Method and system for providing location measurement of network based to mobile communication terminal by using G-pCell database

• US 8,073,466 B2
• Filed: 05/29/2007
• Issued: 12/06/2011
• Est. Priority Date: 11/07/2006
• Status: Active Grant

• Current Assignee: SK Planet Co., Ltd. (SK Telecom Co., Ltd.), SK Telecom Co., Ltd.
• Original Assignee: SK Telecom Co., Ltd.
• Inventors: Han, Gyuyoung, Oh, Sehyun, Ihm, Jongtae, Ha, Seongho, Yang, Hojin, Moon, Jungbae, Cho, Chaehwan, Shim, Kihak
• Primary Examiner(s): Doan, Kiet
• Application Number:
  US12/513,567
• Publication Number:
  US 20100062792A1
• Time in Patent Office: 1,652 Days
• Field of Search: 455/404.2, 455/456.2, 455/456.1, 455/456.3, 455/436, 370/335, 370/350, 370/342, 370/252, 342/457, 342/357.4, 342/357.42, 342/357.25, 342/357.22
• US Class Current: 455/456.2
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Disclosed are a method and a system for providing a mobile communication terminal with network-based location measurement by using a G-pCell database. The method and system are advantageous in that, when a mobile communication system employs a network-based location measurement scheme, the influence of repeaters is reduced to improve the positioning stability and measurement accuracy and provide more stable location-based services.

Claims

1. A method for providing a mobile communication terminal with network-based location measurement by using a G-pCell database, the method comprising the steps of:

(a) receiving a location measurement request signal from the mobile communication terminal by an SUPL (Secure User Plane Location) positioning center;

(b) extracting a primary G-pCell candidate group from the G-pCell database by using measurement data contained in the location measurement request signal received from the mobile communication terminal;

(c) extracting a secondary G-pCell candidate group from the primary G-pCell candidate group by excluding G-pCell IDs from the primary G-pCell candidate group, the G-pCell IDs having a distance equal to or larger than a predetermined value relative to location of the mobile communication terminal;

(d) selecting a G-pCell ID having best pattern matching with the measurement data from the secondary G-pCell candidate group; and

(e) transmitting a latitude and a longitude of the G-pCell ID selected in step (d) to the mobile communication terminal.

2. The method as claimed in claim 1, wherein step (b) comprises the steps of:

(b1) searching through the location measurement request signal received from the mobile communication terminal to extract the measurement data;

(b2) extracting an MCC (Mobile Country Code), an MNC (Mobile Network Code), an LAC (Location Area Code), a CI (Cell Identity), and a BSIC (Base Station Identity Code) from the measurement data, the MCC being a country code of a GSM service region, the MNC being a network code for identifying a business provider of a GSM network service region, the LAC being a code indicating a coverage of a GSM base station, the CI being only information used to recognize base station information, the BSIC being information for identifying an adjacent base station; and

(b3) selecting G-pCell IDs from the G-pCell database as the primary G-pCell candidate group, all of the MCC, MNC, LAC, CI, and BSIC extracted from the measurement data matching with the G-pCell IDs.

3. The method as claimed in claim 1, wherein, in step (c), the secondary G-pCell candidate group is extracted by excluding G-pCell IDs from the primary G-pCell candidate group, degree of spacing of the G-pCell IDs from center points of cells exceeding a predetermined threshold.

4. The method as claimed in claim 1, wherein, in step (c), the secondary G-pCell candidate group is extracted by excluding G-pCell IDs from the primary G-pCell candidate group, degree of spacing of the G-pCell IDs from center points of cells exceeding an average distance from the center points of the cells of the primary G-pCell candidate group.

5. The method as claimed in claim 3, wherein, in step (c), the secondary G-pCell candidate group is extracted by selecting only G-pCell IDs existing within a predetermined TA (Timing Advance) radius by using TA information, the TA information being a parameter indicating a distance from a center point of a base station currently used by the mobile communication terminal to the mobile communication terminal.

6. The method as claimed in claim 3, wherein, in step (c), the secondary G-pCell candidate group is extracted by selecting only G-pCell IDs existing in a range of TA−

1˜

TA+1 by using TA information, the TA information being a parameter indicating a distance from a center point of a center cell of the primary G-pCell candidate group to the mobile communication terminal.

7. The method as claimed in claim 4, wherein, in step (c), the secondary G-pCell candidate group is extracted by selecting only G-pCell IDs existing within a predetermined TA (Timing Advance) radius by using TA information, the TA information being a parameter indicating a distance from a center point of a base station currently used by the mobile communication terminal to the mobile communication terminal.

8. The method as claimed in claim 4, wherein, in step (c), the secondary G-pCell candidate group is extracted by selecting only G-pCell IDs existing in a range of TA−

1˜

TA+1 by using TA information, the TA information being a parameter indicating a distance from a center point of a center cell of the primary G-pCell candidate group to the mobile communication terminal.

9. The method as claimed in claim 1, wherein, in step (d), a G-Cell ID having best pattern matching is selected from G-pCell IDs belonging to the secondary G-pCell candidate group according to at least one method of:

comparing at least one of an MNC (Mobile Network Code), an LAC (Location Area Code), a CI (Cell Identity), and an ARFCN (Absolute Radio Frequency Channel Number) contained in the measurement data with an MNC, an LAC, a CI, and an ARFCN stored in a database table of each G-pCell ID belonging to the secondary G-pCell ID to assign a weight based on degree of matching, the MNC being a network code for identifying a business provider of a GSM network service region, the LAC being a code indicating a coverage of a GSM base station, the CI being only information used to recognize base station information, the ARFCN being a channel number used to identify a designated RF channel of a GSM wireless system;

comparing a BSIC (Base Station Identity Code) contained in the measurement data with a database table of each G-pCell ID belonging to the secondary G-pCell candidate group to assign a weight based on degree of matching, the BSIC being adjacent base station identification information;

assigning a weight according to a degree of matching in each designated step between an OTD of each adjacent base station contained in the measurement data and an OTD value regarding a BSIC stored in a database table of each G-pCell ID of the secondary G-pCell candidate group; and

assigning a weight according to a degree of matching in each designated step between signal intensity (Ec/Io) of each adjacent base station contained in the measurement data and signal intensity regarding a BSIC stored in a database table of each G-pCell ID of the secondary G-pCell candidate group.

10. The method as claimed in claim 1, further comprising, after step (a), a step of:

drawing connection lines between every BSIC based on information regarding a TA related to location of the mobile communication terminal and every BSIC measured by the mobile communication terminal, as well as based on latitude and longitude data for each BSIC, the data corresponding to BSA (Base Station Almanac) information stored in a network positioning server, drawing circles of TA+1 and TA−

1 based on a latitude and a longitude of a base station currently used by the mobile communication terminal, finding intersection points, and transmitting a center point of the intersection points to the mobile communication terminal as a location measurement result, when the primary G-pCell candidate group cannot be extracted by using the measurement data.

11. The method as claimed in claim 1, wherein the measurement data is basically collected by the mobile communication terminal to use the LBS and comprises, as information regarding a system currently providing a service, an MCC (Mobile Country Code) of a GSM service region, an MNC (Mobile Network Code) for recognizing a business provider in a GSM network service region, an LAC (Location Area Code) as a code indicating coverage of a GSM base station, CI (Cell Identity) as only information used to identify base station information, a BSIC (Base station Identity Code) as an ID of an adjacent base station, an ARFCN (Absolute Radio Frequency Channel Number) as an RF channel identification number of GSM, a TA (Timing Advance) meaning a round trip delay measured from a base station to the mobile communication terminal, an RSSI (Received Signal Strength Indicator) corresponding to intensity of all signals received by the base station currently used by the mobile communication terminal, an RXLEV indicating intensity of signals received by the mobile communication terminal, an RXQUAL parameter indicating degree of the received signal intensity, an OTD value of each adjacent base station as a difference in received signals between the base station currently used by the mobile communication terminal and an adjacent base station, and an RXLEV value as a parameter indicating signal intensity of each adjacent base station.

12. A method for constructing a G-pCell database for providing a mobile communication terminal with network-based location measurement, the method comprising the steps of:

(a) dividing a location measurement service target region into lattices of a predetermined size by an network positioning server, defining each lattice as a G-pCell, and assigning a G-pCell ID having proper information;

(b) receiving a log file created by an SUPL (Secure User Plane Location) positioning center as a result of positioning a mobile communication terminal with a reference satellite receiving device self-constructed in the SUPL positioning center, the mobile communication terminal having requested location measurement;

(c) conducting program parsing for extracting only parameters necessary to update the G-pCell database to create separate data; and

(d) comparing a latitude and a longitude corresponding to data regarding a positioning result for each LBS (Location Based Service) call from the separate data file with a latitude and longitude range of the G-pCell ID to find a G-pCell ID belonging to a nearest range, composing a database table based on measurement data collected by the mobile communication terminal at time of the LBS call with regard to the G-pCell ID found, and storing the database table.

13. The method as claimed in claim 12, wherein the G-pCell ID comprises latitude and longitude data corresponding to a center point of the lattices of a predetermined size, and latitude and longitude data regarding four vertices of the lattices.

14. The method as claimed in claim 12, wherein the log file is created by selecting only a satellite call having good positioning accuracy based on RF characteristic data received from the mobile communication terminal by the SUPL positioning center for each LBS call positioning and then creating the log file from the selected satellite call, when commercially available satellite positioning data is used.

15. The method as claimed in claim 12, wherein the measurement data is basically collected by the mobile communication terminal to use the LBS and comprises, as information regarding a system currently providing a service, an MCC (Mobile Country Code) of a GSM service region, an MNC (Mobile Network Code) for recognizing a business provider in a GSM network service region, an LAC (Location Area Code) as a code indicating coverage of a GSM base station, CI (Cell Identity) as only information used to identify base station information, a BSIC (Base station Identity Code) as an ID of an adjacent base station, an ARFCN (Absolute Radio Frequency Channel Number) as an RF channel identification number of GSM, a TA (Timing Advance) meaning a round trip delay measured from a base station to the mobile communication terminal, an RSSI (Received Signal Strength Indicator) corresponding to intensity of all signals received by the base station currently used by the mobile communication terminal, an RXLEV indicating intensity of signals received by the mobile communication terminal, an RXQUAL parameter indicating degree of the received signal intensity, an OTD value of each adjacent base station as a difference in received signals between the base station currently used by the mobile communication terminal and an adjacent base station, and an RXLEV value as a parameter indicating signal intensity of each adjacent base station.

16. A method for updating a G-pCell database for providing a mobile communication terminal with network-based location measurement, the method comprising the steps of:

(a) receiving a log file from an SUPL (Secure User Plane Location) positioning center by a network positioning server;

(b) parsing the log file to create separate data and searching for a G-pCell ID matching with the created separate data;

(c) confirming whether or not an MCC (Mobile Country Code), an MNC (Mobile network code), an LAC (Location Area Code), and a CI (Cell Identity) stored in a database table of each G-pCell ID with an MCC, an MNC, an LAC, and a CI contained in the separate data;

(d) comparing a CI, the CI being an ID of a base station currently used by the mobile communication terminal, and a BSIC of an adjacent base station collected by the mobile communication terminal with every CI and every BSIC stored in a database table of a corresponding G-pCell ID when it has been confirmed in step (c) that the MCC, MNC, LAC, and CI stored in the database table of the G-pCell are identical to the MCC, MNC, LAC, and CI contained in the separate data, calculating an average of OTD and signal intensity values of the separate data with regard to matching CI and BSIC, and updating the database table of an existing G-pCell ID; and

(e) adding a BSIC missing from a database table of the corresponding G-pCell ID to the database table of the G-pCell ID when it has been confirmed in step (c) that the MCC, MNC, LAC, and CI stored in the database table of the G-pCell ID are identical to the MCC, MNC, LAC, and CI contained in the separate data but the BSIC missing from a BSIC list of the database table of the corresponding G-pCell ID exists only in the separate data, storing OTD and signal intensity regarding the added BSIC, and updating the database table.

17. The method as claimed in claim 16, wherein a result of manual A-GPS positioning is used to update the G-pCell database in a region having no available A-GPS service.

18. The method as claimed in claim 16, further comprising, after step (c), a step of:

(c1) storing the separate data as a separate group in the database table of the corresponding G-pCell ID by the network positioning server when it has been confirmed in step (c) that at least one of the MCC, MNC, LAC, and CI stored in the database table of the G-pCell ID does not match with the corresponding MCC, MNC, LAC, and CI contained in the separate data parsed from the log file.

19. The method as claimed in claim 16, wherein, in step (d), when a plurality of OTD and signal intensity values exist with regard to matching BSIC in the database table of the G-pCell ID, an average of all OTD and signal intensity values is obtained and separately stored in the database table of the G-pCell when the OTD or signal intensity values are less than a predetermined number, and, when the OTD or signal intensity values are equal to or larger than the predetermined number, values lying out of a predetermined range are excluded, and an average of remaining values is obtained and separately stored in the database table of the G-pCell ID.

20. A method for reflecting base station change information in a G-pCell database for providing a mobile communication terminal with network-based location measurement, the method comprising the steps of:

(a) receiving base station change information created in a mobile communication network from a central management system by a network positioning server;

(b) searching through the base station change information to confirm whether or not the base station change information is base station deletion information;

(c) searching for all G-pCell IDs constructed in the G-pCell database with reference to a corresponding base station and deleting all information constructed with reference to the corresponding base station from group information stored in the

G-pCell IDs when it has been confirmed in step (b) that the base station change information is base station deletion information;

(d) confirming whether or not the base station change information is base station addition information when it has been confirmed in step (b) that the base station change information is not base station deletion information; and

(e) requesting that an SUPL (Secure User Plane Location) positioning center provides a log file regarding a result of A-GPS positioning for a period of time set by an administrator or for a period of time after a point of time set by the administrator with regard to an added base station and constructing a database table of G-pCell IDs when it has been confirmed in step (d) that the base station change information is base station addition information.

21. The method as claimed in claim 20, further comprising, after step (d), steps of:

(d1) confirming whether or not the base station change information is base station replacement information when it has been confirmed in step (d) that the base station change information is not base station addition information; and

(d2) conducting steps (c) and (e) successively with regard to a corresponding base station when it has been confirmed in step (d1) that the base station change information is base station replacement information.

22. A system for providing a mobile communication terminal with network-based location measurement by using a G-pCell database, the system comprising:

an SUPL positioning center acting as a network element for providing an A-GPS (Assisted GPS) service in a user plane type defined by SUPL (Secure User Plane Location) standards corresponding to OMA (Open Mobile Alliance) standards, the SUPL positioning center simultaneously providing a network-based solution service by using an A-GPS fallback solution even in an indoor region, an underground region, or other non-open regions having no available A-GPS service, the SUPL positioning center creating a separate log file for each A-GPS positioning from measurement data collected by the mobile communication terminal for network-type location measurement;

a network positioning server for storing the G-pCell database, requesting data necessary for positioning by using a protocol defined separately from SUPL POS data in case of interworking with the SUPL positioning center, parsing the log file when the log file is received from the SUPL positioning center to extract measurement data transmitted to the SUPL positioning center by the mobile communication terminal, and searching through the G-pCell database based on the measurement data to select a G-pCell ID having best pattern matching from G-pCell IDs;

a base station controller for controlling each base station arranged cell by cell and adapted to receive a location measurement request signal transmitted by the mobile communication terminal via a traffic channel among signal channels, the base station controller receiving the location measurement request signal from the base station;

an SGSN (Serving GPRS Support Node) having a hardware structure adapted to provide ATM-based switch and routing access for a GPRS (General Packet Radio Service), the SGSN supporting an OS (Operating System) for various data service processing, the SGSN receiving the location measurement request signal from the base station controller; and

a GGSN (Gateway GPRS Support Node) acting as a serving node in an IP-based packet network providing a high-speed packet data service for a data service, the GGSN transmitting the location measurement request signal to the SUPL positioning center via a WAP gateway when the location measurement request signal is received from the SGSN.

23. The system as claimed in claim 22, wherein the mobile communication terminal is adapted to add the measurement data to the location measurement request signal and transmit the location measurement request signal to the SUPL positioning center, and, when the SUPL positioning center does not interwork, mobile communication terminal transmits the measurement data to the network positioning server.

24. The system as claimed in claim 22, wherein the SUPL positioning center is adapted to interwork by using an IS-801 protocol when the mobile communication terminal is based on CDMA (Code Division Multiple Access), by using an RRC protocol when the mobile communication terminal is based on W-CDMA, and by using an RRLP protocol when the mobile communication terminal is based on GSM (Global System for Mobile communication) so as to request that the mobile communication terminal collects the measurement data for constructing the G-pCell database.

25. The system as claimed in claim 24, wherein an execution mode of the protocol is a TCP/IP mode so that the mobile communication terminal interworks with the SUPL positioning center or the network positioning server in a TCP/IP type via the base station, the base station controller, the SGSN, and the GGSN.

26. The system as claimed in claim 22, further comprising an SUPL location center as a server for processing result data transmitted by the SUPL positioning center and the network positioning server as a location measurement result, the SUPL location center interworking with a data network via the WAP gateway to transmit the location measurement result to the mobile communication terminal in an HTTP type.

27. The system as claimed in claim 22, further comprising a central management system for collecting and managing information regarding change of all base stations existing in the system, the central management system transmitting base station change information to the network positioning server when a base station in the system changes.

28. The system as claimed in claim 27, wherein the network positioning server is adapted to search through the base station change information received from the central management system;

when the base station change information is base station deletion information, the network positioning server searches for all G-pCell IDs constructed in the G-pCell database with reference to a corresponding base station and deletes all information constructed with reference to the corresponding base station from group information stored in the G-pCell IDs;

when the base station change information is base station addition information, the network positioning server requests that the SUPL positioning center provides a log file regarding a result of A-GPS positioning for a period of time set by an administrator or for a period of time after a point of time set by the administrator and constructs a database table of G-pCell IDs; and

, when the base station change information is base station replacement information, the network positioning server searches for all G-pCell IDs constructed in the G-pCell database with reference to a corresponding base station, deletes all information constructed with reference to the corresponding base station from group information stored in the G-pCell IDs, requests that the SUPL positioning center provides a log file regarding a result of A-GPS positioning for a period of time set by the administrator or for a period of time after a point of time set by the administrator, and constructs a database table of G-pCell IDs.