Methods and apparatus for efficiently synchronizing a transmitter and a receiver in a communication system

• US 8,270,550 B2
• Filed: 07/15/2005
• Issued: 09/18/2012
• Est. Priority Date: 12/22/2004
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Horn, Gavin
• Primary Examiner(s): Yu, Lihong
• Application Number:
  US11/182,294
• Publication Number:
  US 20060133554A1
• Time in Patent Office: 2,622 Days
• Field of Search: 375/354
• US Class Current: 375/354
• CPC Class Codes: H04L 7/00 Arrangements for synchronising receiver with transmitter synchronisation of generators of electric oscillations or pulses H03L7/00
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

The disclosed embodiments provide methods and systems for synchronizing a transmitter and a receiver. In one embodiment, a method for synchronizing a transmitter and a receiver includes the transmitter performing a reset operation, and the receiver responding by performing a reset operation. In another embodiment, a method for synchronizing a transmitter and a receiver includes the receiver performing a reset operation, and the transmitter responding by performing a reset operation. The reset indicator includes toggling a reset indicator.

Claims

1. A method of synchronizing a transmitter (Tx) entity and a receiver (Rx) entity, wherein the Tx entity initiates a synchronization and the Rx entity responds to the synchronization, the method comprising:

with the Tx entity;

transmitting an initial plurality of frames to the Rx entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

in response to a determination to perform a Tx entity reset operation;

performing the Tx entity reset operation; and

transmitting a subsequent plurality of frames to the Rx entity, each of the subsequent plurality of frames having the Tx reset indicator field in the header set to a second state to indicate that the Tx entity has performed the Tx entity reset operation; and

with the Rx entity;

in response to identifying that the Tx reset indicator field in the header of a received frame in the subsequent plurality of frames changed from the first state to the second state;

performing an Rx entity reset operation; and

transmitting a reset acknowledge message comprising a Rx reset indicator to the Tx entity, the Rx reset indicator being set to indicate that the Rx entity has performed the Rx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

2. The method of claim 1, wherein the Tx entity reset operation comprises performing a Tx entity initialization procedure comprising:

resetting a send state variable; and

clearing a retransmission buffer.

3. The method of claim 2, wherein the send state variable comprises information about a sequence number of a next data unit to be sent.

4. The method of claim 2, wherein the Rx entity reset operation comprises:

performing an Rx entity initialization procedure.

5. The method of claim 4, wherein the Rx entity initialization procedure comprises:

resetting at least two receive state variables; and

clearing a resequencing buffer.

6. The method of claim 5, wherein the receive state variables comprise a first receive state variable providing information indicating a sequence number of a next data unit of new data expected to arrive, and a second receive sate variable providing information indicating a sequence number of a first missing data unit.

7. A method of responding by a receiver (Rx) entity to a reset operation performed by a transmitter (Tx) entity, the method comprising:

receiving an initial plurality of frames from the Tx entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

in response to identifying that the Tx reset indicator field in the header of a received frame in a subsequent plurality of frames is set to a second state, wherein the second state is indicative of the Tx entity having performed a Tx entity reset operation;

performing an Rx entity reset operation; and

transmitting a reset acknowledge message comprising a Rx reset indicator to the Tx entity, the Rx reset indicator being set to indicate that the Rx entity has performed the Rx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

8. The method of claim 7, wherein the Rx entity reset operation comprises:

resetting at least two receive state variables; and

clearing a resequencing buffer.

9. The method of claim 8, wherein the receive state variables comprise a first receive state variable providing information indicating a sequence number of a next data unit of new data expected to arrive, and a second receive sate variable providing information indicating a sequence number of a first missing data unit.

10. A method of resetting a receiver (Rx) entity, the method comprising:

receiving an initial plurality of frames from a transmitter (Tx) entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

in response to a determination to perform a Rx entity reset operation;

performing an Rx entity reset operation;

transmitting a reset request message comprising a Rx reset indicator to the Tx entity, the Rx reset indicator being set to indicate that the Rx entity has performed the Rx entity reset operation; and

receiving a subsequent plurality of frames from the Tx entity, each of the subsequent plurality of frames having the Tx reset indicator field in the header set to a second state indicating that the Tx entity performed a Tx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

11. The method of claim 10, wherein the Rx entity reset operation comprises:

resetting at least two receive state variables; and

clearing a resequencing buffer.

12. The method of claim 11, wherein the receive state variables comprise a first receive state variable providing information indicating a sequence number of a next data unit of new data expected to arrive, and a second receive sate variable providing information indicating a sequence number of a first missing data unit.

13. A method of responding by a transmitter (Tx) entity to a reset operation performed by a receiver (Rx) entity, the method comprising:

transmitting an initial plurality of frames to the Rx entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

in response to receiving a reset request message comprising a Rx reset indicator set to indicate that the Rx entity has performed a Rx entity reset operation;

performing a Tx entity reset operation; and

transmitting a subsequent plurality of frames to the Rx entity, each of the subsequent plurality of frames having the Tx reset indicator field in the header set to a second state to indicate that the Tx entity has performed the Tx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

14. The method of claim 13, wherein the Tx entity reset operation comprises:

resetting a send state variable; and

clearing a retransmission buffer.

15. The method of claim 14, wherein the send state variable comprises information about a sequence number of a next data unit to be sent.

16. An apparatus for responding by a receiver (Rx) entity to a reset operation performed by a transmitter (Tx) entity, comprising:

means for receiving an initial plurality of frames from the Tx entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

means for receiving a subsequent plurality of frames from the Tx entity, each of the subsequent plurality of frames comprising the header;

means for identifying that the Tx reset indicator field in the header of a received frame in the subsequent plurality of frames is set to a second state, wherein the second state is indicative of the Tx entity having performed a Tx entity reset operation;

means for performing an Rx entity reset operation, in response to identifying the Tx entity has performed the Tx entity reset operation; and

means for transmitting a reset acknowledge message comprising a Rx reset indicator to the Tx entity, the Rx reset indicator being set to indicate that the Rx entity has performed the Rx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

17. An apparatus for responding by a transmitter (Tx) entity to a reset operation performed by a receiver (Rx) entity, comprising:

means for transmitting an initial plurality of frames to the Rx entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

means for receiving a reset request message from the Rx entity, the reset request message comprising a Rx reset indicator set to indicate that the Rx entity has performed a Rx entity reset operation;

means for performing a Tx entity reset operation, in response to the Rx reset indicator being set to indicate that the Rx entity has performed the Rx entity reset operation; and

means for transmitting a subsequent plurality of frames to the Rx entity, each of the subsequent plurality of frames having the Tx reset indicator field in the header set to a second state to indicate that the Tx entity has performed the Tx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

18. An article comprising:

a non-transitory computer-program product having code instructions stored thereon that are executable by a processor of a receiver (Rx) entity to;

obtain an initial plurality of frames received from a transmitter (Tx) entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

obtain a subsequent plurality of frames from the Tx entity, each of the subsequent plurality of frames comprising the header;

in response to identifying that the Tx reset indicator field in the header of a received frame in the subsequent plurality of frames is set to a second state, wherein the second state is indicative of the Tx entity having performed a Tx entity reset operation;

initiate a Rx entity reset operation; and

in response to performing the Rx entity reset operation, initiate transmission, to the Tx entity, of a reset acknowledge message comprising a Rx reset indicator that is set to indicate that the Rx entity has performed the Rx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

19. An article comprising:

a non-transitory computer-program product having code instructions stored thereon that are executable by a processor of a transmitter (Tx) entity to;

initiate transmission of an initial plurality of frames to a receiver (Rx) entity, each of the plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

in response to receiving a reset request message from the Rx entity, the reset request message comprising a Rx reset indicator set to indicate that the Rx entity has performed a Rx entity reset operation;

initiate a Tx entity reset operation; and

initiate transmission of a subsequent plurality of frames to the Rx entity, each of the subsequent plurality of frames having the Tx reset indicator field in the header set to a second state to indicate that the Tx entity has performed the Tx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

20. An apparatus for use in resetting a transmitter (Tx) entity, the apparatus comprising:

a transmitter;

a receiver; and

a controller to;

initiate transmission, via the transmitter, of an initial plurality of frames to a receiver (Rx) entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

in response to receiving a reset request message from the Rx entity, the reset request message comprising a Rx reset indicator set to indicate that the Rx entity has performed a Rx entity reset operation;

perform a Tx entity reset operation; and

initiate transmission, via the transmitter, of a subsequent plurality of frames to the Rx entity, each of the subsequent plurality of frames having the Tx reset indicator field in the header set to a second state to indicate that the Tx entity has performed the Tx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

21. The apparatus of claim 20, further comprising:

a memory; and

wherein the controller, in performing the Tx entity reset operation, resets a send state variable in the memory, and clears a retransmission buffer in the memory.

22. The apparatus of claim 21, wherein the send state variable comprises information about a sequence number of a next data unit to be sent.

23. An apparatus for use in resetting a receiver (Rx) entity, the apparatus comprising:

a transmitter;

a receiver; and

a controller to;

obtain, via the receiver, an initial plurality of frames from a transmitter (Tx) entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

in response to a determination to perform a Rx entity reset operation;

perform an Rx entity reset operation;

initiate transmission of a reset request message to the Tx entity via the transmitter, the reset request message comprising a Rx reset indicator set to indicate that the Rx entity has performed the Rx entity reset operation; and

obtain, via the receiver, a subsequent plurality of frames from the Tx entity, each of the subsequent plurality of frames having the Tx reset indicator field in the header set to a second state indicating that the Tx entity has performed a Tx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

24. The apparatus of claim 23, further comprising:

a memory; and

wherein the controller, in performing the Rx entity initialization procedure, resets at least two receive state variables in the memory, and clears a resequencing buffer in the memory.

25. The apparatus of claim 24, wherein the receive state variables comprise a first receive state variable providing information indicating a sequence number of a next data unit of new data expected to arrive, and a second receive sate variable providing information indicating a sequence number of a first missing data unit.

26. An apparatus for use in resetting a receiver (Rx) entity, the apparatus comprising:

a transmitter;

a receiver; and

a controller to;

obtain, via the receiver, an initial plurality of frames received from a transmitter (Tx) entity, each of the initial plurality of frames comprising a header having a Tx reset indicator field set to a first state as part of a previously conducted reset operation;

obtain, via the receiver, a subsequent plurality of frames from the Tx entity, each of the subsequent plurality of frames comprising the header;

in response to identifying that the Tx reset indicator field in the header of a received frame in the subsequent plurality of frames is set to a second state, wherein the second state is indicative of the Tx entity having performed a Tx entity reset operation;

perform an Rx entity reset operation; and

initiate transmission of a reset acknowledge message to the Tx entity via the transmitter, the reset acknowledge message comprising a Rx reset indicator set to indicate that the Rx entity has performed the Rx entity reset operation, wherein each of the initial plurality of frames and each of the subsequent plurality of frames further comprises data for use in one or more other operations.

27. The apparatus of claim 26, further comprising:

a memory; and

wherein the controller, in performing the Rx entity initialization procedure, resets at least two receive state variables in the memory, and clears a resequencing buffer in the memory.

28. The apparatus of claim 27, wherein the receive state variables comprise a first receive state variable providing information indicating a sequence number of a next data unit of new data expected to arrive, and a second receive sate variable providing information indicating a sequence number of a first missing data unit.