Expedited handoff

• US 8,838,109 B2
• Filed: 10/17/2011
• Issued: 09/16/2014
• Est. Priority Date: 07/14/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Li, Junyi, Srinivasan, Murari, Laroia, Rajiv, Anigstein, Pablo A
• Primary Examiner(s): PATEL, MAHENDRA R
• Application Number:
  US13/275,138
• Publication Number:
  US 20120034921A1
• Time in Patent Office: 1,065 Days
• Field of Search: 370/331, 370/395, 370/342, 370/328, 370/332, 370/330, 455/436, 455/439, 455/562, 455/561, 455/452, 455/447, 455/448, 455/437, 455/450, 342/357
• US Class Current: 455/436
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point

Abstract

Systems and methodologies are described that facilitate handing off from a first sector to a second sector. An established link to the first sector may be employed to communicate with the second sector. A handoff request from a wireless terminal to the second sector and an associated handoff response from the second sector to the wireless terminal may both traverse the first sector.

Claims

1. A method of handing off from a first sector to a second sector, the method being implemented by a wireless terminal, the method comprising:

detecting a signal emanating from the second sector;

sending a handoff notice to the second sector via a first link with the first sector;

receiving a handoff response from the second sector through the first link and the first sector, wherein the handoff response received through the first sector includes identified information provided by the second sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless terminal;

establishing a second link with the second sector utilizing the identified information;

sending an access signal in the access resource to the second sector;

receiving an access grant message from the second sector, the access grant message including at least a timing correction command;

adjusting a transmitter symbol timing as a function of the timing correction command; and

sending signals to the second sector using the transmitter symbol timing.

2. The method of claim 1, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.

3. The method of claim 1, further comprising:

transmitting an uplink access exchange to the second sector;

receiving a downlink access exchange from the second sector, wherein at least one of the uplink access exchange and the downlink access exchange conveys an identifier; and

using the identifier in the second link.

4. The method of claim 1, wherein the identified information further comprises an identifier, and further comprising using the identifier in the second link.

5. The method of claim 1, further comprising breaking the first link with the first sector prior to establishing the second link with the second sector.

8. The method of claim 1, further comprising:

recording a transmitter symbol timing associated with the first link; and

using the transmitter symbol timing in the second link.

9. The method of claim 1, further comprising:

deriving a connection identifier (CID) associated with second sector based upon the detected signal; and

transmitting the CID as part of a handoff request.

6. A method of handing off from a first sector to a second sector, the method being implemented by a wireless terminal, the method comprising:

detecting a signal emanating from the second sector;

sending a handoff notice to the second sector via a first link with the first sector;

receiving a handoff response from the second sector through the first link and the first sector, wherein the handoff response received through the first sector includes identified information provided by the second sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless terminal;

establishing a second link with the second sector utilizing the identified information;

selecting a random access resource;

sending an access signal in the random access resource to the second sector;

receiving an access grant message from the second sector, the access grant message including at least a timing correction command;

adjusting a transmitter symbol timing as a function of the timing correction command;

sending an uplink access exchange to the second sector using the transmitter symbol timing, wherein the uplink access exchange conveys at least part of the identified information; and

receiving a downlink access exchange from the second sector.

7. The method of claim 6, wherein the identified information includes a time period during which an assigned ID is valid, the random access resource being associated with a time prior to an end of the time period during which the assigned ID is valid.

10. A wireless communications apparatus, comprising:

a memory that retains instructions for handing off from a first sector to a second sector; and

a processor that detects a signal associated with a second sector, transmits a handoff request to the second sector via a first link with the first sector, receives a handoff response from the second sector via the first link and the first sector, and creates a second link with the second sector based upon identified information provided by the second sector included in the handoff response received via the first sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless communications apparatus, transmits an access signal in the allocated access resource to the second sector, receives an access grant message from the second sector including at least a timing correction command, alters a transmitter symbol timing base at least in part upon the timing correction command, and transmits signals to the second sector using the transmitter symbol timing.

11. The wireless communications apparatus of claim 10, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.

12. A wireless communications apparatus for mitigating delay associated with handing off from a first sector to a second sector, comprising:

means for detecting a signal emanating from the second sector;

means for transmitting a handoff request to the second sector via a first link with the first sector;

means for receiving a handoff response from the second sector through the first link and the first sector, wherein the handoff response received through the first sector includes identified information provided by the second sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless communications apparatus;

means for establishing a second link with the second sector;

means for transmitting an access signal in the dedicated access resource to the second sector;

means for obtaining an access grant message from the second sector, the access grant message includes at least a timing correction command;

means for adjusting a transmitter symbol timing as a function of the timing correction command; and

means transmitting signals to the second sector using the transmitter symbol timing.

13. The wireless communications apparatus of claim 12, further comprising:

means for establishing the second link with the second sector with a contention-free access.

14. The wireless communications apparatus of claim 12, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.

15. A non-transitory machine-readable medium having stored thereon machine-executable instructions for:

receiving a beacon associated with a second sector;

transmitting a handoff request to the second sector routed through a first link with a first sector;

obtaining a handoff response from the second sector routed through the first link and the first sector, wherein the handoff response obtained through the first sector includes identified information provided by the second sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to a wireless terminal;

creating a second link with the second sector by utilizing the identified information;

selecting a random access resource;

sending an access signal in the random access resource to the second sector;

receiving an access grant message from the second sector, the access grant message including at least a timing correction command;

adjusting a transmitter symbol timing as a function of the timing correction command;

sending an uplink access exchange to the second sector using the transmitter symbol timing, wherein the uplink access exchange conveys at least part of the identified information; and

receiving a downlink access exchange from the second sector.

16. The machine-readable medium of claim 15, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.

17. A processor that executes the following instructions:

detecting a signal related to a second sector;

sending an expedited handoff request to the second sector via a first link with a first sector;

receiving a handoff response from the second sector via the first link and the first sector, wherein the handoff response received via the first sector includes identified information provided by the second sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to a wireless terminal;

establishing a second link with the second sector utilizing the identified information;

transmitting an access request in an access resource to the second sector;

receiving an access grant from the second sector, the access grant including at least a timing correction command;

modifying a transmitter symbol timing based at least in part upon the timing correction command; and

sending signals to the second sector using the transmitter symbol timing.

18. The processor of claim 17, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.

19. A method that facilitates allocating resources to a wireless terminal to mitigate handoff delay, comprising:

receiving a handoff request from a wireless terminal via a first sector;

allocating resources of a second sector to the wireless terminal;

transmitting a handoff response to the wireless terminal via the first sector, wherein the handoff response includes identified information provided by the second sector related to the allocated resources, and wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless terminal; and

establishing a link with the wireless terminal by employing the allocated resources, wherein establishing the link with the wireless terminal further comprises;

receiving an access request message in the allocated access resource from the wireless terminal;

transmitting an access grant message to the wireless terminal that includes at least a timing correction command; and

receiving signals from the wireless terminal adjusted based upon the timing correction command.

20. The method of claim 19, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.

21. The method of claim 19, further comprising:

receiving an uplink access exchange from the wireless terminal; and

transmitting a downlink access exchange to the wireless terminal, wherein at least one of the uplink access exchange and the downlink access exchange includes an identifier.

22. The method of claim 19, further comprising synchronizing the wireless terminal while establishing the link.

23. A method that facilitates allocating resources to a wireless terminal to mitigate handoff delay, comprising:

receiving a handoff request from a wireless terminal via a first sector;

allocating resources of a second sector to the wireless terminal;

transmitting a handoff response to the wireless terminal via the first sector, wherein the handoff response includes identified information provided by the second sector related to the allocated resources, and wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless terminal;

establishing a link with the wireless terminal by employing the allocated resources;

receiving an access signal in a random access resource;

transmitting an access grant message to the wireless terminal, the access grant message includes at least a timing correction command;

receiving an uplink access exchange from the wireless terminal, the uplink access exchange being synchronized based upon the timing correction command and includes at least part of the identified information; and

transmitting a downlink access exchange to the wireless terminal.

24. The method of claim 23, wherein the identified information includes an index of the allocated access resource, and the random access resource is earlier than the allocated access resource.

25. A wireless communications apparatus for allocating resources to a wireless terminal for utilization in connection with a handoff, comprising:

means for obtaining a handoff request from a wireless terminal through a first sector;

means for allocating resources of a second sector to the wireless terminal;

means for sending identified information provided by the second sector and associated with the allocated resources in a handoff response to the wireless terminal via the first sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless terminal;

means for establishing a link with the wireless terminal utilizing the allocated resources;

means for receiving an access signal in the allocated access resource from the wireless terminal;

means for transmitting an access grant message to the wireless terminal, the access grant message including at least a timing correction command; and

means for receiving signals from the wireless terminal, the signals being modified based upon the timing correction command.

26. The wireless communications apparatus of claim 25, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.

27. A non-transitory machine-readable medium having stored thereon machine-executable instructions for:

receiving a handoff request in response to a beacon from a wireless terminal via a first sector;

allocating resources of a second sector to the wireless terminal;

transmitting identified information provided by the second sector and associated with the resources in a handoff response to the wireless terminal through the first sector, wherein the identified information comprises information about an allocated access resource, and wherein the allocated access resource is dedicated to the wireless terminal;

creating a link with the wireless terminal employing the resources;

receiving an access signal in the allocated access resource from the wireless terminal;

transmitting an access grant message to the wireless terminal, the access grant message including at least a timing correction command; and

receiving signals from the wireless terminal, the signals being modified based upon the timing correction command.

28. The machine-readable medium of claim 27, wherein the identified information further comprises at least one of timing related information, a session ON ID, an active ID, a destination MAC state or a time period during which an assigned ID is valid.