Systems and methods for location positioning within radio access systems

• US 20090176507A1
• Filed: 01/08/2008
• Published: 07/09/2009
• Est. Priority Date: 01/08/2008
• Status: Active Grant

• Current Assignee: Wi-LAN Inc.
• Original Assignee: Wi-LAN Inc.
• Inventors: Wu, Shiquan, Yee, Jung
• Granted Patent: US 8,326,324 B2
• Time in Patent Office: Days
• US Class Current: 455/456.200
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• 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 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method for calculating the geographical position of a user equipment (UE) unit includes collecting position parameters conveying the relative position of the UE unit from two or more base stations using technologies mandated for the modern wireless networks. Particularly, know (predetermined) signals embedded in the downlink and uplink subframes, such as preambles, pilots, ranging codes are used for determining the coordinates of the UE unit. In addition, the methods and systems proposed here take advantage of the multiple antennas systems mandated at both the UE and BTS.

Claims

1. A method for determining the location of a user equipment (UE) unit operating within the coverage area of a two or more base transceiver stations (BTS) that transmit a specified periodic bit sequence over a radio access network, comprising:

a) at said UE unit, monitoring incoming traffic received from said BTSs for detecting said specified periodic bit sequence;

b) determining from said specified periodic bit sequences at least two position parameters that convey the relative position of said UE unit to two or more of said BTSs; and

c) processing said position parameters for establishing the geographical coordinates of said UE unit.

2. A method as claimed in claim 1, wherein step b) comprises:

establishing a first time of arrival (TOA1), a second time of arrival (TOA2) and third time of arrival (TOA3) of said specified periodic bit sequence at a first, second and respectively third BTS;

determining a first position parameter as a first time difference (T12) between the first and the second time of arrival; and

determining a second position parameter as a second time difference (T13) between the first and the third time of arrival.

3. A method as claimed in claim 2, wherein step c) comprises:

obtaining at said UE unit geographical coordinates of said BTSs; and

establishing the geographical coordinates of said UE unit based on said first and second time differences and the geographical coordinates of said BTSs.

4. A method as claimed in claim 1, wherein step b) comprises:

determining a first position parameter as a first angle of arrival (AOA1) of said specified periodic bit sequence from a first BTS on a first antenna of said UE unit; and

determining a second position parameter as a second angle of arrival (AOA1) of said specified periodic bit sequence from a second BTSs on a second antenna of said UE unit.

5. A method as claimed in claim 4, wherein step c) comprises:

obtaining at said UE unit geographical coordinates of said BTS; and

establishing the geographical coordinates of said UE unit based on said first and second angles of arrival and the geographical coordinates of said BTSs.

6. A method as claimed in claim 5, wherein said first and second BTSs are selected based on the strength of said periodic bit sequence at said second antenna.

7. A method as claimed in claim 1, wherein said radio access network is a one of a WiMax, a 3GPP LTE and a UMB network.

8. A method as claimed in claim 1, wherein said specified periodic bit sequence is a preamble transmitted in the downlink subframes by each said BTS.

9. A method as claimed in claim 1, wherein said specified periodic bit sequence is a pilot tone transmitted in the downlink subframes by each said BTS.

10. A method as claimed in claim 1, further comprising:

appending said geographical coordinates to an emergency call generated on said UE unit; and

routing said call from said UE unit to a public safety answering point.

11. A location identification module for a user equipment (UE) unit equipped with a first and a second antenna, comprising:

a monitoring unit for monitoring the incoming traffic and identifying a specified periodic bit sequence received from at least two base transceiver stations (BTSs);

a position parameters calculation arrangement for determining from said specified periodic bit sequences two position parameters conveying the relative position of said UE unit from said respective BTSs; and

a coordinate estimator for processing said two position parameters and establishing the geographical coordinates of said UE unit.

12. A location identification module as claimed in claim 11, wherein said position parameters calculation arrangement includes:

means for establishing a first, second and third time of arrival (TOA1, TOA2, TOA3) of said specified periodic bit sequence from a first BTS, a second BTS and a respectively third BTS; and

means for determining a first position parameter as a first time difference (T12) between the first and the second time of arrival and a second position parameter as a second time difference (T13) between the first and the third time of arrival.

13. A location identification module as claimed in claim 12, wherein said coordinate estimator comprises:

a memory for temporarily storing the geographical coordinates of said BTSs; and

means for establishing the coordinates of said UE unit based on said first and second time differences and the geographical coordinates of said BTSs.

14. A location identification module as claimed in claim 11, wherein said position parameters calculation arrangement comprises means for determining a first position parameter as a first angle of arrival of said specified periodic bit sequence received from a first BTS at said first antenna and means for determining a second position parameter as a second angle of arrival of said specified periodic bit sequence received from a second BTS at said second antenna.

15. A location identification module as claimed in claim 14, wherein said coordinate estimator comprises:

a memory for temporarily storing the geographical coordinates of said BTSs; and

means for establishing the coordinates of said UE unit based on said first and second angles of arrival and the geographical coordinates of said BTSs.

16. A location identification module as claimed in claim 11, further comprising a location call processor for appending said geographical coordinates to an emergency call generated on said UE unit and routing said call from said UE unit to a public safety answering point.

17. A location identification module as claimed in claim 16, further comprising a GPS unit for providing additional detailed location information to said location call processor for insertion into said call.

18. A method for determining the location of a user equipment (UE) unit operating within the coverage area of a plurality of antennae of a base transceiver station (BTS) in a radio access network, said UE unit transmitting uplink a specified periodic bit sequence, comprising:

i) at said BTS, monitoring the incoming traffic received from said UE unit over two receive antennae for detecting said specified periodic bit sequence;

ii) measuring a respective first and second position parameter from said specified periodic bit sequence received as said first and second antenna, respectively; and

iii) processing said first and second position parameters at said BTS for establishing the geographical coordinates of said UE unit.

19. A method as claimed in claim 18, wherein said UE unit is triggered to transmit a signal known to BTS as said specified periodic bit sequence.

20. A method as claimed in claim 18, wherein said first and second position parameters are a first and a second time of arrival (TOA).

21. A method as claimed in claim 20, wherein step iii) comprises:

generating a first and a second function, representing a first and a second circle having said first and respectively second TOA as a radius and said first and second antenna as a center; and

establishing the geographical coordinates of said UE unit at the intersection between said two circles.

22. A method as claimed in claim 18, wherein said first position parameter is the angle or arrival (AOA) of said specified periodic bit sequence on said first antenna, and the second position parameter is the distance between said UE unit and said second antennae.

23. A method as claimed in claim 22, wherein step iii) comprises calculating the coordinates of said UE unit relative to said BTS and establishing the geographical coordinates of said UE unit based on the coordinates of said UE unit relative to said BTS.

24. A method as claimed in claim 18, wherein said radio access network is one of a WiMax, a 3GPP LTE and a UMB network.

25. A method as claimed in claim 18, wherein said specified periodic bit sequence is a ranging code transmitted in the uplink subframes by said UE unit.

26. A method as claimed in claim 18, further comprising operating said UE unit in a location ranging mode, where said specified periodic bit sequence is a location ranging code transmitted by said UE unit.

27. A method as claimed in claim 26, wherein said location ranging code includes a ranging code known to said BTS and a caller identification.

34. A method as claimed in claim 18, wherein said specified periodic bit sequence is an additional symbol transmitted in said uplink frame, which includes an identification of said UE unit and a request for identifying the geographical coordinates of said UE unit.

28. A location identification module for a base transceiver station BTS operating in a radio access network, said BTS having a first and a second antennae, comprising:

a first monitoring unit for monitoring the incoming traffic received on the first antenna and identifying said specified periodic bit sequence received from a user equipment (UE) unit positioned in the area of coverage of said BTS and determining a first position parameter;

a second monitoring unit for monitoring the incoming traffic received on the second antenna and identifying said specified periodic bit sequence received from said UE unit and determining a second position parameter; and

a coordinate estimator for processing said two position parameters and establishing the geographical coordinates of said UE unit.

29. A location identification module as claimed in claim 28, wherein said radio access network is a WiMax network.

30. A location identification module as claimed in claim 29, wherein said specified periodic bit sequence is a ranging code transmitted in the uplink subframes by said UE unit.

31. A location identification module as claimed in claim 28, wherein said first and second position parameters are a first and a second time of arrival (TOA) of said specified periodic bit sequence at said first and second antenna.

32. A location identification module as claimed in claim 28 wherein said first position parameter is the angle or arrival (AOA) of said specified periodic bit sequence on said first antenna, and the second position parameter is the distance between said UE unit and said second antennae measured at said BTS.

33. A location identification module as claimed in claim 28, further comprising a transceiver for receiving two additional position parameters from two neighbouring BTSs and transmitting said first position parameter to said two neighbouring BTSs,

wherein said two additional position parameters are processed with said first position parameter for establishing the geographical coordinates of said UE unit.