Apparatus and method of performing a handoff in a communication network

• US 9,155,008 B2
• Filed: 03/25/2008
• Issued: 10/06/2015
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Parekh, Nileshkumar J., Krasnyanskiy, Maksim (Max)
• Primary Examiner(s): Scheibel, Robert C
• Application Number:
  US12/055,076
• Publication Number:
  US 20080240039A1
• Time in Patent Office: 2,751 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off

Abstract

Apparatus and methods enable an efficient, low-latency handoff of a communication session, which may be especially effective in a high data rate network. The apparatus and methods provide for a source transceiver module to complete a transmission in-progress while at the same time informing a target transmission module of an end point of the transmission such that data in a shadow buffer of an anchor network function module can be sent to the target transceiver function prior to implementation of the handoff. As such, the apparatus and methods allow for an extremely quick handoff that minimizes use of a backhaul network.

Claims

1. A method of performing a session handoff in a wireless communication system, comprising:

receiving by a source transceiver module an ordered sequence of data packets from an anchor network function module after establishing a communication session with an access terminal, wherein the communication session is controlled by the anchor network function module, and the anchor network function module comprises a shadow buffer operable to store a copy of the ordered sequence of data packets transmitted to the source transceiver module;

transmitting, in a transmission, a segment of the ordered sequence of data packets to the access terminal via the communication session;

identifying a sequence marker corresponding to an end of the segment as being a completion point of the transmission;

continuing to complete the transmission through the end of the segment; and

transmitting, in parallel with continuing to complete the transmission, a handoff data state of the communication session to the anchor network function module, wherein the handoff data state comprises an identifier of a target transceiver module and the sequence marker, the handoff data state is operable to trigger the anchor network function module to transmit a portion of the copy of the ordered sequence of data packets to the identified target transceiver module from the shadow buffer prior to completion of handoff, and the portion begins after the end of the segment identified by the sequence marker.

2. The method of claim 1, wherein continuing to complete the transmission further comprises transmitting error correction messages.

3. The method of claim 1, wherein continuing to complete the transmission further comprises transmitting hybrid Automatic Repeat-reQuest (HARQ) messages.

4. The method of claim 1, wherein the handoff occurs with the anchor network function module maintaining a control over the communication session.

5. The method of claim 1, wherein the transmission comprises a data rate of greater than 1 Mbits/second.

6. The method of claim 1, further comprising transmitting a handoff response message to the target transceiver module, wherein the handoff response message includes final state information, and transmits a handoff transfer message to a network control function portion of the anchor network function module to complete the handoff, wherein the anchor control function portion maintains a control of the communication session.

33. The method of claim 1, further comprising:

receiving a handoff request from the target transceiver module during the transmission of a segment of the ordered sequence of data packets to the access terminal via the communication session.

7. At least one processor operable to perform a session handoff in a wireless communication system, comprising:

a first module in a source transceiver module for receiving an ordered sequence of data packets from an anchor network function module after establishing a communication session with an access terminal, wherein the communication session is controlled by the anchor network function module, and the anchor network function module comprises a shadow buffer operable to store a copy of the ordered sequence of data packets transmitted to the source transceiver module;

a second module for transmitting, in a transmission, a segment of the ordered sequence of data packets to the access terminal via the communication session;

a third module for identifying a sequence marker corresponding to an end of the segment as being a completion point of the transmission;

a fourth module for continuing to complete the transmission through the end of the segment; and

a fifth module for transmitting, in parallel with continuing to complete the transmission, a handoff data state of the communication session to the anchor network function module, wherein the handoff data state comprises an identifier of a target transceiver module and the sequence marker, the handoff data state is operable to trigger the anchor network function module to transmit a portion of the copy of the ordered sequence of data packets to the identified target transceiver module from the shadow buffer prior to completion of handoff, and the portion begins after the end of the segment identified by the sequence marker.

8. A computer program product for performing a session handoff in a wireless communication system, comprising:

a non-transitory computer readable medium, comprising;

at least one instruction for causing a source transceiver module to receive an ordered sequence of data packets from an anchor network function module after establishing a communication session with an access terminal, wherein the communication session is controlled by the anchor network function module, and the anchor network function module comprises a shadow buffer operable to store a copy of the ordered sequence of data packets transmitted to the source transceiver module;

at least one instruction for transmitting, in a transmission, a segment of the ordered sequence of data packets to the access terminal via the communication session;

at least one instruction for identifying a sequence marker corresponding to an end of the segment as being a completion point of the transmission;

at least one instruction for continuing to complete the transmission through the end of the segment; and

at least one instruction for transmitting, in parallel with continuing to complete the transmission, a handoff data state of the communication session to the anchor network function module, wherein the handoff data state comprises an identifier of a target transceiver module and the sequence marker, the handoff data state is operable to trigger the anchor network function module to transmit a portion of the copy of the ordered sequence of data packets to the identified target transceiver module from the shadow buffer prior to completion of handoff, and the portion begins after the end of the segment identified by the sequence marker.

9. An access point, comprising:

means for receiving by a source transceiver module an ordered sequence of data packets from an anchor network function module after establishing a communication session with an access terminal, wherein the communication session is controlled by the anchor network function module, and the anchor network function module comprises a shadow buffer operable to store a copy of the ordered sequence of data packets transmitted to the source transceiver module;

means for transmitting, in a transmission, a segment of the ordered sequence of data packets to the access terminal via the communication session;

means for identifying a sequence marker corresponding to an end of the segment as being a completion point of the transmission;

means for continuing to complete the transmission through the end of the segment; and

means for transmitting, in parallel with continuing to complete the transmission, a handoff data state of the communication session to the anchor network function module, wherein the handoff data state comprises an identifier of a target transceiver module and the sequence marker, the handoff data state is operable to trigger the anchor network function module to transmit a portion of the copy of the ordered sequence of data packets to the identified target transceiver module from the shadow buffer prior to completion of handoff, and the portion begins after the end of the segment identified by the sequence marker.

10. An access point, comprising:

a memory comprising a handoff manager module having sequence determination logic;

a processor in communication with the memory and operable to execute the handoff manager module; and

a source transceiver module operable to;

receive an ordered sequence of data packets from an anchor network function module after establishing a communication session with an access terminal, wherein the communication session is controlled by the anchor network function module, and the anchor network function module comprises a shadow buffer operable to store a copy of the ordered sequence of data packets transmitted to the source transceiver module;

transmit, in a transmission, a segment of the ordered sequence of data packets to the access terminal via the communication session, wherein the sequence determination logic is operable to identify a sequence marker corresponding to an end of the segment as being a completion point of the transmission;

continue to complete the transmission through the end of the segment; and

continue to transmit, in parallel with continuing to complete the transmission, a handoff data state of the communication session to the anchor network function module, wherein the handoff data state comprises an identifier of a target transceiver module and the sequence marker, the handoff data state is operable to trigger the anchor network function module to transmit a portion of the copy of the ordered sequence of data packets to the identified target transceiver module from the shadow buffer prior to completion of handoff, and the portion begins after the end of the segment identified by the sequence marker.

11. The access point of claim 10, wherein the transmission further comprises error correction messages.

12. The access point of claim 10, wherein the transmission further comprises hybrid Automatic Repeat-reQuest (HARQ) messages.

13. The access point of claim 10, wherein the handoff occurs with the anchor network function module maintaining a control over the communication session.

14. The access point of claim 10, wherein the transmission comprises a data rate of greater than 1 Mbits/second.

15. The access point of claim 10, wherein the source transceiver module is operable to transmit a handoff response message to the target transceiver module, wherein the handoff response message includes final state information, and transmits a handoff transfer message to a network control function portion of the anchor network function module to complete the handoff, wherein the anchor control function portion maintains a control of the communication session.

34. The access point of claim 10, wherein the source transceiver module is operable to receive a handoff request from the target transceiver module during a transmission of a segment of the ordered sequence of data packets to the access terminal via the communication session.

16. A method of performing a session handoff in a wireless communication system, comprising:

determining that conditions exist for requesting a handoff of an established communication session from a source transceiver module to a target transceiver module upon receiving a segment of an ordered sequence of data packets from the source transceiver module;

transmitting a handoff request based on the determining, wherein the handoff request is operable to cause the source transceiver module to identify a sequence marker corresponding to an end of the segment of the ordered sequence of data packets being transmitted to the access terminal, to transmit to an anchor network function module an identifier of the target transceiver module and the sequence marker, and to trigger the anchor network function module to transmit a portion of a copy of the ordered sequence of data packets to the identified target transceiver module prior to completion of handoff, wherein the portion begins after the end of the segment identified by the sequence marker;

receiving a last transmission corresponding to the segment from the source transceiver module;

establishing the communication session with a target transceiver function after receiving the last transmission from the source transceiver module; and

receiving the copy of the portion of the ordered sequence of data packets from the target transceiver function, under a control of the anchor network function module, without substantial latency after establishing the communication session with the target transceiver function.

17. The method of claim 16, wherein the receiving of the segment further comprises receiving an error correction message.

18. The method of claim 16, wherein the receiving of the segment further comprises receiving a hybrid Automatic Repeat-reQuest (HARQ) message.

19. The method of claim 16, wherein the handoff occurs with the anchor network function module maintaining a control over the communication session.

20. The method of claim 16, wherein the last transmission comprises a data rate of greater than 1 Mbits/second.

21. At least one processor for performing a session handoff in a wireless communication system, comprising:

a first module for determining that conditions exist for requesting a handoff of an established communication session from a source transceiver module to a target transceiver module upon receiving a segment of an ordered sequence of data packets from the source transceiver module;

a second module for transmitting a handoff request based on the determining, wherein the handoff request is operable to cause the source transceiver module to identify a sequence marker corresponding to an end of the segment of the ordered sequence of data packets being transmitted to the access terminal, to transmit to an anchor network function module an identifier of the target transceiver module and the sequence marker, and to trigger the anchor network function module to transmit a portion of a copy of the ordered sequence of data packets to the identified target transceiver module prior to completion of handoff, wherein the portion begins after the end of the segment identified by the sequence marker;

a third module for receiving a last transmission corresponding to the segment from the source transceiver module; and

a fourth module for establishing the communication session with a target transceiver function after receiving the last transmission from the source transceiver module,

wherein the third module further receives the copy of the portion of the ordered sequence of data packets from the target transceiver function, under a control of the anchor network function module, without substantial latency after establishing the communication session with the target transceiver function.

22. A computer program product for performing a session handoff in a wireless communication system, comprising:

a non-transitory computer readable medium, comprising;

at least one instruction for causing a computer to determine that conditions exist for requesting a handoff of an established communication session from a source transceiver module to a target transceiver module upon receiving a segment of an ordered sequence of data packets from the source transceiver module;

at least one instruction for causing the computer to transmit a handoff request based on the determining, wherein the handoff request is operable to cause the source transceiver module to identify a sequence marker corresponding to an end of the segment of the ordered sequence of data packets being transmitted to the access terminal, to transmit to an anchor network function module an identifier of the target transceiver module and the sequence marker, and to trigger the anchor network function module to transmit a portion of a copy of the ordered sequence of data packets to the identified target transceiver module prior to completion of handoff, wherein the portion begins after the end of the segment identified by the sequence marker;

at least one instruction for causing the computer to receive a last transmission corresponding to the segment from the source transceiver module;

at least one instruction for causing the computer to establish the communication session with a target transceiver function after receiving the last transmission from the source transceiver module; and

at least one instruction for causing the computer to receive the copy of the portion of the ordered sequence of data packets from the target transceiver function, under a control of the anchor network function module, without substantial latency after establishing the communication session with the target transceiver function.

23. An access terminal, comprising:

means for determining that conditions exist for requesting a handoff of an established communication session from a source transceiver module to a target transceiver module upon receiving a segment of an ordered sequence of data packets from the source transceiver module;

means for transmitting a handoff request based on the determining, wherein the handoff request is operable to cause the source transceiver module to identify a sequence marker corresponding to an end of the segment of the ordered sequence of data packets being transmitted to the access terminal, to transmit to an anchor network function module an identifier of the target transceiver module and the sequence marker, and to trigger the anchor network function module to transmit a portion of a copy of the ordered sequence of data packets to the identified target transceiver module prior to completion of handoff, wherein the portion begins after the end of the segment identified by the sequence marker;

means for receiving a last transmission corresponding to the segment from the source transceiver module;

means for establishing the communication session with a target transceiver function after receiving the last transmission from the source transceiver module; and

means for receiving the copy of the portion of the ordered sequence of data packets from the target transceiver function, under a control of the anchor network function module, without substantial latency after establishing the communication session with the target transceiver function.

24. An access terminal, comprising:

a memory comprising a handoff manager module having handoff determination logic and handoff requestor logic;

a processor in communication with the memory and operable to execute the handoff manager module,

wherein the handoff determination logic is operable to determine that conditions exist for requesting a handoff of an established communication session from a source transceiver module to a target transceiver module upon receiving a segment of an ordered sequence of data packets from the source transceiver module,

wherein the handoff requestor logic is operable to transmit a handoff request based on the determining, and the handoff request is operable to cause the source transceiver module to identify a sequence marker corresponding to an end of the segment of the ordered sequence of data packets being transmitted to the access terminal, to transmit to an anchor network function module an identifier of the target transceiver module and the sequence marker, and to trigger the anchor network function module to transmit a portion of a copy of the ordered sequence of data packets to the identified target transceiver module prior to completion of handoff, wherein the portion begins after the end of the segment identified by the sequence marker; and

a communications module in communication with memory and the processor and operable to receive a last transmission corresponding to the segment from the source transceiver module,

wherein the handoff manager module is operable to establish the communication session with a target transceiver function after receiving the last transmission from the source transceiver module, and

wherein the communications module is further operable to receive the copy of the portion of the ordered sequence of data packets from the target transceiver function, under a control of the anchor network function module, without substantial latency after establishing the communication session with the target transceiver function.

25. The access terminal of claim 24, wherein the segment further comprises an error correction message.

26. The access terminal of claim 24, wherein the segment further comprises a hybrid Automatic Repeat-reQuest (HARQ) message.

27. The access terminal of claim 24, wherein the handoff occurs with the anchor network function module maintaining a control over the communication session.

28. The access terminal of claim 24, wherein the transmission comprises a data rate of greater than 1 Mbits/second.

29. A method of performing a session handoff by a network-side system of a wireless communication system, comprising:

controlling, by an anchor network function module, a communication session of an access terminal with a source transceiver module;

transmitting to the source transceiver module an ordered sequence of data packets destined for the access terminal;

copying the ordered sequence of data packets into a shadow buffer operable to store the ordered sequence of data packets;

receiving a handoff data state from the source transceiver module in parallel with the source transceiver module continuing to complete a transmission of a segment of the ordered sequence of data packets to the access terminal, wherein the handoff data state is based on the source transceiver module receiving a handoff request from a during the transmission of the segment of the ordered sequence of data packets to the access terminal via the communication session, identifying a sequence marker corresponding to an end of the segment as being a completion point of the transmission, and continuing to complete the transmission through the end of the segment, wherein the handoff data state comprises an identifier of the target transceiver module and the sequence marker; and

transmitting, by an anchor network function module and in response to receiving the handoff data state and prior to completion of a handoff, a portion of the copy of the ordered sequence of data packets to the identified target transceiver module from the shadow buffer, wherein the portion begins after the end of the segment identified by the sequence marker.

30. The method of claim 29, wherein the sequence marker enables tracking of partial data packets.

31. A system for performing a session handoff of a wireless communication system, comprising:

an anchor network function module having a corresponding shadow buffer, wherein the anchor network function module is operable to;

control a communication session of an access terminal with a source transceiver module,

transmit to the source transceiver module an ordered sequence of data packets destined for the access terminal,

copy the ordered sequence of data packets into the shadow buffer, which is operable to store the ordered sequence of data packets,

receive a handoff data state from the source transceiver module in parallel with the source transceiver module continuing to complete a transmission of a segment of the ordered sequence of data packets to the access terminal, wherein the handoff data state is based on the source transceiver module receiving a handoff request during the transmission of the segment of the ordered sequence of data packets to the access terminal via the communication session, and identifying a sequence marker corresponding to an end of the segment as being a completion point of the transmission, wherein the handoff data state comprises an identifier of the target transceiver module and the sequence marker, and

transmit a portion of the copy of the ordered sequence of data packets to the identified target transceiver module from the shadow buffer in response to receiving the handoff data state and prior to completion of a handoff, wherein the portion begins after the end of the segment identified by the sequence marker.

32. The system of claim 31, wherein the sequence marker enables tracking of partial data packets.