System and method for time of arrival positioning measurements based upon network characteristics

• US 6,198,935 B1
• Filed: 11/17/1998
• Issued: 03/06/2001
• Est. Priority Date: 11/17/1998
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Kingdon, Christopher, Hussain, Tahir, Zadeh, Bagher, Saha, Bikash
• Primary Examiner(s): Nguyen, Lee
• Assistant Examiner(s): Nguyen, Simon
• Application Number:
  US09/193,309
• Time in Patent Office: 840 Days
• Field of Search: 455/456, 455/433, 455/457, 342/463, 342/457, 342/464
• US Class Current: 455/456.2
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

An improved system and method for determining a position of a mobile station in a mobile telecommunications network is disclosed. The system includes a database having geographical information pertaining to the service area of the telecommunications network, including whether service areas therein are characterized as urban areas, suburban areas or “badurban” areas in which radio communication is especially limited. The system further includes a mobile location center (MLC) which, among other things, calculates the number of access signal bursts which are required for transmission by the mobile station to be located. The access burst number is calculated based upon the geographical information pertaining to the service areas stored in the database and upon a requested position determination accuracy. By measuring the time of arrival delay of the burst signal transmission received by two or more base transceiver stations, the MLC computes the position of the mobile station.

Claims

1. A method for determining a position of a mobile station within a mobile telecommunications network, comprising the steps of:

maintaining a database having stored therein geographical information pertaining to service areas within the mobile telecommunications network, the geographical information including an ability to perform radio communication within the service areas;

calculating a required number of access burst signals for transmission by the mobile station to be used to determine the position of the mobile station, the calculation occurring prior to transmission of the access burst signals by the mobile station and being based upon the geographical information pertaining to the service areas;

receiving the required number of access burst signals transmitted by the mobile station;

measuring the time of arrival of the required number of access burst signals transmitted by the mobile station during the receiving step; and

calculating a position of the mobile station within the telecommunications network based upon the time of arrival measurements of the required burst signal transmission.

2. The method of claim 1, further including the step of:

identifying a plurality of base transceiver stations in the telecommunications network for participating in performing the mobile station position determination based upon the geographical information pertaining to the service areas;

wherein the identified participating base stations receive the required number of access burst signals transmitted by the mobile station.

3. The method of claim 2, wherein:

the service area geographical information includes an indication of the location of time measuring units associated with the base transceiver stations in the telecommunications network; and

the base transceiver station identifying step identifies the participating base transceiver stations based upon the time measuring unit locations in the service area geographical information.

4. The method of claim 1, wherein:

the geographical information pertaining to the service areas includes an indication whether service areas in the telecommunications network are one of an urban area, suburban area and badurban area in which radio communication is limited relative to radio communication in urban areas and suburban areas.

5. The method of claim 4, wherein:

the required number of access burst signals for transmission by the mobile station is calculated based upon whether a general location of the mobile station is characterized as an urban area, suburban area or badurban area.

6. The method of claim 1, further including the step of:

receiving a request to perform a position determination of the mobile station prior to the calculating step, the request including a requested degree of accuracy for the position determination; and

the calculating step calculates the required number of access bursts based upon the requested degree of positioning accuracy.

7. The method of claim 1, further including the step of:

transmitting a message to the mobile station to discontinue transmission of burst signals following the burst signal number receiving step.

8. The method of claim 1, wherein:

the access burst signals comprise part of a cell handover operation.

9. A mobile telecommunications network, comprising:

at least one mobile switching center (MSC);

a database having stored therein cell area geographical information of the cell areas which indicate an ability to perform radio communication therein;

a mobile location center (MLC) associated with the MSC, for calculating a number of burst signals for transmission by a mobile station to be used to determine a position thereof based upon the cell area geographical information;

wherein the MLC receives measured time of arrival delays of the burst signals transmitted by the mobile station and measured by location measurement units (LMUs) in the mobile telecommunications network, and calculates a position of the mobile station based upon the measured time of arrival delays of the burst signal transmission.

10. The telecommunications network of claim 9, wherein:

the cell area geographical information includes an indication whether cell areas in the telecommunications network are urban cell areas, suburban cell areas or badurban cell areas having a reduced ability for radio communication relative to the urban cell area and the suburban cell area.

11. The telecommunications network of claim 10, wherein:

the number of burst signals for transmission by the mobile station to be used to determine a position thereof is based upon whether the cell area of the mobile station is identified in the database as an urban cell area, a suburban cell area or a badurban cell area.

12. The telecommunications network of claim 9, wherein:

the MLC identifies LMUs for measuring the burst signal transmission based upon the cell area geographical database information.

13. The telecommunications network of claim 9, wherein:

the MLC calculates the number of burst signals based upon a predefined degree of accuracy of the mobile station position determination.

14. The telecommunications network of claim 9, wherein:

the cell area geographical database information includes an indication of the location of the LMUs in the telecommunications network; and

the MLC identifies certain LMUs for measuring the burst signal transmission based upon the LMU location indications in the cell area geographical database.

15. The telecommunications network of claim 14, wherein:

the LMUs instruct the mobile station to discontinue transmitting the burst signals upon the LMUs receiving the calculated number of burst signals.

16. A method for determining a position of a mobile station within a mobile telecommunications network, comprising the steps of:

receiving a request to perform a position determination of the mobile station, the request including a requested degree of accuracy for the position determination;

calculating a required number of access burst signals for reception from the mobile station based upon the requested degree of accuracy for the position determination;

receiving the required number of access burst signals transmitted by the mobile station;

measuring the time of arrival of the required number of access burst signals transmitted by the mobile station during the receiving step; and

calculating a position of the mobile station within the telecommunications network based upon the time of arrival measurements of the required burst signal transmission.

17. The method of claim 16, further including the step of:

maintaining a database of geographical information pertaining to cell areas within the mobile telecommunications network, the geographical cell area information including an indication of an ability to perform radio communication in the cell areas; and

the calculating step calculates the required number of access burst signals received from the mobile station based upon the geographical cell area information.

18. The method of claim 17, wherein:

the indication of an ability to perform radio communication within the cell areas includes an indication of whether each cell area is characterized as one of an urban cell area, a suburban cell area and a badurban cell area having a reduced ability to perform radio communication.

19. The method of claim 17, further including the step of:

identifying one or more base transceiver stations within the telecommunications network for receiving the required number of access burst signals during the access burst signal receiving step, the identifying of the base transceiver stations being based upon the geographical cell area information.

20. The method of claim 16, further including the step of:

instructing the mobile station to discontinue transmitting burst signals following the burst signal receiving step.

21. A device for determining a position of a mobile station within a mobile telecommunications system providing telecommunication services throughout a service area, comprising:

a database having information pertaining to the service area, including information thereof indicating an ability to perform radio communication in the service area; and

a control means for calculating a duration of one or more signals to be transmitted by the mobile station, the calculating occurring prior to transmission of the one or more signals by the mobile station and the calculated signal duration being based upon the information indicating the ability to perform radio communication within a portion of the service area where the mobile station is located, receiving signal measurement information of the one or more signals transmitted by the mobile station, and calculating a position of the mobile station based upon the signal measurement information.

22. The device of claim 21, further including:

a means for receiving a request for determining the position of the mobile station, including a requested degree of accuracy for the mobile station position determination; and

the calculated duration of the signal is based upon the requested degree of accuracy for the mobile station position determination.

23. The device of claim 21, wherein:

the indication of the ability to perform radio communication within the portion of the service area includes an indication whether the portion of the service area is one of an urban area, a suburban area and a badurban area having a lesser ability to perform radio communication.

24. The device of claim 21, wherein:

the mobile telecommunications system includes a plurality of base transceiver stations; and

the control means identifies one or more of the base transceiver stations for receiving the signal transmitted by the mobile station, the base transceiver station identification being based upon the indication of the ability to perform radio communication within the portion of the service area where the mobile station is located.