Making time of arrival measurements

• US 6,470,185 B2
• Filed: 09/28/1998
• Issued: 10/22/2002
• Est. Priority Date: 07/27/1998
• Status: Expired due to Term

• Current Assignee: Unwired Planet LLC (JP Morgan Chase & Co)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Lundqvist, Patrik, Fischer, Sven, Larsson, Erik, Kangas, Ari
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): Gantt, Alan T.
• Application Number:
  US09/162,079
• Publication Number:
  US 20020065075A1
• Time in Patent Office: 1,485 Days
• Field of Search: 455/423, 455/457, 455/456
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A time of arrival measurement apparatus is used to measure the time of arrival of a radio signal transmitted by a mobile communication station operating in a wireless mobile communication network. The apparatus is provided with information indicative of a predetermined point in time at which the radio signal is to be transmitted. The time of arrival measurement apparatus monitors for arrival of the radio signal only during a period of time after the predetermined point in time. The time of arrival measurement apparatus also receives information from which it can determine an informational content of the radio signal.

Claims

1. A method of using a time of arrival measurement apparatus to measure the time of arrival of a radio signal transmitted by a mobile communication station operating in a wireless communication network, comprising the steps of:

providing the time of arrival measurement apparatus with enhanced sensitivity to the radio signal transmitted by the mobile communication station, enhanced sensitivity is achieved by supplying the time of arrival measurement apparatus with first information, from which the time of arrival measurement apparatus can determine in advance certain encrypted bits for improved monitoring of said transmitted radio signal; and

using the time of arrival measurement apparatus to monitor for arrival of the radio signal.

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

utilizing an algorithm in a Global System for Mobile Communication (GSM) standard to produce said certain encrypted bits from said first information.

3. The method of claim 1, wherein said step of supplying the time of arrival measurement apparatus with said first information comprises:

supplying a Handover Reference Number.

4. The method of claim 1, wherein said step of supplying the time of arrival measurement apparatus with said first information comprises:

supplying a BSIC corresponding to an intended handover base transceiver station.

5. The method of claim 4, wherein said BSIC is received from a base station controller.

6. The method of claim 1, wherein said wireless communication network is a GSM network.

7. An apparatus for use in locating a mobile station in a wireless communication network, comprising:

a plurality of time of arrival monitors, each said time of arrival monitors for monitoring an air interface to determine when a radio signal transmitted by the mobile station has arrived at said time of arrival monitor;

each said time of arrival monitor including an input for receiving first information wherein said first information provides enhanced sensitivity to the transmitted radio signal, for said time of arrival monitor, said first information comprises information indicative of certain encrypted bits of the transmitted radio signal; and

each said time of arrival monitor including an output for providing second information indicative of a time of arrival of the radio signal at that time of arrival monitor.

8. The apparatus of claim 7, wherein an algorithm in a Global System for Mobile Communication (GSM) standard is used to produce said certain encrypted bits from said first information.

9. The apparatus of claim 7, wherein said certain encrypted bits are combined with bits from conventional access bursts of said transmitted radio signal, to achieve said enhanced sensitivity to said transmitted radio signal at said time of arrival monitor.

10. The apparatus of claim 7, wherein each of said time of arrival monitor includes an input for receiving third information indicative of frequency hopping parameters used by the mobile station.

11. The apparatus of claim 7, wherein said first information comprises:

a Handover Reference Number.

12. The apparatus of claim 7, wherein said first information comprises:

a BSIC corresponding to an intended handover base transceiver station.

13. The apparatus of claim 7, wherein the wireless communication network is a GSM network.

14. The apparatus of claim 7, further comprising a plurality of timing monitors respectively associated with said time of arrival monitors, each of said timing monitors coupled to the air interface for monitoring a radio channel used by the mobile station and determining therefrom a timing relationship between communication timing used by the mobile station and the local time based of the associated time of arrival monitor, each of said timing monitors including an output for outputting third information indicative of said timing relationship.

15. An apparatus for use in locating a mobile station in a wireless communication network, comprising:

an input for receiving a request to locate the mobile station;

a first output for indicating that a radio signal is to be transmitted from the mobile station for use in locating the mobile station; and

a second output providing to a plurality of time of arrival measurement devices first information providing enhanced sensitivity to the radio signal transmitted by the mobile station, said first information comprising information indicative of certain encrypted bits of the transmitted radio signal.

16. The apparatus of claim 15, wherein an algorithm in a Global System for Mobile Communication (GSM) standard is used to produce said certain encrypted bits from said first information.

17. The apparatus of claim 15, wherein said certain encrypted bits are combined with bits from conventional access bursts of said transmitted radio signal, to achieve said enhanced sensitivity to said transmitted radio signal at said time of arrival monitor.

18. A method of using a time of arrival (TOA) measurement apparatus to measure the time of arrival of at least one radio signal transmitted by a mobile communication station operating in a wireless mobile communication network, comprising:

initiating a handover command for the mobile communication station, the handover command providing starting time information for the mobile communication station to begin sending the at least one radio signal;

determining a period of time during which the TOA measurement apparatus is to monitor for arrival the at least one radio signal, the period of time being based upon the starting time information; and

monitoring, by the TOA measurement apparatus, the arrival of the at least one radio signal only during the period of time.

19. The method of claim 18, wherein the starting time information specifies a TDMA frame and a TDMA time slot within the TDMA frame during which the mobile communication station is to begin sending the at least one radio signal.

20. The method of claim 18, wherein:

the period of time is expressed in a time base of a base transceiver station (BTS) associated with the TOA measurement apparatus.

21. The method of claim 18, wherein:

the period of time is expressed in a time base of the TOA measurement apparatus.

22. The method of claim 18, wherein the step of determining comprises:

determining the period of time based upon an estimate of a location of the mobile communication station.

23. The method of claim 18, wherein the step of determining the period of time comprises:

determining a beginning of the period of time based upon an estimate of a location of the mobile communication station relative to the TOA measurement apparatus.

24. The method of claim 18, wherein the step of determining the period of time comprises:

determining an ending of the period of time based upon an estimate of a location of the mobile communication station relative to the TOA measurement apparatus.

25. The method of claim 18, wherein the step of determining comprises:

determining the period of time based upon a current timing advance (TA) value corresponding to the mobile communication station.

26. The method of claim 18, further comprising:

prior to the step of monitoring, providing to the TOA measurement apparatus a base station identity code (BSIC) corresponding to the base transceiver station (BTS) that is the intended handover target, and a handover reference number (HRN) specified for handover; and

following the step of monitoring, producing encrypted information from the at least one radio signal based upon the BSIC and HRN so as to increase the accuracy of the TOA measurement.

27. The method of claim 18, further comprising:

following the step of determining, providing the period of time to the TOA measurement apparatus; and

providing the TOA measurement apparatus with transmission information indicating a sequence of frequencies utilized by the mobile communication station.

28. The method of claim 27, wherein:

the transmission information includes a starting frame number during which the mobile communication station is to begin sending the at least one radio signal.

29. The method of claim 27, wherein:

the transmission information includes frequency hopping parameters.

30. An apparatus for use in locating a mobile station in a wireless communication network, comprising:

an input for receiving a request to locate the mobile station;

a first output for initiating, in response to receiving the request, a handover operation, the handover operation providing starting time information for the mobile station to begin sending at least one radio signal for use in locating the mobile station;

a module for determining a period of time during which a time of arrival measurement apparatus is to monitor for arrival the at least one radio signal; and

a second output for providing to the TOA measurement device the period of time.

31. The apparatus of claim 30, wherein the starting time information specifies a TDMA frame and a TDMA time slot within the TDMA frame during which the mobile station is to begin sending the at least one radio signal.

32. The apparatus of claim 30, wherein:

the period of time is expressed in a time base of the TOA measurement device.

33. The apparatus of claim 30, wherein:

the period of time is expressed in a time base of a base transceiver station (BTS) associated with the TOA measurement device.

34. The apparatus of claim 30, wherein:

the module determines the period of time based upon an estimate of a location of the mobile communication station.

35. The apparatus of claim 30, wherein:

the module determines a beginning of the period of time based upon an estimate of a location of the mobile communication station relative to the TOA measurement device.

36. The apparatus of claim 30, wherein:

the module determines an ending of the period of time based upon an estimate of a location of the mobile communication station relative to the TOA measurement apparatus.

37. The apparatus of claim 30, wherein:

the module determines the period of time based upon a current timing advance (TA) value corresponding to the mobile communication station.

38. The apparatus of claim 30, further comprising:

the second output provides to the TOA measurement device a base station identity code (BSIC) corresponding to the base transceiver station (BTS) that is the intended handover target, and a handover reference number (HRN) specified for handover, for allowing encryption of portions of the at least one radio signal.

39. The apparatus of claim 30, wherein:

the apparatus provides to the TOA measurement device with transmission information indicating a sequence of frequencies utilized by the mobile station.

40. The apparatus of claim 30, wherein:

the apparatus provides to the TOA measurement device frequency hopping parameters of the mobile station.

41. The apparatus of claim 30, wherein:

the apparatus provides to the TOA measurement device a starting frame number during which the mobile station is to begin sending the at least one radio signal.

42. A method of using a time of arrival (TOA) measurement apparatus to measure the time of arrival of at least one radio signal transmitted by a mobile communication station operating in a wireless mobile communication network, comprising:

providing starting time information for the mobile communication station to begin sending the at least one radio signal;

determining a period of time during which the TOA measurement apparatus is to monitor for arrival the at least one radio signal, the period of time being based upon the starting time information and upon an estimate of a location of the mobile communication station relative to the TOA measurement apparatus; and

monitoring, by the TOA measurement apparatus, the arrival of the at least one radio signal only during the period of time.

43. The method of claim 42, wherein:

the step of providing comprises initiating a handover command for the mobile communication station; and

the starting time information comprising an identification of a frame and time slot for the mobile communication station to begin sending the at least one radio signal.