technologies Co., Ltd. filed Critical Huawei Technologies Co., Ltd.
Publication of WO2008067721A1 publication Critical patent/WO2008067721A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2602—Signal structure
    • H04L27/261—Details of reference signals

Definitions

  • Synchronous processing method base station, user equipment and communication system
  • the present invention relates to the field of communications technologies, and in particular, to a synchronization processing method, a base station, a user equipment, and a communication system. Background technique
  • the main physical layer technology OFDM Orthogonal Frequency Division Multiplexing
  • OFDM Orthogonal Frequency Division Multiplexing
  • SCH Synchronization Channel
  • the SCH occupies part of the bandwidth of the system center in the frequency domain, and occupies one or more OFDM symbols in the frame structure in the time domain (two in the 3GPP LTE).
  • OFDM system The functions of downlink slot timing, frame timing, frequency offset estimation and cell search can be realized by SCH-specific structure.
  • the timing frequency offset function and the cell search function are implemented by the same SCH symbol, it is called non-hierarchical SCH; when the timing frequency offset function and the cell identification function are respectively implemented by different SCH symbols, Is a hierarchical SCH (hierarchical SCH).
  • 3GPP LTE is designed with a layered SCH, where P-SCH (primary SCH) is used for timing frequency offset estimation, and S-SCH (secondary SCH) carries cell identity (cell ID) information for cell search.
  • P-SCH primary SCH
  • S-SCH secondary SCH
  • the P-SCH occupies one or more OFDM symbols in the time domain, and the first half of the OFDM symbol containing the P-SCH is the same as the second half.
  • the UE After receiving the signal, the UE first implements the coarse timing frequency offset through differential correlation, and then achieves precise synchronization through sequence correlation and matching processing.
  • the number of sequences used on the P-SCH directly affects the time and performance of the synchronization.
  • One implementation in the prior art is that all cells use a common P-SCH sequence as the primary synchronization channel, for example in Asynchronous system
  • the UE since each cell uses the same PSC (the sequence used by the P-SCH), the UE only needs to use one sequence to search for the synchronization signal, and the timing complexity is low.
  • the same PSC of each cell is equivalent to a multipath component, thereby enhancing energy and being easy to detect.
  • the P-SCH-based channel estimation is a superposition of the multi-cell propagation channel, which may cause a mismatch with the actual unicast channel, that is, the actual channel condition of the cell cannot be characterized. Therefore, the scheme cannot use the P-SCH for coherent detection to obtain the information of the S-SCH. Especially in a synchronous system, for a UE at a large cell edge, such a mismatch can seriously deteriorate the cell search performance. Many implementations of LTE and TDD-based communication systems are implemented as synchronous systems. Therefore, this mismatch problem needs to be solved.
  • Embodiments of the present invention provide a synchronization processing method, a base station, a user equipment, and a communication system, to implement coherent detection of an S-SCH, improve cell search performance, and facilitate detection of a synchronization signal.
  • a synchronization processing method comprising the steps of:
  • the sequence PSC used by the primary synchronization channel P-SCH is mapped to the subcarriers of the OFDM symbol, wherein the first partial P-SCH in each frame is mapped using a common PSC, and the second partial P-SCH is selected from multiple PSCs. Mapping by a PSC;
  • a time domain OFDM symbol is formed and transmitted according to all subcarriers in each frame.
  • a synchronization processing method comprising the steps of:
  • a partial OFDM symbol in each frame carries a first partial P-SCH mapped using a common PSC, and a partial OFDM symbol carries a second partial P-SCH mapped using one of a plurality of PSCs ;
  • the demodulated second partial P-SCH and the demodulated S-SCH information are used for cell search.
  • a base station comprising:
  • a unit for transmitting OFDM symbols A unit for transmitting OFDM symbols.
  • a user equipment including:
  • Means for receiving a plurality of OFDM symbols wherein a partial OFDM symbol in each frame carries a first partial P-SCH mapped using a common PSC, and a partial OFDM symbol carries a second mapping using one of a plurality of PSCs Partial P-SCH;
  • the demodulated second partial P-SCH and the demodulated S-SCH information perform cell search.
  • a communication system comprising:
  • a base station configured to map a sequence PSC used by the primary synchronization channel P-SCH to an OFDM symbol On the subcarrier, where the first part of the P-SCH in each frame is mapped using a common PSC, and the second part of the P-SCH selects one PSC from the plurality of PSCs for mapping; and, according to all subcarriers in each frame Time domain OFDM symbols and sent;
  • a user equipment configured to demodulate the first partial P-SCH, the second partial P-SCH, and the S-SCH information from the received OFDM symbol, using the demodulated first portion P-SCH and demodulating
  • the second part of the P-SCH performs coarse timing or frame timing, and uses the demodulated first partial P-SCH to perform timing frequency offset estimation, and uses the demodulated second partial P-SCH and the demodulated S.
  • the -SCH information is used for cell search.
  • the first part of the P-SCH in each frame is mapped by using a common PSC, and the second part of the P-SCH is selected by selecting one PSC from the plurality of PSCs.
  • FIG. 1 is a schematic structural diagram of a communication system according to an embodiment of the present invention.
  • FIG. 2 is a schematic diagram of mapping and converting a first part of a P-SCH according to an embodiment of the present invention
  • FIG. 3 is a schematic diagram of a second part P-SCH mapping and conversion according to an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of a time domain structure of a hierarchical SCH in an embodiment of the present invention.
  • FIG. 5 is a schematic structural diagram of a base station according to an embodiment of the present invention.
  • FIG. 6 is a flowchart of synchronization processing of a base station according to an embodiment of the present invention.
  • FIG. 7 is a schematic structural diagram of a user equipment according to an embodiment of the present invention.
  • FIG. 8 is a flowchart of synchronization processing of a user equipment according to an embodiment of the present invention. detailed description
  • the P-SCH in each frame is divided into two parts.
  • the first part of the P-SCH is mapped to the subcarriers of the OFDM symbol by using a common PSC, and the second part of the P-SCH is selected from the multiple PSCs.
  • a PSC is mapped to the subcarriers of the OFDM symbol, and then converted into a time domain OFDM symbol and sent to the user equipment for processing, which improves the timing synchronization performance and the cell search performance of the synchronization system.
  • a communication system in this example includes: a base station 100 and a user equipment 101.
  • the base station 100 is located in the E-UTRAN of the universal terrestrial radio access network, and is configured to receive uplink data sent by the user equipment 101 and send downlink data to the user equipment 101.
  • the primary synchronization channel P-SCH in each frame is divided into two parts, and the first part of the P-SCH is mapped to the subcarriers of the OFDM symbol by using a common PSC.
  • the second part of the P-SCH selects one PSC from the plurality of PSCs to be mapped to the subcarriers of the OFDM symbol; and forms an OFDM symbol of the time domain according to all the subcarriers in each frame and sends the OFDM symbol to the user equipment 101.
  • the user equipment 101 is configured to receive downlink data sent by the base station 100 and send uplink data to the base station 100, where the user equipment 101 receives an OFDM symbol sent by the base station 100, and demodulates the first part P from the user equipment 101.
  • the P-SCH maps the elements of the PSC used by it to the subcarriers of the OFDM symbol at equal intervals.
  • the first part P-SCH ⁇ uses a common sequence P c , and the common sequence P c is N symbols long.
  • the common sequence P c is N symbols long.
  • each element of P ⁇ is mapped to an even-numbered subcarrier, and an odd-numbered subcarrier is an empty subcarrier.
  • all the subcarriers in each frame are subjected to inverse discrete fast Fourier transform (IFFT), and the cyclic prefix CP is added to form an OFDM symbol with the same characteristics in the front and back of the time domain and transmitted.
  • IFFT inverse discrete fast Fourier transform
  • the second part P-SCH uses a set of sequences ⁇ P ⁇ , ( 1 , M );
  • the system selects one sequence from the M sequences according to the number of the cell group and the PSC, and uses the sequence transmitted on the P-SCH of the second part of the cell to map the elements of the sequence to the subcarriers with the even number.
  • the subcarriers whose odd number is odd are empty subcarriers.
  • all subcarriers in each frame are subjected to inverse discrete fast Fourier transform IFFT, and after the cyclic prefix CP is formed, an OFDM symbol having exactly the same characteristics in the front and rear regions is formed and transmitted.
  • each element of the PSC is mapped to an even-numbered subcarrier, and the odd-numbered subcarrier is an empty subcarrier, so that the processing is for the time.
  • the OFDM symbols with the same characteristics of the two parts are obtained on the domain.
  • the elements of the PSC can be mapped to the subcarriers with odd ordinal numbers, and the subcarriers with even numbers are null subcarriers.
  • the two parts of the domain OFDM symbol are identical after modulo.
  • the time domain structure of the layered SCH in the present embodiment is as shown in FIG. 4, where the P-SCH is repeated twice in a frame.
  • the slot spacing between the OFDM symbols is the same; and, in order to facilitate the coherent detection, the OFDM symbol carrying the secondary synchronization channel S-SCH information or the broadcast channel BCH information and the OFDM symbol carrying the second partial P-SCH are in the time domain Adjacent.
  • the structure of the base station 100 in this embodiment includes: a mapping unit 500, a converting unit 501, and a sending unit 502.
  • the mapping unit 500 is configured to map a sequence PSC used by the primary synchronization channel P-SCH. Going to the subcarrier of the OFDM symbol, wherein the first part of the P-SCH in each frame is mapped using a common PSC, and the second part of the P-SCH is selected from a plurality of PSCs for mapping; the converting unit 501 is used And forming, according to all subcarriers in each frame, a unit of an OFDM symbol in a time domain; and the sending unit 502, configured to send an OFDM symbol.
  • Step 600 Divide the primary synchronization channel P-SCH in each frame into two parts.
  • the first part of the P-SCH is mapped to the subcarriers of the OFDM symbol by using a common PSC, and the second part of the P-SCH is selected from the multiple PSCs.
  • One PSC is mapped onto the subcarriers of the OFDM symbol.
  • Step 601 Perform inverse inverse fast Fourier transform IFFT on all subcarriers in each frame, and add a cyclic prefix CP to form an OFDM symbol with the same characteristics in the front and back of the time domain.
  • Step 602 Send an OFDM symbol.
  • the user equipment 101 After demodulating the first partial P-SCH and the second partial P-SCH from the received OFDM symbols, the user equipment 101 performs coarse timing by using the first partial P-SCH and the second partial P-SCH. Since the first part P-SCH and the second part P-SCH are both repeating structures, the correlation peak of the received signal can be detected by using a differential correlation method, and the intra-frame average can also be used (ie, the first part P- The correlation peaks of the SCH and the second part of the P-SCH are superimposed after modulo or multi-frame averaging to detect the correlation peak of the received signal.
  • the user equipment 101 performs frame timing by using the demodulated first part P-SCH and the second part P-SCH, and performs matching with the PSC corresponding to the first part P-SCH at the peak of the received signal, and finds The frame timing is implemented when the first portion of the P-SCH is located.
  • the OFDM symbol carrying the first part of the P-SCH and the second part P- Different timing arrangements of the OFDM symbols of the SCH carry related information of other demodulated OFDM symbols, such as indicating the length of the CP symbol or the number of antennas.
  • the user equipment 101 performs timing offset estimation using the demodulated first partial P-SCH.
  • part of the cell identity information may also be carried to improve the cell search function.
  • sequence detection of the second partial P-SCH does not affect the synchronization time, it is possible to appropriately carry more information (not limited to the maximum number of sequences in the prior art).
  • the OFDM symbol carrying the S-SCH information in the time domain is adjacent to the OFDM symbol carrying the second part of the P-SCH, It is advantageous for S-SCH coherent demodulation, that is, the identification information of a specific cell is obtained from the S-SCH detection.
  • a structure of the user equipment 101 in this embodiment is as shown in FIG. 7, and includes: a receiving unit 700, and a solution
  • the modulating unit 701 is configured to receive a plurality of OFDM symbols, where a part of the OFDM symbols in each frame carries a first part of the P-SCH that is mapped using a common PSC, and the part of the OFDM symbol is carried.
  • the processing unit 702 is configured to perform coarse timing or frame timing by using the first part P-SCH and the second part P-SCH, perform timing frequency offset estimation by using the first part P-SCH, and use the second A unit for performing cell search by the partial P-SCH and the demodulated S-SCH information.
  • the processing unit 702 also performs coherent detection using the second portion P-SCH.
  • Step 800 Receive multiple OFDM symbols, where a partial OFDM symbol in each frame carries a first partial P-SCH mapped using one common PSC, and a partial OFDM symbol carries a second portion mapped using one of a plurality of PSCs P-SCH.
  • Step 801 Demodulate the first partial P-SCH and the second partial P-SCH from the received OFDM symbols.
  • Step 802 Perform coarse timing or frame timing by using the first part P-SCH and the second part P-SCH, perform timing frequency offset estimation by using the first part P-SCH, and utilize the second part P-SCH and demodulation
  • the generated S-SCH information is used for cell search.
  • Step 802 can also include performing coherent detection using the second portion of the P-SCH.
  • mapping a PSC to a subcarrier of an OFDM symbol when mapping a PSC to a subcarrier of an OFDM symbol, the first part of the P-SCH in each frame is mapped using a common PSC, and the second part of the P-SCH is selected from a plurality of PSCs.
  • Performing the mapping preserves the advantages of the synchronization signal energy gain and the low sequence complexity when mapping with a common PSC in the prior art, and solves the problem that the prior art only uses a common PSC for mapping and causes P-SCH.
  • the second part of the P-SCH carries partial cell identification information, which reduces inter-cell interference, and the grouping ratio is only Carrying cell identification information with S-SCH is more conducive to improving detection accuracy and speed.

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

Abstract

L'invention concerne un procédé de processus de synchronisation pour résoudre le problème dans l'état antérieur de la technique selon lequel il ne supporte pas la détection cohérente en raison du fait que l'estimation de canal P-SCH ne correspond pas au canal d'unidiffusion réel lors de l'utilisation d'un seul PSC ; et le problème selon lequel la détection de synchronisation est à peine réalisée en raison de la puissance des multiples cellules qui ne pas être améliorée lors de l'utilisation de multiples PSC ; le procédé comprend les opérations consistant à : mapper le PSC de séquence utilisé par le P-SCH à l'onde de sous-porteuse du signal OFDM, la première partie de P-SCH de chaque trame utilisant un PSC public pour réaliser le mappage, et la seconde partie de P-SCH sélectionnant un P-SCH à partir de multiples P-SCH pour réaliser le mappage ; et former les signaux OFDM à la région temporelle selon toutes les ondes de sous-porteuses de chaque trame ; puis les envoyer. L'invention concerne également une station de base, un dispositif utilisateur et un système de communication.
PCT/CN2007/003382 2006-12-04 2007-11-29 Procédé de processus de synchronisation, station de base, dispositif utilisateur et système de communication WO2008067721A1 (fr)

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CN102186236B (zh) * 2011-04-27 2013-10-02 京信通信***（中国）有限公司 一种微蜂窝基站间定时同步方法及装置
CN102769477B (zh) * 2011-05-06 2014-08-27 普天信息技术研究院有限公司 实现小区搜索和下行同步的方法和***
CN104125184B (zh) 2013-04-23 2018-07-20 电信科学技术研究院 一种导频信号的传输方法及设备
CN115333571B (zh) * 2022-06-22 2023-12-19 飞芯智控(成都)科技有限公司 跳频通信***的同步处理方法及装置

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US20050002446A1 (en) * 2003-07-02 2005-01-06 Litwin Louis Robert Method and apparatus for frequency-robust detection of a wideband code division multiple access secondary synchronization channel
WO2005041514A1 (fr) * 2003-10-18 2005-05-06 Technische Universität Dresden Procede de synchronisation lors de la transmission de signaux de multiplexage frequentiel optique (ofdm)
CN1736052A (zh) * 2001-10-17 2006-02-15 北方电讯网络有限公司 多载波码分多址***中的同步

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1736052A (zh) * 2001-10-17 2006-02-15 北方电讯网络有限公司 多载波码分多址***中的同步
US20050002446A1 (en) * 2003-07-02 2005-01-06 Litwin Louis Robert Method and apparatus for frequency-robust detection of a wideband code division multiple access secondary synchronization channel
WO2005041514A1 (fr) * 2003-10-18 2005-05-06 Technische Universität Dresden Procede de synchronisation lors de la transmission de signaux de multiplexage frequentiel optique (ofdm)

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CN101197804B (zh) 2011-09-21

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