Apparatus and method for multimode device handover

• US 8,396,039 B2
• Filed: 04/15/2010
• Issued: 03/12/2013
• Est. Priority Date: 04/15/2010
• Status: Expired due to Fees

• Current Assignee: Clearwire Ip Holdings LLC (Deutsche Telekom AG)
• Original Assignee: Clearwire Ip Holdings LLC (Deutsche Telekom AG)
• Inventors: Pawar, Hemanth Balaji, Sitaram, Krishna D., Vivanco, Daniel
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US12/760,987
• Publication Number:
  US 20110255516A1
• Time in Patent Office: 1,062 Days
• Field of Search: None
• US Class Current: 370/331
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• 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

Systems and methods of operating multimode 3G/4G communications devices in an overlapping 3G/4G coverage area (e.g., WiMAX or LTE/CDMA EvDO) include determining if a number associated with temporarily-disabled sectors of an available sector set of the multimode device while the device is operational with a 3G base station is at least equal to a threshold number. If the number is at least equal to the threshold number, a scan for a sector in the 4G network to handover the operation of the multimode device from the 3G base station associated with the 3G coverage to a 4G base station associated with the 4G coverage is initiated. A scan for a fixed period of time for a new available sector in the 3G network to be added in the available sector set may be initiated; and, if a new available sector is added to the sector set, it may be redetermined if the number associated with the temporarily-disabled sectors is at least equal to the threshold number, before initiating the scan for a sector in the 4G network.

Claims

1. A method of operating a multimode third generation (3G) and fourth generation (4G) communications device capable of operating in either a 4G network or a 3G network when in an area with overlapping 3G and 4G coverage, the method comprising:

determining, using a processor, if a number associated with temporarily-disabled sectors of an available sector set of the multimode device is at least equal to a threshold number, wherein the available sector set of the multimode device is stored in a memory operatively coupled to the processor, while the multimode device is operational with a 3G base station in the 3G network; and

initiating a scan for a sector in the 4G network to handover the operation of the multimode device from the 3G base station associated with the 3G coverage to a 4G base station associated with the 4G coverage if the number is at least equal to the threshold number.

2. The method of claim 1, wherein the number associated with the temporarily-disabled sectors is a ratio of a number of temporarily-disabled sectors of the available sector set to the total number of sectors in the available sector set.

3. The method of claim 1, wherein the 3G base station comprises a CDMA/EvDO base station.

4. The method of claim 1, wherein the 4G base station comprises a WiMAX base station.

5. The method of claim 1, wherein the 4G base station comprises an LTE base station.

6. The method of claim 1, wherein the multimode device comprises a dual-mode CDMA/EvDO-4G device.

7. The method of claim 6, wherein the multimode device comprises a dual-mode CDMA/EvDO-LTE device or a dual-mode CDMA/EvDO-WiMax device.

8. The method of claim 1, wherein the multimode device comprises a device associated with a user priority determined by at least one of an application QoS or a user rate plan.

9. The method of claim 1, wherein a multiple access scheme of the 4G network comprises an Orthogonal Frequency Division Multiple Access (OFDMA) modulation scheme.

10. The method of claim 1, wherein the temporarily-disabled sectors are disabled by the 3G base station by enabling Data Rate Control Lock (DRCLock).

11. The method of claim 1, further comprising:

responsive to the determination that the number is at least equal to the threshold number, scanning, using the processor, for a fixed time period for a new available sector in the 3G network to be added in the available sector set.

12. The method of claim 11, wherein the scanning for the fixed time period is performed before initiating the scan for a sector in the 4G network.

13. The method of claim 11, wherein the scanning for the fixed time period is performed in tandem with the scanning for a sector in the 4G network.

14. The method of claim 11, further comprising:

redetermining, before initiating the scan for a sector in the 4G network, if the number associated with the temporarily-disabled sectors of the available sector set is at least equal to the threshold number, if the scanning results in the addition of a new available sector in the available sector set.

15. The method of claim 11, wherein the new available sector is added to the available sector set based on either a frequency of the new available sector, a signal strength of the new available sector, or both.

16. The method of claim 11, wherein the fixed time period is configurable by a user through an interface with the processor.

17. A multimode third generation (3G) and fourth generation (4G) communications apparatus capable of operating in either a 3G network or a 4G network when in an area with overlapping 3G and 4G coverage, the apparatus comprising:

a 3G transceiver configured to transmit and receive information over a 3G network;

a 4G transceiver configured to selectively transmit and receive data over a 4G network;

a memory device configured to store an available sector set associated with the 3G transceiver, while the apparatus is in communication with a 3G base station in the 3G network; and

a processor operatively coupled to the memory device, the 3G transceiver and the 4G transceiver, wherein the processor is configured to;

determine if a number associated with temporarily-disabled sectors in the available sector set is at least equal to a threshold number, and

if the number is determined to be at least equal to the threshold number, enable control signals configured to initiate a scan for a sector in the 4G network and handover the communication of the multimode apparatus from the 3G base station associated with the 3G coverage to a 4G base station associated with the 4G coverage.

18. The apparatus of claim 17, wherein the number associated with the temporarily-disabled sectors is a ratio of a number of temporarily-disabled sectors of the available sector set to the total number of sectors in the available sector set.

19. The apparatus of claim 17, wherein, responsive to the determination that the number is at least equal to the threshold number, the processor is further configured to enable control signals to scan for a fixed time period for a new available sector in the 3G network to be added in the available sector set of the 3G transceiver.

20. The apparatus of claim 18, wherein the processor is further configured to enable the control signals to scan for a new available sector in the 3G network before enabling the control signals to scan for a sector in the 4G network.

21. The apparatus of claim 18, wherein the processor is further configured to enable the control signals to scan for a new available sector in the 3G network in tandem with the enabling of the control signals to scan for a sector in the 4G network.

22. The apparatus of claim 18, wherein, before enabling the control signals to scan for a sector in the 4G network, the processor is further configured to redetermine if the number associated with the temporarily-disabled sectors of the available sector set is at least equal to a threshold number responsive to a new available sector being added in the available sector set.

23. The apparatus of claim 18, wherein processor is further configured to add the new available sector to the available sector set based at least on a frequency of the new available sector, signal strength of the new available sector, or both.

24. The apparatus of claim 18, wherein the processor is further configured to determine the fixed time period for the scan in response to a user input.

25. The apparatus of claim 17, wherein the 3G transceiver comprises a CDMA/EvDO transceiver.

26. The apparatus of claim 17, wherein the 4G transceiver comprises a WiMAX transceiver.

27. The apparatus of claim 17, wherein the 4G transceiver comprises an LTE transceiver.

28. A non-transitory computer-readable medium comprising computer readable code physically embodied thereon which, when executed by a processor arranged in a multimode third generation (3G) and fourth generation (4G) communications device capable of operating in either a 4G network or a 3G network mode, causes the processor to carry out operations comprising:

determining if a number associated with temporarily-disabled sectors of an available sector set of the multimode device is at least equal to a threshold number, wherein the available sector set is stored in a memory operatively coupled to the processor, while the multimode device is operational with a 3G base station in the 3G network; and

initiating a scan for a sector in the 4G network to handover the operation of the multimode device from the 3G base station associated with the 3G coverage to a 4G base station associated with the 4G coverage if the number is at least equal to the threshold number.

29. The computer-readable medium of claim 28, wherein the number associated with the temporarily-disabled sectors is a ratio of a number of temporarily-disabled sectors of the available sector set to the total number of sectors in the available sector set.

30. The computer-readable medium of claim 28, wherein the multimode device comprises a dual-mode CDMA/EvDO-LTE device.

31. The computer-readable medium of claim 28, wherein the multimode device comprises a dual-mode CDMA/EvDO-WiMAX device.

32. The computer-readable medium of claim 28, the operations further comprising, responsive to a determination that the number is at least equal to the threshold number, scanning for a fixed time period for a new available sector in the 3G network to be added in the available sector set.

33. The computer-readable medium of claim 32, wherein said scanning operation comprises scanning for a fixed time period for a new available sector in the 3G network to be added in the available sector set before initiating the scan for a sector in the 4G network.

34. The computer-readable medium of claim 32, wherein said scanning operation comprises scanning for a fixed time period for a new available sector in the 3G network to be added in the available sector set in tandem with initiating the scan for a sector in the 4G network.

35. The computer-readable medium of claim 32, the operations further comprising:

re-determining, before initiating the scan for a sector in the 4G network, if the number associated with the temporarily-disabled sectors of the available sector set is at least equal to the threshold number, if said scanning for a fixed time period results in the addition of a new available sector in the available sector set.

36. The computer-readable medium of claim 32, the operations further comprising:

adding the new available sector to the available sector set based on a frequency of the new available sector, a signal strength of the new available sector, or both.