JP2012002623A - Radio base station, server, radio base station system, and synchronization method for radio base station system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio base station that can receive orbit information from a GPS satellite with high sensibility without requiring installation of a large number of servers, a server, a radio base station system, and a synchronization method for the radio base station system.SOLUTION: A GPS module 10 receives orbit information from a GPS satellite. When the GPS module 10 does not receive any orbit information, an orbit information request section 11 requires a radio base station to transmit the orbit information not being received. An assist data generation section 14 generates assist data including the orbit information transmitted from the radio base station in response to the request and the orbit information received from the GPS satellite. An assistant data providing section 13 provides the generated assist data to the radio base station.

Description

  The present invention relates to a radio base station, a server, a radio base station system, and a radio base station system synchronization method, and in particular, a radio base station, a server, and a radio base station system that synchronize time based on a signal from a GPS satellite. And a synchronization method of a radio base station system.

  In order to align the transmission / reception timing among a plurality of radio base stations, a GPS module is provided as a timing acquisition device (see, for example, Patent Document 1). The GPS module acquires orbit information from a plurality of GPS satellites in the sky through a GPS antenna, and generates a reference time signal from the acquired orbit information. In order to generate a correct reference time signal, it is necessary to acquire accurate orbit information from four or more GPS satellites. For this reason, the GPS antenna is generally installed in a place with a good view of the sky outside. However, the sky view is not always good at all locations. In addition, in an indoor radio base station, since a GPS antenna is installed indoors, it is difficult to see the whole sky, and it can be seen only within a certain angle.

  In order to cope with such a problem, a system using an assist method is used. The assist method is a method in which the radio base station increases the reception sensitivity of the orbit information from the GPS satellites by acquiring the orbit information of the GPS satellites from a server (also called an assist server) installed at an arbitrary location. is there.

JP 2002-318275 A

  However, since the assist server also acquires the orbit information of the GPS satellites using the GPS module similarly to the radio base station, the orbit information from all the satellites is not necessarily acquired.

  For example, as shown in FIG. 14, the assist server cannot receive orbit information from a GPS satellite hidden behind an obstacle. That is, the assist server 601 can receive the orbit information from the GPS satellites # 1 to # 3, but cannot receive the orbit information from the GPS satellite # 4 due to the obstacle 503.

  Further, as shown in FIG. 15, the assist server cannot receive orbit information from GPS satellites below the horizon. That is, the assist server 701 can receive orbit information from GPS satellite # 1 and GPS satellite # 2 above the horizon, but cannot receive orbit information from GPS satellite # 3 below the horizon.

  As a result, the radio base station may not be able to acquire necessary satellite information from the assist server, and may not be able to increase the reception sensitivity of orbit information from GPS satellites. Such a problem may be solved by installing a large number of assist servers, but if a large number of assist servers are installed, the cost increases.

  Therefore, an object of the present invention is to provide a radio base station, a server, and a radio base station that can receive orbit information from a GPS satellite with good sensitivity in a radio base station without installing a large number of servers. A system and a synchronization method of a radio base station system are provided.

  In order to solve the above problems, the present invention is a server that is connected to a radio base station for communication, and a GPS receiver that receives orbit information from GPS satellites, and the GPS receiver can receive any orbit information. Orbit information requesting unit that requests transmission of orbit information that could not be received to the radio base station, and orbit information transmitted from the radio base station and orbit information received from the GPS satellite in response to the request. An assist data generating unit that generates assist data including the assist data providing unit that provides the generated assist data to the radio base station.

  Preferably, the trajectory information requesting unit may receive the trajectory information that could not be received based on the position where the plurality of radio base stations are installed and the almanac among the trajectory information received by the GPS receiving unit. A radio base station having a higher value is selected, and a transmission request for orbit information that could not be received is transmitted to the selected radio base station.

  The present invention is a server that is communicatively connected to a radio base station, and provides an assist data generation unit that generates assist data including trajectory information transmitted from the radio base station, and provides the generated assist data to the radio base station. And an assist data providing unit.

  Preferably, when the assist data generation unit acquires orbit information of the same GPS satellite from a plurality of radio base stations, the frequency of occurrence of a value indicating the orbit among the plurality of orbit information of the same GPS satellite is the highest. High trajectory information is selected, and assist data including the selected trajectory information is created.

  Preferably, the assist data generation unit acquires information indicating the reception level of the orbit information together with the orbit information from the radio base station, and when orbit information of the same GPS satellite is acquired from a plurality of radio base stations, Among the orbit information of a plurality of the same GPS satellites, orbit information having the maximum reception level is selected, and assist data including the selected orbit information is created.

  The present invention is a radio base station that is communicatively connected to a server, a GPS receiving unit that receives orbit information from GPS satellites, a request to send orbit information from the server, and the received orbit information has been received. In this case, a track information providing unit that transmits the requested track information to the server, and an assist data acquiring unit that acquires assist data transmitted from the server, and the GPS receiving unit uses the acquired assist data. Then, the unreceived orbit information is received, and the GPS receiver generates a reference time signal based on the received plurality of orbit information.

  The present invention is a wireless base station that is communicatively connected to a server, and includes a GPS receiving unit that receives orbit information from GPS satellites, an orbit information providing unit that transmits received orbit information to the server, and a server that transmits the information. An assist data acquisition unit that acquires assist data, the GPS reception unit receives unreceived orbit information using the acquired assist data, and the GPS reception unit is based on the received plurality of orbit information. A reference time signal is generated.

  Preferably, the GPS receiving unit measures the reception level of the received orbit information, and the orbit information providing unit transmits information indicating the reception level of the orbit information together with the orbit information to the server.

  The present invention is a wireless base station system including a plurality of wireless base stations and a server that is connected to the plurality of wireless base stations, and the server receives first GPS reception that receives orbit information from GPS satellites. The orbit information requesting unit for requesting transmission of orbit information that could not be received to the radio base station when any of the orbit information could not be received by the first GPS receiving unit, and wirelessly in response to the request An assist data generating unit that generates assist data including orbit information transmitted from a base station and orbit information received from a GPS satellite, and an assist data providing unit that provides the generated assist data to a radio base station The base station receives a second GPS receiver that receives orbit information from a GPS satellite and a transmission request for orbit information from a server, and has received the requested orbit information. A trajectory information providing unit that transmits the requested trajectory information to the server, and an assist data acquiring unit that acquires assist data transmitted from the server, and the second GPS receiving unit uses the acquired assist data The unreceived orbit information is received, and the second GPS receiver generates a reference time signal based on the received plurality of orbit information.

  The present invention relates to a synchronization method in a radio base station system including a plurality of radio base stations and a server connected to the plurality of radio base stations, wherein the server receives orbit information from a GPS satellite; The radio base station receiving orbit information from a GPS satellite; and the server requesting the radio base station to transmit orbit information that could not be received if the server could not receive any orbit information; When the radio base station receives a request for transmission of orbit information from the server and has received the requested orbit information, the step of transmitting the requested orbit information to the server, and the server responds to the request. Generating assist data including the orbit information transmitted from the radio base station and the orbit information received from the GPS satellite, and the server Providing to the base station, a step in which the radio base station acquires assist data transmitted from the server, a step in which the radio base station receives unreceived orbit information using the acquired assist data, A radio base station generating a reference time signal based on the received plurality of pieces of trajectory information.

  According to the present invention, orbit information from a GPS satellite can be received with good sensitivity at a radio base station without installing a large number of servers.

It is a figure showing the structure of the radio base station system of 1st Embodiment. It is a figure showing the structure of the wireless base station of 1st Embodiment. It is a figure showing the structure of the assist server of 1st Embodiment. It is a flowchart showing the operation | movement procedure of the radio base station system of 1st Embodiment. It is a flowchart showing the operation | movement procedure of the radio base station system of 2nd Embodiment. It is a figure showing the structure of the assist server of 2nd Embodiment. It is a flowchart showing the operation | movement procedure of the radio base station system of 2nd Embodiment. It is a figure showing the structure of the assist server of 3rd Embodiment. It is a figure showing the structure of the wireless base station of 3rd Embodiment. It is a flowchart showing the operation | movement procedure of the radio base station system of 3rd Embodiment. It is a figure showing the structure of the assist server of 4th Embodiment. It is a figure showing the structure of the wireless base station of 4th Embodiment. It is a flowchart showing the operation | movement procedure of the radio base station system of 4th Embodiment. It is a figure showing the example of the positional relationship of an assist server and a GPS satellite. It is a figure showing another example of the positional relationship of an assist server and a GPS satellite.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating a configuration of a radio base station system according to the first embodiment.

  Referring to FIG. 1, this radio base station system includes an assist server 1 and a plurality of radio base stations 5a to 5n. The assist server 1 and the plurality of radio base stations 5a to 5n are connected by a wired network 504. The assist server 1 and the plurality of radio base stations 5a to 5n include GPS modules 50a to 50n, respectively. The GPS modules 50a to 50n receive orbit information from a plurality of GPS satellites belonging to the GPS satellite group (32 GPS satellites) by the GPS antennas 57a to 57n.

(Configuration of radio base station)
FIG. 2 is a diagram illustrating the configuration of the radio base station according to the first embodiment.

  With reference to FIG. 2, the radio base station 5 includes a GPS module 50, an orbit information providing unit 55, an assist data acquiring unit 53, and a network interface 56.

  The GPS module 50 includes a GPS antenna 57 and receives a navigation message through the GPS antenna 57.

  The navigation message includes the orbit information (ephemeris) of the GPS satellite that transmitted the navigation message and the orbit information (almanac) of all GPS satellites. The almanac includes rough position information of all GPS satellites. The ephemeris includes accurate position information of the GPS satellite that transmitted the ephemeris and time information that transmitted the GPS satellite.

  The GPS module 50 selects a GPS satellite in a visible position based on the almanac, the position of the device itself, and the approximate time.

  The GPS module 50 receives the ephemeris in the navigation message from the selected GPS satellite. When the ephemeris cannot be received from the navigation message from the selected GPS satellite, the GPS module 50 selects the other wireless base station or the assist server 1 included in the assist data received from the assist server 1. The ephemeris of the selected satellite is received by increasing the ephemeris reception sensitivity of the selected satellite using the ephemeris of the selected GPS satellite.

  The GPS module 50 generates an accurate reference time signal tb using the ephemeris of the four satellites received by the own station, the position of the own device, and the approximate time held.

  The navigation message acquisition unit 52 extracts individual orbit information, that is, almanac and ephemeris, from the navigation message received by the GPS module 50 and stores them in the orbit information storage unit 54. The navigation message acquisition unit 52 deletes the data because the validity of the data is lost when a predetermined time elapses after the navigation message is stored in the trajectory information storage unit 54.

  When the trajectory information providing unit 55 receives a transmission request for any of the trajectory information from the assist server 1, if the trajectory information requested for transmission is stored in the trajectory information storage unit 54, the trajectory information providing unit 55 reads out the trajectory information. 56 to the assist server 1.

  The assist data acquisition unit 53 acquires assist data from the assist server 1 through the network interface 56 and supplies the assist data to the GPS module 50.

  The network interface 56 receives assist data from the assist server 1 through the network 504 or receives a trajectory information transmission request, and transmits the trajectory information to the assist server 1.

  The wireless communication unit 51 performs communication processing of the signal received from the antenna 59 and the signal output from the antenna 59 in synchronization with the reference time signal tb output from the GPS module 50.

(Assist server configuration)
FIG. 3 is a diagram illustrating the configuration of the assist server according to the first embodiment.

  Referring to FIG. 3, the assist server 1 includes a GPS module 10, a navigation message acquisition unit 12, a trajectory information request unit 11, an assist data generation unit 14, an assist data provision unit 13, and an assist data storage unit. 16 and a network interface 18.

  The GPS module 10 includes a GPS antenna 17 and receives navigation messages from GPS satellites through the GPS antenna 17 in the same manner as the GPS module 50 of the radio base station.

  The navigation message acquisition unit 12 extracts individual orbit information, that is, almanac and ephemeris, from the navigation message received by the GPS module 10 and outputs the extracted information to the assist data generation unit 14.

  The assist data generation unit 14 generates assist data using the trajectory information output from the navigation message acquisition unit 12 and the trajectory information transmitted from the radio base station, and stores the assist data in the assist data storage unit 16. The assist data generation unit 14 deletes the orbit information constituting the assist data after a predetermined time has elapsed since reception or acquisition because the validity of the data is lost.

  When the assist data generation unit 14 receives orbit information of the same GPS satellite from a plurality of radio base stations in response to a request for orbit information, the assist data generation unit 14 represents the orbit within a predetermined time range among the plurality of orbit information. The trajectory information with the highest occurrence frequency is selected and added to the assist data. For example, in the activation information from three radio base stations, the assist data generating unit has a value representing a trajectory a, and the trajectory information from one radio base station is obtained when the numeric value representing the trajectory is b. Selects the trajectory of a. When the assist data generating unit 14 receives the trajectory information from one radio base station, the assist data generating unit 14 adds the received trajectory information to the assist data.

  The orbit information request unit 11 checks whether the assist data stored in the assist data storage unit 16 includes the almanac and the ephemeris of all GPS satellites. The orbit information requesting unit 11 specifies orbit information that is not included in the assist data, and specifies the specified orbit information (for example, the number of the GPS satellite) for all the radio base stations connected to the assist server 1. Broadcast a transmission request).

  The assist data providing unit 13 provides assist data to all wireless base stations connected via the network 504 through the network interface 18.

  The network interface 18 receives the trajectory information from the radio base stations 5a to 5n through the network 504, transmits assist data to the radio base stations 5a to 5n, or transmits a trajectory information transmission request.

(Operation)
FIG. 4 is a flowchart showing an operation procedure of the radio base station system according to the first embodiment.

  With reference to FIG. 4, first, in the assist server 1, the GPS module 10 receives a navigation message (almanac and ephemeris) from a GPS satellite. The navigation message acquisition unit 12 extracts individual orbit information, that is, almanac and ephemeris, from the navigation message received by the GPS module 10, and outputs them to the assist data generation unit 14. In the assist server 1, the assist data generation unit 14 generates assist data using the acquired trajectory information and stores it in the assist data storage unit 16 (step S100).

  In the assist server 1, the orbit information request unit 11 obtains orbit information (ephemeris of any one or more GPS satellites) that is not included (is missing) in the assist data stored in the assist data storage unit 16. Specify (step S101).

  In the assist server 1, the trajectory information request unit 11 sends the trajectory information transmission request specified in step S <b> 102 to all the radio base stations 5 a to 5 n connected to the assist server 1 through the network interface 18 ( Step S102).

  In parallel with steps S100, S101, and S102, in each radio base station 5, the GPS module 50 receives a navigation message (almanac and ephemeris) from a GPS satellite. The navigation message acquisition unit 52 acquires the navigation message received by the GPS module 50 and stores individual trajectory information (almanac and ephemeris) in the trajectory information storage unit 54 (step S103).

  Next, in each wireless base station, the trajectory information providing unit 55 receives a trajectory information transmission request from the assist server 1 through the network interface 56 (step S104).

  Next, when the requested trajectory information is stored in the trajectory information storage unit 54 (YES in step S105), the trajectory information providing unit 55 reads the requested trajectory information from the trajectory information storage unit 54. Then, the data is transmitted to the assist server 1 through the network interface 56 (step S106).

  Next, in the assist server 1, the assist data generation unit 14 receives the orbit information of the GPS satellite from the radio base station (step S107).

  Next, in the assist server 1, when the assist data generation unit 14 receives orbit information of the same GPS satellite from a plurality of radio base stations (for example, orbit information of the first GPS satellite from a plurality of radio base stations). (YES in step S108), the trajectory information having the highest occurrence frequency of the numerical value (value representing the trajectory) within a predetermined time range is selected from a plurality of trajectory information and added to the assist data (step S109). ).

  On the other hand, when the assist data generation unit 14 receives orbit information from one radio base station (NO in step S108), the received orbit information is added to the assist data (step S110).

  Next, in the assist server 1, when the assist data is completed, that is, when the assist data includes all orbit information (almanac and ephemeris of all GPS satellites) (YES in step S111). ), Assist data is transmitted to all the radio base stations connected to the assist server 1 through the network interface 18 (step S112).

  Next, in each radio base station 5, the assist data acquisition unit 53 receives the assist data through the network interface 56 (step S113).

  Next, the assist data acquisition unit 53 gives the received assist data to the GPS module 50 (step S114).

  Next, the GPS module 50 receives an ephemeris of an unreceived GPS satellite using the assist data. When the GPS module 50 has received the navigation messages of the four GPS satellites, the GPS module 50 performs orbit calculation using the four received ephemeris, and the timing information of each GPS satellite created from the signals received from the GPS satellites and A reference time signal tb is generated from the distance to the GPS satellite (step S115).

  As described above, according to the first embodiment, the assist server generates assist data including orbit information from all GPS satellites by acquiring the missing orbit information from the radio base station, Provide to radio base stations. Thereby, the radio base station can receive orbit information from GPS satellites with good sensitivity. In addition, when the assist server acquires orbit information of the same GPS satellite from a plurality of radio base stations, the assist server obtains assist data using orbit information having the maximum occurrence frequency of the numerical value representing the orbit within a predetermined time range. Since it generates, the reliability of assist data can be improved.

[Second Embodiment]
When the assist server of the second embodiment receives a plurality of orbit information for the same GPS satellite from a plurality of radio base stations, the assist server selects one of the orbit information by a method different from that of the first embodiment. To do.

(Configuration of radio base station)
FIG. 5 is a diagram illustrating a configuration of a radio base station according to the second embodiment.

  The radio base station 6 in FIG. 5 differs from the radio base station 5 in FIG. 2 in a GPS module 60, a navigation message acquisition unit 63, a trajectory information storage unit 64, and a trajectory information provision unit 65.

  The GPS module 60 receives navigation messages (almanac and ephemeris) from GPS satellites, and measures the reception level of orbit information (ephemeris) in the navigation message.

  The navigation message acquisition unit 62 acquires the navigation message (almanac and ephemeris) and the ephemeris reception level received by the GPS module 60 and stores them in the trajectory information storage unit 64.

  When the trajectory information providing unit 65 receives the trajectory information and the reception level transmission request from the assist server 2, if the requested trajectory information and the reception level are stored in the trajectory information storage unit 64, Read out and transmit to the assist server 2.

(Assist server configuration)
FIG. 6 is a diagram illustrating the configuration of the assist server according to the second embodiment.

  The assist server 2 in FIG. 6 is different from the assist server 1 in FIG. 3 in a track information request unit 21 and an assist data generation unit 24.

  The orbit information request unit 21 transmits unacquired orbit information and a transmission request for the reception level to all the radio base stations connected to the assist server 2.

  When the assist data generation unit 24 receives orbit information and the reception level of the same GPS satellite from a plurality of radio base stations, the assist data generation unit 24 selects the orbit information having the highest reception level from the plurality of orbit information, and assists Append to data. The assist data generation unit 24 adds the received orbit information to the assist data when the orbit information and the reception level thereof are received from one radio base station.

(Operation)
FIG. 7 is a flowchart showing an operation procedure of the radio base station system according to the second embodiment.

  Referring to FIG. 7, in assist server 2, first, GPS module 10 receives a navigation message (almanac and ephemeris) from a GPS satellite. The navigation message acquisition unit 12 extracts individual orbit information, that is, almanac and ephemeris, from the navigation message received by the GPS module 10, and outputs them to the assist data generation unit 24. In the assist server 2, the assist data generation unit 24 generates assist data using the acquired trajectory information and stores it in the assist data storage unit 16 (step S100).

  In the assist server 2, the trajectory information requesting unit 21 specifies trajectory information (any one or more GPS satellite ephemeris) not included in the assist data stored in the assist data storage unit 16 (step S101). .

  In the assist server 2, the trajectory information request unit 21 sends the trajectory information specified in step S <b> 102 and a transmission request for its reception level to all the radio base stations connected to the assist server 2 through the network interface 18. (Step S202).

  In parallel with steps S100, S101, and S202, in each radio base station, the GPS module 60 receives navigation messages (almanac and ephemeris) from GPS satellites and measures the reception level of orbit information (ephemeris). . The navigation message acquisition unit 62 acquires the navigation message received by the GPS module 60 and the measured ephemeris reception level, and stores the individual orbit information (almanac and ephemeris) and the ephemeris reception level in the orbit information storage unit 64. (Step S203).

  Next, in each radio base station, the trajectory information providing unit 65 receives the trajectory information and a transmission request for the reception level from the assist server 2 through the network interface 56 (step S204).

  Next, when the requested trajectory information and its reception level are stored in the trajectory information storage unit 64 (YES in step S205), the trajectory information providing unit 65 displays the requested trajectory information and its reception level. The data is read from the trajectory information storage unit 64 and transmitted to the assist server 2 through the network interface 56 (step S206).

  Next, in the assist server 2, the assist data generation unit 24 receives the orbit information of the GPS satellite and the reception level thereof from the radio base station (step S207).

  Next, in the assist server 2, the assist data generation unit 24 includes the orbit information of the same GPS satellite from a plurality of radio base stations (for example, the orbit information of the first GPS satellite from the plurality of radio base stations) and the reception level thereof. Is received (YES in step S208), the trajectory information having the highest reception level is selected from the plurality of trajectory information and added to the assist data (step S209).

  On the other hand, when the assist data generation unit 24 receives the trajectory information and the reception level from one radio base station (NO in step S208), the received trajectory information is added to the assist data (step S110).

  Next, in the assist server 2, when the assist data is completed, that is, when the assist data includes all orbit information (almanac and ephemeris of all GPS satellites) (YES in step S111). ), Assist data is transmitted to all the radio base stations connected to the assist server 2 through the network interface 18 (step S112).

  Next, in each radio base station, the assist data acquisition unit 53 receives the assist data through the network interface 56 (step S113).

  Next, the assist data acquisition unit 53 gives the received assist data to the GPS module 60 (step S114).

  Next, the GPS module 60 receives an ephemeris of an unreceived GPS satellite using the assist data. When the GPS module 60 has received the navigation messages of the four GPS satellites, the GPS module 60 performs the orbit calculation using the four received ephemeris, and the timing information of each GPS satellite created from the signals received from the GPS satellites and A reference time signal tb is generated from the distance to the GPS satellite (step S115).

  As described above, according to the second embodiment, as in the first embodiment, the assist server acquires orbit information from all GPS satellites by acquiring the missing orbit information from the radio base station. Assist data including information is generated and provided to the radio base station. Thereby, the radio base station can receive orbit information from GPS satellites with good sensitivity. In addition, when the assist server acquires orbit information of the same GPS satellite from a plurality of radio base stations, the assist data is generated using the orbit information having the maximum reception level, thereby improving the reliability of the assist data. Can be made.

[Third Embodiment]
The assist server according to the third embodiment transmits a request for transmitting satellite orbit information that cannot be acquired only to a specific radio base station, not to all radio base stations.

(Assist server configuration)
FIG. 8 is a diagram illustrating the configuration of the assist server according to the third embodiment.

  The assist server 3 shown in FIG. 8 is different from the assist server 1 shown in FIG.

  The trajectory information request unit 31 specifies trajectory information not included in the assist data stored in the assist data storage unit 16, and acquires the acquired almanac and the GPS module of the radio base station connected to the assist server. Based on the position information, a radio base station at a position where the specified orbit information can be received is selected. The orbit information request unit 31 sends a transmission request for the specified orbit information to the selected radio base station.

(Configuration of radio base station)
FIG. 9 is a diagram illustrating a configuration of a radio base station according to the third embodiment.

  The radio base station 7 in FIG. 9 is different from the radio base station 5 in FIG.

  The trajectory information providing unit 75 receives the trajectory information transmission request from the assist server 3 and stores the requested trajectory information in the trajectory information storage when the requested trajectory information is stored in the trajectory information storage unit 54. The data is read from the unit 54 and transmitted to the assist server 3.

(Operation)
FIG. 10 is a flowchart showing an operation procedure of the radio base station system according to the third embodiment.

  With reference to FIG. 10, first, in the assist server 3, the GPS module 10 receives a navigation message (almanac and ephemeris) from a GPS satellite. The navigation message acquisition unit 12 extracts individual orbit information, that is, almanac and ephemeris, from the navigation message received by the GPS module 10, and outputs them to the assist data generation unit 14. In the assist server 3, the assist data generation unit 14 generates assist data using the acquired trajectory information and stores it in the assist data storage unit 16 (step S100).

  In the assist server 3, the orbit information requesting unit 31 identifies orbit information (any ephemeris of one or more GPS satellites) that is not included in the assist data stored in the assist data storage unit 16 (step S101). .

  In the assist server 3, the trajectory information requesting unit 31 performs step S <b> 101 based on the acquired almanac and the position information (longitude and latitude installed) of the GPS module of the radio base station connected to the assist server. A radio base station in a position where the specified orbit information can be received is selected (step S302).

  The trajectory information request unit 31 sends a transmission request for the trajectory information specified in step S302 to the selected radio base station connected to the assist server 3 through the network interface (step S303).

  In parallel with steps S100, S101, S302, and S303, in each radio base station 7, the GPS module 50 receives a navigation message (almanac and ephemeris) from a GPS satellite. The navigation message acquisition unit 52 acquires the navigation message received by the GPS module 50 and stores individual trajectory information (almanac and ephemeris) in the trajectory information storage unit 54 (step S103).

  Next, in each radio base station, when the trajectory information providing unit 75 receives a trajectory information transmission request from the assist server 3 and the requested trajectory information is stored in the trajectory information storage unit 54 ( In step S305, YES, the requested trajectory information is read from the trajectory information storage unit 54 and transmitted to the assist server 3 through the network interface 56 (step S106).

  Next, in the assist server 3, the assist data generation unit 14 receives the orbit information of the GPS satellite from the radio base station (step S107).

  Next, in the assist server 3, when the assist data generation unit 14 receives orbit information of the same GPS satellite from a plurality of radio base stations (for example, orbit information of the first GPS satellite from a plurality of radio base stations). (YES in step S108), the trajectory information having the highest occurrence frequency of the numerical value (value representing the trajectory) within a predetermined time range is selected from a plurality of trajectory information and added to the assist data (step S109). ).

  On the other hand, when the assist data generation unit 14 receives orbit information from one radio base station (NO in step S108), the received orbit information is added to the assist data (step S110).

  Next, in the assist server 3, the assist data providing unit 13 determines that the assist data is completed, that is, if the assist data includes all orbit information (almanac and ephemeris of all GPS satellites) (YES in step S111). ), Assist data is transmitted to all the radio base stations connected to the assist server 3 through the network interface 18 (step S112).

  Next, in each radio base station, the assist data acquisition unit 53 receives the assist data through the network interface 56 (step S113).

  Next, the assist data acquisition unit 53 gives the received assist data to the GPS module 50 (step S114).

  Next, the GPS module 50 receives an ephemeris of an unreceived GPS satellite using the assist data. When the GPS module 50 has received the navigation messages of the four GPS satellites, the GPS module 50 performs orbit calculation using the four received ephemeris, and the timing information of each GPS satellite created from the signals received from the GPS satellites and A reference time signal tb is generated from the distance to the GPS satellite (step S115).

  As described above, according to the third embodiment, as in the first embodiment, the assist server acquires orbit information from all GPS satellites by acquiring the missing orbit information from the radio base station. Is generated and provided to the radio base station. Thereby, the radio base station can receive orbit information from GPS satellites with good sensitivity. In addition, the assist server selects a radio base station that is likely to receive the missing trajectory information based on the position information of the almanac and the GPS module of the radio base station connected to the assist server. The transmission request for the missing orbit information is sent only to the selected radio base station. As a result, it is possible to prevent unnecessary communication from occurring due to sending a transmission request for trajectory information to a radio base station that is unlikely to be receiving.

[Fourth Embodiment]
The fourth embodiment relates to an assist server that does not have a GPS module.

(Assist server configuration)
FIG. 11 is a diagram illustrating a configuration of the assist server according to the fourth embodiment.

  The assist server 4 of FIG. 11 is different from the assist server 1 of FIG. 3 in that it does not include a GPS module and an orbit information request unit 41.

  The trajectory information request unit 41 transmits a transmission request for all trajectory information to all the radio base stations connected to the assist server 4.

(Configuration of radio base station)
FIG. 12 is a diagram illustrating a configuration of a radio base station according to the fourth embodiment.

  The radio base station 9 in FIG. 12 is different from the radio base station 5 in FIG.

  When the trajectory information providing unit 95 receives a transmission request for all the trajectory information from the assist server 4, the trajectory information providing unit 95 reads out all the trajectory information from the trajectory information storage unit 54 and transmits it to the assist server 4.

(Operation)
FIG. 13 is a flowchart showing an operation procedure of the radio base station system according to the fourth embodiment.

  First, in the assist server 4, the trajectory information request unit 41 sends a transmission request for all trajectory information to all the radio base stations connected to the assist server 4 through the network interface 18 (step S403).

  In parallel with step S403, in the radio base station 9, the GPS module 50 receives navigation messages (almanac and ephemeris) from GPS satellites. The navigation message acquisition unit 52 acquires the navigation message received by the GPS module 50 and stores individual trajectory information (almanac and ephemeris) in the trajectory information storage unit 54 (step S103).

  Next, in each radio base station, the trajectory information providing unit 95 receives a transmission request for all trajectory information from the assist server 4 through the network interface 56 (step S404).

  Next, the trajectory information providing unit 95 reads all trajectory information from the trajectory information storage unit 54 and transmits it to the assist server 4 through the network interface 56 (step S406).

  Next, in the assist server 4, the assist data generation unit 14 receives the orbit information of the GPS satellite from the radio base station (step S107).

  Next, in the assist server 4, the assist data generation unit 14 receives orbit information of the same GPS satellite from a plurality of radio base stations (for example, orbit information of the first GPS satellite from a plurality of radio base stations). (YES in step S108), the trajectory information having the highest occurrence frequency of the numerical value (value representing the trajectory) within a predetermined time range is selected from a plurality of trajectory information and added to the assist data (step S109). ).

  On the other hand, when the assist data generation unit 14 receives orbit information from one radio base station (NO in step S108), the received orbit information is added to the assist data (step S110).

  Next, in the assist server 4, when the assist data is completed, that is, when the assist data includes all orbit information (almanac and ephemeris of all GPS satellites) (YES in step S111). ), Assist data is transmitted to all the radio base stations connected to the assist server 4 through the network interface 18 (step S112).

  Next, in each radio base station, the assist data acquisition unit 53 receives the assist data through the network interface 56 (step S113).

  Next, the assist data acquisition unit 53 gives the received assist data to the GPS module 50 (step S114).

  Next, the GPS module 50 receives an ephemeris of an unreceived GPS satellite using the assist data. When the GPS module 50 has received the navigation messages of the four GPS satellites, the GPS module 50 performs orbit calculation using the four received ephemeris, and the timing information of each GPS satellite created from the signals received from the GPS satellites and A reference time signal tb is generated from the distance to the GPS satellite (step S115).

  As described above, according to the fourth embodiment, even when the assist server does not include a GPS module, the assist server acquires the orbit information of all the GPS satellites from the radio base station, thereby Assist data including the orbit information is generated and provided to the radio base station. Thereby, the radio base station can receive orbit information from GPS satellites with good sensitivity.

(Modification)
The present invention is not limited to the above embodiment, and includes, for example, the following modifications.

(1) Assist Server In the embodiment of the present invention, the radio base station system includes one assist server. However, the present invention is not limited to this, and may include a plurality of assist servers. However, providing too many assist servers is not desirable in terms of cost.

  When a plurality of assist servers are provided, a GPS satellite to be managed may be assigned to each of the assist servers, and the plurality of assist servers may cooperate to generate one assist data.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1-4, 601, 701 Assist server, 5-9, 5a-5n, 705 Wireless base station 10, 50, 50a-50n, 60, 501 GPS module 11, 21, 31, 31, 41 Orbit information request unit, 12 , 52, 62 Navigation message acquisition unit, 13 Assist data provision unit, 14, 24 Assist data generation unit, 16 Assist data storage unit, 17, 57, 57a to 57n GPS antenna, 18, 56 network interface, 51 Wireless communication unit, 54, 64 orbit information storage unit, 55, 65, 75, 95 orbit information providing unit, 59 antenna, 503 obstacle, 504 network, 505 GPS satellite group.

Claims (10)

A server connected to a radio base station,
A GPS receiver that receives orbit information from GPS satellites;
An orbit information requesting unit that requests transmission of orbit information that could not be received to the radio base station when any of the orbit information could not be received by the GPS receiving unit;
In response to the request, an assist data generation unit that generates assist data including orbit information transmitted from a radio base station and orbit information received from the GPS satellite;
A server comprising: an assist data providing unit that provides the generated assist data to a radio base station.   The orbit information requesting unit may have received orbit information that could not be received based on the position where a plurality of radio base stations are installed and the almanac of the orbit information received by the GPS receiving unit. The server according to claim 1, wherein a high radio base station is selected, and a transmission request for orbit information that could not be received is transmitted to the selected radio base station. A server connected to a radio base station,
An assist data generation unit that generates assist data composed of orbit information transmitted from the radio base station;
A server comprising: an assist data providing unit that provides the generated assist data to a radio base station.   When the assist data generation unit acquires orbit information of the same GPS satellite from a plurality of radio base stations, the occurrence frequency of the value indicating the orbit is highest among the orbit information of the same GPS satellite. The server according to any one of claims 1 to 3, wherein trajectory information is selected and assist data including the selected trajectory information is generated.   The assist data generation unit obtains information indicating the reception level of the orbit information together with the orbit information from the radio base station, and when orbit information of the same GPS satellite is obtained from a plurality of radio base stations, The orbit information with the highest reception level is selected from the orbit information of the plurality of the same GPS satellites, and assist data including the selected orbit information is generated. server. A wireless base station connected to a server,
A GPS receiver that receives orbit information from GPS satellites;
When receiving a transmission request for trajectory information from the server, and having received the requested trajectory information, a trajectory information providing unit that transmits the requested trajectory information to the server;
An assist data acquisition unit for acquiring assist data transmitted from the server;
The GPS receiver uses the acquired assist data to receive unreceived orbit information,
The GPS receiving unit is a radio base station that generates a reference time signal based on a plurality of received orbit information. A wireless base station connected to a server,
A GPS receiver that receives orbit information from GPS satellites;
An orbit information providing unit for transmitting the received orbit information to the server;
An assist data acquisition unit for acquiring assist data transmitted from the server;
The GPS receiver uses the acquired assist data to receive unreceived orbit information,
The GPS receiving unit is a radio base station that generates a reference time signal based on a plurality of received orbit information. The GPS receiving unit measures the reception level of the received orbit information,
The radio base station according to claim 6 or 7, wherein the orbit information providing unit transmits information indicating a reception level of the orbit information together with the orbit information to the server. A radio base station system comprising a plurality of radio base stations and a server connected to the plurality of radio base stations,
The server
A first GPS receiver that receives orbit information from a GPS satellite;
A trajectory information requesting unit that requests transmission of trajectory information that could not be received to the radio base station when any of the orbit information could not be received by the first GPS receiving unit;
In response to the request, an assist data generation unit that generates assist data including orbit information transmitted from a radio base station and orbit information received from the GPS satellite;
An assist data providing unit for providing the generated assist data to a radio base station,
The radio base station is
A second GPS receiver that receives orbit information from GPS satellites;
When receiving a transmission request for trajectory information from the server, and having received the requested trajectory information, a trajectory information providing unit that transmits the requested trajectory information to the server;
An assist data acquisition unit for acquiring assist data transmitted from the server;
The second GPS receiving unit receives unreceived orbit information using the acquired assist data,
The second GPS receiving unit is a radio base station system that generates a reference time signal based on a plurality of received orbit information. A synchronization method in a radio base station system comprising a plurality of radio base stations and a server connected to the plurality of radio base stations,
The server receives orbit information from a GPS satellite;
The radio base station receiving orbit information from a GPS satellite;
If the server fails to receive any orbit information, requesting transmission of orbit information that could not be received to the radio base station; and
The wireless base station receives a request for transmission of orbit information from the server, and if the requested orbit information has been received, transmits the requested orbit information to the server;
In response to the request, the server generates assist data including orbit information transmitted from a radio base station and orbit information received from the GPS satellite;
The server providing the generated assist data to a radio base station;
The wireless base station obtaining assist data transmitted from the server;
The wireless base station receives unreceived trajectory information using the acquired assist data;
And a step of generating a reference time signal based on the received plurality of pieces of trajectory information.

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