Methods And Apparatus For Dynamically Adjusting A Data Packet Window Size For Data Packet Transmission In A Wireless Communication Network

• US 20070076626A1
• Filed: 09/29/2006
• Published: 04/05/2007
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Research In Motion Limited (Blackberry Limited)
• Inventors: Wise, Simon, Patterson, Ian, Plumb, Marc, Lewis, Allan
• Granted Patent: US 7,869,395 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• CPC Class Codes: H04L 47/27 Evaluation or update of window size, e.g. using information derived from acknowledged [ACK] packets
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 40/00 Communication routing or communication path finding
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

In one illustrative example, a method in a wireless router system for transmitting data packets to a mobile communication device through the wireless communication network based upon a round trip time associated with communication of each data packet is provided. The round trip time is a time period between the transmission of each data packet and reception of a corresponding acknowledgement signal from the mobile communication device. A number of data packets matched for a window size are transmitted to the mobile communication device, and a round trip time associated with communication of each of the transmitted data packets is measured. The window size for data packet transmission is re-sized by increasing the window size if the round trip time associated with the communication of each of the transmitted data packets is within a first time threshold, and decreasing the window size if the round trip time associated with the communication of any of the transmitted data packets is more than the first time threshold but less than a second time threshold. The window size is also decreased if the round trip time of any of the transmitted data packets is more than the second time threshold, where each such data packet is further marked as a lost data packet. A number of data packets matched for the re-sized window is subsequently transmitted, including a retransmission any data packets marked as lost. The steps of the method are repeated from the measuring step until data packets to be transmitted are exhausted.

Claims

1. A method in a wireless router system for use in transmitting data packets to a wireless mobile communication device through a wireless communication network based upon a round trip time associated with communication of each data packet, the round trip time being a time period between the transmission of each data packet and reception of a corresponding acknowledgment signal from the mobile device, the method comprising:

transmitting a number of data packets matched for a window size;

measuring a round trip time associated with communication of each of the transmitted data packets;

increasing the window size if the round trip time associated with the communication of each of the transmitted data packets is within a first time threshold;

decreasing the window size if the round trip time associated with the communication of any of the transmitted data packets is more than the first time threshold but less than a second time threshold.

if the round trip time associated with the communication of any of the transmitted data packets is more than the second time threshold, decreasing the window size and marking each data packet having the round trip more than the second time threshold as a lost data packet;

transmitting a number of data packets matched for the re-sized window, including retransmitting any data packets marked as lost; and

repeating from the measuring step until data packets to be transmitted are exhausted.

2. The method of claim 1, wherein measuring the round trip time of each of the transmitted data packets includes:

identifying the round trip time of a data packet to be more than the second time threshold upon failing to receive a corresponding acknowledgment signal within the second time threshold.

3. The method of claim 2, wherein transmitting a number of data packets matched for a window size further comprises:

transmitting a number of data packets matched for a default window size.

4. The method of claim 3, wherein increasing the window size includes:

increasing the window size if the window size is less than a maximum window size.

5. The method of claim 3, wherein decreasing the window size further comprises:

decreasing the window size if the window size is larger than a minimum window size.

6. The method of claim 5, wherein the default window size comprises the minimum window size.

7. The method of claim 2, wherein the increasing of the window size comprises an increment of one data packet.

8. The method of claim 2, wherein the increasing of the window size comprises an increase in more than one data packet.

9. The method of claim 2, wherein the increasing of the window size is based on a predetermined algorithm.

10. The method of claim 2, further comprising:

using a last-used window size for transmitting if more data packets become available for transmitting to the mobile device within a predetermined interval after the previous data packets are exhausted; and

using the default window size for transmitting if more data packets become available for transmitting to the mobile device after the predetermined interval after the previous data packets are exhausted.

11. The method of claim 2, further comprising:

using a last-used window size for transmitting if more data packets become available for transmitting to the mobile device within a predetermined interval after the previous data packets are exhausted;

using the default window size for transmitting if more data packets become available for transmitting to the mobile device after the predetermined interval, followed by using the last-used window size for transmitting if any of the more data packets are successfully delivered.

12. The method of claim 1, further comprising:

setting at least one of the first and the second time thresholds based on traffic of a plurality of mobile communication devices operating in the wireless communication network operating through the wireless router system.

13. The method of claim 1, further comprising:

regularly setting at least one of the first and the second time thresholds based on traffic of a plurality of mobile communication devices operating in the wireless communication network through the wireless router system.

14. The method of claim 1, further comprising:

regularly setting at least one of the first and the second time thresholds based on round trip times associated with a plurality of mobile communication devices operating in the wireless communication network through the wireless router system.

27. The computer program product of claim 14, wherein the computer instructions are further executable to measure the round trip time of each of the transmitted data packets by identifying the round trip time of a data packet to be more then the second time threshold upon failing to receive a corresponding acknowledgment signal within the second time threshold.

28. The computer program product of claim 27, wherein the computer instructions are further executable to cause a number of data packets matched for a window size to be transmitted by transmitting a number of data packets matched for a default window size.

29. The computer program product of claim 28, wherein the computer instructions are further executable to re-size the window size by increasing the window size by increasing the window size if the window size is less than a maximum window size.

30. The computer program product of claim 28, wherein the computer instructions are further executable to re-size the window size by decreasing the window size by decreasing the window size if the window size is larger than a maximum window size.

31. The computer program product of claim 30, wherein the default window size is the minimum window size.

32. The computer program product of claim 27, wherein the increasing and decreasing of the window size include an increment of one data packet.

15. A wireless router system configured for data packet transmission to a wireless mobile communication device through a wireless communication network, the wireless router system comprising:

a transmitter configured to transmit a number of data packages matched for a window size;

a receiver configured to receive an acknowledgment signal indicative of reception of a corresponding data packet by the mobile device;

a timer coupled to the transmitter and the receiver, the timer configured to measure a round trip time associated with communication of each of the data packets;

a window size adapter coupled to the timer and the transmitter, the window size adapter configured to adapt the window size based upon the round trip time associated with the communication of each of the data packets, such that it increases the window size if the round trip time is within a first time threshold and decreases the window size if the round trip time of any data packet is more than the first time threshold;

the window size adapter being further configured to decrease the window size if the round trip time of any data packet is greater than a second time threshold; and

the transmitter being further configured to re-transmit data packets having the round trip time greater than the second time threshold.

16. The wireless router system of claim 15, wherein the round trip time is a time period between the transmission of each data packet and reception of a corresponding acknowledgment signal from the mobile device.

17. The wireless router system of claim 15, wherein the window size adapter is further configured to increase the window size by one data packet and to decrease the window size by one data packet.

18. The wireless router system of claim 15, wherein the window size adapter is further configured to increase the window size until a predetermined maximum window size is reached and to decrease the window size until a predetermined minimum window size is reached.

19. The wireless router system of claim 15, wherein the window size adapter is further configured to use a previous window size if more data packets become available to be transmitted to the mobile device within a predetermined interval after the previous data packets are exhausted, and use a default window size if more data packets become available to be transmitted to the mobile device after the predetermined interval after the previous data packets are exhausted.

20. The wireless router system of claim 15, wherein the window size adapter is further configured to use a last-used window size for transmitting if more data packets become available for transmitting to the mobile device within a predetermined interval after the previous data packets are exhausted, and to use the default window size for transmitting if more data packets become available for transmitting to the mobile device after the predetermined interval, followed by the use of the last-used window size for transmitting if the more data packets are successfully delivered.

21. The wireless router system of claim 15, wherein the window size adapter is further configured to set at least one of the first and the second time thresholds based on traffic of a plurality of mobile communication devices operating in the wireless communication network operating through the wireless router system.

22. The wireless router system of claim 15, wherein the window size adapter is further configured to regularly set at least one of the first and the second time thresholds based on traffic of a plurality of mobile communication devices operating in the wireless communication network through the wireless router system.

23. The wireless router system of claim 15, wherein the window size adapter is further configured to regularly set at least one of the first and the second time thresholds based on round trip times associated with a plurality of mobile communication devices operating in the wireless communication network through the wireless router system.

24. The wireless router system of claim 15, wherein the window size adapter is further configured to increase the window size by more than one data packet.

25. The wireless router system of claim 15, wherein the window size adapter is further configured to increase the window size based on a predetermined algorithm.

26. A computer program product, comprising:

a computer readable medium;

computer instructions stored in the computer readable medium;

the computer instructions being executed by one or more processors for data packets to be transmitted a mobile communication device through a wireless communication network by;

causing a number of data packets matched for a window size to be transmitted;

measuring a round trip time associated with communication of each of the transmitted data packets, the round trip time being a time period between the transmission of each data packet and reception of a corresponding acknowledgment signal,

increasing the window size if the round trip time associated with the communication of each of the transmitted data packets is within a first time threshold;

decreasing the window size if the round trip time associated with the communication of any of the transmitted data packets is more than the first time threshold but less than a second time threshold;

if the round trip time associated with the communication of any of the transmitted data packets is more than the second time threshold, decreasing the window size and marking each data packet having the round trip time more than the second time threshold as a lost data packet;

causing a number of data packets matched for the re-sized window to be transmitted, including retransmitting any data packets marked as lost; and

repeating from the measuring step until data packets to be transmitted are exhausted.

33. The computer program product of claim 26, wherein the computer instructions are further executable to set at least one of the first and the second time thresholds based don traffic of a plurality of mobile communication devices operating in the wireless communication network operating through the wireless router system.

34. The computer program product of claim 26, wherein the computer instructions are further executable to set at least one of the first and the second time thresholds based on round rip times associated with a plurality of mobile communication devices operating in the wireless communication network through the wireless router system.