METHOD AND ARRANGEMENT FOR BASE STATION LOCATION, BASE STATION SYNCHRONIZATION, AND MOBILE STATION LOCATION

• US 20070252761A1
• Filed: 09/25/2006
• Published: 11/01/2007
• Est. Priority Date: 04/27/2006
• Status: Abandoned Application

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Koorapaty, Havish, Hafeez, Abdulrauf
• Application Number:
  US11/534,987
• Publication Number:
  US 20070252761A1
• Time in Patent Office: Days
• US Class Current: 342/464
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• 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: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04W 56/0025 synchronizing potentially movable access points

Abstract

A complete positioning solution for mobile communications networks such as WLAN or ad-hoc/multi-hop networks, which lack location information for one or more base stations. A method and arrangement computes the locations and transmit timing of the base stations utilizing GPS location information and GPS timing information from multiple GPS-capable mobile stations operating in the service areas of such base stations. Once the base station locations and transmit timing are known, this information is used in conjunction with the reported GPS information to synchronize transmissions from the base stations using a marker in a downlink transmission such as the start of a particular frame. Finally, the locations and transmit timing from three or more base stations are used to determine the locations of mobile stations that are not GPS-capable.

Claims

1. A method of determining location information for a base station in a wireless communication system, said method comprising:

receiving in the base station or other network node, Global Positioning System (GPS) location and timing information from at least three mobile stations having GPS capability, and

computing in the base station or other network node, the location information for the base station utilizing the received GPS location and timing information.

2. The method according to claim 1, wherein the step of receiving GPS location and timing information includes receiving from each of the at least three mobile stations, an identity of a marker in a received downlink frame and the GPS time at which the mobile station received the marker.

3. The method according to claim 2, wherein the step of computing the location information also includes computing transmit time information for the base station, said step of computing the location and transmit time information utilizing the equation:

4. The method according to claim 2, wherein the step of computing the location information includes computing the location information by computing time differences of arrival for signals transmitted from or received at two mobile stations.

5. The method according to claim 4, wherein the step of computing the location information by computing time differences of arrival for signals from two mobile stations includes computing the location information utilizing the equation:

6. A method of synchronizing transmissions from a base station in a wireless communication system in which the location of the base station is not known, said method comprising:

determining location information and transmit time for the base station, said location and transmit time determining step comprising;

receiving information in the base station or other network node from at least three reporting mobile stations having Global Positioning System (GPS) capability, said information including for each reporting mobile station, GPS location information, an identity of a marker in a received downlink frame, and the GPS time at which the mobile station received the marker; and

computing in the base station or other network node, the location information for the base station and the GPS time corresponding to the base station'"'"'s transmission time for the marker utilizing the received information; and

adjusting the base station transmission timing to satisfy a pre-determined relationship between the base station'"'"'s transmission time for the marker and GPS time.

7. A method of synchronizing transmissions from a base station in a wireless communication system in which the location of the base station is not known, said method comprising:

determining location information for the base station, said location determining step comprising;

receiving information in the base station or other network node from at least three reporting mobile stations having GPS capability, said information including for each reporting mobile station, Global Positioning System (GPS) location information, an identity of a marker in a received downlink frame, and the GPS time at which the mobile station received the marker; and

computing in the base station or other network node, the location information for the base station utilizing the received information;

calculating a distance from the base station to a given reporting mobile station based on the received GPS location of the given mobile station and the computed location information for the base station;

computing a propagation delay between the base station and the given mobile station;

computing a GPS time corresponding to the transmission time for the marker; and

adjusting the base station transmission timing to satisfy a pre-determined relationship between the base station'"'"'s transmission time for the marker and GPS time.

8. A method of determining location information for a mobile station which is not Global Positioning System (GPS) capable, said non-GPS-capable mobile station operating in a wireless communication system in which the location of a given base station in communication with the non-GPS-capable mobile station is not known, said method comprising:

computing location and transmit time information for the given base station based upon GPS location and timing information received by the given base station from at least three GPS-capable mobile stations; and

determining the location information for the non-GPS-capable mobile station utilizing the computed location and transmit time of the given base station and the locations and transmit times of at least two other base stations in communication with the non-GPS-capable mobile station.

9. The method according to claim 8, wherein the step of computing location and transmit time information for the given base station includes:

receiving GPS location and timing information in the given base station or other network node from at least three reporting mobile stations having GPS capability, said information including for each reporting mobile station, GPS location information, an identity of a marker in a received downlink frame, and the GPS time at which the mobile station received the marker;

computing the location information for the given base station utilizing the received information; and

computing a GPS time corresponding to the transmission time of the marker utilizing the received information

10. The method according to claim 9, wherein the step of determining the location information for the non-GPS-capable mobile station includes:

measuring time-of-arrival information for an uplink signal transmitted by the non-GPS-capable mobile station, wherein the uplink signal is received at the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station; and

computing the location of the non-GPS-capable mobile station from the time of arrival information and the computed base station location and transmit time information.

11. The method according to claim 9, wherein the step of determining the location information for the non-GPS-capable mobile station includes:

measuring time-of-arrival information for an uplink signal transmitted by the non-GPS-capable mobile station, wherein the uplink signal is received at the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station;

calculating time differences of arrival for the uplink signal at the base stations; and

computing the location of the non-GPS-capable mobile station from the time differences of arrival and the computed base station location and transmit time information.

12. The method according to claim 9, wherein the step of determining the location information for the non-GPS-capable mobile station includes:

measuring time-of-arrival information of a downlink signal at the non-GPS-capable mobile station, wherein the downlink signal is transmitted by the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station; and

computing the location of the non-GPS-capable mobile station from the time of arrival information and the computed base station location and transmit time information.

13. The method according to claim 9, wherein the step of determining the location information for the non-GPS-capable mobile station includes:

measuring time-of-arrival information of downlink signals at the non-GPS-capable mobile station, wherein the downlink signals are transmitted by the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station; and

calculating time differences of arrival for the downlink signals at the non-GPS-capable mobile station; and

computing the location of the non-GPS-capable mobile station from the time differences of arrival and the computed base station location and transmit time information.

14. The method according to claim 9, wherein the step of computing a GPS time corresponding to the transmission time of the marker includes:

calculating a distance from the given base station to a given GPS-capable mobile station based on the received GPS location of the given GPS-capable mobile station and the computed location information for the given base station;

computing a propagation delay between the given base station and the given GPS-capable mobile station; and

computing a GPS time corresponding to the transmission time for the marker.

15. The method according to claim 9, wherein the step of determining the location information for the non-GPS-capable mobile station includes:

modifying the computed base station transmission times to synchronize base stations by adjusting the given base station transmission timing to satisfy a predetermined relationship between the given base station'"'"'s transmission time for the marker and GPS time.

16. In a wireless communication system, an arrangement for determining location information for the base station, said arrangement comprising:

communication means for receiving Global Positioning System (GPS) location and timing information from at least three mobile stations having GPS capability; and

a location computation unit for computing the location information for the base station utilizing the received GPS location and timing information.

17. The arrangement of claim 16, wherein the GPS location and timing information received from each of the at least three mobile stations includes an identity of a marker in a received downlink frame and the GPS time at which the mobile station received the marker.

18. The arrangement of claim 16, wherein the marker is a frame number of the received downlink frame, and the GPS time is the GPS time at the start of the received frame.

19. The arrangement of claim 16, wherein the base station is located in a wireless local area network (WLAN).

20. The arrangement of claim 16, wherein the base station is located in an ad-hoc/multi-hop wireless network.

21. In a wireless communication system in which location information for a base station is not known, an arrangement for synchronizing transmissions from the base station, said arrangement comprising:

communication means for receiving information in the base station or other network node from at least three reporting mobile stations having Global Positioning System (GPS) capability, said information including for each reporting mobile station, GPS location information, an identity of a marker in a received downlink frame, and the GPS time at which the mobile station received the marker;

a location computation unit for computing the location information and GPS transmission time of the marker for the base station utilizing the received information; and

means for adjusting the base station transmission timing to satisfy a pre-determined relationship between the base station'"'"'s transmission time for the marker and GPS time.

22. The arrangement of claim 21, wherein the marker is a frame number of the received downlink frame, and the GPS time is the GPS time at the start of the received frame.

23. In a wireless communication system in which location information for a base station is not known, an arrangement for synchronizing transmissions from the base station, said arrangement comprising:

communication means for receiving information in the base station or other network node from at least three reporting mobile stations having Global Positioning System (GPS) capability, said information including for each reporting mobile station, GPS location information, an identity of a marker in a received downlink frame, and the GPS time at which the mobile station received the marker;

a location computation unit for computing the location information for the base station utilizing the received information;

means for computing a propagation delay between the base station and a given mobile station based on the received GPS location of the given mobile station and the computed location information for the base station;

means for computing a GPS time corresponding to the transmission time for the marker based on the GPS time at which the mobile station received the marker and the computed propagation delay; and

means for adjusting the base station transmission timing to satisfy a pre-determined relationship between the base station'"'"'s transmission time for the marker and GPS time.

24. The arrangement of claim 23, wherein the marker is a frame number of the received downlink frame, and the GPS time is the GPS time at the start of the received frame.

25. An arrangement for determining location information for a mobile station which is not Global Positioning System (GPS) capable, said non-GPS-capable mobile station operating in a wireless communication system in which the location of a given base station in communication with the non-GPS-capable mobile station is not known, said arrangement comprising:

a location computation unit for computing location information and transmit time information for the given base station based upon GPS location and timing information received from at least three GPS-capable mobile stations; and

a mobile location unit for determining the location information for the non-GPS-capable mobile station utilizing the location and transmit time of the given base station and the locations and transmit times of at least two other base stations in communication with the non-GPS-capable mobile station.

26. The arrangement according to claim 25, wherein the location computation unit includes:

communication means for receiving GPS location and timing information in the given base station or other network node from at least three reporting mobile stations having GPS capability, said information including for each reporting mobile station, GPS location information, an identity of a marker in a received downlink frame, and the GPS time at which the mobile station received the marker; and

means for computing the location information and GPS transmission time of the marker for the given base station utilizing the received information.

27. The arrangement according to claim 26, wherein the means for computing GPS transmission time of the marker includes:

a distance computation unit for computing a distance from the given base station to a given GPS-capable mobile station based on the received GPS location of the given mobile station and the computed location information for the given base station;

a delay computation unit for computing a propagation delay between the given base station and the given GPS-capable mobile station; and

means for computing a GPS time corresponding to the transmission time for the marker.

28. The arrangement according to claim 26, wherein the means for computing GPS transmission time of the marker includes:

means for adjusting the given base station transmission timing to satisfy a predetermined relationship between the given base station'"'"'s transmission time for the marker and GPS time.

29. The arrangement according to claim 26, wherein the mobile location unit includes:

means for measuring time-of-arrival information for an uplink signal transmitted by the non-GPS-capable mobile station, wherein the uplink signal is received at the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station; and

means for triangulating the location of the non-GPS-capable mobile station from the measured time-of-arrival information.

30. The arrangement according to claim 26, wherein the mobile location unit includes:

means for measuring time-of-arrival information for an uplink signal transmitted by the non-GPS-capable mobile station, wherein the uplink signal is received at the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station;

means for calculating time differences of arrival for the uplink signal at the base stations; and

means for computing the location of the non-GPS-capable mobile station from the time differences of arrival.

31. The arrangement according to claim 26, wherein the mobile location unit includes:

means for measuring time-of-arrival information for downlink signals received by the non-GPS-capable mobile station, wherein the downlink signals are transmitted by the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station; and

means for triangulating the location of the non-GPS-capable mobile station from the measured time-of-arrival information.

32. The arrangement according to claim 26, wherein the mobile location unit includes:

means for measuring time-of-arrival information for downlink signals received by the non-GPS-capable mobile station, wherein the downlink signals are transmitted by the given base station and the at least two other base stations in communication with the non-GPS-capable mobile station;

means for calculating time differences of arrival for the downlink signals at the base stations; and

means for computing the location of the non-GPS-capable mobile station from the time differences of arrival.

33. In a cellular network having a plurality of base stations, a method of propagating location information through the network, wherein initial location information is not known for at least some of the base stations, and a plurality of mobile stations operate within the network, wherein some of the mobile stations are Global Positioning System (GPS)-capable and others of the mobile stations are non-GPS-capable, said method comprising:

computing location and synchronization information for at least one of three base stations (BS1, BS2, and BS3) based on GPS location and GPS time information received from at least three GPS-capable mobile stations in communication with the at least one base station;

computing location information for at least one non-GPS-capable mobile station in communication with BS1, BS2, and BS3 based on the computed location information for BS1, BS2, and BS3 and time-of-arrival information for signals from the non-GPS-capable mobile stations received at BS1, BS2, and BS3; and

computing location information for a fourth base station (BS4) in communication with three mobile stations comprising a combination of non-GPS-capable mobile stations and GPS-capable mobile stations based on GPS-location and GPS-time information received from the GPS-capable mobile stations and time differences of arrival information reported by the non-GPS-capable mobile station, said time differences of arrival comprising time-of-arrival information for signals transmitted from BS4 and one of BS1, BS2, and BS3.

34. The method according to claim 33, wherein one of BS1, BS2, and BS3 is a fixed or mobile relay station.

35. The method according to claim 33, wherein one of the mobile stations is a fixed or mobile relay station.

36. In a cellular network having a plurality of base stations, a method of propagating location information through the network, wherein initial location information is not known for at least some of the base stations, and a plurality of mobile stations operate within the network, wherein some of the mobile stations are Global Positioning System (GPS)-capable and others of the mobile stations are non-GPS-capable, said method comprising:

computing location and synchronization information for at least one of three base stations (BS1, BS2, and BS3) based on GPS location and GPS time information received from at least three GPS-capable mobile stations in communication with the at least one base station;

computing location information for a non-GPS-capable mobile station in communication with BS1, BS2, and BS3 based on the computed location information for BS1, BS2, and BS3 and time-of-arrival information for signals from the non-GPS-capable mobile stations received at BS1, BS2, and BS3; and

computing location information for a fourth base station (BS4) in communication with the non-GPS-capable mobile station and two of the GPS-capable mobile stations based on GPS-location and GPS-time information received from the GPS-capable mobile stations and time differences of arrival reported by the non-GPS-capable mobile station, said time differences of arrival comprising time-of-arrival information for signals transmitted from BS4 and one of BS1, BS2, and BS3.

37. A method of determining location and transmit timing information for a given base station in a wireless communication system, said method comprising:

receiving or computing in the given base station or other network node, locations of at least three mobile stations; and

receiving in the given base station or other network node, timing information from the at least three mobile stations, said timing information comprising GPS time of arrival of a signal received at the mobile station from the given base station if the mobile station is GPS-capable, and comprising time differences of arrival of signals from the given base station and a different base station with known location and transmit timing if the mobile station is non-GPS-capable; and

computing in the given base station or other network node, the location and transmit timing information for the given base station utilizing the received GPS time of arrival or time difference of arrival information from the at least three mobile stations, the locations of the at least three mobile stations, and location and timing information for the base stations with known location and transmit timing.

38. The method according to claim 37, wherein the step of receiving GPS time of arrival information includes receiving from each of the at least three mobile stations, an identity of a marker in a received downlink frame and the GPS time at which the mobile station received the marker.

39. The method according to claim 37, wherein the step of receiving time difference of arrival information includes receiving from each of the at least three mobile stations, an identity of a marker in a received downlink frame and the differences in the time at which the mobile station received the marker from the given base station and the different base station with known location and transmit timing.

40. The method according to claim 38, wherein the step of computing the location and transmit timing information includes computing the location and transmit timing information utilizing the equation.

41. The method according to claim 37, wherein one of the base stations is a fixed or mobile relay station.

42. The method according to claim 37, wherein one of the mobile stations is a fixed or mobile relay station.

43. A method of determining a transmission time of a downlink signal transmitted from a base station in a wireless communication system in which the location of the base station is known, said method comprising:

receiving information in the base station or another network node from at least one reporting mobile station having Global Positioning System (GPS) capability, said information including for each reporting mobile station, GPS location information, an identity of a marker in a received downlink frame, and a GPS time at which the mobile station received the marker; and

computing in the base station or other network node, the GPS time corresponding to the base station'"'"'s transmission time for the marker utilizing the received information.