CN1578294A - Method and device for detecting synchronous signal - Google Patents

Method and device for detecting synchronous signal Download PDF

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Publication number
CN1578294A
CN1578294A CNA2004100691114A CN200410069111A CN1578294A CN 1578294 A CN1578294 A CN 1578294A CN A2004100691114 A CNA2004100691114 A CN A2004100691114A CN 200410069111 A CN200410069111 A CN 200410069111A CN 1578294 A CN1578294 A CN 1578294A
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China
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signal
synchronizing signal
temporal information
ofdm
synchronous
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CNA2004100691114A
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Chinese (zh)
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朴义俊
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Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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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
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2656—Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/0079—Receiver details

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

The invention relates to a device for detecting the synchronous signals, which comprises : a time information receiving element which is used to receive the time information from the global positioning system (GPS); and a synchronous signal detector which is used to calculate the position of the synchronous signal of the received frame based on the time information and produce the synchronous detecting signal. Because the device for detecting synchronous signal uses the GPS time to confirm the position of the synchronous signal arranged in the frame and the frame structure of the OFDM signal transmitted from the sending end, and further detect the synchronous signal, so the synchronous signal detecting device has the advantages of simplifying the implementation of the hardware for detecting the synchronous signals, and obviating the need for the process of calculating the correlation.

Description

Be used to detect the method and apparatus of synchronizing signal
Technical field
The present invention relates to a kind of receiver that is used to receive OFDM (OFDM) carrier signal.Relate in particular to a kind of being used for by using global positioning system (GPS) to come to detect the method and apparatus of synchronizing signal from the OFDM carrier signal.
Background technology
OFDM (OFDM) scheme is a kind of digital modulation system that is proposed the transmission rate that improves each bandwidth and prevents the multipath interference.According to the OFDM scheme, whole bandwidth is divided into a plurality of arrowbands orthogonal sub-channels, and modulates each subchannel by QAM (quadrature amplitude modulation) and transmit data.Because ofdm system becomes data a plurality of parallel datas and this data-modulated is arrived a plurality of each subcarriers, and transmit this data, so ofdm system can improve the volume of transmitted data of each chronomere, and receiving terminal is subjected to the influence of the transmission delay that caused by multipath little.
In ofdm system, the data owner that transfers out will comprise synchronizing signal and OFDM data.Synchronizing signal is commonly referred to as pseudo noise (PN) sequence.Receiving terminal have with from the identical PN sequence of the PN sequence of transmitting terminal, and for PN sequence synchronously and relatively.
Fig. 1 shows the schematic diagram of frame structure that is transferred to the ofdm signal of receiving terminal from transmitting terminal.
Ofdm signal comprises pseudo noise (PN) sequence, the OFDM data of using as synchronizing signal (DFT3780) and the protection that is used for preventing inserting between PN sequence and OFDM data (DFT3780) in the interference of OFDM data (DFT3780) (GI) at interval.OFDM receiver (not having to show) detects the PN sequence from the ofdm signal in that receives, and carries out Frequency Synchronization, symbol synchronization and channel equalization based on detected PN sequence.Therefore, has the reference PN sequence that the signal mode identical with the pattern of the synchronizing signal of the ofdm signal that receives arranged according to the receiving terminal of conventional art, calculating is with reference to the correlation between PN sequence and the ofdm signal, and in the peaked position probing synchronizing signal that has in correlation.Because the order of the synchronizing signal of ofdm signal changes according to predetermined rule, so during the signal that is complementary with the reference PN sequence of receiving terminal on being created in pattern, receiving terminal can detect synchronizing signal.Therefore, if the ofdm signal that transmits from transmitting terminal is a broadcast singal, then up to energising back preset time, digital broadcasting transmitter can receiving broadcast signal.
Fig. 2 is the conceptual block diagram that is used to detect the conventional apparatus of synchronizing signal.
The conventional apparatus that is used to detect synchronizing signal comprises: correlation calculator 10, comparing unit 20, counter 30 and sync generator 40.
That correlation calculator 10 comprises is a plurality of, and (10a～10n) its each has the correlator that put to start with the position of different ofdm signal in.The part that correlation calculator 10 is divided into predetermined number with ofdm signal in detects the position of the synchronizing signal that comprises as quickly as possible in ofdm signal in, and calculates respectively from a plurality of correlators (each correlation of 10a～10n) at different initial points.
Comparing unit 20 is when (when producing maximum in the correlation of 10a～10n), producing update signal (w_en) from each correlator.Counter 30 is counted predetermined times according to the cycle identical with code-element period.For example, if transmitting terminal is that unit sends digital broadcast signal based on the 5us cycle with 3780 code elements, then in the 5us interval, 3780 code elements have been counted.
In response to the update signal (w_en) that in comparing unit 20, produces, maximum value detector 40 is stored in the value that counts out in the counter 30, and, produce synchronous detection signal (sync) when the identical number of times of value after per the 3780th code element should counting during greater than predetermined number.For example,, and during second counting, produce maximum once more, then produce synchronous detection signal (sync) in the 1200th position in the 1200th code element if during the counting of counter 30, produce maximum in the 1200th code element.Maximum value detector 40 is from producing synchronous detection signal (sync) corresponding to the count value that produces peaked position with the specific cycle.Because the device that is used for detecting the synchronizing signal with said structure can not detect the position of the synchronizing signal of ofdm signal in, so when being realized by single correlator, it needs a large amount of time to detect synchronizing signal.In order to solve this shortcoming, the conventional apparatus that is used to detect synchronizing signal improves the detection speed of synchronizing signal with the part that ofdm signal in is divided into predetermined number, and has a plurality of correlators (10a～10n) come to calculate correlation from the initial point of various piece.Yet more than the parts of Yao Qiuing have caused being used for the increase of product cost of the receiver of ofdm signal in, and each correlator (10a～10n) should calculate ofdm signal in and continuously with reference to the correlation between the PN sequence (R_PN sequence).In addition, (10a～10n) should equip adder and multiplier is because be provided with the correlator of a plurality of numbers, so the realization of hardware is complicated in correlation detector 10 owing to each correlator.
Summary of the invention
Developed the present invention in order to solve above-mentioned prior art problems.The object of the present invention is to provide a kind ofly to be used for using the temporal information that comprises at ofdm signal to detect the device of synchronizing signal, wherein the realization of hardware is simplified, and can reduce production costs.
In order to realize above-mentioned aspect and other characteristics of the present invention, a kind of device that is used to detect synchronizing signal is provided, comprising: the temporal information receiving element is used for from global positioning system (GPS) receiving time information; And synchronized signal detector, be used for calculating the position of synchronizing signal of the frame of the ofdm signal receive, and therefore produce synchronous detection signal based on temporal information.
This device that is used for detecting synchronizing signal also comprise with from the synchronous timer of the temporal information of global positioning system, and the temporal information that will periodically produce is applied to synchronized signal detector.
This synchronized signal detector detects the synchronizing signal of ofdm signal based on the temporal information that produces in timer.
According to a further aspect in the invention, provide a kind of device that is used for detecting from ofdm signal synchronizing signal, comprising: the temporal information receiving element is used for from global positioning system (GPS) receiving time information; The locking range calculator is used for calculating based on temporal information the position of the synchronizing signal of the frame that is applied to the ofdm signal that receives; Correlator is used for comprising from the position calculation of synchronizing signal the ofdm signal and the correlation between the predetermined pseudo noise sequence that receiving terminal is provided with of synchronizing signal; And maximum value detector, be used for producing synchronous detection signal at point with maximum correlation.
This device that is used for detecting synchronizing signal also comprise with from the synchronous timer of the temporal information of global positioning system, and the temporal information that will periodically produce is applied to the locking range calculator.
According to this aspect on the other hand, provide a kind of method that is used for detecting synchronizing signal, comprised step: from global positioning system (GPS) receiving time information from ofdm signal; With the position of calculating the synchronizing signal in the ofdm signal that receives based on this temporal information.
Be used for also comprising step: the reference time information that the temporal information that produces and receive is synchronous from the method for ofdm signal detection synchronizing signal; And the therefore position of calculating synchronizing signal based on the preset time unit.
According to a further aspect in the invention, provide a kind of method that is used for detecting synchronizing signal, comprised step: from global positioning system (GPS) receiving time information from ofdm signal; Calculate the position of the synchronizing signal of the frame that is applied to the ofdm signal that receives based on temporal information; The ofdm signal and the correlation between the predetermined reference pseudo noise sequence that receiving terminal is provided with that comprise synchronizing signal from detected position calculation; With the position that is created in the synchronizing signal that comprises in the ofdm signal based on this correlation.
Be used for also comprising step: produce and the synchronous reference time information of temporal information, and therefore detect the position of synchronizing signal based on the preset time unit from the method for ofdm signal detection synchronizing signal.
Description of drawings
By describing its preferred embodiment with reference to the accompanying drawings in detail, above-mentioned purpose of the present invention and characteristic will become apparent, wherein:
Fig. 1 shows the schematic diagram of example of frame structure that is transferred to the ofdm signal of receiving terminal from transmitting terminal;
Fig. 2 is the notional block diagram that is used to detect the conventional apparatus of synchronizing signal;
Fig. 3 is the integrally-built diagrammatic sketch that shows ofdm signal;
Fig. 4 is the conceptual block diagram of device that is used to detect synchronizing signal according to the embodiment of the invention;
Fig. 5 is the conceptual block diagram that is used to detect the device of synchronizing signal in accordance with another embodiment of the present invention;
Fig. 6 is the flow chart of method that is used to detect synchronizing signal according to the embodiment of the invention; With
Fig. 7 is the flow chart that is used to detect the method for synchronizing signal in accordance with another embodiment of the present invention.
Embodiment
Below, describe the preferred embodiments of the present invention in detail with reference to accompanying drawing.
With reference to figure 3, the overall structure of this ofdm signal will be described below.
Generally, 255 single frames that show in Fig. 1 are called the frame group altogether, and 512 frame groups are called superframe altogether and 478 superframes are called the superframe group altogether.The forward part of superframe with ofdm signal of said structure generally has the temporal information of the beginning that is illustrated in superframe group at zero point.
Fig. 4 is the conceptual block diagram of device that is used to detect synchronizing signal according to the embodiment of the invention.
This device that is used to detect synchronizing signal comprises: gps receiver 50, timer (this locality) 60 and synchronized signal detector 70.
This gps receiver 50 receives from artificial satellite (not have to show) or from being used for the temporal information of the ofdm signal in that relaying receives from the base station (not having demonstration) of the ofdm signal of artificial satellite transmission.As explaining with reference to figure 3, transmitting terminal is with the ofdm signal of the time interval transmit frame structure of rule, and comprises the temporal information of representing zero point at the frame that zero hour transmits constantly.Gps receiver 50 receives these temporal informations (for example, zero point), and uses it as the reference time information that is used to detect the device of synchronizing signal according to the present invention.
Timer (this locality) 60 and the temporal information that in gps receiver 50, receives (for example, on the stroke of midnight) synchronous, and come gate time to receive next temporal information on the stroke of midnight up to gps receiver 50 based on the temporal information that receives.
Synchronized signal detector 70 is estimated the frame structure of the ofdm signal in that imports based on the time of counting in timer (this locality) 60.Owing to the time interval synchronous signal transmission of the rule of being scheduled to rule from the ofdm signal basis of transmitting terminal, so synchronized signal detector 70 is estimated position corresponding to the synchronizing signal of the time that counts out according to the rule of reaching an agreement with transmitting terminal in timer (this locality) 60, and detects this synchronous detection signal.The accuracy of the time that employing counts out in timer (this locality) 60 is determined the accuracy of synchronization signal detection.Since synchronized signal detector 70 do not need to calculate the synchronizing signal that in ofdm signal in, comprises and and the reference pseudo noise sequence (P_N sequence) of synchronizing signal model identical between correlation, so can simplify structure according to sync detection circuit of the present invention.Because this synchronous detection signal (sync) is to produce according to the temporal information that receives, avoided postponing the problem of generation by the detection of synchronous detection signal (sync) in gps receiver 50.For example, when being applied in broadcast signal receiver, avoided problem of the present invention as the delay of inspecting about energising or channel variation.
Fig. 5 is the notional block diagram that is used to detect the device of synchronizing signal according to another embodiment of the present invention.
Sync signal detection apparatus comprises: gps receiver 100, timer (this locality) 110, locking range detector 120, correlator 130 and maximum value detector 140.
Gps receiver 50 among the operation of gps receiver 100 and timer (this locality) 110 and Fig. 4 is identical with the operation of timer 60, has therefore omitted it hereinafter consciously.Present embodiment solved about when the receiving terminal with gps receiver 100 away from the artificial satellite that sends ofdm signal (not have to show) or when being used for the base station (not demonstration) of the ofdm signal that relaying transfers out from artificial satellite, the problem of the mistake of the time that in gps receiver 100, receives.
Locking range detector 120 is according to the temporal information that provides from the timer (this locality) 110 that has with the synchronous temporal information of gps receiver 100, estimates the Position Approximate of the synchronizing signal in ofdm signal in and is positioned at the signal mode of the synchronizing signal of the position that estimates.Because the order of the pattern of the synchronizing signal of ofdm signal in gradually changes according to predetermined rule, so can be in the pattern of reviewing synchronizing signal based on the time that receives in the whole temporal information of the first zero.Locking range calculator 120 is based on the temporal information that receives in gps receiver 100 (zero point constantly), can access frame and frame group among the ofdm signal in that receives according to the time that is counted out by timer (this locality) 110.Do not change at the ready signal mode with reference to pseudo noise sequence (R_PN sequence) of receiving terminal, the synchronizing signal that comprises in ofdm signal in has then changed.Therefore, locking range calculator 120 is comprising having and operate correlator 130 with reference to the position in the frame of the synchronizing signal of the identical signal mode of pseudo noise sequence (R_PN sequence).
Correlator 130 calculates the ofdm signal in that receives from the time point that is provided with and with reference to the correlation between the pseudo noise sequence (R_PN sequence) locking range detector 120.Correlator 130 only uses single correlator 130, and is opposite with traditional situation that the ofdm signal in that receives is divided into predetermined part for the fast detecting of synchronizing signal.Therefore, it is unnecessary having simplified the realization of hardware and the computational process of correlation.
Maximum value detector 140 is producing ofdm signal in and is producing synchronous detection signal (sync) with reference to the peaked time point of the correlation between the pseudo noise sequence (R_PN sequence).At this moment, maximum value detector 140 determines that whether these maximums repeat predetermined times as three times with the time interval of rule, with the maximum detection mistake that prevents to produce by multipath fading or external noise, and if like this, synchronous detection signal (sync) then produced.
Fig. 6 outlines the flow chart be used to detect according to the method for the synchronizing signal of the embodiment of the invention.
Gps receiver 100 is received in the temporal information (S210) that ofdm signal in comprises from artificial satellite (do not have show) or from being used for relaying from the base station (not have demonstration) of the ofdm signal of artificial satellite transmission.Temporal information is included in 24 hours to be the leading end among the superframe group of gap periods transmission.Gps receiver 100 synchronous timers (this locality) 60 (S220) built-in in receiving terminal.Therefore, the time of the timer (this locality) 60 that is provided with at receiving terminal is with synchronous from the ofdm signal in of artificial satellite or base station transmits.The time of receiving terminal reference counting in the timer synchronous with gps time (this locality) 110 is estimated the position of the synchronizing signal in ofdm signal in, and produces synchronous detection signal (S230) in the position that is estimating.The process that this method that is used to detect synchronizing signal does not need to calculate single correlation detects synchronizing signal.
Fig. 7 is the flow chart that shows the method that is used to detect synchronizing signal according to another embodiment of the present invention.
Present embodiment is applied in this situation: when receiving terminal places artificial satellite away from transmission OFDM signal in (not having to show) or during away from the position of the base station (not have demonstration) that is used for the ofdm signal in that relaying propagates from artificial satellite, makes a mistake in the gps time that receiving terminal receives.
Gps receiver 100 receives from artificial satellite (not have demonstration) or from being used for the temporal information (S310) of the ofdm signal in that relaying receives from the base station of the ofdm signal in of artificial satellite.It is the superframe group's of gap periods transmission leading end that temporal information is included in 24 hours.Next, gps receiver 100 synchronous timers (this locality) 110 (S320) built-in in receiving terminal.The time of the timer that therefore, is provided with in receiving terminal (this locality) 110 is with synchronous from the ofdm signal in of artificial satellite or base station transmission.
Calculate about position and pattern (S330) based on the synchronizing signal in the ofdm signal of the time input that counts out by gps time or timer (this locality) 110.Since this ofdm signal based on zero hour at each regular time interval transmission frame, and the pattern of the synchronizing signal that comprises in frame changes according to predetermined order, so can calculate pattern from the frame information of the ofdm signal of transmitting terminal and the synchronizing signal that comprises in frame information by definite temporal information.
Gps receiver 100 is according to the information that is gone out by gps time or timer (this locality) 110, calculates correlation (S340) at the point of the frame with signal mode identical with the reference pseudo noise sequence (R_PN sequence) of receiving terminal.Owing to begin correlation calculations at point, so can more effectively calculate correlation than traditional method of the correlation between the reference pseudo noise sequence (R_PN sequence) of the ofdm signal in that detects all inputs continuously and all inputs near synchronizing signal.
Gps receiver 100 determines to have the number of times (S350) whether peaked position in correlation repeats to surpass predetermined number.If maximum repeats to surpass predetermined times (for example, three times) in identical position, then gps receiver 100 produces synchronous detection signal (sync).Therefore, according to the method that is used to detect synchronizing signal of the present invention not needs detect the process of correlation, and when be applied in hardware, the enough very simple circuit of energy make up.
As mentioned above, in exemplary embodiments more of the present invention, use gps time to estimate the position of the synchronizing signal that in frame, comprises and the frame structure of the ofdm signal that receives, and therefore detect synchronizing signal then.Consequently, can simplify the realization of hardware, and the process of calculating correlation is unnecessary.
Advantage, purpose and the characteristic of additional embodiments of the invention partly set forth and will be partly open to the personnel that have general technical ability in this area, perhaps can learn from realization of the present invention.Can be as particularly pointing out in the claims, realizing and obtain the purpose and the advantage of embodiments of the invention.

Claims (9)

1, a kind of device that is used to detect synchronizing signal comprises:
The temporal information receiving element is used for from global positioning system (GPS) receiving time information; With
Synchronized signal detector is used for calculating based on temporal information the position of the synchronizing signal of the frame that receives, and therefore produces synchronous detection signal.
2, the device that is used to detect synchronizing signal as claimed in claim 1, also comprise with from the synchronous timer of the temporal information of global positioning system, the temporal information with the generation of preset time gap periods wherein is applied to synchronized signal detector.
3, the device that is used to detect synchronizing signal as claimed in claim 2, wherein, synchronized signal detector detects the synchronizing signal of ofdm signal based on the temporal information that produces in timer.
4, a kind of device that is used to detect synchronizing signal comprises:
The temporal information receiving element is used for from global positioning system (GPS) receiving time information;
The locking range calculator is used for calculating based on temporal information the position of the synchronizing signal of the frame that is applied to the ofdm signal that receives;
Correlator is used for comprising from the position calculation of synchronizing signal the ofdm signal and the correlation between the predetermined pseudo noise sequence that receiving terminal is provided with of synchronizing signal; With
Maximum value detector is used for producing synchronous detection signal at the point with maximum correlation.
5, the device that is used to detect synchronizing signal as claimed in claim 4, also comprise with from the synchronous timer of the temporal information of global positioning system, the temporal information with the generation of preset time gap periods wherein is applied to synchronized signal detector.
6, a kind of method that is used for detecting from ofdm signal synchronizing signal comprises step:
From global positioning system (GPS) receiving time information; With
Calculate the position of the synchronizing signal of the ofdm signal that receives based on temporal information.
7, the method that is used to detect synchronizing signal as claimed in claim 6 also comprises step: the reference time information that the temporal information that produces and receive is synchronous, and the position of therefore calculating synchronizing signal based on preset time unit.
8, a kind of method that is used to detect synchronizing signal comprises step:
From global positioning system (GPS) receiving time information;
Calculate the position of the synchronizing signal of the frame that is applied to the ofdm signal that receives based on temporal information;
The ofdm signal and the correlation between the predetermined reference pseudo noise sequence that receiving terminal is provided with that comprise synchronizing signal from detected position calculation; With
Be created in the position of the synchronizing signal that comprises in the ofdm signal based on this correlation.
9, the method that is used to detect synchronizing signal as claimed in claim 8, wherein, the step that detects synchronizing signal position produces and the synchronous reference time information of temporal information, and therefore detects the position of synchronizing signal based on preset time unit.
CNA2004100691114A 2003-07-08 2004-07-06 Method and device for detecting synchronous signal Pending CN1578294A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100461652C (en) * 2005-08-03 2009-02-11 中兴通讯股份有限公司 Method and device for air frame synchronization between TDD-SCDMA base stations
CN101690283A (en) * 2007-07-06 2010-03-31 高通股份有限公司 Methods and apparatus related to peer discovery and/or paging in peer to peer wireless communications
CN101488932B (en) * 2008-01-15 2012-04-04 华为技术有限公司 Method, device and system for positioning broadcast channel in orthogonal frequency division multiplexing system
US8599823B2 (en) 2007-07-06 2013-12-03 Qualcomm Incorporated Communications methods and apparatus related to synchronization with respect to a peer to peer timing structure
CN104517443A (en) * 2013-10-02 2015-04-15 泓格科技股份有限公司 Vehicle passing detection device and system with synchronization function

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100461652C (en) * 2005-08-03 2009-02-11 中兴通讯股份有限公司 Method and device for air frame synchronization between TDD-SCDMA base stations
CN101690283A (en) * 2007-07-06 2010-03-31 高通股份有限公司 Methods and apparatus related to peer discovery and/or paging in peer to peer wireless communications
US8599823B2 (en) 2007-07-06 2013-12-03 Qualcomm Incorporated Communications methods and apparatus related to synchronization with respect to a peer to peer timing structure
US8601156B2 (en) 2007-07-06 2013-12-03 Qualcomm Incorporated Methods and apparatus related to peer discovery and/or paging in peer to peer wireless communications
CN101488932B (en) * 2008-01-15 2012-04-04 华为技术有限公司 Method, device and system for positioning broadcast channel in orthogonal frequency division multiplexing system
CN104517443A (en) * 2013-10-02 2015-04-15 泓格科技股份有限公司 Vehicle passing detection device and system with synchronization function

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