Method and system for automated determination of inter-system border thresholds

• US 7,408,900 B2
• Filed: 06/23/2003
• Issued: 08/05/2008
• Est. Priority Date: 06/28/2002
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Hunkeler, Teresa
• Primary Examiner(s): Pham; Chi H.
• Assistant Examiner(s): TRAN, PHUC H
• Application Number:
  US10/601,786
• Publication Number:
  US 20040008647A1
• Time in Patent Office: 1,870 Days
• Field of Search: 370280-332, 455/67.11
• US Class Current: 370/331
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data

Abstract

A method and system for determining thresholds for evaluating inter-system handovers in a wireless communication system includes determining a quality level of a first digital duplexing type, determining a quality level of a second digital duplexing type, and comparing the quality levels to determine whether to handover from the first digital duplexing type to the second duplexing type.

Claims

1. A method for determining thresholds for evaluating handovers in a wireless communication network, the method comprising:

determining a quality level of a first digital duplexing type based on the threshold value for intra-system handover of the first digital duplexing type;

determining a quality level of a second digital duplexing type based on the coverage report from a plurality of multi-mode wireless transmit/receive units (WTRUs); and

comparing the quality levels to determine whether to handover from the first digital duplexing type to the second duplexing type;

initiating a handover from the first duplexing type to the second duplexing type if the first quality level is below a first threshold and the second quality level is above a second threshold.

2. The method of claim 1, wherein a WTRU is operating in the first digital duplexing type and the quality level of the first digital duplexing type is determined by using primary channel signal levels.

3. The method of claim 2, wherein the quality level of the second digital duplexing type is determined using secondary channel signal levels derived from an estimated quality of a non-used frequency.

4. The method of claim 1, wherein the first digital duplexing type is time division duplex and the second digital duplexing type is frequency division duplex.

5. The method of claim 1, wherein the first digital duplexing type is frequency division duplex and the second digital duplexing type is time division duplex.

6. The method of claim 1, wherein the first quality level of the first digital duplexing type is based on a received signal code power of a primary common control physical channel;

and

the second quality level of the second digital duplexing type is based on information provided by a WTRU regarding the extent of coverage of the second digital duplexing type.

7. A method for determining thresholds for evaluating handovers between a first duplexing type and a second duplexing type in a wireless communications network, the method comprising:

determining a first minimum quality level for the first duplexing type based on a threshold value for intra-system handover of the first digital duplexing type;

determining a second minimum quality level for the second duplexing type based on a coverage report received from a plurality of multi-mode wireless transmit/receive units (WTRUs);

comparing the first minimum quality level with a first threshold and comparing the second minimum quality level with a second threshold; and

initiating a handover from the first duplexing type to the second duplexing type if the first minimum quality level is below the first threshold and the second minimum quality level is above the second threshold.

8. The method of claim 7, wherein the first threshold is an average of the first minimum quality level values, and the second threshold is an average of the second minimum quality level values.

9. The method of claim 7, wherein the first threshold and the second threshold are percentile values.

10. The method of claim 7, wherein the first duplexing type is Time Division Duplex and the second duplexing type is Frequency Division Duplex.

11. The method of claim 10, wherein determining a first minimum quality level includes calculating a received signal code power of a primary common control physical channel.

12. The method of claim 10, wherein determining a second minimum quality level includes calculating a received signal code power of a common pilot channel.

13. The method of claim 10, wherein determining a second minimum quality level includes calculating a signal-to-noise ratio of a common pilot channel.

14. The method of claim 7, wherein the first duplexing type is Frequency Division Duplex and the second duplexing type is Time Division Duplex.

15. The method of claim 14, wherein determining a first minimum quality level includes calculating a received signal code power of a common pilot channel.

16. The method of claim 14, wherein determining a first minimum quality level includes calculating a signal-to-noise ratio of a common pilot channel.

17. The method of claim 14, wherein determining a second minimum quality level includes calculating a received signal code power of a primary common control physical channel.

18. The method of claim 7, wherein the first duplexing type and the second duplexing type are the same, and the handover is between different cells of the same duplexing type.

19. A radio network controller (RNC) for determining thresholds for handovers between a first duplexing type and a second duplexing type, the RNC comprising:

a receiver configured to receive from a wireless transmit/receive unit (WTRU) a report of the extent of coverage of the second duplexing type;

processor configured to set a first minimum quality level for the first duplexing type, and to decide

whether to handover a WTRU from the first duplexing type to the second duplexing type if the first minimum quality level for the first duplexing type is below a first threshold and a second minimum quality level for the second duplexing type is above a second threshold.