Method and Apparatus for Neighbor List Updates

• US 20090137246A1
• Filed: 09/11/2008
• Published: 05/28/2009
• Est. Priority Date: 09/17/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chirala, Ramesh Chandra, Khan, Muhammad Khawar R., Xing, Helen Jun, Alnatsheh, Rami H., Bhattacharjee, Supratik
• Granted Patent: US 8,144,662 B2
• Time in Patent Office: Days
• US Class Current: 455/434
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase

Abstract

An apparatus and method for maintaining information during neighbor list updates comprising acquiring information of a first plurality of GSM neighbor cells; recording and keeping the information for a time period T; receiving a second plurality of GSM neighbor cells; comparing the second plurality of GSM neighbor cells with the first plurality of GSM cells in the record; if a GSM neighbor cell from the second plurality of GSM neighbor cells is not in the record, gathering information pertaining to the GSM neighbor cell; and if at least one GSM neighbor cell from the second plurality of GSM neighbor cells is in the record, determining if the age of the information pertaining to the at least one GSM neighbor cell is less than the time period T and if less than T, locating the at least one GSM neighbor cell.

Claims

1. A method of maintaining frequency offset and timing information during neighbor list updates, comprising the steps of:

acquiring a frequency offset and a timing information of each of a first plurality of GSM neighbor cells;

recording an identity, the frequency offset and the timing information of each of the first plurality of GSM neighbor cells and keeping the frequency offset and the timing information for a time period T in a record;

receiving a list of a second plurality of GSM neighbor cells;

comparing an identity of each of the second plurality of GSM neighbor cells with the identity of each of the first plurality of GSM cells in the record;

if a GSM neighbor cell from the second plurality of GSM neighbor cells is not in the record, gathering frequency offset and timing information pertaining to the GSM neighbor cell; and

if at least one GSM neighbor cell from the second plurality of GSM neighbor cells is in the record, determining if an age of the frequency offset and timing information pertaining to the at least one GSM neighbor cell is less than the time period T and if the age is less than the time period T, locating the at least one GSM neighbor cell.

2. The method of claim 1 further comprising receiving a measurement control message (MCM) which includes a list of the first plurality of GSM neighbor cells.

3. The method of claim 2 further comprising configuring for a WCDMA compressed mode wherein frequency offset and timing information from the first plurality of GSM neighbor cells is acquired during the WCDMA compressed mode.

4. The method of claim 3 further comprising acquiring a primary scrambling code (PSC) from at least one of a plurality of WCDMA cells in an active set.

5. The method of claim 4 further comprising reporting an event 1A to indicate that a new WCDMA cell with a different primary scrambling code has a power level above a predetermined power threshold Th_pwr, wherein the new WCDMA cell is not part of the plurality of WCDMA cells.

6. The method of claim 5 further comprising receiving an ActiveSetUpdate message to add the new WCDMA cell to the active set.

7. The method of claim 1 wherein the time period T is a maximum time duration allowed for reconfirming frequency offset and timing information.

8. A user equipment comprising a processor and a memory, the memory containing program code executable by the processor for performing the following steps:

acquiring a frequency offset and a timing information of each of a first plurality of GSM neighbor cells;

recording an identity, the frequency offset and the timing information of each of the first plurality of GSM neighbor cells and keeping the frequency offset and the timing information for a time period T in a record;

receiving a list of a second plurality of GSM neighbor cells;

comparing an identity of each of the second plurality of GSM neighbor cells with the identity of each of the first plurality of GSM cells in the record;

if a GSM neighbor cell from the second plurality of GSM neighbor cells is not in the record, gathering frequency offset and timing information pertaining to the GSM neighbor cell; and

if at least one GSM neighbor cell from the second plurality of GSM neighbor cells is in the record, determining if an age of the frequency offset and timing information pertaining to the at least one GSM neighbor cell is less than the time period T and if the age is less than the time period T, locating the at least one GSM neighbor cell.

9. The user equipment of claim 8 wherein the memory further comprising program code for receiving a measurement control message (MCM) which includes a list of the first plurality of GSM neighbor cells.

10. The user equipment of claim 9 wherein the memory further comprising program code for configuring for a WCDMA compressed mode wherein frequency offset and timing information from the first plurality of GSM neighbor cells is acquired during the WCDMA compressed mode.

11. The user equipment of claim 10 wherein the second plurality of GSM neighbor cells is received from a second measurement control message (MCM) triggered by an event 1A report.

12. A wireless communication device for maintaining frequency offset and timing information during neighbor list updates comprising:

means for acquiring a frequency offset and a timing information of each of a first plurality of GSM neighbor cells;

means for recording an identity, the frequency offset and the timing information of each of the first plurality of GSM neighbor cells and keeping the frequency offset and the timing information for a time period T in a record;

means for receiving a list of a second plurality of GSM neighbor cells;

means for comparing an identity of each of the second plurality of GSM neighbor cells with the identity of each of the first plurality of GSM cells in the record;

means for determining if an age of the frequency offset and timing information pertaining to at least one GSM neighbor cell from the second plurality of GSM neighbor cells is less than the time period T, wherein the at least one GSM neighbor cell is in the record; and

means for locating the at least one GSM neighbor cell from the second plurality of GSM neighbor cells, wherein the age of the frequency offset and timing information is less than the time period T.

13. The wireless communication device of claim 12 further comprising means for gathering frequency offset and timing information pertaining to a GSM neighbor cell from the second plurality of GSM neighbor cells wherein the GSM neighbor cell is not in the record.

14. The wireless communication device of claim 13 further comprising means for receiving a measurement control message (MCM) which includes a list of the first plurality of GSM neighbor cells.

15. The wireless communication device of claim 14 further comprising means for configuring for a WCDMA compressed mode wherein frequency offset and timing information from the first plurality of GSM neighbor cells is acquired during the WCDMA compressed mode.

16. The wireless communication device of claim 12 wherein the wireless communication device is one of a mobile phone, a computer with wireless Internet connectivity, a WiFi compatible device or a WiMAX compatible device.

17. A computer program recorded on a computer-readable medium, comprising the steps of:

acquiring a frequency offset and a timing information of each of a first plurality of GSM neighbor cells;

recording an identity, the frequency offset and the timing information of each of the first plurality of GSM neighbor cells and keeping the frequency offset and the timing information for a time period T in a record;

receiving a list of a second plurality of GSM neighbor cells;

comparing an identity of each of the second plurality of GSM neighbor cells with the identity of each of the first plurality of GSM cells in the record;

determining if an age of the frequency offset and timing information pertaining to at least one GSM neighbor cell from the second plurality of GSM neighbor cells is less than a time period T, wherein the at least one GSM neighbor cell is in the record; and

locating the at least one GSM neighbor cell from the second plurality of GSM neighbor cells, wherein the age of the frequency offset and timing information is less than the time period T.

18. The computer program of claim 17 further comprising a step of gathering frequency offset and timing information pertaining to a GSM neighbor cell from the second plurality of GSM neighbor cells wherein the GSM neighbor cell is not in the record.

19. The computer program of claim 18 further comprising a step of receiving a measurement control message (MCM) which includes a list of the first plurality of GSM neighbor cells.

20. The computer program of claim 19 further comprising a step of configuring for a WCDMA compressed mode wherein frequency offset and timing information from the first plurality of GSM neighbor cells is acquired during the WCDMA compressed mode.