Method and apparatus for controlling flow of data in a communication system

• US 6,920,504 B2
• Filed: 05/13/2002
• Issued: 07/19/2005
• Est. Priority Date: 05/13/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Rezaiifar, Ramin, Black, Peter J., Grob, Matthew S., Bender, Paul E.
• Primary Examiner(s): Alam, Hosain
• Assistant Examiner(s): WANG, LIANG CHE A
• Application Number:
  US10/144,973
• Publication Number:
  US 20030212816A1
• Time in Patent Office: 1,163 Days
• Field of Search: 709/224, 709/229, 709/232, 713/201, 370/231, 370/331
• US Class Current: 709/232
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 47/323 Discarding or blocking control packets, e.g. ACK packets

Abstract

A control system (900, 1100) and various methods and apparatus for efficient communications of data across various protocol layers are disclosed. Generally, various aspects of the invention provide for efficient use of communication resources in a communication system (100) by efficiently controlling delay of a TCP acknowledgment message of reception of data from one communication protocol layer to another. Moreover, the delay of the TCP acknowledgment message and the message may be controlled to effect an efficient and consistent flow of data from a source end to a destination end, in particular, in case of encrypted communications.

Claims

1. A method comprising:

receiving an acknowledgment message which indicates reception of a packet of data at a destination;

determining a statistical mean and variance of delays of a plurality of previously received acknowledgment messages associated with a corresponding plurality of transmitted packets of data, wherein each delay is a time interval between transmitting a packet of data and receiving an acknowledgment;

determining a delay period based on said statistical mean and variance of delays; and

delaying passing said received acknowledgment message from a first protocol layer to a second protocol layer by said determined delay period.

2. The method as recited in claim 1 wherein said second protocol layer is a TCP protocol layer.

3. A data processing unit comprising:

an input for receiving an acknowledgment message which indicates reception of a packet of data at a destination;

a processing unit for determining a statistical mean and variance of delays of a plurality of previously received acknowledgment messages associated with a corresponding plurality of transmitted packets of data, wherein each delay is a time interval between transmitting a packet of data and receiving an acknowledgment, and for determining a delay period based on said statistical mean and variance of delays; and

a data storage unit for delaying passing said received acknowledgment message from a first protocol layer to a second protocol layer by said determined delay period.

4. The data processing unit as recited in claim 3 wherein said second protocol layer is a TCP protocol layer.

5. The data processing unit as recited in claim 3 wherein said destination is a mobile station in a communication system.

6. A method comprising:

receiving an encrypted acknowledgment message which indicates reception of a packet of data at a destination, wherein said encrypted acknowledgment message is combined with encrypted data;

determining a statistical mean and variance of delays of a plurality of previously received acknowledgment messages associated with a corresponding plurality of transmitted packets of data, wherein each delay is a time interval between transmitting a packet of data and receiving an acknowledgment;

determining a delay period based on said statistical mean and variance of delays; and

delaying passing said received encrypted acknowledgment message and encrypted data from a first protocol layer to a second protocol layer by said determined delay period.

7. The method as recited in claim 6 wherein said second protocol layer is a TCP protocol layer.

8. A data processing unit, comprising:

an input for receiving an encrypted acknowledgment message which indicates reception of a packet of data at a destination, wherein said encrypted acknowledgment message is combined with encrypted data;

a processing unit for determining a statistical mean and variance of delays of a plurality of previously received acknowledgment messages associated with a corresponding plurality of transmitted packets of data, wherein each delay is a time interval between transmitting a packet of data and receiving an acknowledgment, and for determining a delay period based on said statistical mean and variance of delays; and

a data storage unit for delaying passing said received encrypted acknowledgment message and said encrypted data from a first protocol layer to a second protocol layer by said determined delay period.

9. The data processing unit as recited in claim 8 wherein said second protocol layer is a TCP protocol layer.

10. The data processing unit as recited in claim 8 wherein said destination is a mobile station in a communication system 3.

11. A system for communications of data, comprising:

a base station for communicating radio link protocol (RLP) packets of data over a physical layer protocol and processing an acknowledgment message which indicates reception of a Transmission Control Protocol (TCP) packet of data at a destination, wherein said TCP packet of data comprises one or more said RLP packets of data;

a processor coupled to said base station for passing the acknowledgment message from a lower protocol layer to a TCP protocol layer, determining a statistical mean and variance of delays of a plurality of acknowledgment messages associated with a corresponding plurality of transmitted TCP packets of data, wherein each delay is a time interval between transmitting a TCP packet of data and receiving an acknowledgment, determining a delay period based on said statistical mean and variance of delays, delaying passing said received acknowledgment message from the lower protocol layer to the TCP protocol layer by said determined delay period; and

a network communicatively coupled to said base station for routing said TCP packets of data to the destination.

12. The system as recited in claim 11 wherein said destination is a mobile station.

13. A system for communications of data, comprising:

a base station for communicating radio link protocol (RLP) packets of data over a physical layer protocol and processing an encrypted acknowledgment message which indicates reception of a Transmission Control Protocol (TCP) packet of data at a destination, wherein said TCP packet of data comprises one or more said RLP packets of data, and said encrypted acknowledgment message is combined with encrypted data;

a processor coupled to said base station for passing the encrypted acknowledgment message and encrypted data from a lower protocol layer to a TCP protocol layer, determining a statistical mean and variance of delays of a plurality of acknowledgment messages associated with a corresponding plurality of transmitted TCP packets of data, wherein each delay is a time interval between transmitting a TCP packet of data and receiving an acknowledgment, determining a delay period based on said statistical mean and variance of delays, delaying passing said received encrypted acknowledgment message and said encrypted data from the lower protocol layer to the TCP protocol layer by said determined delay period; and

a network communicatively coupled to said base station for routing said TCP packets of data to the destination.

14. The system as recited in claim 13, wherein said destination is a mobile station.

15. An apparatus configured to change a rate of communicating data packets to a destination, the apparatus comprising:

a stack of protocol layers comprising a lower protocol layer and an upper protocol layer, the lower protocol layer being configured to (a) pass a data packet from the upper protocol layer toward the destination, and (b) pass an acknowledgment message to the upper protocol layer, the acknowledgment message indicating the destination properly received the data packet from the upper protocol layer;

the upper protocol layer being configured to (a) determine an expected delay between sending the data packet and receiving the acknowledgment message based on delays of previous acknowledgment messages, and (b) retransmit the data packet if the acknowledgment message has not been received within the expected delay;

wherein the lower protocol layer controls the expected delay;

wherein the expected delay is based on a history of actual delays of acknowledgement messages being received by the upper protocol layer, the apparatus further comprising;

means for determining a delay period using a statistical mean of the actual delay history and a variance of the actual delay history,

wherein the lower protocol layer is configured to delay the propagation of the acknowledgement message to the upper protocol layer substantially by the determined delay period.

16. The apparatus of claim 15, wherein the lower protocol layer comprises a plurality of protocol layers.

17. The apparatus of claim 15, where the upper protocol layer determines the expected delay based on a history of actual delays of acknowledgement messages received by the upper protocol layer, the upper protocol layer being configured to employ a variance of the actual delays to determine the expected delay, wherein the lower protocol layer controls the expected delay by increasing the variance of the actual delays.

18. The apparatus of claim 15, where the upper protocol layer data packet comprises a plurality of lower protocol layer data packets, where the lower protocol layer delays propagation of at least one of the lower protocol layer data packets to the destination.

19. The apparatus of claim 18, where the lower protocol layer is configured to randomly delay propagation of at least one of the lower protocol layer data packets.

20. The apparatus of claim 17, where the upper protocol layer is configured to employ a statistical mean of the actual delays to compute the expected delay.

21. The apparatus of claim 15, where the lower protocol layer delays propagation of the acknowledgement message to the upper protocol layer.

22. The apparatus of claim 21,

where the data packet includes a plurality of data packets,

where the lower protocol layer comprises means for delaying propagation of both the acknowledgement message and at least one of the data packets to the upper protocol layer, and

where the lower protocol layer is configured to delay the propagation of the acknowledgement message and the at least one of the data packets to the upper protocol layer by the determined delay period.

23. The apparatus of claim 15, where the lower protocol layer is a radio link protocol (RLP) layer and the upper protocol layer is a transmission control protocol (TCP) layer.