Method and apparatus for modulating radio link control (RLC) ACK/NAK persistence to improve performance of data traffic

• US 20060146831A1
• Filed: 01/04/2005
• Published: 07/06/2006
• Est. Priority Date: 01/04/2005
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Pazhyannur, Rajesh S., Tzavidas, Stavros, Argyropoulos, Yiannis
• Granted Patent: US 7,181,667 B2
• Time in Patent Office: Days
• US Class Current: 370/394
• CPC Class Codes: H04L 49/90 Buffering arrangements

Abstract

Methods and apparatus are provided for modulating ACK/NACK persistence to improve data traffic performance. In one implementation, a method for control of automatic repeat requests between a transmitting terminal (102) and a receiving terminal (104) comprises: defining (1404) a buffer window of a buffer, the window to buffer multiple higher layer data blocks each segmented into multiple physical layer data blocks, the window beginning at a current higher layer block in which at least one physical layer block has not been received; obtaining (1406) an indication of whether physical layer blocks are completely received; determining (1408), based on the obtaining step, that a subsequent higher layer block within the window has been completely received; and discarding (1410) the current higher layer block when a time delay of the current higher layer block exceeds an estimate of a delay tolerance corresponding to a higher layer application.

Claims

1. A method for control of automatic repeat requests between a transmitting terminal and a receiving terminal comprising:

defining a buffer window of a buffer at a communication device, the buffer window to buffer multiple higher layer data blocks, each higher layer data block segmented into multiple physical layer data blocks, the buffer window beginning at a current higher layer data block in which at least one physical layer data block has not been received;

obtaining an indication of whether physical layer data blocks are completely received at the receiving terminal;

determining, based on the obtaining step, that a subsequent higher layer data block within the buffer window has been completely received; and

discarding the current higher layer data block when a time delay of the current higher layer data block exceeds an estimate of a delay tolerance corresponding to a higher layer application.

2. The method of claim 1 wherein the discarding step comprises:

discarding the current higher layer data block when the time delay of the current higher layer data block exceeds an estimate of a maximum delay tolerance corresponding to the higher layer application based on requirements of the higher layer application.

3. The method of claim 1 further comprising:

starting a timer corresponding to the current higher layer data block upon receipt of a first physical layer data block of the current higher layer data block;

setting an expiration of the timer to the estimate of the delay tolerance such that the current higher layer data block is discarded when the timer expires.

4. The method of claim 1 further comprising:

storing an arrival time of the current higher layer data block;

determining that a time elapsed since the arrival time exceeds the estimate of the delay tolerance such that the current higher layer data block is discarded when the delay time elapsed since the arrival time exceeds the estimate of the delay tolerance.

5. The method of claim 1 further comprising:

advancing the buffer window to a next higher layer data block that includes at least one physical layer data block that has not been completely received.

6. The method of claim 5 further comprising:

causing the subsequent higher layer data block to be forwarded to the higher layer.

7. The method of claim 5 wherein the buffer window is implemented at the receiving terminal and wherein the method further comprises:

causing an acknowledgement of the current higher layer data block to be sent to the transmitting terminal.

8. The method of claim 5 wherein the buffer window is implemented at the transmitting terminal and wherein the method further comprises:

discarding the subsequent higher layer data block; and

causing a move buffer window message to be sent to the receiving terminal.

9. The method of claim 1 further comprising:

checking whether the higher layer application awaiting complete higher layer data blocks at the receiving terminal needs data;

discarding the current higher layer data block when the higher layer application needs the data; and

causing the subsequent higher layer data block to be forwarded to the higher layer when the higher layer application needs the data.

10. An apparatus for use in control of automatic repeat requests from a transmitting terminal to a receiving terminal comprising:

a buffer having a buffer window to buffer multiple higher layer data blocks, each higher layer data block segmented into multiple physical layer data blocks, the buffer window beginning at a current higher layer data block in which at least one physical layer data block has not been received; and

a controller adapted to obtain an indication of whether physical layer data blocks are completely received and determine based on the indication that a subsequent higher layer data block within the buffer window has been completely received; and

the controller adapted to cause the current higher layer data block to be discarded when a time delay of the current higher layer data block exceeds an estimate of a delay tolerance corresponding to a higher layer application.

11. The apparatus of claim 10 wherein the controller is adapted to discard the current higher layer data block when the time delay of the current higher layer data block exceeds an estimate of a maximum delay tolerance corresponding to the higher layer application based on requirements of the higher layer application.

12. The apparatus of claim 10 further comprising:

a timer corresponding to the current higher layer data block and adapted to be started upon receipt of a first physical layer data block of the current higher layer data block;

the timer having an expiration set to the estimate of the delay tolerance such that the current higher layer data block is discarded when the timer expires.

13. The apparatus of claim 10 wherein the controller is adapted to:

store an arrival time of the current higher layer data block; and

determine that a time elapsed since the arrival time exceeds the estimate of the delay tolerance such that the current higher layer data block is discarded when the delay time elapsed since the arrival time exceeds the estimate of the delay tolerance.

14. The apparatus of claim 10 wherein the controller is adapted to advance the buffer window to a next higher layer data block that includes at least one physical layer data block that has not been completely received.

15. The apparatus of claim 14 wherein the controller is adapted to cause the subsequent higher layer data block to be forwarded to the higher layer.

16. The apparatus of claim 14 wherein the apparatus is implemented at the receiving terminal and wherein the controller is adapted to cause an acknowledgement of the current higher layer data block to be sent to the transmitting terminal.

17. The apparatus of claim 14 wherein the apparatus is implemented at the transmitting terminal and wherein the controller is adapted to discard the subsequent higher layer data block and cause a move buffer window message to be sent to the receiving terminal.

18. The apparatus of claim 10 wherein the apparatus is implemented at the receiving terminal and the controller is adapted to:

check whether the higher layer application awaiting complete higher layer data blocks at the receiving terminal needs data;

discard the current higher layer data block when the higher layer application needs the data; and

cause the subsequent higher layer data block to be forwarded to the higher layer when the higher layer application needs the data.

19. An apparatus for use in control of automatic repeat requests from a transmitting terminal to a receiving terminal comprising:

means for defining a buffer window of a buffer at a communication device, the buffer window to buffer multiple higher layer data blocks, each higher layer data block segmented into multiple physical layer data blocks, the buffer window beginning at a current higher layer data block in which at least one physical layer data block has not been received;

means for obtaining an indication of whether physical layer data blocks are completely received at the receiving terminal;

means for determining, based on the obtaining step, that a subsequent higher layer data block within the buffer window has been completely received; and

means for discarding the current higher layer data block when a time delay of the current higher layer data block exceeds an estimate of a delay tolerance corresponding to a higher layer application.

20. The apparatus of claim 19 wherein the means for discarding comprise:

means for discarding the current higher layer data block when the time delay of the current higher layer data block exceeds an estimate of a maximum delay tolerance corresponding to the higher layer application based on requirements of the higher layer application.