System and method for time of arrival based positioning during handover

• US 6,366,781 B1
• Filed: 07/08/1999
• Issued: 04/02/2002
• Est. Priority Date: 07/08/1999
• Status: Expired due to Term

• Current Assignee: CE Nuclear Power, LLC
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Hussain, Tahir, Zadeh, Bagher
• Primary Examiner(s): MAUNG, NAY AUNG
• Application Number:
  US09/350,042
• Time in Patent Office: 999 Days
• Field of Search: 455/422, 455/432, 455/436, 455/456, 455/560, 342/357.01, 342/357.17, 342/457
• US Class Current: 455/456.5
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/322 by location data
• CPC Class Codes: H04W 36/38 by fixed network equipment

Abstract

A telecommunications system and method is disclosed for allowing an ongoing Time of Arrival (TOA) based positioning of a mobile station to proceed if a radio related handover has occurred before the expiration of a delta timer in a Base Station Controller (BSC). The BSC stores an HOTIMER value therein, which corresponds to the amount of time involved in a normal radio-related handover procedure from the sending of a Handover Command to the reception of a Handover Complete message. If the BSC delta timer is active, e.g., positioning is ongoing, and the BSC determines that a radio related handover is needed, the BSC checks the amount of time remaining in the BSC delta timer. If that amount is more than the HOTIMER, then the ongoing positioning is not canceled.

Claims

1. A telecommunications system for performing a radio-related handover during an ongoing time of arrival based positioning of a mobile station within a cellular network, comprising:

a base station controller in wireless communication with said mobile station, said base station controller receiving a message associated with said ongoing time of arrival based positioning and determining that said radio-related handover needs to be performed after reception of said message;

a timer within said base station controller, said timer being initiated substantially upon receipt of said message; and

a handover value within said base station controller for indicating the amount of time needed to perform said radio-related handover, said base station controller comparing a remaining amount of time in said timer with said handover value and continuing said ongoing positioning when said handover value is less than said remaining amount of time.

2. The telecommunications system of claim 1, wherein said message is a BSSMAP CHANNEL INFORMATION message.

3. The telecommunications system of claim 1, further comprising:

a mobile switching center connected to said base station controller for sending said message to said base station controller.

4. The telecommunications system of claim 3, wherein, in response to said message, said base station controller transmits an acknowledgment message to said mobile switching center, said timer being initiated at substantially the same time as the transmission of said acknowledgment message.

5. The telecommunications system of claim 4, further comprising:

a serving mobile location center connected to said mobile switching center for originating said message and receiving said acknowledgment message from said base station controller via said mobile switching center.

6. The telecommunications system of claim 5, further comprising:

at least one location measurement unit in wireless communication with said base station controller for obtaining measurements associated with the time of arrival of access bursts transmitted from said mobile station during said ongoing positioning.

7. The telecommunications system of claim 6, wherein said serving mobile location center configures said at least one location measurement unit upon receipt of said acknowledgment message and calculates the location of said mobile station within said cellular network using said measurements.

8. The telecommunications system of claim 1, wherein said message includes a timer value for said timer, said timer being initiated with said timer value.

9. The telecommunications system of claim 1, wherein said base station controller cancels said ongoing positioning when said handover value is greater than said remaining amount of time.

10. A method for determining whether an ongoing positioning of a mobile station within a cellular network should be continued upon initiation of a radio-related handover of said mobile station, comprising the steps of:

initiating a timer associated with said ongoing positioning of said mobile station;

determining that said radio-related handover needs to be performed;

comparing a remaining amount of time of said timer with a predetermined handover value that indicates the amount of time needed to perform said radio-related handover;

if said predetermined handover value is less than said remaining amount of time, continuing said ongoing positioning;

otherwise, canceling said ongoing positioning.

11. The method of claim 10, further comprising the step of:

receiving a message having a timer value therein, said step of initiating being performed using said timer value.

12. The method of claim 10, wherein said step of receiving further comprises the step of:

sending said message from a mobile switching center to a base station controller in wireless communication with said mobile station.

13. The method of claim 12, further comprising the step of:

in response to said message, transmitting an acknowledgment message from said base station controller to said mobile switching center, said step of initiating said timer being performed at substantially the same time as said step of transmitting.

14. The method of claim 13, wherein said step of receiving further comprises the step of:

sending said message from a serving mobile location center to said mobile switching center.

15. The method of claim 14, wherein said step of transmitting further comprises the step of:

receiving, by said serving mobile location center, said acknowledgment message from said base station controller via said mobile switching center.

16. The method of claim 15, wherein said step of continuing further comprises the step of:

obtaining, by at least one location measurement unit in wireless communication with said base station controller, measurements associated with the time of arrival of access bursts transmitted from said mobile station during said ongoing positioning.