Technical field
[0001]
BACKGROUND The present disclosure relates to transmission apparatus for use in the time synchronization system and the time synchronization system.
BACKGROUND
[0002]
A system for time synchronization required between a plurality of devices, GPS (Global Positioning System) positioning satellite system, such as: a method of utilizing a (Global Navigation Satellite System GNSS) has been generalized. Typically, CDMA (Code Division Multiple Access) scheme mobile communication base station (hereinafter, simply referred to as "base station".), From a practical initially, the radio signals from the GNSS (hereinafter, both "GNSS signal" referred.) was used to have realized system synchronization necessary for data transmission and reception control.
[0003]
　As a typical configuration, the GNSS receiver installed in each base station, the timing signal output from the receiver (in the case of the GPS, PPS (Pulse Per Second) signal, etc.) based on and the time the message , that each base station manages time, to achieve a time synchronization among a plurality of base stations (see also non-Patent Document 1).
[0004]
　To accommodate increasing traffic, LTE-Advanced called communication technologies are being put to practical use, further advanced technical investigation and development also next generation mobile communication system called 5G ( see also non-Patent Document 2). LTE-Advanced is a technique to improve the throughput, and and the like MIMO (multiple-input and multiple-output) and CoMP (Coordinated Multiple Point transmission / reception), in order to realize such a technique is more accurate high time synchronization of is required.
[0005]
　Further, as an approach to increase the communication capacity by increasing the utilization efficiency of frequency, miniaturization of the cell are also underway, also referred to as a femtocell SSBS has been put to practical use. Such micro base stations, it is necessary to realize a system synchronization like a normal base station.
CITATION
Non-patent literature
[0006]
Non-Patent Document 1: Kaoru Arai, Makoto Murakami, "Standardization of network synchronization technology in the ITU-T", NTT Technical Journal, 2015 December
Non-Patent Document 2: Taoka other, between MIMO and cell in the "LTE-Advanced cooperation sending and receiving technology ", NTT DOCOMO technical journal Vol. 18 No. 2, July 2010
Non-Patent Document 3: "IMES user Interface Specification (IS-IMES)", the Japan Aerospace Exploration Agency, 10 May 2016
Summary of the Invention
Problems that the Invention is to Solve
[0007]
　SSBS as described above, for example, it is assumed to be installed indoors such as a user's home. Ultra small base station installed in such indoors can not receive the GNSS signals, or, in many cases the strength of the GNSS signals received are not sufficient, as is employed in conventional base station there is a problem that can not be realized, such time synchronization.
[0008]
　This technology, be one obtained by considering the above problems, it is another object to provide a system for time synchronization can be achieved for a plurality of devices installed in a position that can not receive GNSS signals.
Means for Solving the Problems
[0009]
　Time synchronization system according to an aspect of the present invention is based on the radio signal from the positioning satellite system, a reference time acquisition unit for acquiring time information corresponding to the timing shown first timing signal and said first timing signal , connection is connected to a wiring that branches plurality, a modulation unit for sending on a line generated by synchronizing the modulated signal containing the corresponding time information to the first timing signal, to one of the branch wirings while being, one or more demodulator for demodulating a modulated signal propagating on interconnect, based on the second timing signal and the time information acquired by demodulation with either demodulator, from a positioning satellite system and a wireless signal and one or more transmitting unit for transmitting a first radio signal having compatibility.
[0010]
　Preferably, the serial first timing signal is output cyclically, the modulator is sent to the wire relative to the time of the modulation signal first timing signal is output, the modulation signal is added to the time information Te includes a synchronization word.
[0011]
　Preferably, the demodulation unit detects the synchronization word contained in the modulated signal propagating on interconnect outputs the subsequent information to the detected synchronization word as demodulated data, predetermined from the time of detecting the synchronization word and it outputs a second timing signal on the basis of the correction time only before the time that is.
[0012]
　Preferably, the time synchronization system, to obtain the first third of the timing signal is a timing signal substantially identical acquired at the reference time acquiring unit, output from the third timing signal and the demodulation unit further comprising a calibration device for determining a correction time by measuring the time difference between the second timing signal.
[0013]
　Preferably, the transmission unit is a longer period than the period of second timing output from the demodulator, for transmitting a first radio signal.
[0014]
　Preferably, the first radio signal, a first format including information of the number of seconds between the beginning elapsed week and the week from a predetermined reference date and year year, month, day, hour, minute, seconds of the second format containing information, to support at least one.
[0015]
　Preferably, the first radio signal is constructed as a frame consisting of a plurality of words, a plurality of words constituting the frame head are associated with the beginning of the transmission cycle, the first in the frame word is fixed to a predetermined value.
[0016]
　Preferably, the time synchronization system includes demodulates the first radio signal from the transmitting unit, a receiving unit for acquiring time information corresponding to the timing shown fourth timing signal and said fourth timing signal further , receiving unit includes a circuit for executing a plurality of convolution processing with respect to the first word.
[0017]
　Preferably, the transmission unit, in a period during which the first radio signal is not transmitted, transmits the second radio signal to replace the radio signal from the positioning satellite system.
[0018]
　Preferably, the wiring comprises a signal line co acousto-optic systems, cable television signal lines, and, at least one of the signal lines for communication.
[0019]
　Preferably, the first radio signal comprises a predetermined length of the message, which is calculated based on the time information acquired by the reference time acquiring unit.
[0020]
　More preferably, the predetermined length of the message, as an input a secret key and time information is calculated according to the cryptographic hash function.
[0021]
　Time synchronization system according to an aspect of the present invention is based on the radio signal from the positioning satellite system, a reference time acquisition unit for acquiring time information corresponding to the timing shown first timing signal and said first timing signal includes is connected to a wiring that branches plurality, and the modulated signal containing the corresponding time information modulating section for sending on to generate synchronously wire to the first timing signal. The branch wiring, one or more terminals are provided for connecting the demodulator for demodulating the modulated signal propagating on interconnect.
[0022]
　Transmitting apparatus according to one aspect of the present invention is connected to any position of a wiring that branches plurality includes a demodulator for demodulating a modulated signal propagating on interconnect. Modulated signal, the first timing signal and said first timing signal as a reference is generated based on time information corresponding to the timing indicated, sent on the synchronization with the wiring to the first timing signal it is intended. Transmitting device includes a transmitting unit based on the second timing signal and the time information obtained by the demodulation in the demodulator, transmits radio signals having a wireless signal compatible with the positioning satellite system.
[0023]
　Transmitting apparatus according to one aspect of the invention, based on the first and receiving unit for receiving the first timing signal generated based on the radio signals, the signal and the time information received by the receiving unit from the positioning satellite system Te, and a transmission unit for transmitting a second radio signal having a radio signal compatible with the positioning satellite system. The second radio signal includes a position, a time, and the timing signal, and authentication information.
Effect of the invention
[0024]
　According to one embodiment of the present invention can provide a system capable of realizing time synchronization for a plurality of devices installed in a position that can not receive GNSS signals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025]
FIG. 1 is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to the present embodiment.
It is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to FIG. 2 embodiment.
3 is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to the present embodiment.
4 is a schematic diagram showing an exemplary configuration of a base station included in the mobile communication system according to the present embodiment.
5 is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to the present embodiment.
6 is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to the present embodiment.
7 is a block diagram showing a circuit configuration example of S2 modulator constituting the time synchronization system according to the present embodiment.
8 is a diagram showing a structural example of a transmission RF signal generated by S2 modulator constituting the time synchronization system according to the present embodiment.
9 is a block diagram showing a circuit configuration example of S2 demodulator constituting the time synchronization system according to the present embodiment.
FIG. 10 is a block diagram showing a circuit configuration example at S3 transmitter constituting a time synchronization system according to the present embodiment.
11 is a diagram showing an example of a message type of the signal transmitted (MT) to S3 transmitter constituting a time synchronization system according to the present embodiment.
Is a diagram showing an example of a frame structure of the message format used in the time synchronization system according to FIG. 12 embodiment as IMES-TS signal.
13 is a diagram showing another example of a message type of the signal transmitted to S3 transmitter constituting a time synchronization system according to the present embodiment (MT).
14 is a diagram showing an example of a frame structure of the message formats used as IMES-TS signals in the time synchronization system according to the present embodiment.
Is a diagram showing an example of a frame structure of the message formats used as IMES-TS signals in the time synchronization system according to FIG. 15 embodiment.
16 is a diagram showing still another example of a message type of a signal transmitted from S3 transmitter constituting a time synchronization system according to the present embodiment (MT).
17 is a diagram showing an example of a frame structure of the message formats used as IMES-TAS signal in the time synchronization system according to the present embodiment.
18 is a diagram showing an example of a frame structure of the message formats used as IMES-TAS signal in the time synchronization system according to the present embodiment.
19 is a diagram showing still another example of a message type of the signal transmitted to S3 transmitter constituting a time synchronization system according to the present embodiment (MT).
Is a diagram showing an example of a frame structure of the message format used in the time synchronization system according to FIG. 20 embodiment as IMES-TAS signal.
21 is a diagram illustrating an example of a frame structure of the message formats used as IMES-TAS signal in the time synchronization system according to the present embodiment.
22 is a diagram for explaining an example of a timing code transmitted as IMES-TAS signal in the time synchronization system according to the present embodiment.
It is a diagram for explaining an example of a message sent to S3 transmitter in the time synchronization system according to FIG. 23 embodiment.
It is a diagram for explaining another example of a message sent from S3 transmitter in the time synchronization system according to FIG. 24 embodiment.
It is a flowchart illustrating a processing procedure for generating and transmitting IMES-TAS signal from FIG. 25] S3 transmitter constituting a time synchronization system according to the present embodiment.
FIG. 26 is a block diagram showing a circuit configuration example at S3 receiver constituting the time synchronization system according to the present embodiment.
It is a diagram for explaining a reception processing of a message including the telemetry word in FIG 27] S3 receiver constituting the time synchronization system according to the present embodiment.
It is a diagram for explaining the structure of a message employed in the time synchronization system according to FIG. 28 embodiment.
It is a diagram for explaining an example of information included in the signal transmitted in the time synchronization system according to FIG. 29 embodiment.
[FIG. 30] is a diagram for explaining an example of a method of generating the authentication code at the time synchronization system according to the present embodiment.
[FIG. 31] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
[FIG. 32] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
[33] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
FIG. 34 is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
Is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to FIG. 35 embodiment.
[FIG. 36] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
[FIG. 37] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
[FIG. 38] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
[39] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
[FIG. 40] is a diagram showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
It is a diagram for explaining the transmission delay occurring in the time synchronization system according to FIG. 41 embodiment.
[FIG. 42] is a diagram for explaining an application example of a timing correcting device in a time synchronization system according to the present embodiment.
[43] is a block diagram showing a circuit configuration example of a timing correcting device provided in the time synchronization system according to the present embodiment.
[FIG. 44] is a diagram for explaining the automatic correction function of the delay time in the time synchronization system according to the present embodiment.
It is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to FIG. 45 Modification 1 of the embodiment.
Is [46] a schematic diagram illustrating an exemplary configuration of a base station included in the mobile communication system shown in FIG. 45.
FIG 47 is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to the second modification of the embodiment.
Is [48] a schematic diagram illustrating an exemplary configuration of a base station included in the mobile communication system shown in FIG. 47.
It is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to FIG. 49 Modification 3 of the present embodiment.
It is a schematic diagram showing an example of a mobile communication system including a time synchronization system according to FIG. 50 Modification 4 of the present embodiment.
DESCRIPTION OF THE INVENTION
[0026]
　Embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding elements in the drawings, and description thereof is not repeated the same reference numerals.
[0027]
　
　First, an outline of the time synchronization system according to the present embodiment. In the following, a typical application of a time synchronization system according to the present embodiment, configuration will be described when applied to time synchronization in a mobile communication system including a base station such as a femtocell, the configuration described not only it can be applied to any device or system.
[0028]
　(A1: Implementation Example 1)
　FIGS. 1 to 3 are schematic views illustrating an example of a mobile communication system 1 including a time synchronization system according to the present embodiment. Mobile communication system 1 shown in FIGS. 1 to 3, as an example, a plurality of base stations 300-1 and 300-2 to an existing building 10, ... (hereinafter, collectively referred to as "base station 300" also.) and the formed by newly installed. Typically, the base station 300 is installed for each room of the building 10.
[0029]
　The base station 300 to have a receiver capable of realizing a system synchronization by receiving a GNSS signal. Time synchronization system, the base station 300, to provide a pseudo signal to complement the GNSS signals, to realize the system synchronization in a mobile communication system including a base station 300. In the present embodiment, as an example, the pseudo signal to complement referred GNSS signal with the known "IMES (Indoor Messaging System) signal" was based, using alternative signal suitable for time synchronization it that (for IMES signal, refer to non-Patent Document 3).
[0030]
　In the following description, it is provided to the base station 300, a signal for system synchronization "IMES-TS (Indoor Messaging System - Timing Sync)" also referred to as or "IMES-TS signal".
[0031]
　IMES-TS signal typically includes position (Position), time (Clock), the timing signal (Timing). For more information on these information will be described later. In addition, the IMES-TS signals may be included an authentication code (Authentication Code). Authentication code is typically utilized for purposes such as to ensure the integrity or authenticity of the information, such as received location and time. Such will be described later detail the authentication code.
[0032]
　The IMES-TS signal further comprises an authentication code, "IMES-TAS (Indoor Messaging System - Timing Authentication Sync)" also referred to as or "IMES-TAS signal". Such IMES-TAS signal is, for example, may be provided to the mobile terminal such as a smart phone or a cellular phone.
[0033]
　For convenience of explanation, will be described IMES-TAS signal, it is obvious that equally applicable to IMES-TS signals except the authentication code from the IMES-TAS signal.
[0034]
　In the present embodiment, illustrates a time synchronization system having backward compatibility and forward compatibility for existing IMES, to adopt such a IMES based signals are for convenience, any it can be employed signal format. In other words, the technical scope of the present invention is not limited to the technique related to the known IMES, it should be determined on the basis of the description of the claims.
[0035]
　In the mobile communication system 1, each base station 300-1 and 300-2, a position ... can receive IMES-TAS signal transmission unit for supplying IMES-TAS signal 200-1,200 -2, ... (hereinafter, sometimes collectively referred to as "transmission unit 200".) it is placed respectively. Furthermore, for each transmission unit 200, a signal for generating the IMES-TAS signal (hereinafter, also referred to as "transmission RF (Radio Frequency) signal".) Reference unit 100 to be supplied is installed. In the mobile communication system 1 shown in FIG. 1, assume a configuration in which one reference unit 100 to the existing building 10 each is installed. Transmission unit 200-1, 200-2 based on the transmission RF signal provided from the reference unit 100, ... are respectively generated the IMES-TAS signal, the base station 300-1, 300-2, ... are by receiving the respective IMES-TAS signal, it can determine the current time.
[0036]
　IMES-TAS signal from the transmitting unit 200 to the base station 300 is assumed to be transmitted wirelessly. Transmission of the transmission RF signal from the reference unit 100 to the transmitting unit 200 may be a wireless, but basically, it is transmitted by wire is assumed.
[0037]
　As an example, assuming that the new multiple base stations 300 on the building 10 of the existing, may be newly laid signal lines building 10, so as to utilize the existing cable that exists in the building 10 of the existing it may be. Such existing cables, telephone lines, communication lines, power lines, can be utilized such as an antenna wire. Further, the medium for transmitting the signal may be a conductor (metal wiring), it may be an optical fiber.
[0038]
　In the present embodiment, it is assumed to use a joint acousto-optic systems installed in the building 10 as an example. In this case, the antenna wire 16 constituting the joint acousto-optic system is utilized. Antenna wires 16 are run throughout the mixing amplifier 12 in building 10, on the path of the antenna wire 16, one or more terminals 18 for connecting the television apparatus is installed. For example, the terminal 18 may be installed in each room.
[0039]
　As described above, the transmitting unit 200 receives the first timing signal generated based on a first radio signal from the positioning satellite system. The transmission unit 200, based on the signal and the time information received by the receiving unit, the second radio signal having a radio signal compatible with the positioning satellite system (IMES-TS signal / IMES-TAS signal) Send. IMES-TAS signal includes a position, a time, and the timing signal, and authentication information.
[0040]
　Reference unit 100, via the mixed amplifier 12, is electrically connected to the antenna wire 16. Each transmitter unit 200, via one of the terminals 18 is electrically connected to the reference unit 100. That is, the transmission RF signal output from the reference unit 100, through the mixing amplifier 12 and the antenna wire 16, are provided to the respective transmission units 200, each of the transmission unit 200, a transmission RF signal from the reference unit 100 based generates the IMES-TAS signal is transmitted to the base station 300. The branch of the antenna wire 16, one or more terminals 18 for connecting the transmission unit 200 for demodulating a transmission RF signal propagating on the antenna wiring 16 is provided. By adopting such a configuration, it is possible to realize a system synchronization in a mobile communication system including a base station 300.
[0041]
　At the time synchronization system according to the present embodiment, the processing and function are hierarchically structured, each hierarchy of processes and functions also referred to as "segments". More specifically, as shown in FIG. 3, referred to the processes and functions to acquire necessary information from such GNSS signal a "segment 1" or "S1". The processes and functions to transmit information necessary for generating the IMES-TAS signal or IMES-TS signal is referred to as "Segment 2" or "S2". IMES-TAS signal or IMES-TS signal generation and processing and functions related to the transmission of the referred to as "segment 3" or "S3".
[0042]
　In the following description, in order to indicate whether the function belongs to the segment, "S1", "S2", it is described by adding the description such as "S3".
[0043]
　Reference unit 100 includes a GNSS receiver 110 for processing a GNSS signal received via the GNSS antenna 102, S2 modulator generates a transmission RF signal for generating an IMES-TAS signal 120 (S2TX) including. It shows an example configuration implementing the GNSS receiver 110 and S2 modulator 120 a reference unit 100 may implement respective device independently. It will be described later in detail GNSS receiver 110 and S2 modulator 120.
[0044]
　Typically, the reference unit 100 is to acquire information that is time synchronization of criteria based on GNSS signals, for information as a time synchronization of the reference is not limited to the GNSS signals, even using other information good.
[0045]
　The secret key for the reference unit 100 generates an authentication code may be provided to the transmitting unit 200. In this case, the reference unit 100 receives the secret key issued by any of the authentication server 108, may transmit the transmission RF signal including the secret key to the transmission unit 200. Note that the secret key, it is preferable to use something unique among the plurality of transmission units 200. Therefore, the reference unit 100, a secret key that is directed to certain transmission unit 200, a combination of the identification information indicating a destination of the secret key, may be incorporated into the transmission RF signal.
[0046]
　Between the authentication server 108 and the reference unit 100 may be configured to communicate via a network 109 such as the Internet or private networks.
[0047]
　Transmission unit 200, based on the time information provided by the reference unit 100 generates an authentication code. In other words, the authentication code is equivalent to a predetermined length of the message, which is calculated based on the time information acquired by the GNSS receiver 110 that serves as a reference time acquiring unit. Such authentication code, for example, one-time password which depends on the current value of the time (TOTP: Time-Based One-Time Password) can be used. Hereinafter also referred to as "TOTP" the authentication code. By sending in conjunction with such TOTP the position and time information, it is possible to realize an authentication position.
[0048]
　Transmission unit 200, S2 modulator 120 S2 demodulator 210 for demodulating a transmission RF signal transmitted from the (S2RX), S3 generates an IMES-TAS signal from the demodulation result of S2 demodulator 210 transmitter 220 (S3TX) including the door. The S2 demodulator 210 and S3 transmitter 220 illustrates an example structure that is mounted on the transmission unit 200 may be implemented each device independently. S2, described later in detail demodulator 210 and S3 transmitter 220.
[0049]
　Figure 4 is a schematic diagram showing a configuration example of the base station 300 included in the mobile communication system 1 according to the present embodiment. Referring to FIG. 4, the base station 300 includes a wireless transceiver 310 for exchanging radio signals with the mobile terminals in the cell area, GNSS signals and IMES-TAS receives a signal S3 receiver 320 (S3RX ) a.
[0050]
　The wireless transceiver 310 is connected to an antenna 340 used for transmission and reception of radio signals between the mobile terminal, an antenna 340 for receiving GNSS signals or IMES-TAS signal is connected to step S3 receiver 320 ing. The base station 300 may be configured to support any communication method. As an example, the base station 300 when supporting TD-LTE (Time Division Long Term Evolution), even as a wireless transceiver 310, configurations are employed for exchanging the mobile terminal and data time division multiplex . Note that the base station 300, in addition to TD-LTE, it may be configured to support FDD-LTE (Frequency Division Duplex Long Term Evolution). Since the structure of the wireless transceiver 310 is well known, a detailed description thereof will not be given. S3, will be described in detail later in the receiver 320.
[0051]
　As described above, according to this embodiment, by maximum use of existing facilities, it can be realized mobile communication system 1. When installing the base station 300 by utilizing the existing equipment, as shown in FIG. 2, only it needs to newly install a reference unit 100 and one or more transmission units 200. Incidentally, the IMES-TAS signals transmitted from the same transmitting unit 200 a plurality of base stations 300 may be utilized. Therefore, it is not necessary to newly established as many transmission unit 200 of the base station 300 is newly installed.
[0052]
　Thus, in a case where it is necessary to newly install a base station 300, such as a micro base station, by using a time synchronization system according to the present embodiment can be realized at lower cost.
[0053]
　(A2: implementation 2)
　in FIG. 1 and FIG. 2 described above, an example of installing a reference unit 100 in the building 10 each, so as to share a single reference unit 100 between a plurality of building 10 it may be employed Do configuration. Hereinafter, as compared to the mobile communication system 1 shown in FIG. 1 and FIG. 2 illustrates a configuration can reduce the number of reference unit 100.
[0054]
　5 and 6 are schematic views showing an example of a mobile communication system 2 including a time synchronization system according to the present embodiment. 5 and the mobile communication system 2 shown in FIG. 6, as in the mobile communication system 1 shown in FIGS. 1 to 3, a plurality of base stations 300-1 and 300-2 to an existing building 10, ... - and constructed by the newly installed.
[0055]
　Here, the building 10 of the existing and cable television (CATV) have been introduced. That is, the lead line 20 of the CATV network is connected to the mixing amplifier 12. In such a configuration, by installing the reference unit 100 to any of the CATV network, by transmitting a transmission RF signal through the CATV network, can utilize the IMES-TAS signals in a plurality of building 10 .
[0056]
　As a specific configuration, as shown in FIG. 5, the head end 30 of the CATV broadcast stations, and transmission lines 32 constituting the plurality of CATV network is connected, the receiver distributor to each of the transmission lines 32 34 are connected. Receiver distributor 34, a signal from the CATV broadcasting station demodulates and distribution, each transmit a signal through a plurality of drop line 20 to a plurality of buildings.
[0057]
　In general, the transmission line 32, a coaxial cable or an optical cable is used. Time synchronization system according to the present embodiment is applicable without being limited to the type of transmission line 32.
[0058]
　As described above, according to this embodiment, by maximum use of existing equipment, it can be achieved a number of mobile communication system 1 at a lower cost. When installing the base station 300 by utilizing the existing equipment, as shown in FIG. 6, the building 10 of the existing need not be any modification, including the lead-in wire 20 of existing CATV networks, the existing it established a reference unit 100 to the CATV network, using existing antenna wires 16 and the terminal 18, where needed, only have to install one or more transmission units 200. Incidentally, the IMES-TAS signals transmitted from the same transmitting unit 200 a plurality of base stations 300 may be utilized. Therefore, it is not necessary to newly established as many transmission unit 200 of the base station 300 is newly installed.
[0059]
　Thus, by using the existing facilities such as a CATV network, even if it is necessary to newly install a base station 300, such as a micro base station, in addition to the transmission unit 200 of the required number, by installing a reference unit 100, such as CATV broadcasting stations, it is possible to realize a system synchronization between all the base stations 300. Therefore, even when installing a number of base station 300, to suppress the installation costs can be achieved widespread.
[0060]
　The present invention is not limited to the CATV network, if capable of transmitting and receiving transmission lines some signal to a plurality of buildings is installed, by using such transmission lines, time synchronization system according to the present embodiment It can also be implemented. For example, you may be using, for example district of disaster prevention contact network.
[0061]
　: (A3 system synchronization accuracy)
　with reference to FIGS. 1 and 5, system synchronization may include that base station 300 is kept below the upper limit value in the timing offset previously determined among cell area to provide each . For example, assume a cell area 350-1,350-2,350-3,350-4 the base station 300-1, 300-2, 300-3 or 300-4 is provided, respectively. In the example shown in FIGS. 1 and 5, the cell area 350-1 and a cell area 350-2 are overlapped. By using the time synchronization system according to the present embodiment, the timing offset Terr1-2 of cell area with each other that this overlap, for example, can be suppressed to below ± 500 nanoseconds. Similarly, the timing deviation Terr1-3 the cell area 350-1 and a cell area 350-3, can be maintained at the same level of accuracy. Also, the usual base station (not shown) for the timing deviation Terr3-out between the cell area 350-4 for providing the cell area 400 and the base station 300-4 to provide, can be maintained at the same level of accuracy. Such accuracy, timing offset between the mobile communication system 1 shown in FIGS. 1 to 3, the reference unit 100 and transmission unit 200 may be realized be suppressed to below ± 500 nanoseconds.
[0062]
　(A4: Small Batch)
　As described above, in the time synchronization system according to the present embodiment, the transmission RF signal based on the reference time reference unit 100 manages superimposed on the transmission line to distribute to a plurality of terminals 18. Each connected to the transmission unit of the terminal 18 200 receives a transmission RF signal distributed for receivable base stations 300 a GNSS signal, wirelessly transmits IMES-TAS signal with GNSS signals compatible to. The base station 300 may implement the system synchronization based on IMES-TAS signal.
[0063]
　At the time synchronization system according to the present embodiment, since the IMES-TAS signal is generated and supplied by the transmission unit 200 installed in the vicinity of the base station 300, the transmission path from the reference unit 100 to the transmission unit 200 of the constraints are fewer. Therefore, it is possible to use the existing facilities, even if you have to install a large number of base stations 300, can reduce the cost.
[0064]
　: (A5 providable service)
　time synchronization system according to the present embodiment can provide the following services.
[0065]
　(1) providing location services in indoor
　GNSS (GPS or QZSS (Quasi-Zenith Satellite System: QZSS ) etc.) even indoors it can not receive GNSS signals from the positioning service and the hierarchy has a GNSS compatible It can provide information.
[0066]
　(2) provide time information which is synchronized with the GNSS
　The year that is synchronized with the GNSS, month, day, hour, minute, it is possible to provide the information in seconds. Also be considered for the leap year and leap second.
[0067]
　(3) providing a timing source, synchronized to GNSS
　can provide a timing signal synchronized with the GNSS (such as a GPS or QZSS) (e.g., 1 second pulse signal / 1PPS signal).
[0068]
　(4) providing a frequency source, synchronized to GNSS
　may provide GNSS frequency source available for comparison calibration (such as GPS or QZSS) (clock).
[0069]
　(5) provide position and authentication service time using
　can provide authentication services to prove "when" and "where" (e.g., described later TOTP). In such as cloud services and E call mass service, in addition to the user authentication of the order to prove the "Who", can control the constraint that the "when" and "where". By using such an authentication service, for example, functions predominantly as a geo-fence for cloud services.
[0070]
　(6) Complex provision of ID information
　with respect to such mobile terminal from IMES-S3 transmitter connected to the network, it broadcasts a complex of ID information that can be used in such message notification and ticketing.
[0071]
　(7) Indoor delivery or indoor broadcasting disaster information
　such as QZSS has received disaster information (Disaster Message) to be broadcast to provide a distribution or function of the broadcast with respect to such mobile terminals existing indoors. More specifically, the function of receiving the disaster information broadcast from QZSS, and a function of generating a message conforming to IMES message format, mounted on the reference unit 100. By adopting such a configuration, the position can not receive radio signals from QZSS (e.g., indoors or home) even mobile terminals that are present in, receives the disaster information, notifies the user be able to. With such a function, it is possible to realize a indoor disaster prevention system.
[0072]
　Hereinafter, details of each apparatus constituting the mobile communication system including a time synchronization system according to the present embodiment.
[0073]
　 reference unit 100
　reference unit 100 obtains the time serving as a reference at the time synchronization system according to the present embodiment. The method for acquiring the time, any method can be envisaged. At the time synchronization system according to the present embodiment, and the use of GNSS signals or PTP (Precision Time Protocol) technology.
[0074]
　When using a GNSS signal, a reference unit 100, GNSS receiver 110 is implemented. GNSS receiver 110 receives the GNSS signal, and acquires various types of information including at least time information.
[0075]
　GNSS signal for the GNSS receiver 110 obtains the reference time may be an arbitrary one. The GNSS, as a typical, GPS, GLONASS (Global Navigation Satellite System), SBAS (Satellite-based augmentation system), Beidou positioning satellite system (BeiDou Navigation Satellite System), Galileo, Quasi-Zenith Satellite (Quasi-Zenith Satellite System: QZSS) and the like are known. Can utilize any GNSS signal that can be received at a position reference unit 100 is installed.
[0076]
　The GNSS receiver 110 for receiving GNSS signals, can be employed general-purpose device. GNSS receiver 110 based on the received GNSS signals, perform PVT (position, time and speed) operation. GNSS receiver 110, obtained by these PVT operation, position information, time information, information such as frequency signal, and a timing signal (in the case of GPS, the 1PPS signal).
[0077]
　Thus, GNSS receiver 110, based on the radio signal (GNSS signal) from the GNSS, the timing signal (e.g., 1PPS signal) as a reference time acquiring unit for acquiring time information corresponding to the timing indicated by and timing signals Function.
[0078]
　Instead of the GNSS signals, or, in addition to the GNSS signal, it may acquire the time synchronization reference using PTP technique. Typical examples of PTP techniques may be employed slave clock 104 in accordance with the protocol defined in IEEE (Institute of Electrical and Electronic Engineers) 1588 (PTP) or IEEE1588v2 (PTPv2) (see FIGS. 2 and 3). Slave clock 104 is to time synchronization between the grand master clock, not shown, with respect to S2 modulator 120, provides information that is time synchronization reference. When further connected a clock to synchronize the slave clock 104 may implement the slave clock 104 as a ground slave clock. Incidentally, the slave clock 104 may be previously installed as a backup in case can not receive GNSS signals in a GNSS receiver 110.
[0079]
　Instead of the GNSS signals, or, in addition to the GNSS signal, it may acquire the time synchronization reference from the system synchronization signal transmitted from the base station of the mobile communication system. When this configuration is employed, for example, it may be used the receiver 106 for receiving the system synchronization signal. The receiver 106, in addition to the receiving circuit and the demodulation circuit of the same radio signal and being mounted such as mobile terminals, may have a circuit for calculating the time from the system synchronization signal to be decoded. Such By adopting the receiver 106 can be relative to S2 modulator 120, provides information that is time synchronization reference.
[0080]
　Reference unit 100, a slave clock 104, time information, etc. Timing signals can be obtained. That is, when utilizing the PTP technique, but can not obtain the location information, to the extent that they achieve the system synchronization is not operational problems even not retrieve location information.
[0081]
　When realizing the mobile communication system 2 shown in FIGS. 5 and 6, since the transmission RF signal from the reference unit 100 multiple transmit unit 200 is to utilize a high reliability by increasing redundancy it is preferable to achieve. Therefore, mounting a plurality of GNSS receivers 110 based unit 100 or may be installed together GNSS receiver 110 and the slave clock 104 to the reference unit 100.
[0082]
　
　Next, processing for generating a transmission RF signal in S2 modulator 120 of the reference unit 100 will be described.
[0083]
　S2 modulator 120 generates a transmission RF signal various kinds of information modulated and such time information GNSS receiver 110 is included in the GNSS signal received. S2 modulator 120 generates a transmission RF signal in synchronization with the timing signal (1PPS signal). Transmission RF signal is superimposed on the existing joint acousto-optic systems and / or existing CATV network. As described above, the transmission RF signal superimposed on joint acousto-optic system or a CATV network is transmitted to all the home that are connected to the joint acousto-optic system.
[0084]
　Thus, S2 modulator 120 is connected to a wiring that branches plurality, corresponding modulation signals containing time information (transmission RF signal) a timing signal (1PPS signal) on generated synchronously wire functions as a modulator for sending to. Here, wiring for transmitting RF signal is transmitted, the conductor may be any of (metal wire) and an optical fiber. Such wiring may, for example, the signal line joint acousto-optic systems, CATV signal lines, and, for communication either at least one of the signal lines (telephone, DSL (Digital Subscriber Line), FTTH (Fiber To The Home)) or it can be utilized.
[0085]
　The existing joint acousto-optic systems and existing CATV networks, it is common to video and audio signals are transmitted in one or more frequency channels. Therefore, when superimposing the transmission RF signal, it is necessary to use the idle channel having a sufficient transmission band. In view of such circumstances, S2 as the modulator 120, it is preferable that the variable according to RF frequency of the transmission RF signal generated in the free channel. Further, it is preferable that the one corresponding to the occupied frequency width vacant channel of the transmission RF signal.
[0086]
　At the time synchronization system according to the present embodiment, as an example, phase shift keying input signal outputted from the GNSS receiver 110: converting a digital signal with (PSK phase-shift keying). As an example of the phase shift keying, BPSK (binary phase-shift keying) may be employed modulation.
[0087]
　Figure 7 is a block diagram showing a circuit configuration example of a time synchronization system constituting S2 modulator 120 according to the present embodiment. Referring to FIG. 7, S2 modulator 120 includes a IF (Intermediate Frequency) signal generating circuit 121, a carrier oscillator 125, an up-conversion circuit 126.
[0088]
　IF signal generation circuit 121, after processing the input signals from the GNSS receiver 110, and outputs the IF signal by BPSK modulation. Input signal includes time information and telemetry signals. For each set of time information and telemetry signals, synchronization word (hereinafter also referred to as "SYNC word".) Is added, as described below, it facilitates the demodulation process in S2 demodulator 210 of the transmission unit 200 It is adapted to reduction.
[0089]
　More specifically, IF signal generation circuit 121, a modulation circuit 122, a low pass filter and a:: (Digital Analog Converter DAC) 124 and (LPF Low Pass Filter) 123, digital-to-analog converter.
[0090]
　Modulation circuit 122, based on the timing signal from the GNSS receiver 110, extracts the time information and the telemetry signal of the information included in the input signal from the GNSS receiver 110, after adding the SYNC word, NRZ performing -BPSK modulation to generate a modulated signal. When containing the authorization code IMES-TAS signal, the authentication code to the modulation circuit 122 is input, a modulation signal including an authentication code is generated.
[0091]
　Signal after NRZ-BPSK modulation bandwidth is limited by an FIR (Finite Impulse Response) filter. For example, the modulation circuit 122 outputs a modulated signal that receives an input frequency TBD [MHz] according to the transmission path empty channel transmission RF signal is superimposed, the center frequency and TBD. In this embodiment, the bit rate of the modulated signal is 1 Mbps. However, such modulation method and bit rate of the modulated signal, without being particularly limited to the configuration described above, in accordance with the required specifications and system configurations, may be selected as appropriate optimized. Eg, BPSK instead of (binary phase shift keying) modulation, may also be used, such as QPSK (Quadrature Phase Shift Keying) modulation, in place of the NRZ (Non Return to Zero) method, NRZI (Non Return it may be used, such as to Zero Inversion) method. With the change of such modulation schemes, bit rate, etc. can also be appropriately changed.
[0092]
　Modulated signal outputted from the modulation circuit 122, on band-limited by the low-pass filter 123, and converted to analog by the digital to analog converter 124, and output as an IF signal.
[0093]
　Note that the modulation circuit 122 or the modulation circuit 122 and its peripheral circuits may be digital processing using a FPGA (field-programmable gate array).
[0094]
　Up-conversion circuit 126 outputs the IF signal from the modulation circuit 122 carrier waves from the carrier oscillator 125 (e.g., 10 MHz) as the transmission RF signal up-converted by. Specifically, up-conversion circuit 126 includes a mixer 127, a variable amplifier 128, a low pass filter 129. The mixer 127 multiplies the carrier wave from the carrier oscillator 125 into an IF signal from the modulation circuit 122. Signal output from the mixer 127, through the variable amplifier 128 and low pass filter 129, is output as a transmission RF signal.
[0095]
　Figure 8 is a diagram showing a structural example of a transmission RF signal generated by the time synchronization system constituting S2 modulator 120 according to the present embodiment. Referring to FIG. 8, in the S2 modulator 120, transmission RF signal is generated in synchronization with the periodic timing signal output (1PPS signal). Typically, the start position and the timing signal the rise of the SYNC word contained in each of the transmission RF signal (or falling) match. By adopting such a configuration, in S2 demodulator 210 of the transmission unit 200, in addition to the time information, it is possible to reproduce the timing signal. That is, the transmission RF signal includes a SYNC word in addition to the time information, the transmission RF signal including the SYNC word is sent to the time the timing signal is output on line as a reference.
[0096]
　By adopting the circuit configuration described above, it is possible to generate transmission RF signals including input signals from the GNSS receiver 110.
[0097]
　
　Next, a description will be given demodulation processing of a transmission RF signal in S2 demodulator 210 of the transmission unit 200.
[0098]
　S2 demodulator 210 demodulates the transmission RF signal transmitted through the joint acousto-optic systems, and / or a CATV network, to extract the data contained in the transmitted RF signal.
[0099]
　At the time synchronization system according to the present embodiment, depending from S2 modulator 120 of the reference unit 100 in the transmission path to the S2 demodulator 210 of the transmission unit 200, a function of correcting the transmission delay of the transmission RF signal (Delay Compensation )have. Correction amount of transmission delay (correction time) may be measured in advance, fixed value, or a variable value dynamically changes according to the state of the transmission path.
[0100]
　When assuming a real joint acousto-optic systems and CATV network as a transmission path is a transmission direction of the transmission RF signal is unidirectional, and, since the transmission RF signal occupies a frequency of a particular idle channel, previously measured it is sufficient to use a fixed transmission delay and. However, as described below, may implement automatic correction function of delay time.
[0101]
　Figure 9 is a block diagram showing a circuit configuration example of a time synchronization system constituting S2 demodulator 210 according to the present embodiment. Referring to FIG. 9, S2 demodulator 210, after changing the transmission RF signal received from S2 modulator 120 into an IF signal, demodulates the digital signal, detects the SYNC word contained in the demodulated digital signal doing, to output the demodulated data in synchronism with the timing signal (1PPS signal). Specifically, S2 demodulator 210 includes a down-conversion circuit 212, a demodulation circuit 214, a carrier oscillator 217, and a system oscillator 218.
[0102]
　Downconverting circuit 212 outputs a transmission RF signal received as an IF signal down converted by a carrier wave from the carrier oscillator 217 (I and Q components). Carrier oscillator 217, according to a clock obtained by the system clock which is loop control from the system oscillator 218 by dividing, for generating a carrier wave. Specifically, down-conversion circuit 212 includes a variable amplifier 2121, a mixer 2122, an amplifier 2123,2125, and low-pass filter 2124,2126.
[0103]
　Transmission RF signal, after being adjusted amplitude by the variable amplifiers 2121, that carrier wave from the carrier oscillator 125 by the mixer 2122 is multiplied, I and Q components of the IF signal is output. I component of the transmission RF signal output from mixer 2122 via amplifier 2123 and a low-pass filter 2124, and output to the demodulation circuit 214. Similarly, Q components of the transmission RF signal output from mixer 2122 via amplifier 2125 and a low-pass filter 2126, and output to the demodulation circuit 214.
[0104]
　Demodulation circuit 214 demodulates the IF signal outputted from the down-converted circuit 212, and outputs the demodulated data. Specifically, the demodulation circuit 214, a digital-to-analog converter 2141 and 2142, the phase rotator 2143, a low-pass filter 2144,2145, a mixer 2146, a bit synchronization portion 2147, a SYNC detection unit 2148, a data extraction a Department 2149, a serial / parallel converter 2150, a delay correction amount holding section 2151, the synchronization adjustment section 2152, a phase comparator 2153, a frequency divider 2154,2159, a loop filter 2156,2157, digital-to-analog converter a vessel 2158, and an amplifier 2160. Note that all or a portion of demodulator 214 may be digitally processed using FPGA.
[0105]
　I and Q components from down-conversion circuit 212, after being converted respectively by the digital-analog converters 2141 and 2142 into a digital signal, is outputted to the phase rotator 2143. I and Q components are BPSK demodulated by the phase rotator 2143, each of the demodulation result is output to the mixer 2146. Further, the demodulation result of the I component is demodulated is input to the bit synchronization section 2147 into a bit string. SYNC detection unit 2148, by detecting the SYNC word contained in the bit string outputted from the bit synchronization unit 2147 to generate a timing signal (1PPS signal). Timing signal from the SYNC detection unit 2148 is output to the synchronization adjustment section 2152. The data extraction unit 2149 extracts the data that follows the SYNC word SYNC detection unit 2148 detects. Finally, the data extracted by the data extraction unit 2149, is shaped by the serial / parallel converter 2150 to a predetermined data format, and output as demodulated data. Demodulated data is provided to step S3 transmitter 220. Incidentally, the serial / parallel converter 2150, for example, can be realized by using a circuit such as a UART (Universal Asynchronous Receiver Transmitter).
[0106]
　If the secret code is included in the IMES-TAS signal may be further implements an interface for outputting the secret code included in the demodulation result of the transmission RF signal to the secure.
[0107]
　Mixer 2146 constitutes a part of the Costas loop called loop, the output from the mixer 2146 is fed back via a loop filter 2157 and a digital to analog converter 2158 to the system oscillator 218. System oscillator 218 is an oscillator for providing a system clock of the demodulator circuit 214, for example, a transmission carrier wave of the RF signal (e.g., 10 MHz) generates a clock of 100MHz is a frequency obtained by 10 times. System oscillator 218 varies the oscillation frequency in response to a feedback signal from the digital-to-analog converter 2158. The system oscillator 218, a voltage controlled crystal oscillator (VCXO: Voltage Controlled Crystal Oscillator) or a temperature compensated crystal oscillator (TCXO: Temperature Compensated Crystal Oscillator) may be employed.
[0108]
　System clock from the system oscillator 218, is 1/10 frequency-divided by the frequency divider 2159, is reproduced as a carrier wave of the transmission RF signal received. Thus, the carrier wave of a transmission RF signal (10 MHz) demodulates the BPSK-modulated signal in the Costas loop, is output by reproducing at the carrier recovery loop.
[0109]
　SYNC detection unit 2148, by detecting the SYNC word contained in the transmission RF signal to reproduce the timing signal (1PPS signal). Timing signal from the SYNC detection unit 2148, after being corrected transmission delays by the synchronization adjustment section 2152, and is the phase comparison timing signal generated within the demodulation circuit 214 by the system oscillator 218 (1 Hz). That is, the phase comparator 2153, and the timing signal from the synchronization adjustment section 2152, and a timing signal obtained by dividing the system clock by the frequency divider 2154 is inputted. Phase difference detected by the phase comparison unit 2153, via the loop filter 2156 is fed back to the phase rotator 2143. In other words, these loops operation, will be phase to be input to the Costas loop is properly rotated, it can be synchronized with the timing signal (1PPS signal) and the system clock. Then, for example, the timing signal obtained by dividing the system clock by the frequency divider 2154 is output as a 1PPS signal. At this time, timing signal (1PPS signal) taking into account the transmission delay, so that the SYNC word contained in the transmission RF signal is outputted before the timing to be detected. That is, the output of the timing signal (1PPS signal) will be done prior to the extraction of data following the SYNC word.
[0110]
　As described above, S2 demodulator 210 is connected to one of the branch wirings branching plurality, functions as a demodulator for demodulating a modulated signal propagating on interconnect (transmission RF signal). As shown in FIGS. 1 and 5, basically, a plurality of S2 demodulator 210 for one reference unit 100 is installed.
[0111]
　Function to correct the transmission delay of the transmission RF signal employed at the time synchronization system according to the present embodiment (Delay Compensation) is mainly achieved by the delay correction amount holding unit 2151 Oobi synchronization adjustment section 2152. By setting the predetermined delay time measured in advance to the delay correction amount holding section 2151, will be the timing signal (1PPS signal) is corrected by the set time, thereby, the transmission delay of the transmission RF signal It can be corrected. More specifically, S2 demodulator 210 detects a SYNC word contained in the modulated signal (transmission RF signal) propagating through the upper wire, and outputs the subsequent information to the detected SYNC word as demodulated data, a timing signal (1PPS signal) time earlier by a predetermined correction time from the time of detecting the SYNC word as a reference. By applying such a delay correction function, the output of the timing signal (1PPS signal), but so that the output of the demodulated data is shifted, since the 1PPS signal is high cycle accuracy, utilizing the periodicity in, not a problem of generating and transmitting an IMES-TAS signal.
[0112]
　The delay compensation function in S2 demodulator 210 according to the present embodiment, the transmission RF signal processed by the transmission unit 200 connected to the same time synchronization system in a state synchronized with an accuracy of ± 500 ns (target value) It can be maintained.
[0113]
　By adopting the configuration described above, in the S2 demodulator 210 connected to the terminal 18 of the respective home, the demodulation and synchronization tracking process with respect to the transmission RF signal, the position information, time information, information such as frequency signal and outputs a timing signal (1PPS signal).
[0114]
　
　Next, a description will be given generation processing and transmission processing of IMES-TAS signal in S3 transmitter 220 of the transmission unit 200. S3 transmitter 220, based on the demodulated data and timing signals from S2 demodulator 210 generates and transmits the IMES-TAS signal. For example, S3 receiver 320 of base station 300 when it is compatible with the GPS as GNSS is, RF frequency of IMES-TAS signal is set to 1.57542 GHz. However, depending on the radio administrative constraints in the preceding to operate the present system may be appropriately changed RF frequency. Further, when implemented as a system that has a compatibility with other positioning satellite system other than GPS may be adopted one or more of the RF frequency corresponding to the positioning satellite system in question.
[0115]
　(E1: circuitry)
　Fig. 10 is a block diagram illustrating's S3 circuit configuration example of a transmitter 220 of a time synchronization system according to the present embodiment. Referring to FIG. 10, S3 transmitter 220 includes a digital processing block 221, an EEPROM (Electronically Erasable and Programmable Read Only Memory) 222, an analog processing block 223, an antenna 224, a digital output interface 225, the timing It includes an interface 226, an oscillator 227, an analog processing block 223 are electrically connected to digital processing block 221, and a power supply 228.
[0116]
　Digital processing block 221 includes a CPU (Central Processing Unit) 2212, a RAM (Random Access Memory) 2214. And the EEPROM, and the digital input-output interface 225, a timing interface 226, the oscillator 227, and is electrically connected to digital processing block 221. The antenna 224 is electrically connected to analog processing block 223.
[0117]
　EEPROM222, a program CPU2212 digital processing block 221 is executed, and stores data necessary to generate the IMES signal and IMES-TAS signal. Programs and necessary data is stored in EEPROM222 is read when the S3 transmitter 220 is activated, it is transferred to RAM2214. EEPROM222 may further store data input from the outside at S3 transmitter 220. The storage device for storing programs and necessary data is not limited to the EEPROM, at least, it may be a storage device in which data can be nonvolatile manner store.
[0118]
　Digital processing block 221 via the digital output interface 225, the obtained demodulated data from the S2 demodulator 210 (position information, time information, information such as a frequency signal), from S2 demodulator 210 through a timing interface 226 It receives the acquired timing signal (1PPS signal), and generates data to be a source for generating an IMES signal and IMES-TAS signal. Digital processing block 221, the analog processing block 223, and sends the generated data as a bit stream.
[0119]
　Oscillator 227, a clock for generating a clock or carrier wave, which defines the operation of the CPU2212, and supplies to the digital processing block 221.
[0120]
　Analog processing block 223, using the bit stream output from digital processing block 221 to generate a transmission signal by modulating a carrier wave of 1.57542 GHz, and sends it to the antenna 224. Its signal is sent from antenna 224. In this way, IMES signal and IMES-TAS signal is sent to S3 transmitter 220.
[0121]
　Power 228 supplies power to each unit constituting's S3 transmitter 220. The power supply 228, as shown in FIG. 10, may be incorporated in the S3 transmitter 220 may be a mode for receiving the power supply from the outside.
[0122]
　In the above description, CPU2212 is used as an arithmetic processing unit for realizing the process in digital processing block 221, other processing devices may be used. Alternatively, the digital processing block 221 may be constituted by a FPGA.
[0123]
　In Figure 10, the clock (Clk) is supplied from digital processing block 221 to analog processing block 223 may be supplied directly from the oscillator 227 to the analog processing block 223.
[0124]
　Furthermore, for clarity of description, in the present embodiment, the digital processing block 221 and the analog processing block 223 are shown separately, on implementation, may be mixed on one chip.
[0125]
　(E2: Message Format: examples of IMES-TS signal (1))
　Next, an example of a message format of IMES-TS signal transmitted to S3 transmitter 220. At the time synchronization system according to the present embodiment, as an example, employing the IMES based signal. Therefore, for the signal structure employed as IMES-TS signals, preferably those which can realize the IMES signal backward compatible. That, S3 transmitter 220, a timing signal (1PPS signal) obtained by the demodulation in the corresponding S2 demodulator 210 and based on the time information, radio signal compatible with a radio signal from a GNSS (GNSS signal) functions as a transmission unit for transmitting.
[0126]
　Figure 11 is a diagram illustrating an example of a message type of the signal transmitted time synchronization system according to the present embodiment to S3 transmitter 220 of (MT). Referring to FIG. 11, in addition to the four message types (MT0, MT1, MT3, MT4), which is defined as a known IMES signal, for IMES-TS signals, even if the message format 260A (MT7) is employed good. Message shown in FIG. 11 is an example, as long as it contains the information required for time synchronization may be utilized any message format.
[0127]
　As an example, the message format 260A is, GPSNav message compatible GPSWeek and TOW (Time Of Week), month, day, hour, minute, including information of seconds. For more information about this message format 260A will be explained.
[0128]
　Figure 12 is a diagram showing an example of a frame structure of the message format 260A used in the time synchronization system according to the present embodiment as IMES-TS signal. Referring to FIG. 12, a message format 260A shown in FIG. 12 is a format conforming to the format of GPSNav message compatible.
[0129]
　Specifically, the message format 260A is composed of four words 261, 262, 263, 264. Each word 261, 262, 263, 264 is composed of 30 bits. The first word 261 includes a preamble field 2611, a message type field 2612, a telemetry region 2613, and a parity bit area 2614. The second word 262 includes a counter area 2621, a leap second region 2627, the GPS week area 2628, the time source region 2625, and a parity bit area 2626. Third word 263 includes a counter area 2631, the TOW region 2637, a satellite Healthy region 2635, and a parity bit area 2636. TOW (Time Of Week) refers to the total seconds from the beginning the week. Fourth word 264 includes a counter area 2641, the time area 2642, a frequency region 2643, a second region 2644, a satellite Healthy region 2645, and a parity bit area 2646.
[0130]
　Contained in the message format 260A, by using and TOW information stored in the area 2637 (elapsed weeks from baseline (January 6, 1980)) the information stored in the GPS week region 2628, as the time information, the year, month, day, hour, minute, can be calculated in seconds.
[0131]
　As shown in FIG. 11, IMES-TS signal is configured as a frame composed of a plurality of words.
[0132]
　(E3: Message Format: examples of IMES-TS signal (2))
　will be described another example of a message format of IMES-TS signal transmitted to S3 transmitter 220. At the time synchronization system according to the present embodiment, as an example, employing the IMES based signal. Therefore, for the signal structure employed as IMES-TS signals, preferably those which can realize the IMES signal backward compatible. That, S3 transmitter 220, a timing signal (1PPS signal) obtained by the demodulation in the corresponding S2 demodulator 210 and based on the time information, radio signal compatible with a radio signal from a GNSS (GNSS signal) functions as a transmission unit for transmitting.
[0133]
　Figure 13 is a diagram showing another example of a message type of the signal transmitted time synchronization system according to the present embodiment to S3 transmitter 220 of (MT). Referring to FIG. 13, in addition to the four message types defined as known IMES signal, as IMES-TS signals, two types of message formats 250 and 260 may be employed. Incidentally, two not necessarily need to implement both message format, it may be mounted only one. Further, an example message is illustrated in FIG. 13, as long as it contains the information required for time synchronization may be utilized any message format.
[0134]
　As an example, the message format 250 includes information with GPSWeek and TOW of GPSNav message compatible. Message format 260, and year, month, day, hour, minute, including the information of the second. Whether to use any message format 250 and message format 260 is appropriately determined depending on the implementation at S3 receiver 320. Thus, IMES-TS signal may be support at least one of a message format 250 and message format 260. The following describes details of each message format.
[0135]
　Figure 14 is a diagram showing an example of a frame structure of a message format 250 used in the time synchronization system according to the present embodiment as IMES-TS signal. Message format 250 shown in FIG. 14 is a format of GPSNav message compatible. S3 is the case where the receiver 320 is compatible with the GPS, because it has a message decoder for processing a message format 250, without modifying the message decoder, as the time information, and year, month, day, hour , minutes, it is possible to get a second.
[0136]
　Specifically, the message format 250 consists of three words 251, 252 and 253. Each word 251, 252 and 253 is composed of 30 bits. The first word 251 includes a preamble field 2511, a message type field 2512, a telemetry region 2513, and a parity bit area 2514. The second word 252 includes a counter area 2521, a leap second region 2522, the GPS week area 2523, the time source region 2524, and a parity bit area 2525. Third word 253 includes a counter area 2531, the TOW region 2532, a satellite Healthy region 2533, and a parity bit area 2534.
[0137]
　Included in message format 250, by using and TOW information stored in the area 2532 (elapsed weeks from baseline (January 6, 1980)) the information stored in the GPS week region 2523, as the time information, the year, month, day, hour, minute, can be calculated in seconds.
[0138]
　Figure 15 is a diagram showing an example of a frame structure of a message format 260 used in the time synchronization system according to the present embodiment as IMES-TS signal. With reference to FIG. 15, message format 260 shown in FIG. 15, The year, month, day, hour, minute, is a format that directly represent the second.
[0139]
　Specifically, the message format 260 consists of three words 261, 262, 263. Each word 261, 262, 263 is composed of 30 bits. The first word 261 includes a preamble field 2611, a message type field 2612, a telemetry region 2613, and a parity bit area 2614. The second word 262 includes a counter area 2621, a year area 2622, a month area 2623, a day area 2624, and the time source region 2625, and a parity bit area 2626. Third word 263 includes a counter area 2631, the time area 2632, a frequency region 2633, a second region 2634, a satellite Healthy region 2635, and a parity bit area 2636.
[0140]
　Included in message format 260, the year area 2622, a month area 2623, a day area 2624, when the region 2632, a frequency region 2633, by directly utilizing the information stored respectively in the second area 2634, time as information, and year, month, day, hour, minute, can be acquired in seconds.
[0141]
　As shown in FIGS. 14 and 15, IMES-TS signal is configured as a frame composed of a plurality of words.
[0142]
　(E4: Message Format: examples of IMES-TAS signal (1))
　Next, an example of a message format of IMES-TAS signal transmitted to S3 transmitter 220. At the time synchronization system according to the present embodiment, as an example, employing the IMES based signal. Therefore, for the signal structure employed as IMES-TAS signals, preferably those which can realize IMES signal backward compatible. That, S3 transmitter 220, a timing signal (1PPS signal) obtained by the demodulation in the corresponding S2 demodulator 210 and based on the time information, radio signal compatible with a radio signal from a GNSS (GNSS signal) functions as a transmission unit for transmitting.
[0143]
　Figure 16 is a diagram showing still another example of a message type of the signal transmitted to S3 transmitter 220 of the time synchronization system according to the present embodiment (MT). Referring to FIG. 16, in addition to the four message types defined as known IMES signal, as IMES-TAS signal, message format 270 may be employed. Message shown in FIG. 16 is an example, as long as it contains the information required for time synchronization may be utilized any message format.
[0144]
　In the message format 270 (MT7) of IMES-TAS signal shown in FIG. 16, by introducing the concept of a "page", while maintaining compatibility with existing message formats, so that it can transmit more information It has been extended to. That is, the message format 270 includes a value of the message type, by combining the value of the page, for a particular message type of the message, it is possible to send a message of number of words exceeds the number existing words. Figure 16 is a message format 270 shows an example where four words of data may exist three pages, without being limited thereto, for the number of pages, may be extended to the required number.
[0145]
　17 and 18 are diagrams showing an example of a frame structure of a message format 270 used in the time synchronization system according to the present embodiment as IMES-TAS signal. Message format 270, depending on the application, can be the number of pages in the variable, in addition to the case of only the message format (4 words / one page) shown in FIG. 17, a message format and diagrams shown in FIG. 17 18 configuration that combines the message format shown in (8 words / 2 pages in total) may be employed. It may also be employed (4 words × number of pages in total) repeating combination constituting the message format (4 words) shown in FIG. 18. Such length of the message format (number of words / pages) may be variable depending on the application.
[0146]
　Message format 270 shown in FIG. 17 and FIG. 18 shows a format of GPSNav message compatible. S3 is the case where the receiver 320 is compatible with the GPS, because it has a message decoder for processing a message format 270, without modifying the message decoder, as the time information, and year, month, day, hour , minutes, it is possible to get a second.
[0147]
　Specifically, the message format 270 is composed of at least four words 271, 272, 273 and 274. Furthermore, in the case of adding the authentication code may be combined word 275,276,277,278 shown in FIG. 18. Each word 271,272,273,274,275,276,277,278 is composed of 30 bits.
[0148]
　The first word 271 includes a preamble field 2711, a Message Type field 2712 in which information for identifying the message type is stored, the telemetry region 2713 where telemetry information is stored, and a parity bit area 2714.
[0149]
　The second word 272, a counter area 2721 count of the message is stored, a message page area 2722, a leap second region 2723, the reference date (e.g., January 6, 1980) contains the elapsed week from a GPS week region 2724 to be, and a parity bit area 2725. The leap seconds area 2723, information showing the timing of leap seconds are inserted or deleted, and information indicating which one insertion or deletion is stored.
[0150]
　Message format 270, since also be configured over a plurality of pages (4 words per page), the message page area 2722, stores information for each message to identify how many page It is.
[0151]
　Third word 273 includes a counter area 2731, the TOW region 2732, the LAS region 2733, the time source region 2734, and a parity bit area 2734. The TOW region 2732, starting midnight Sunday, the count value is incremented by one count every 1.5 seconds is stored. If the message format 270 is sent every 3 seconds, between the preceding IMES-TAS signal and IMES-TAS signal subsequent to that of, the incremented value by two counts are stored in the TOW region 2732 become. The LAS region 2733, whether the status value application of leap seconds is enabled is stored.
[0152]
　Fourth word 274, a counter area 2741, a leap seconds application week region 2742, a leap second effective date area 2743, and applies leap second region 2744, a transmitter ID2745, satellite Healthy region 2746, the parity bit area 2747 including the door. By the day of the week it is stored in the elapsed week and leap seconds application date area 2743 which is stored in the leap seconds application week region 2742, timing a leap second is applied is scheduled. The application leap seconds region 2744, the magnitude of the applied leap seconds is defined. For example, the application leap seconds region 2744, or to apply a "1 second" as a leap second, or information indicating whether to apply the "one second" is stored. The transmitter ID2745 is identification information for identifying the transmission unit 200 that generated the IMES-TAS signal is stored.
[0153]
　Note that the information stored in the message format 270 shown in FIG. 17, the above-described FIG. 12, FIG. 14, description of the message format shown in FIG. 15 see also.
[0154]
　Referring to FIG. 18, the word 275,276,277,278 message format 270 provides a region for transmitting TOTP. As described below, words 275,276,277,278 is the sum, it is possible to transmit a 64-bit TOTP. By continuously transmits the same message format as the word 275,276,277,278 can transmit 128 bits TOTP.
[0155]
　5 th word 275 includes a counter area 2751, the control area 2752, and TOTP region 2753, and a parity bit area 2747. The control area 2752, the procedure control codes indicating, for example, required for the authentication process using the TOTP is stored. The TOTP region 2753, 6 bits among the data constituting the TOTP is stored.
[0156]
　6 th word 276 includes a counter area 2761, a message page area 2762, the TOTP region 2763, and a parity bit area 2764. The TOTP region 2763, 17 bits of data constituting the TOTP is stored.
[0157]
　7 th word 277 includes a counter area 2771, the TOTP region 2772, and a parity bit area 2773. The TOTP region 2772, 21 bits of data constituting the TOTP is stored. 8 th word 278 includes like the seventh word 277, a counter area 2781, the TOTP region 2782, and a parity bit area 2783.
[0158]
　(E5: Message Format: examples of IMES-TAS signal (2))
　will be described another example of a message format of IMES-TAS signal transmitted to S3 transmitter 220. Instead of the IMES based message format defined in FIGS. 16 to 18, may be employed message format as shown below.
[0159]
　Figure 19 is a diagram showing still another example of a message type of the signal transmitted to S3 transmitter 220 of the time synchronization system according to the present embodiment (MT). Referring to FIG. 19, in addition to the four message types defined as known IMES signal, as IMES-TAS signals, two types of message formats 250A and 270A may be employed. Message shown in FIG. 19 is an example, as long as it contains the information required for time synchronization may be utilized any message format.
[0160]
　In the message format 250A of IMES-TAS signal shown in FIG. 19 (MT6) and message format 270A (MT7), by introducing the concept of a "page", while maintaining compatibility with existing message formats, and more It has been extended to be able to send a lot of information.
[0161]
　Figure 20 is a diagram illustrating an example of a frame structure of the message format 270A used in the time synchronization system according to the present embodiment as IMES-TAS signal. Message format 270A, depending on the intended use, can be the number of pages in the variable, in addition to the case of only the message format (4 words / one page) shown in FIG. 20, described above with the message format shown in FIG. 20 it is possible to use a construction in which a combination of a message format shown in FIG. 18 (8 words / 2 pages in total). Figure 20 configuration combined repeated message format (4 words) shown in (4 words × number of pages in total) may be employed. Such length of the message format (number of words / pages) may be variable depending on the application.
[0162]
　Message format 270A shown in FIG. 20 is a format of GPSNav message compatible. S3 is the case where the receiver 320 is compatible with the GPS, because it has a message decoder for processing the message format 270A, without modifying the message decoder, as the time information, and year, month, day, hour , minutes, it is possible to get a second.
[0163]
　Specifically, the message format 270A includes at least four word 271A, 272A, 273A, consists of 274A. Word 271A, 272A, 273A, each 274A is composed of 30 bits.
[0164]
　First word 271A includes a preamble field 2711, a Message Type field 2712 in which information for identifying the message type is stored, the telemetry region 2713 where telemetry information is stored, and a parity bit area 2714.
[0165]
　The second word 272A includes a counter area 2721 count of the message is stored, a message page area 2726, a leap second region 2723, the reference date (e.g., January 6, 1980) contains the elapsed week from and IMES week area 2727 to be, and a DPC area 2728.
[0166]
　Third word 273A includes a counter area 2731, the EOW rollover region 2736, a TOW region 2732, the LAS region 2733, and LTF region 2734, and a parity bit area 2734.
[0167]
　Fourth word 274A includes a counter area 2741, a leap seconds application Seconds region 2748, a leap second effective date area 2743, a delay time domain 2749, a transmitter ID2745, satellite Healthy region 2746, and a parity bit area 2747 including.
[0168]
　Note that the information stored in the message format 270A shown in FIG. 20, above 12, 14, 15, describes the message format shown in FIG. 18 see also.
[0169]
　Figure 21 is a diagram showing an example of a frame structure of the message format 250A used in the time synchronization system according to the present embodiment as IMES-TAS signal. Message format 250A shown in FIG. 21 is used to provide authentication services using location and time. Referring to FIG. 21, the word 251A message format 250A, 252A, 253A, 254A are used to store data used for the authentication service.
[0170]
　Specifically, the message format 250A is four words 251A, 252A, 253A, consists of 254A. Word 251A, 252A, 253A, each 254A is composed of 30 bits.
[0171]
　First word 251A includes a preamble field 2511, a message type field 2512, a telemetry region 2513, and a parity bit area 2514. The second word 252A includes a counter area 2526, the message type field 2527, a content area 2828, and a parity bit area 2525. Third word 253A includes a counter area 2535, the content area 2536, and a parity bit area 2534. Fourth word 254A includes a counter area 2541, the content area 2542, and a parity bit area 2543.
[0172]
　In addition to the message format 250A shown in FIG. 21, above 12, 14, 15, describes the message format shown in FIG. 18 see also.
[0173]
　(E6: transmission cycle / transmission sequence)
　Next, a transmission cycle of the IMES-TAS signal transmitted to S3 transmitter 220 will be described. At the time synchronization system according to the present embodiment, as the timing code IMES-TAS signal, a message containing the telemetry word to be stored in the telemetry area 2513 is transmitted every predetermined transmission period. Here, the telemetry word, fixed code is used that is determined in advance. By using code such fixing, it can function as a SYNC word for synchronization.
[0174]
　As an example, S3 transmitter 220, and to repeatedly transmit the timing code a message containing the telemetry word every 3 seconds as an interval. In this case, for example, by setting the bit rate of the signal transmitted to S3 transmitter 220 to 250 bps, it is possible to transmit 25 words per 3 seconds (250 bps × 3 seconds ÷ 30bit).
[0175]
　In the following description, the bit rate of the signal transmitted to S3 transmitter 220 will be described as an example in the case of 250 bps, for bit rate, without being limited thereto, it is a value appropriate for the system it can. For example, messages sent from the GPS satellites is 50 bps, to conform to the existing specifications may be the bit rate of the signal transmitted to S3 transmitter 220 to 50 bps. In this case, since the amount of data that can be transmitted per unit time becomes 1/5 (= 50/250), as described below, for such transmission period set on the premise of 250bps is by changing the 5-fold Bayoi. As for the interval is not limited to 3 seconds, for example, it may be changed to time, such as 6 seconds. Such, for interval and the bit rate, in accordance with the required specifications and system configurations, may be selected as appropriate optimized.
[0176]
　Figure 22 is a diagram for explaining an example of a timing code transmitted as IMES-TAS signal in the time synchronization system according to the present embodiment. Referring to FIG. 22, when the transmission cycle of IMES-TAS signal to S3 transmitter 220 arrives, the transmission of each word constituting the message format 270 (MT7) shown in FIGS. 17 and 18 is started. More specifically, so that the word 271,272,273,274,275,276,277,278 constituting the message format 270 (MT7) are sequentially transmitted. When sending messages MT7 is completed, the transmission of another message is performed.
[0177]
　(In this example, three seconds) transmission period Ts from the transmission of the first word 271 after the elapse, since the transmission period of the next IMES-TAS signal arrives, the configuration message format 270 (MT7) word 271, 272, 273 , the transmission of 274,275,276,277,278 is repeated. Similarly, for each transmission period Ts, the data relating to the message format 270 (MT7), and other message formats are sent repeatedly. That is, a plurality of word beginning (first word) constituting the frame of the IMES-TAS signal is associated with the beginning of the transmission cycle at S3 transmitter 220. The IMES-TAS signal, since telemetry word of a fixed value is used, the beginning of the word is fixed at a predetermined value. Therefore, it is also possible to use the entire top of the word as a SYNC word or replica during demodulation. In S3 the receiver 320, based on the periodic timing code that is repeatedly transmitted, to achieve a time synchronization.
[0178]
　In reality, the message format 270 is a IMES-TAS signals are configured at eight words, among the message that can be sent (25 words) in the transmission period of 3 seconds, 8 word occupies in IMES-TAS signal It is. About it other 17 words, known IMES signal can be freely assign a message (FIG. 11, FIG. 13, MT0, MT1, MT3, MT4 shown in FIG. 16).
[0179]
　That is, if it is satisfied even condition that messages containing always telemetry word in each transmission period Ts (MT7 or MT6) is transmitted, for the type of message transmitted in the other time may be determined arbitrarily. Note that, before the transmission timing of the message including the telemetry word, there is a case where some of the extra word will be present. In such a case, by inserting the message completed in one word, such as MT3, it is necessary to pad.
[0180]
　S3 transmitter 220, in the period (1 second) longer than the period (3 seconds) of the timing (1PPS) output from S2 demodulator 210, and transmits the IMES-TAS signal. Thus, by lengthening the transmission period of IMES-TAS signals, it can also send the IMES signal in clearance time can diversify method provides information to the base station 300 side. That, S3 transmitter 220, in a period in which the IMES-TAS signal is not transmitted, it is also possible to transmit a radio signal (IMES signal) to replace the radio signal (GNSS signal) from the GNSS.
[0181]
　Figure 23 is a diagram for explaining an example of a message sent to S3 transmitter 220 in the time synchronization system according to the present embodiment. As shown in FIG. 23, (in this example, three seconds) transmission period Ts for each, it can be seen that eight words constituting the message format 270 is always transmitted. For other time, any message is sent.
[0182]
　As described above, S3 IMES-TAS signal transmitted from the transmitter 220, because of the GNSS signal and the IMES signal and the backward compatibility, it is possible to simultaneously operate. That, S3 receiver 320, together can receive and decode the GNSS signals can be received and decoded even the IMES signal and IMES-TAS signal.
[0183]
　Note that (distance and S3 transmitter 220 and S3 receiver 320) service area at S3 transmitter 220 several m ~ several tens of m is assumed, the delay time required for transmission of the IMES-TAS signal every 10m since approximately 33 nanoseconds, the system specification for time synchronization system according to the present embodiment, the delay time of the transmission of the IMES-TAS signal is negligible.
[0184]
　Figure 23 described above, an example of sending a message format 270 is a IMES-TAS signal in 3-second cycles may be employed a longer transmission period. For example, S3 transmitter 220, and to repeatedly transmit the timing code messages (message according to the message format 250) comprising a telemetry word every 6 seconds as an interval. In this case, for example, by setting the bit rate of the signal transmitted to S3 transmitter 220 to 250 bps, it is possible to transmit 50 words per 6 seconds (250 bps × 6 seconds ÷ 30bit).
[0185]
　Figure 24 is a diagram for explaining another example of a message sent to S3 transmitter 220 in the time synchronization system according to the present embodiment. As shown in FIG. 24, (in this example, 6 seconds) transmission period Ts for each, it can be seen that three words constituting the message format 250 is always transmitted. For other time, any message is sent.
[0186]
　As described above, S3 IMES-TS signal transmitted from the transmitter 220, because of the GNSS signal and the IMES signal and the backward compatibility, it is possible to simultaneously operate. That, S3 receiver 320, together can receive and decode the GNSS signals can be received and decoded even the IMES signal and IMES-TS signal.
[0187]
　(E7: processing procedure of a generation / transmission of IMES-TAS signal)
　Next, an example of a processing procedure according to the generation and transmission of IMES-TAS signal in S3 transmitter 220.
[0188]
　Figure 25 is a flowchart showing a processing procedure for generating and transmitting IMES-TAS signal to S3 transmitter 220 of the time synchronization system according to the present embodiment. Each step shown in FIG. 25 is basically executed by the digital processing block 221 at S3 transmitter 220.
[0189]
　Referring to FIG. 25, S3 transmitter 220 determines whether the generation and transmission preparation of IMES-TAS signal is completed (step S200). S2, based from demodulator 210 to whether to receive the demodulated data and timing signals, may determine the presence or absence of completion of the transmission preparation. If generation and transmission preparation of IMES-TAS signal has not been completed (NO in step S200), the process of step S200 is repeated.
[0190]
　When generation and transmission preparation of IMES-TAS signal is completed (YES in step S200), S3 transmitter 220 waits to receive a next timing signal from S2 demodulator 210 (step S202). When the S2 demodulator 210 receives the next timing signal, S3 transmitter 220, based on the demodulated data from the S2 demodulator 210 at that time, the message format 270 of IMES-TAS signal (or message format 250 or 260) first word generates and transmits constituting the (step S204). That, MT7 or MT6 message is generated and transmitted. Subsequently, in the S3 transmitter 220, based on the same demodulated data from the S2 demodulator 210, message format 270 of IMES-TAS signal (or message format 250 or 260) to generate a subsequent word constituting the sequentially transmits (step S206).
[0191]
　Subsequently, S3 transmitter 220 determines whether it has received a timing signal from S2 demodulator 210 (step S208). S2 when receiving the timing signal from the demodulator 210 (YES in step S208), S3 transmitter 220 reaches the number of times the reception cumulative number of the timing signal after transmission of the last IMES-TAS signal corresponds to the transmission period Ts determines whether the (step S210). If the transmission period Ts is 3 seconds, whether or not the reception of the third timing signal after transmission of the last IMES-TAS signal is determined.
[0192]
　If the received cumulative number of timing signals after the transmission of the last IMES-TAS signal has reached the count corresponding to the transmission period Ts (YES in step S210), the following process is repeated step S206.
[0193]
　In contrast, if not receive a timing signal from S2 demodulator 210 (NO in step S208), or, corresponding to the received cumulative number transmission period Ts of the timing signal after transmission of the last IMES-TAS signal if not reached the number of times (step S210 NO in), in the S3 transmitter 220, according to a predetermined rule, it generates and transmits IMES signal (step S212). That, MT0, MT1, MT3, MT4 any message is generated and transmitted. Then, the following process is repeated step S208.
[0194]
　The processing procedure described above, with respect to S3 transmitter 220 to S3 receiver 320, IMES-TAS signal is transmitted.
[0195]
　
　Next, a description will be given reception processing and demodulation processing of IMES-TAS signal in S3 the receiver 320 of base station 300.
[0196]
　Figure 26 is a block diagram showing a circuit configuration example of a time synchronization system constituting's S3 receiver 320 according to the present embodiment. Referring to FIG. 26, S3 receiver 320 includes a plurality of channel blocks 321, a navigation processing unit 322, a selection control section 323, a synchronization detector 324, a frequency divider 325 and 327, stabilization loop and a 326.
[0197]
　Each of the plurality of channel block 321 demodulates the received signal (RF signal), and outputs the message contained therein. A plurality of channel blocks 321 demodulates and message output respective received signals performed in parallel, the output from each channel block 321 the selection control unit 323 selectively outputs to the subsequent stage.
[0198]
　Specifically, each channel block 321, a correlator 3211 and 3212, a message extracting unit 3213, a C / A (coarse / access) code generator 3214, a convolution operation unit 3215, an integration circuit 3216 including.
[0199]
　Correlator 3211 calculates the correlation between the C / A code is a spread code output from the received signal and the C / A code generator 3214.
[0200]
　Message extractor 3213 extracts the message (frame) included in the output from the correlator 3211. Message extractor 3213 outputs the bit stream (bit, stream) indicating the extracted message. In addition, the message extracting unit 3213, by adjusting the phase of the clock (Clock) generated by the loop control and manage synchronization detection timing in the channel block 321.
[0201]
　Integration circuit 3216, together with synchronizing the phase in accordance with the clock from the message extracting unit 3213, and outputs the output to the convolution arithmetic unit 3215. Convolution operation unit 3215 performs convolution operation between the synchronizing signal from the received signal and integrating circuit 3216. And it outputs the result to the correlator 3212. Correlator 3212 calculates the correlation between the C / A code output from the result and C / A code generator 3214 of convolution operation from convolution operation section 3215. That is, using a correlator 3212 and convolution operation section 3215, C / A code coherent integration process is performed. The output from the correlator 3212 is provided to the message extracting unit 3213. Message extractor 3213, based on the respective outputs from the correlators 3211 and correlator 3212, to adjust the phase of the clock. Such loop control, the message contained in the received signal can be detected with high accuracy.
[0202]
　Loop count for the messages in the integration circuit 3216 (convolution calculation process) may be different according to the type of message. For example, to implement the convolution calculation process for 120 times for IMES-TAS signal (MT6 and MT7), IMES signal (MT0, MT1, MT3, MT4) for performing the four convolution processing, GNSS signals it may be carried out 20 times of convolution calculation process for. It will be described later convolution calculation process for IMES-TAS signal.
[0203]
　The navigation processing unit 322, a message is output that contains from one channel block 321 in GNSS signal or IMES signal to perform PVT operation on the message. The navigation processing unit 322 obtained as a result of PVT operation position (GNSS Position), time (GNSS time), the timing signal (GNSS 1PPS), and IMES outputs data (including the authentication data).
[0204]
　Selection control unit 323 detects a message that is output by IMES-TAS signal to channel block 321 is input, and outputs the detected message to the synchronization detector 324 and stabilization loop portion 326.
[0205]
　Synchronization detector 324 detects a message containing a telemetry word transmitted periodically, and outputs it as timing signals IMES-TAS signal. As described above, since the message including the telemetry word is sent by the 3-second period, the synchronization detecting unit 324 outputs one pulse signal (IMES-TAS 1pulse / 3second) every 3 seconds.
[0206]
　The synchronous detection unit 324 outputs the timing of each bit to be input as a clock (CLK). As described above, when the 250bps bit rate of the signal transmitted to S3 transmitter 220, the synchronization detector 324 will output a clock of 250 Hz. Divider 325 is a kind of counter, which outputs a single pulse to 250 times of the clock. That is, the timing signal outputted from the frequency divider 325 (IMES-TAS 1PPS (Real)) corresponds to the 1PPS signal. Incidentally, S3 When 50bps the bit rate of the signal transmitted from the transmitter 220, it may be adopted divider that outputs a single pulse to 50 times the clock.
[0207]
　Regulation loop unit 326, a clock from the message extracting unit 3213 receives the bit string from the navigation processing unit 322, by phase-locked by using a PLL (Phase Locked Loop) loop including a local oscillator, IMES- It outputs a clock of the TAS signals and GNSS signal (IMTS-TAS / GNSS clock (Stable)). The PLL loop by regulation loop unit 326, the clock output is more stable.
[0208]
　Divider 327, like the divider 325 is a kind of counter, which outputs a single pulse to 250 times of the clock. That is, the timing signal outputted from the frequency divider 327 (IMES-TAS 1PPS (Stable)) is a stable signal from corresponding to the 1PPS signal.
[0209]
　Regulation loop unit 326 and the frequency divider 327 is an optional configuration, in accordance with the time synchronization accuracy required in the radio transceiver unit 310 which is utilized destination base station 300, is provided as appropriate.
[0210]
　As described above, S3 receiver 320 demodulates the IMES-TAS signal to S3 transmitter 220, functions as a receiving unit for acquiring time information corresponding to the timing indicated by the timing signal (1PPS) and the timing signal . When IMES-TAS signal MT7 is received, it can obtain the GPSWeek and TOW of GPSNav message compatibility (see Figure 17). Further, when the IMES-TAS signal MT8 is received, and year, month, day, hour, minute, it can be acquired seconds directly (see Figure 18).
[0211]
　(In this example, 3 seconds) IMES-TAS signal (MT7 or MT8) transmission period Ts are repeatedly transmitted every, also, the first word 271 shown in the message (FIG. 22 that includes a telemetry word, or, in FIG. 23 in words 271) first shown, all 30 bits from the preamble region to the parity bit area becomes a fixed value, the C / a code coherent integration process of the correlator 3212, a higher C / N (Carrier to Noise ) ratio it is possible to obtain a. As a result, it is possible to improve the synchronization accuracy.
[0212]
　Figure 27 is a diagram for explaining the process of receiving a message containing a telemetry word in S3 receiver 320 constituting a time synchronization system according to the present embodiment. Referring to FIG. 27, S3 receiver 320 (in this example, 3 seconds) rising transmission period Ts of the first bit of the message (word 251 or word 261) comprising a telemetry word is an integer multiple of one it can be determined that. The two messages are sent subsequently to the message containing the telemetry word (word 252 and 253, or word 262 and 263) by receiving, can obtain all the necessary information about the time.
[0213]
　For example, S3 receiver 320 receives the MT7 as IMES-TAS signal, its time is to have been decoded as "23 minutes 30 seconds at 10 June 30, 2016". Thereafter, the transmission period Ts (3 seconds) Upon receipt of a new MT7 after, and the time that has received the first bit of the newly MT7 of the received frame is "23 minutes and 33 seconds at 2016 June 30, 2010 10" It can be interpreted. Such process is repeated for each transmission period Ts (3 seconds).
[0214]
　Moreover, since the bit rate of the signal transmitted to S3 transmitter 220 is 250 bps, from the reception of the message including the telemetry word, by detecting the 250 count (1 bit 1 count) in the counter, as the timing signal can output a 1PPS signal. That is, the synchronization detector 324 and the frequency divider 325 shown in FIG. 26 reproduces the 1PPS signal based on the IMES-TAS signal transmitted to S3 transmitter 220. S3 accuracy of 250bps modulated signals transmitted from the transmitter 220, since the constantly keeping accuracy required for time synchronization, as long as the special stability is not required, the synchronization detector 324 and the frequency divider shown in FIG. 26 1PPS signal output from the 325 has a practically sufficient accuracy.
[0215]
　S3 is when the bit rate of the signal transmitted from the transmitter 220 is 50bps, by detecting synchronization over 5 times longer, the bit rate can be achieved the same accuracy as the case is 250 bps.
[0216]
　In the case where a special stability is required, regulation loop unit 326 and the frequency divider 327 shown in FIG. 26 is used. Regulation loop unit 326, by performing the correlation process with the C / N ratio improvement by integration process using the telemetry word, to reduce the phase noise of the extraction and timing signals clearer signal. In regulation loop portion 326, rather than simply counting the bits constituting the message, and a phase synchronization mechanism for telemetry word using PLL. Further, the regulation loop portion 326, in order also to achieve a stable loop with respect to a relatively long transmission period of 3 seconds, a high-precision crystal oscillator (OCXO: Oven Controlled Crystal Oscillator) or a temperature compensated crystal oscillator oscillator is used with a high accuracy and high stability such (TCXO).
[0217]
　Thus, for MT7 and MT8 used as IMES-TAS signal has extensibility can sufficiently cope with the demand for greater stability.
[0218]
　Further, S3 receiver 320 may may receive GNSS signals and IMES-TAS signals simultaneously. However, in an environment that can receive IMES-TAS signal, the reliability of the time information and the timing signal is obtained from the GNSS signal is very low. This is in the S3 transmitter 220, in general, the environment can not receive GNSS signals, or, GNSS signal reliability is significantly low environmental received (e.g., indoor) in order is disposed to like is there.
[0219]
　In view of this reason, in the case of receiving GNSS signals and IMES-TAS signals simultaneously, time information and the timing signal is obtained from the GNSS signals it would be preferable not to use. Alternatively, if the IMES-TAS signal is received, a configuration may be adopted so as not to receive any GNSS signals. Further alternatively, it may be pre-set to receive a GNSS signal to S3 receiver 320. For example, in S3 the receiver 320, so indicating that the indoor receiver by setting to "0" BD (Binary Decoder) for MT3. That is, low reliability of positioning based on the GNSS signal, or indicates that GNSS signal is not received. By blocking the processing of the GNSS signal, power consumption can be reduced in S3 the receiver 320, and it is possible to obtain a stable synchronization signal.
[0220]
　Incidentally, when receiving the IMES-TAS signals transmitted from a plurality at S3 transmitters 220 installed close to in S3 receiver 320 selects the IMES-TAS signal received at the earliest timing it may be. This timing difference is only order of nanoseconds, it is preferable to detect the earlier timing signal by using a correlator.
[0221]
　It will now be described technique the C / N ratio improvement in S3 the receiver 320.
　Figure 28 is a diagram for explaining the structure of a message employed in the time synchronization system according to the present embodiment. FIG 24 shows the relationship between the C / A code and the IMES-TAS signal (message format 270 of MT7). In IMES-TAS signal, representing one bit of the message in the repeated 4 times the C / A code is a spreading code. In the normal GNSS signals, to represent one bit of the message in 20 iterations of the C / A code.
[0222]
　Therefore, typical GNSS receiver constitutes a signal tracking loop when capturing the C / A code, to implement the coherent integration process (convolution calculation process) at the timing of the C / A code on the received signal. This improves the C / N ratio, improves the stability of the signal tracking loop.
[0223]
　In contrast, in the IMES-TAS signal used in the time synchronization system according to the embodiment, and representing one bit in four repetitions of the C / A code. Therefore, in the same convolution operation and general GNSS receiver, the effect of improving the C / N ratio is small.
[0224]
　Therefore, in the IMES-TAS signals, messages for signal tracking and integration process is provided. In other words, the first word 271 of IMES-TAS signal (message format 270 of MT7) can be made to function as a synchronization word. As described above, the first word 271, since 30-bit all is a fixed value, in in the S3 receiver 320, can be used as a replica like the C / A code. By using a message containing such telemetry word it can be performed up to 120 times of coherent integration process (convolution calculation process). That, S3 receiver 320 is a circuit for performing a plurality of convolution processing with respect to first word constituting the IMES-TAS signal is implemented. To improve the C / N ratio using the convolution calculation process of such a plurality of times, to improve the stability of the signal tracking loop, increasing the frequency and timing performance is an essential of the IMES-TAS signal can.
[0225]
　As described above, in in the S3 receiver 320, by utilizing the characteristics of the IMES-TAS signal transmitted to S3 transmitter 220, by improving the C / N ratio, and outputs a highly accurate time information and timing signal be able to.
[0226]
　
　will now be described the generation and use of the authentication code.
[0227]
　Figure 29 is a diagram for explaining an example of information included in the signal transmitted in the time synchronization system according to the present embodiment. Referring to FIG. 29, GNSS signal 103 is received by the reference unit 100 is typically a timing signal 1031, a clock 1032, and the position information 1033, time information 1034, and leap second information 1035 including.
[0228]
　Timing signal 1031 may include, for example, is information for providing a timing signal synchronized with GNSS, for example, 1 second pulse signal (1PPS signal).
[0229]
　The clock 1032 includes, for example, is information for providing a frequency source, synchronized to GNSS, for example, a 10MHz pulse signal.
[0230]
　Position information 1033 includes an information for providing a location service, for example, latitude, longitude, height, etc. floor information.
[0231]
　Time information 1034, including a information in order to provide time information that is synchronized to the GNSS, for example, The year, month, day, hour, minute, and second of information. Similarly, the leap second information 1035 is information for providing a time information synchronized with the GNSS, including information for correcting the leap seconds.
[0232]
　Further, IMES-TAS signal 203 transmitted to S3 transmitter 220 of the transmission unit 200 is typically a timing signal 2031, a clock 2032, and the position information 2033, time information 2034, and leap second information 2035 , including an authentication code 2036.
[0233]
　A timing signal 2031, a clock 2032, and the position information 2033, time information 2034, for the leap second information 2035 is similar to the corresponding information contained in the GNSS signal 103, detailed description will not be repeated.
[0234]
　Authentication code 2036, for example, contains the value of TOTP as a one-time password which depends on the current value of the position and time.
[0235]
　Such as S3 base station 300 or mobile terminal receives the IMES-TAS signal 203 from the transmitter 220 of the transmission unit 200, by receiving the IMES-TAS signal 203, in addition to position and time, a complete position and time it is also possible to realize an authentication process to ensure the sexual or authenticity.
[0236]
　Figure 30 is a diagram for explaining an example of a method of generating the authentication code at the time synchronization system according to the present embodiment. Referring to FIG. 30, S3 transmitter 220 of the transmitting unit 200, generates the encoder 280 for generating a TOTP, the IMES-TAS signal containing TOTP generated by the encoder 280 (message) to and a IMES-TAS generator 282.
[0237]
　Encoder 280, with respect to the time information and any seed code acquired by demodulating the transmission RF signal, by executing a predetermined irreversible calculation, generates a TOTP a predetermined number of bits. Typically, TOTP can be a 64-bit or 128-bit. Of course, it may be employed TOTP consisting more bits may be adopted TOTP consisting fewer bits.
[0238]
　The irreversible calculation for generating TOTP, typically, it is preferable to use a cryptographic hash function. Such cryptographic hash function, it may be a function of the SHA (Secure Hash Algorithm) series. Such a message digest that is output from the cryptographic hash function is equivalent to TOTP. Alternatively, it may be employed TOTP generated according generation algorithm is defined as RFC6238.
[0239]
　In the encoder 280, the time information and the secret key that is set for each transmission unit 200 is provided to the cryptographic hash function. TOTP Thus, a message of predetermined length as input a secret key and time information is calculated according to the cryptographic hash function.
[0240]
　Secret key is used as a seed code for generating a message digest (TOTP). When employing such a configuration, it is preferable to employ a hardware having high tamper resistance to attack relative to the reference unit 100. For example, it is preferable to employ a configuration can be realized such key pair generation and message digest computed in a single chip. An example of such a configuration, such as TPM (Trusted Platform Module) is known. In TPM, the physical reverse engineering is attempted to defeat the built-in memory, also have been devised to prevent read the stored which was value. Such high by adopting the hardware having tamper resistance can be kept in a secure against such attacks and physical reverse engineering from the network.
[0241]
　Alternatively, instead of setting the advance secret key transmission unit 200, it may be used a secret key that the authentication server 108 generates. Authentication server 108, to generate a secret key at random. Secret key by the authentication server 108 generates, from the reference unit 100 may be included in the transmission RF signal transmitted to the transmission unit 200. By using the secret key from the authentication server 108, it is not necessary to hold a static secret key based unit 100 itself, it is possible to enhance the security strength.
[0242]
　IMES-TAS generator 282, position information, time information, IMES message, in addition to the identification information, from TOTP generated by the encoder 280, to generate the IMES-TAS signal as described above.
[0243]
　By implementing the reference unit 100 configured as shown in FIG. 30, it is possible to broadcast the IMES-TAS signal containing TOTP.
[0244]
　
　receives the IMES-TAS signal transmitted from the transmission unit 200, information obtained by decoding the IMES-TAS signal thereof received, for example, the received data is output from the common GPS receiver module it may be output in a form that conforms to NMEA format used when it is.
[0245]
　31 to 40 are diagrams showing an example of a data output format of the IMES-TAS signal in the time synchronization system according to the present embodiment.
[0246]
　Figure 31 shows an example of a format (IMTCS) for outputting information for receiving the position and time of the service. In the format shown in FIG. 31, including the current time, basic information is stored.
[0247]
　Figure 32 shows an example of a format (IMTCR) for outputting a more primitive information for receiving the position and time of the service. In the format shown in FIG. 32, information contained in the IMES-TAS signal received is stored as it is.
[0248]
　Figure 33 shows an example of a format (IMASC) for outputting information for receiving a service using the authorization code. In the format shown in FIG. 33, in addition to the information of the position, an authentication code associated with the information of the position (TOTP) is stored.
[0249]
　Figure 34 shows an example of a format (IMMSG) for outputting information such as reception processing of the IMES-TAS signal. In the format shown in FIG. 34, the type and the received bit stream itself IMES-TAS signal received is stored.
[0250]
　Figure 35 shows an example of a format (IMIPI) for outputting the position information of itself. In the format shown in FIG. 35, information of the current position that is included in the IMES-TAS signal received from a particular transmitting unit 200 are stored.
[0251]
　Figure 36 shows an example of a format (IMSPI) for outputting the synthesized position information. In the format shown in FIG. 36, information of the current position synthesized based on the plurality of information is stored.
[0252]
　FIG 37 shows an example of a format (IMSID) for outputting such short ID included in the message sent. In the format shown in FIG. 37, information such as the short ID and and boundary bits obtained from the received message is stored.
[0253]
　Figure 38 shows an example of a format (IMMID) for outputting such medium ID included in the message sent. In the format shown in FIG. 38, information such as media beam ID and and boundary bits obtained from the received message is stored.
[0254]
　Figure 39 shows an example of a format (IMDSA) in the case of transmission using the time synchronization system according disaster information such as QZSS broadcasts the (Disaster Message) to the present embodiment. In the format shown in FIG. 39, information for notifying the disaster information is stored.
[0255]
　FIG 40 shows an example of a format (GPGGA) for outputting the contents of the IMES-TAS signal broadcast. FIG 40, etc. for debugging, the contents themselves contained in IMES-TAS signal is output.
[0256]
　Format shown in FIGS. 31 to 40 is merely an example, it is possible to employ any NMEA format.
[0257]
　
　Next, the delay time for operating the Delay Compensation in time synchronization system according to the present embodiment the measuring and the processing of setting.
[0258]
　Figure 41 is a diagram for explaining the transmission delay occurring in the time synchronization system according to the present embodiment. Referring to FIG. 41, for example, a message was sent from S2 modulator 120 of the reference unit 100 at a certain time T1. In S2 demodulator 210 of the transmission unit 200, the same message is received at time T2. In this case, the difference between time T1 and time T2 corresponding to the delay time. In particular, in the mobile communication system 2 shown in FIGS. 5 and 6, since the transmission path from the S2 modulator 120 of the reference unit 100 to the S2 demodulator 210 of the transmission unit 200 is relatively long, ignoring delay time it can not, it is necessary to correct. To this delay correction function effectively function is, it is necessary to set the correction amount of transmission delay (correction time) for each of the S2 demodulator 210.
[0259]
　To facilitate the measurement and setting of such a delay time, it may be adopted timing calibration device.
[0260]
　Figure 42 is a diagram for explaining an application example of a timing correcting device 500 in a time synchronization system according to the present embodiment. Referring to FIG. 42, after configuring the time synchronization system according to the present embodiment, by connecting to the S2 demodulator 210 of the transmission unit 200, automatically measures the delay time, based on the measurement result, correction amount of transmission delay (correction time) can be set to S2 demodulator 210. Timing calibration device 500 typically performs setting of measurement and correction time of the delay time.
[0261]
　Figure 43 is a block diagram showing a circuit configuration example of a timing correcting device 500 is provided to the time synchronization system according to the present embodiment. Referring to FIG. 43, a timing calibrator 500, by comparing the timing signal generated within (1PPS signal), and a timing signal S2 demodulator 210 is reproduced from the transmission RF signal (1PPS signal), delay to measure the time.
[0262]
　That is, the timing calibration apparatus 500 acquires the timing signal obtained (1PPS) substantially timing signal generated within the same (1PPS) in GNSS receiver 110 of the reference unit 100, therein determining the timing signals generated correction amount of the transmission delay by measuring the time difference between (1PPS) and S2 timing signal output from the demodulator 210 (1PPS) (correction time).
[0263]
　Specifically, the timing calibration device 500 includes a CPU 502, a time difference detector 504, a reference timing generator 506, a mixer 510, a high pass filter 512, an analog-to-digital converter 514, a display 516, a battery 518 including.
[0264]
　CPU502 gave suggestions to each unit, based on the processing results, set the correct time to S2 demodulator 210. Further, CPU 502 may deviation for the carrier wave, various set values, also set such as the S2 demodulator 210 status information.
[0265]
　Time difference detector 504 is responsive to a command from the CPU 502, detects the timing signal from the reference timing generator 506 (1PPS) and S2 delay time of the timing signal (1PPS) from the demodulator 210 (phase difference) , and outputs the delay time has been detected to the CPU502. The delay time is the correction amount to be set to S2 demodulator 210.
[0266]
　Reference timing generating unit 506, chip-scale atomic clock (CSAC: Chip Scale Atomic Clock) has, on the basis of the information obtained by decoding the GNSS signal received via the antenna 508, a high-precision reference and it outputs a timing signal. Specifically, the reference timing generator 506 outputs a RF signal (10 MHz) that corresponds to the timing signal (1PPS signal) and a carrier wave.
[0267]
　The mixer 510 multiplies the RF signal from the reference timing generator 506, and a carrier wave from the S2 demodulator 210. Multiplication result of the mixer 510 is passed through a high pass filter 512, it is converted by analog-to-digital converter 514 to a digital signal. Value output from the analog-to-digital converter 514 indicates the frequency deviation of the carrier wave.
[0268]
　Thus, a mixer 510, a high pass filter 512, the analog-digital converter 514 constitute a frequency deviation detection unit 509 for detecting the frequency deviation. Signal output from the frequency deviation detecting unit 509 is counted by the CPU 502. However, it may be implemented using an external counter frequency deviation detection unit 509.
[0269]
　On the display 516, the operating state of the timing calibration device 500 (e.g., measured in or during configuration) in addition to the information such as the measured delay time and the correction time, and the output state of the timing signal in the reference timing generator 506 it may be displayed.
[0270]
　A series of operations, including timing calibration apparatus 500 delay time by measuring and correcting time setting can be done automatically. By automating such a series of operations, even when the transmission unit 200 (S2 demodulator 210 and S3 transmitter 220) is installed a number, to set the correct time required in a few easy steps it can.
[0271]
　The Delay Compensation adopted in time synchronization system according to the present embodiment, for each of the S2 demodulator 210, it is necessary to set the correct time, by using the timing calibration apparatus 500, the working time the shortening can be realized.
[0272]
　
　will now be described automatic correction function of the delay time in the time synchronization system according to the present embodiment.
[0273]
　Figure 44 is a diagram for explaining the automatic correction function of the delay time in the time synchronization system according to the present embodiment. Referring to FIG. 44, for example, it established the TAS transceiver master (TASTRX-M) 520 on the downstream side of the head end 30 of the CATV broadcasting station, installing the TAS transceiver slave 530 connected to S2 demodulator 210. Then, between the TAS transceiver master 520 and TAS transceiver slave 530, constituting a two-way synchronization mechanism. In the case of utilizing the CATV network is bi-directional synchronization mechanism may be configured in BS / CS band.
[0274]
　In this case, by issuing a measurement request to TASTRX-SID to be encapsulated in TASTRX-M broadcast packet, it measures the delay time between the TAS transceiver master 520 and TAS transceiver slave 530. By configuring the FLL (Frequency Locked Loop) correction loop with a measured delay time can be established loops can be corrected automatically delay time. The results of such FLL correction loop, by applying an automatic correction function of the delay time in S2 demodulator 210, even in an environment such as the state of the transmission path changes frequently, dynamically corrected time it can be optimized. Therefore, regardless of the situation of the transmission path, it is possible to always maintain a high time synchronization accuracy.
[0275]
　
　: (k1 generation and transmission of a transmission RF signal)
　in the form of the above embodiment has been illustrated configuration for respectively receiving a transmission RF signal transmitted from one reference unit 100 in a plurality of transmission units 200, to increase redundancy, it may be provided a plurality of reference units 100. In this case, it may be a plurality of reference units 100 transmits a transmission RF signal with different frequencies (channels). In the transmission unit 200, and can receive transmission RF signals in a plurality of channels may be selectively receive those predetermined Of these receivable transmission RF signal.
[0276]
　Alternatively, by performing mutual monitoring among the plurality of reference units 100, one only one reference unit 100 so as to transmit the transmission RF signal, other reference unit 100 is responsible for transmission of the transmission RF signal If there is some trouble in the reference unit 100, the role may be stand by interchanging be such forms on the fly.
[0277]
　In the time synchronization system according to the present embodiment, and transmits a timing signal (1PPS) and time information using the transmission RF signal, quality of the transmission path from the reference unit 100 to the transmission unit 200 is not required so much. Therefore, a plurality of transmission paths, for example, or a combination of coaxial cable and optical cable can be made of any of the transmission path such as a combination of a telephone line and CATV networks, it is possible to widen the application range.
[0278]
　: (K2 signal transmission from the transmission unit)
　In the above description has exemplified the case of using the IMES-TAS signal based IMES signal which is an example of a pseudo signal to complement the GPS signal, the base It is not limited to this as a signal. For example, other than the GPS GLONASS, SBAS, Beidou positioning satellite system, according to the format having a radio signal compatible with the positioning satellite systems such as Galileo, location information, a system clock, even if the information such as time information to be wirelessly transmitted good.
[0279]
　Alternatively, if the reception circuit of the base station 300 corresponds, using the radio signals according to known or proprietary protocol, the system clock may be information such as time information to be wirelessly transmitted. For example, while adopting a similar protocol called radio clock, it may be transmitted a radio signal in a manner that enhances the accuracy.
[0280]
　Furthermore, as exemplified below, the transmission unit and the base station may be a wired connection. In this case, it is possible to employ any type of signal.
[0281]
　: (K3 wired connection Example 1 of the transmitting unit and the base station)
　FIG. 45 is a schematic diagram showing an example of a mobile communication system 1A including a time synchronization system according to the first modification of the embodiment. Figure 46 is a schematic diagram showing a configuration example of the base station 300A included in the mobile communication system 1A shown in FIG. 45.
[0282]
　Sending unit 200A-1,200A-2 in the mobile communication system 1A shown in FIG. 45, ... (hereinafter, sometimes collectively referred to as "transmission unit 200A."), The transmission sent from S2 modulator 120 including and S2 demodulator 210 for demodulating the RF signal, and a transmission interface 230 for transmitting the demodulation result of S2 demodulator 210 to the base station 300A. Each transmitter unit 200A, the base station 300A-1,300A-2, ··· (hereinafter, sometimes collectively referred to as "base station 300A".) Any one through the signal line 232 electrically in It is connected.
[0283]
　To the transmitting unit 200A from the transmission unit 200A, via a signal line 232, included in the demodulated result of S2 demodulator 210, time information, timing signals, various data is transmitted. Transmission format signal may be any method and procedures. Referring to FIG. 46, the base station 300A, S3 instead of the receiver 320 (see FIG. 4), the transmission interface 330 is disposed. That is, the transmission interface 330 for transmission interface 230 and the base station 300A of the transmission unit 200A has a configuration for transmitting the necessary information via the signal line 232.
[0284]
　By adopting such a configuration, even places like the transmission of radio signals, such as IMES-TAS signal is restricted, it is possible to place the base station 300A.
[0285]
　: (K4 wired connection Example 2 of the transmitting unit and the base station)
　FIG. 47 is a schematic diagram showing an example of a mobile communication system 1B including a time synchronization system according to the second modification of the embodiment. Figure 48 is a schematic diagram showing a configuration example of the base station 300B included in the mobile communication system 1B shown in FIG. 47.
[0286]
　In the mobile communication system 1B shown in FIG. 47, the transmitting unit 200B-1,200B-2, ··· (hereinafter, sometimes collectively referred to as "transmission unit 200B.") Via a network cable 242, base station 300B-1,300B-2, ··· (hereinafter, also. If collectively referred to as "base station 300B") are connected one or more and the. For example, as the network cable 242, by adopting those conforming to the Ethernet (registered trademark), it is possible to configure a kind of network. If you configure such a network, to one transmission unit 200B, may be connected to multiple base stations 300B.
[0287]
　In the mobile communication system 1B shown in FIG. 47, each of the transmission units 200B includes and S2 demodulator 210 for demodulating a transmission RF signal transmitted from the S2 modulator 120, the reference time based on the demodulation result of S2 demodulator 210 to generate and a master clock 240. Master clock 240 is, for example, a reference time generator for performing time synchronization using PTP technique, for example, it may be adopted a master clock according to the protocol specified in the IEEE 1588 (PTP) or IEEE1588v2 (PTPv2) . Referring to FIG. 48, the base station 300B, S3 instead of the receiver 320 (see FIG. 4), the slave clock 360 is disposed. Slave clock 360, via the network cable 242 with synchronizing master clock 240 and the time, to provide the synchronized time information to the wireless transceiver 310.
[0288]
　By adopting such a configuration, even places like the transmission of radio signals, such as IMES-TAS signal is restricted, it is possible to place the base station 300B. Further, for a single transmission unit 200B, since it is also possible to connect a plurality of base stations 300B, flexibility in arranging the base station 300B.
[0289]
　: (K5 use example of a signal transmitted from the transmission unit)
　In the above description, as a typical example, the time synchronization system, the base station 300 is applied to the application that time synchronization with another base station 300 has been illustrated case, not limited to this, another device, location information, the system clock may be use information such as time information.
[0290]
　Figure 49 is a schematic diagram showing an example of a mobile communications system 1C including a time synchronization system according to the third modification of this embodiment. In the mobile communication system 1C shown in FIG. 49, either (in the example shown in FIG. 49, the base station 300-2) of the base station the mobile terminal 370 present in the cell area provided by the corresponding base station 300 Although it is possible to acquire necessary information from -2 acquisition therewith, receives a radio signal from the transmission unit 200-2 is transmitted by the wireless signal, the position information, the system clock, such as the time information it may be. In situations such as that shown in FIG. 49, the mobile terminal 370, there is a high possibility not available GNSS signals, and acquires position information by radio signals from the transmission unit 200-2, to provide the necessary services to the user be able to.
[0291]
　Furthermore, for any communications device 380, it may provide a variety of information transmitted by a radio signal from the transmitting unit 200. For example, any communication device 380 may be such as to obtain the position information and time information thereof by radio signals from the transmission unit 200, along with other information is collected and reported to such higher-level server device . By adopting such a configuration, the communication device 380, only be implemented before receiving circuit of the radio transmission circuitry and GNSS signals, in both outdoor and indoor also can collect position information and time information, further , in association with their position information and time information, since such can report collected field information can be provided inexpensively various system that applies IoT (Internet of Things) technology.
[0292]
　: (K6 use example of a signal transmitted from the transmission unit)
　FIG 50 is a schematic diagram showing an example of a mobile communication system 1D that includes a time synchronization system according to the fourth modification of this embodiment. In the mobile communication system 1D shown in FIG. 50, reference unit 100D is opposed to an interface for generating a transmission RF signal, and a S2 modulator 120D having an interface for a network connection, such as Ethernet. S2 modulator 120D further has a built-in (ground) master clock according to the protocol specified in the IEEE 1588 (PTP) or IEEE1588v2 (PTPv2).
[0293]
　On the other hand, each of the transmit unit 200D is opposed to an interface for receiving a transmission RF signal, and a S2 demodulator 210D with an interface for a network connection, such as Ethernet. S2 demodulator 210D incorporates a slave clock according to the protocol specified in the IEEE 1588 (PTP) or IEEE1588v2 (PTPv2). S2 demodulator 210D in synchronization with the master clock that is built to S2 modulator 120D, manages time.
[0294]
　Similar to the above configuration, the transmission unit 200D from the reference unit 100D, information for generating the IMES-TAS signal is provided via a network. The transmission unit 200D, to the base station, provides the IMES-TS signal or IMES-TAS signal. IMES-TS signal typically includes position (Position), time (Clock), the timing signal (Timing). IMES-TAS signal in addition to the information contained in the IMES-TS signals, including an authentication code (Authentication Code).
[0295]
　By adopting such a configuration, can relax the equipment requirements for information transmission to the transmitting unit 200D from the reference unit 100D, it promoted the widespread use of mobile communication system according to the present embodiment.
[0296]
　
　In the time synchronization system according to the present embodiment, sends a timing signal and time information needed for time synchronization in the form of a transmission RF signal to the S2 demodulator 210, using the data demodulated by S2 demodulator 210 (typically, IMES-TAS signal as described above) any signal to S3 transmitter 220 Te radio transmission or wired transmission in the form of. By adopting such a signal transmission form, jointly acousto-optic can utilize existing facilities such systems and CATV networks, further, easily connected to such a terminal that is installed in each home (TV wiring connector) because Do equipment can be utilized, in a case it is placed indoors in a large amount of ultra-small base station such as a femtocell while reducing the cost of installation, the time synchronization of the entire system including a plurality of SSBS It can be easily realized.
[0297]
　The embodiments disclosed herein are to be considered as not restrictive but illustrative in all respects. The scope of the invention, rather than the description above, indicated by the appended claims, and is intended to include all modifications within the meaning and range of equivalency of the claims.
DESCRIPTION OF SYMBOLS
[0298]
　1, 1A, 1B, 1C, 2 mobile communication system, 10 building, 12 mixing amplifier, 16 an antenna wire, 18 Terminal, 20 incoming line, 30 headend, 32 transmission lines, 34 receiver distributor, 100 reference units, 102 GNSS antenna, 103 GNSS signals, 104,360 slave clock, 106 a receiver, 108 authentication server 109 network, 110 GNSS receiver, 120 S2 modulator, 121 IF signal generating circuit, 122 a modulation circuit, 123, 129 low-pass filter, 124,2141,2142,2158 digital-to-analog converter, 125,217 carrier oscillator, 126 up conversion circuit, 127,510,2122,2146 mixer, 128,2121 variable amplifier, 200, 200A, 200B, transmission 200D Unit, 203 IMES-TAS signal, 210 S2 demodulator 212 down-conversion circuit, 214 a demodulation circuit, 218 a system oscillator, 220 S3 transmitter, 221 a digital processing block, 222 EEPROM, 223 analog processing block, 224,340,508 antenna , 225 digital output interface, 226 a timing interface, 227 an oscillator, 228 a power supply, 230, 330 transmission interface, 232 signal line, 240 master clock, 242 a network cable, 280 encoder, 282 IMES-TAS generator, 300, 300A , 300B base station 310 wireless transceiver, 320 S3 receiver, 321 channel block, 322 navigation processing unit, 323 a selection control section, 324 synchronization Out portion, 325,327,2154,2159 divider, 326 regulation loop section, 350, 400 cell area, 370 mobile terminal, 380 communication device, 500 timing calibration device, 502,2212 CPU, 504 hours difference detector, 506 reference timing generator, 509 a frequency deviation detecting unit, 512 high-pass filter, 514 an analog to digital converter, 516 a display, 518 a battery, 520 a transceiver master, 530 transceiver slave, 1031,2031 timing signal, 1032,2032 clock, 1033,2033 position information, 1034,2034 time information, 1035,2035 leap second information, 2036 authentication code, 2123,2125,2160 amplifier, 2124,2126,2144,2145 low Pass filter, 2143 phase rotator, 2147 bit synchronization unit, 2148 SYNC detection unit, 2149 data extraction unit, 2150 parallel converter, 2151 a delay correction amount holding section, 2152 the synchronization adjustment section, 2153 phase comparator, 2156,2157 loop filter , 2214 RAM, 3211 and 3212 correlators, 3213 message extractor, 3214 code generator, 3215 convolution operation unit, 3216 an integration circuit.

The scope of the claims
[Requested item 1]
　Based on the radio signal from the positioning satellite system, a reference time acquisition unit for acquiring time information corresponding to the timing of the first timing signal and said first timing signal indicates,
　is connected to a wiring that branches plurality a modulator for sending on the wire generated in synchronism with the modulation signal containing the corresponding time information to said first timing signal,
　is connected to one of the branches of the wire, on the wire and one or more demodulator for demodulating the modulated signal propagating,
　based on the second timing signal and the time information obtained by the demodulation of either of the demodulation section, a radio signal compatible with the positioning satellite system and a least one transmission unit for transmitting a first radio signal having sex, time synchronization system.
[Requested item 2]
　It said first timing signal is output periodically,
　the modulation unit, the sending on the wire the time of the modulated signal said first timing signal is output as the reference,
　the modulation signal, the time including the sync word in addition to the information, the time synchronization system according to claim 1.
[Requested item 3]
　The demodulation unit detects the synchronization word contained in the modulated signal propagating on the interconnect, and outputs the subsequent information to the detected synchronization word as demodulated data in advance from the time of detecting the synchronization word and outputs a second timing signal as a reference only previous time correction time determined, the time synchronization system according to claim 2.
[Requested item 4]
　Obtains the third timing signal is said first timing signal substantially identical acquired at the reference time acquiring unit, said second output from said third timing signal and the demodulation unit further comprising a time synchronization system according to claim 3 calibration device for determining the correction time by measuring the time difference between the timing signal.
[Requested item 5]
　And the transmission unit, a longer period than the period of second timing output from the demodulation unit, for transmitting the first radio signal, the time synchronization system according to any one of claims 1-4.
[Requested item 6]
　The first radio signal,
　　a first format including information of the number of seconds between the beginning elapsed week and the week from a predetermined reference date and
　　year year, month, day, hour, minute, the information in seconds second format comprising
of, supporting at least one, the time synchronization system according to any one of claims 1 to 5.
[Requested item 7]
　The first radio signal is constructed as a frame consisting of a plurality of words,
　the beginning of the plurality of words constituting the frame are associated with the beginning of the transmission cycle,
　the first in the frame word is fixed to a predetermined value, the time synchronization system according to any one of claims 1 to 5.
[Requested item 8]
　Wherein demodulating the first radio signal from the transmitting unit, the receiving unit further comprises a for acquiring time information corresponding to the timing shown fourth timing signal and said fourth timing signal,
　the receiving unit, It includes circuitry for executing a plurality of convolution processing with respect to the first word, the time synchronization system of claim 7.
[Requested item 9]
　And the transmission unit, in a period during which the first radio signal is not transmitted, transmits the second radio signal to replace the radio signal from the positioning satellite system, the time of any one of claims 1 to 8 synchronization system.
[Requested item 10]
　The wiring joint acousto-optic system of the signal lines, cable television signal lines, and, among the signal lines for communication comprising at least one, the time synchronization system according to any one of claims 1-9.
[Requested item 11]
　It said first radio signal comprises a predetermined length of the message, which is calculated based on the time information acquired by the reference time acquiring unit, the time synchronization system according to any one of claims 1 to 10.
[Requested item 12]
　Wherein the predetermined length of the message, as an input a secret key and the time information is calculated according to the cryptographic hash function, time synchronization system according to claim 11.
[Requested item 13]
　Based on the radio signal from the positioning satellite system, a reference time acquisition unit for acquiring time information corresponding to the timing of the first timing signal and said first timing signal indicates,
　is connected to a wiring that branches plurality , and a modulation unit for generating in synchronism with the modulation signal containing the corresponding time information to said first timing signal is sent on the line,
　the branch of the wiring, the modulation propagating on the line one or more terminals for connecting the demodulator for demodulating the signal provided, the time synchronization system.
[Requested item 14]
　Is connected to any position of the plurality of branched lines, a demodulation unit for demodulating the modulated signal propagating on the line, the modulated signal, a primary first timing signal and the first together they are generated based on time information corresponding to the timing indicated by the timing signal, which the sent on the synchronization line to the first timing signal,
　first obtained by demodulation by the demodulating unit based on the second timing signal and time information, a transmitting unit that transmits a radio signal having a radio signal compatible with the positioning satellite system, the transmitting device.
[Requested item 15]
　A receiver for receiving the first timing signal generated based on a first radio signal from the positioning satellite system,
　on the basis of the signal and the time information received by the receiving unit, a radio signal from a positioning satellite system and a transmission unit for transmitting a second radio signal having a compatible,
　the second wireless signal includes a position, a time, and the timing signal, and authentication information, transmitting apparatus.