Method and system for transmission control protocol (TCP) packet loss recovery over a wireless link

• US 6,646,987 B1
• Filed: 06/08/1999
• Issued: 11/11/2003
• Est. Priority Date: 10/05/1998
• Status: Expired due to Term

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Qaddoura, Emad
• Primary Examiner(s): Nguyen, Steven
• Assistant Examiner(s): Duong, Duc
• Application Number:
  US09/327,610
• Time in Patent Office: 1,617 Days
• Field of Search: 370/230, 370/231, 370/232, 370/233, 370/234, 370/235, 370/252, 370/254, 714/774, 714/776, 714/779
• US Class Current: 370/231
• CPC Class Codes: H04L 41/00 Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks

Abstract

A method and system for Transmission Control Protocol (TCP) packet loss recovery over a wireless link where the packet loss is due to a high Bit Error Rate (BER). Such a method and system allows the exponential growth of a TCP congestion window for every acknowledgement packet that is received after a retransmission timers expires and/or three duplicate acknowledgement packets are received. In such a scenario, a maximum amount of data is transmitted via the exponentially growing TCP congestion window thereby optimizing and increasing packet throughput. A method and system for setting the congestion window to a greater amount than originally set of the maximum allowed window size is also presented. Further, a method and system for, as the BER changes between low and high, automatically adjusting the congestion window size to be a variable of the maximum allowed window size and dynamically adjusting the packet size is presented.

Claims

1. A method for Transmission Control Protocol (TCP) packet loss recovery over a wireless link, wherein the packet loss is due to a high Bit Error Rate (BER), the method comprising:

exponentially growing a TCP congestion window for every acknowledgement packet received after at least one of;

expiration of a retransmission timer and receipt of three duplicate acknowledgment packets, wherein exponentially growing the TCP congestion window further comprises;

as the BER changes between low and high, automatically adjusting the congestion window size to be a variable of the maximum allowed window size and dynamically adjusting the packet size; and

transmitting, via the exponentially growing TCP congestion window, a maximum amount of data.

2. The method of claim 1 further comprising:

if the BER is high, reducing the packet size to get higher throughput; and

if the BER is low, increasing the packet size to get higher throughput.

3. A system for Transmission Control Protocol (TCP) packet loss recovery over a wireless link, wherein the packet loss is due to a high Bit Error Rate (BER), the system comprises:

means for exponentially growing a TCP congestion window for every acknowledgement packet received after at least one of;

a retransmission timer expires and three duplicate acknowledgment packets are received, wherein the means for exponentially growing the TCP congestion window comprises, as the BER changes between low and high, means for automatically adjusting the congestion window size to be a variable of the maximum allowed window size, and dynamically adjusting the packet size; and

means for transmitting, via the exponentially growing a TCP congestion window, a maximum amount of data.

4. The system of claim 3 wherein the means for exponentially growing the TCP congestion window further comprises:

means for setting a slow start threshold to the maximum allowed window size; and

means for incrementing the congestion window by one packet for every received acknowledgement packet.

5. The system of claim 3 wherein the means for transmitting the maximum amount of data within the threshold further comprises:

means for immediately retransmitting half of the maximum allowed window size.

6. The system of claim 3 wherein the variable of the maximum allowed window size is greater than half of the maximum allowed window size.

7. The system of claim 3 further comprises:

if the BER is high, means for reducing the packet size to get higher throughput; and

if the BER is low, means for increasing the packet size to get higher throughput.

8. The system of claim 3 wherein the variable of the maximum allowed window size is a value that is significantly larger than the value provided in standard TCP.

9. A system for Transmission Control Protocol (TCP) packet loss recovery over a wireless link, wherein the packet loss is due to a high Bit Error Rate (BER), the system comprising:

a basestation; and

mobile terminals, wherein TCP packets are transmitted and received between the basestation and the mobile terminals and between the mobile terminals, wherein a TCP congestion window is exponentially grown for every acknowledgement packet received after at least one of;

a retransmission timer expires and three duplicate acknowledgment packets are received, wherein exponentially growing the congestion window further comprises;

as the BER changes between low and high, automatically adjusting the congestion window size to be a variable of the maximum allowed window size and dynamically adjusting the packet size; and

wherein a maximum amount of data is transmitted via the exponentially grown TCP congestion window.

10. The system of claim 9 further comprises:

if the BER is high, reducing the packet size to get higher throughput; and

if the BER is low, increasing the packet size to get higher throughput.

11. A computer comprising:

a processor; and

memory coupled to the processor, wherein the memory stores programming instructions that, when read by the processor, cause the processor to;

exponentially grow a TCP congestion window for every acknowledgement packet received after at least one of;

a retransmission timer expires and three duplicate acknowledgment packets are received;

transmit, via the exponentially growing TCP congestion window, a maximum amount of data;

as the BER changes between low and high, automatically adjust the value of the congestion window size to be a variable of the maximum allowed window size; and

dynamically adjust the packet size.

12. The computer of claim 11 wherein the memory further comprises programming instructions that cause the processor to:

if the BER is high, reduce the packet size to get higher throughput; and

if the BER is low, increase the packet size to get higher throughput.