Method for identification of base stations and for checking measurement values of an observed time difference between transmissions from base stations

• US 7,280,831 B2
• Filed: 11/05/2001
• Issued: 10/09/2007
• Est. Priority Date: 11/05/2001
• Status: Expired due to Fees

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Ruutu, Ville, Moilanen, Jani M.
• Primary Examiner(s): Ferguson; Keith
• Application Number:
  US10/250,459
• Publication Number:
  US 20040082344A1
• Time in Patent Office: 2,164 Days
• Field of Search: 455436-444, 455/422.1, 455/432.1, 455/432.2, 455/432.3, 455/434, 455/550.1, 455/561, 455/502, 455/500, 455/517, 455/524, 455/525, 455/67.11, 455/423, 455/424, 455/425, 455/456.1, 455/456.6, 455/445, 370/328, 370/329, 370/331, 370/332, 370/333, 370/334, 370/310
• US Class Current: 455/436
• 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 identification of transceiver devices in a radio communication network, includes the steps of pre-identifying transceiver devices, judging that there is an ambiguous result obtained in the pre-identification, and verifying the ambiguous result by identifying the transceiver devices based on real time difference (RTD) values between the transceiver devices. Also the method may include checking measurement values of an observed time difference (OTD) obtained at a mobile transceiver device operated within a radio communication network constituted by transceiver devices, wherein the checking is based on real time difference values between the transceiver devices. Thus, an improved method is obtained for mobile station location determination and/or for taking handover decisions as well as a way of verifying the reliability of obtained measurement results.

Claims

1. A method for identification of transceiver devices constituting a radio communication network, said method comprising

pre-identifying said transceiver devices,

judging that there is an ambiguous result obtained in said pre-identification, and

verifying said ambiguous result by identifying said transceiver devices based on real time difference values between said transceiver devices.

2. A method according to claim 1, wherein

said pre-identifying is accomplished based on respective broadcast control channel broadcast control channel information of said transceiver devices.

3. A method according to claim 1, wherein

said pre-identifying is accomplished based on a respective base station identity code of said transceiver devices.

4. A method according to claim 1, wherein

it is judged that there is an ambiguous result obtained in said pre-identification, if the transceiver devices can no longer be distinguished from each other.

5. A method according to claim 4, wherein

the transceiver devices can no longer be distinguished from each other if the respective broadcast control channel information of said transceiver devices are identical.

6. A method according to claim 4, wherein

the transceiver devices can no longer be distinguished from each other, if the respective base station identity code of said transceiver devices are identical.

7. A method according to claim 1, wherein

said verifying is based on a relation between

an observed time difference OTD at a mobile transceiver device,

the real time difference RTD of transmission times between said transceiver devices constituting said radio communication network, and

the geometric time difference GTD being due to different propagation times between the mobile transceiver device and the transceiver devices constituting said radio communication network, the relation being expressed as

OTD=RTD+GTD.

8. A method according to claim 7, wherein

said verifying comprises

estimating a minimum GTD_expected,min and a maximum GTD_expected,max value of said geometric time difference GTD,

deriving, based on said observed time difference OTD and said estimated maximum and minimum geometric time difference GTD, a respective minimum RTD_expected,min and a maximum RTD_expected,max expected value of said real time difference RTD such that

RTD_expected,min=OTD−

GTD_expected,max

RTD_expected,max=OTD−

GTD_expected,min.

9. A method according to claim 8, wherein

said verifying further comprises

comparing known real time difference values of said transceiver devices with said range of expected real time difference values RTD_{expected,min.}, RTD_expected,max, and

if the real time difference value of the transceiver device is found to be within said range of expected real time difference values, identifying this transceiver device as an unambiguous neighbor transceiver device to a reference transceiver device.

10. A method according to claim 8, wherein

said estimation of maximum and minimum geometric time difference is based on information about the location of the mobile transceiver device already available in the communication network.

11. A method according to claim 10, wherein

said already available information about the location of the mobile transceiver device is obtained, in Global System for Mobile communication systems, using Cell Identity and/or Cell Identity and Timing Advance values of the mobile transceiver device, and, in Universal Mobile telecommunication systems, using Cell Identity and/or Cell Identity and Service Area Identifier and/or Round Trip Time values.

12. A method according to claim 8, wherein

said estimation of maximum and minimum geometric time difference GTD_max, GTD_min further comprises

setting the maximum GTD value GTD_max equal to the distance between the two transceiver devices divided by the speed of radio waves, and

setting the minimum GTD value GTD_min equal to the negative of the distance between the two transceiver devices divided by the speed of radio waves.

13. A method according to claim 8, wherein

said estimation of maximum and minimum geometric time difference GTD_max, GTD_min further comprises

estimating maximum and minimum geometric time difference based upon information about the location of a mobile transceiver device already available in the communication network;

estimating maximum and minimum geometric time difference by setting the maximum GTD value GTD_max equal to the distance between the two transceiver devices divided by the speed of radio waves, and setting the minimum GTD value GTD_min equal to the negative of the distance between the two transceiver devices divided by the speed of the radio waves, and

selecting for the maximum GTD_max the value of the estimates obtained in the two steps above which is smaller, and

selecting for the minimum GTD_min the value of the estimates obtained in the two steps above which is larger.

14. The method according to claim 1, further comprising checking measurement values of an observed time difference obtained at a mobile transceiver device operated within a radio communication network constituted by transceiver devices, wherein

said checking is based on real time difference values between said transceiver devices.

15. A method according to claim 14, wherein

said checking is based on a relation between

an observed time difference OTD at a mobile transceiver device,

the real time difference RTD of transmission times between said transceiver devices constituting said radio communication network, and

the geometric time difference GTD being due to different propagation times between the mobile transceiver device and the transceiver devices constituting said radio communication network, the relation being expressed as

OTD=RTD+GTD.

16. A method according to claim 15, wherein

said checking comprises

estimating a minimum GTD_expected,min and a maximum GTD_expected,max value of said geometric time difference,

obtaining, based on said real time difference and said estimated maximum and minimum geometric time difference, a respective minimum OTD_expected,min and a maximum OTD_expected,max expected value of said observed time difference such that

OTD_expected,min=RTD+GTD_expected,max

OTD_expected,max=RTD+GTD_expected,min.

17. A method according to claim 16, wherein

said checking further comprises

comparing measured observed time difference values with said range of expected observed time difference values OTD_expected,min, OTD_expected,max, and

if the observed time difference value at the mobile transceiver device is found to be within said range of expected observed time difference values, this measurement value is accepted, while otherwise it is rejected.

18. A device for identification of transceiver devices constituting a radio communication network, the device configured to:

pre-identify said transceiver devices;

judge that there is an ambiguous result obtained at said pre-identification; and

verify said ambiguous result by identifying said transceiver devices based on real time difference values between said transceiver devices.

19. The device according to claim 18, further configured to check measurement values of an observed time difference obtained at a mobile transceiver device operated within a radio communication network constituted by transceiver devices, the device comprising a checking unit configured to perform a check based on real time difference values between said transceiver devices.

20. A device for identification of transceiver devices, comprising

means for pre-identifying transceiver devices in a radio network;

means for judging that there is an ambiguous result obtained in a pre-identifying process; and

means for verifying the ambiguous result by identifying the transceiver devices based on real time difference values between the transceiver devices.

21. The device according to claim 20, further comprising:

a checking means for performing a check based on real time difference values between at least two transceiver devices,

wherein an observed time difference is obtained at a mobile transceiver device operated within a radio communication network constituted by transceiver devices.