Handoffs and Handoff Selection in a Wireless Access Network

• US 20080268844A1
• Filed: 06/03/2005
• Published: 10/30/2008
• Est. Priority Date: 06/07/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Zhang, Hang, Tong, Wen, Ma, Jianglei, Zhu, Peiying, Fong, Mo-Han
• Granted Patent: US 8,909,226 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 36/00692 using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] allocation of physical resources in CoMP or in CA H04L5/0035
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/302 due to low signal strength

Abstract

The present invention facilitates handoffs for a mobile terminal in a wireless access network that is capable of supporting different types of handoffs. The different handoff types may include soft handoffs and fast base station switching (FBSS). In operation, context information associated with supporting wireless communications between the wireless access network and the mobile terminal are determined. Based on whether the context information is shared between base stations involved in the handoff or transferred from one base station to another of the base station involved in the handoff, a particular handoff type is selected from the different handoff types that are available. Selecting the specific type of handoff to use may also be based on the level of context information that is available, the actual content of the context information, application preferences, channel conditions, base station or mobile terminal capabilities, or any combination thereof.

Claims

1. A method for facilitating a handoff for a mobile terminal in a wireless access network capable of supporting a plurality of different handoff types, the method comprising:

determining context information associated with supporting wireless communications between the wireless access network and the mobile terminal; and

selecting a selected handoff type from the plurality of handoff types based on whether the context information is shared between base stations involved in a handoff or transferred from one base station to another of the base stations involved in the handoff.

2. The method of claim 1 wherein at least one of the plurality of handoff types is fast base station switching.

3. The method of claim 1 wherein at least one of the plurality of handoff types is soft handoff.

4. The method of claim 3 wherein the soft handoff is macro-diversity soft handoff.

5. The method of claim 3 wherein the soft handoff is selective soft handoff.

6. The method of claim 1 wherein at least two of the plurality of handoff types are fast base station switching and soft handoff.

7. The method of claim 1 wherein the context information is associated with a plurality of levels, and selecting the selected handoff is further based on a level associated with the context information.

8. The method of claim 7 wherein the level associated with the context information corresponds to service-related information for a communication session.

9. The method of claim 7 wherein the level associated with the context information corresponds to layer 2 processing related information provided at the base stations involved in the handoff.

10. The method of claim 7 wherein the plurality of levels comprises four levels, each of the four levels representing different levels of information associated with wireless communications.

11. The method of claim 1 wherein selecting the selected handoff is further based on the content of the context information.

12. The method of claim 1 wherein selecting the selected handoff is further based on an application associated with a communication session.

13. The method of claim 1 wherein selecting the selected handoff is further based on channel conditions.

14. The method of claim 1 further comprising determining if the base station supports the plurality of handoff types.

15. The method of claim 1 further comprising determining if the mobile terminal supports the plurality of handoff types.

16. The method of claim 1 wherein when the context information is not shared or transferred, the method further comprising selecting a hard handoff.

17. The method of claim 1 wherein when either the mobile terminal or the base stations involved in the handoff do not support one of the plurality of handoff types, the method further comprising selecting a hard handoff.

18. The method of claim 1 wherein one of the base stations involved in the handoff selects the selected handoff type.

19. The method of claim 1 wherein the mobile terminal selects the selected handoff type.

20. An apparatus for facilitating a handoff for a mobile terminal in a wireless access network capable of supporting a plurality of different handoff types, the apparatus comprising:

at least one communication interface; and

a control system associated with the at least one communication interface adapted to;

determine context information associated with supporting wireless communications between the wireless access network and the mobile terminal; and

select a selected handoff type from the plurality of handoff types based on whether the context information is shared between base stations involved in a handoff or transferred from one base station to another of the base stations involved in the handoff.