ARQ (automatic repeat request) for broadband fixed wireless network

• US 7,000,021 B1
• Filed: 10/12/2001
• Issued: 02/14/2006
• Est. Priority Date: 10/12/2001
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Radhakrishnan, Ramesh, Gurbuz, Ozgur, Ayanoglu, Ender, Bernstein, Alon, Khanna, Arun, Chan, Cindy, Patel, Kushal
• Primary Examiner(s): SHAH, KAMINI S
• Application Number:
  US09/976,627
• Time in Patent Office: 1,586 Days
• Field of Search: 709/217, 709/229, 370/394, 370/473
• US Class Current: 709/230
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/1883 using multiple timers

Abstract

Systems and methods for retransmitting unsuccessfully transmitted data across a communication link. The retransmission mechanism may be applied to point to multipoint networks including wireless networks. Each packet is encapsulated in an ARQ frame and assigned a sequence number for the purpose of coordinating acknowledgments and retransmissions. Information as to which packets require retransmission is communicated in the form of a bitmap where each bit indicates an acknowledgment status for a given packet. Any missing packets in the received sequence are assumed to require retransmission.

Claims

1. In a data communication network wherein data is transmitted from a first node to a second node, a method for operating said first node, said method comprising:

transmitting data packets from said first node to said second node;

determining when space is available in a retransmission buffer;

storing, said data packets in said retransmission buffer when it is determined that space is available in said retransmission buffed;

holding said data packets in a queue when it is determined that space is not available in said retransmission buffer and space is available in said queue;

discarding said data packets when it is determined that space is not available in said retransmission buffer and space is not available in said queue; and

receiving bitmap information from said second node that identifies packets to be retransmitted.

2. The method of claim 1 further comprising:

retransmitting said packets identified by said bitmap information to said second node.

3. The method of claim 1 wherein said data communication network comprises a point to multipoint network.

4. The method of claim 3 wherein transmitting comprises:

transmitting employing a DOCSIS MAC protocol.

13. The method of claim 2 wherein retransmitting said packets identified by said bitmap information to said second node includes retransmitting said packets until a retry limit is approximately reached.

16. The method of claim 1 wherein transmitting said data packets from said first node to said second node includes encapsulating said data packets such that a sequence number is appended in a header for each transmitted data packet to facilitate retransmission.

5. In a data communication network wherein data is transmitted from a first node to a second node, apparatus for operating said first node, said

apparatus comprising:

means for transmitting data packets from said first node to said second node;

means for determining when space is available in a retransmission buffer;

means for storing said data packets in said retransmission buffer when it is determined that space is available in said retransmission buffer;

means for holding said data packets in a queue when it is determined that space is not available in said retransmission buffer and space is available in said queue;

means for discarding said data packets when it is determined that space is not available in said retransmission buffer and space is not available in said queue;

and means for receiving bitmap information from said second node that identifies packets to be retransmitted.

6. The apparatus of claim 5 further comprising:

means for retransmitting said packets identified by said bitmap information to said second node.

7. The apparatus of claim 5 wherein said data communication network comprises a point to multipoint network.

8. The apparatus of claim 7 wherein said means for transmitting comprises:

means for transmitting employing a DOCSIS MAC protocol.

14. The apparatus of claim 6 wherein said means for retransmitting said packets identified by said bitmap information to said second node include means for retransmitting said packets until a retry limit is approximately reached.

17. The method of claim 5 wherein said means for transmitting comprises means for including a sequence number with each transmitted data packet to facilitate retransmission.

9. In a data communication network wherein data is transmitted from a first node to a second node, a computer program product on computer-readable storage medium for operating said first node, said apparatus comprising:

code that transmits data packets from said first node to said second node;

code that determines when space is available in a retransmission buffer;

code that stores said data packets in said retransmission buffer when it is determined that space is available in said retransmission buffer;

code that holds said data packets in a queue when it is determined that space is not available in said retransmission buffer and space is available in said queue;

code that discards said data packets when it is determined that space is not available in said retransmission buffer and space is not available in said queue;

code that receives bitmap information from said second node that identifies packets to be retransmitted; and

a computer-readable storage medium that stores the codes.

10. The computer program product on computer readable-storage medium of claim 9 further comprising:

code that retransmits said packets identified by said bitmap information to said second node.

11. The computer program product on computer readable-storage medium of claim 9 wherein said data communication network comprises a point to multipoint network.

12. The computer program product on computer readable-storage medium of claim 11 wherein said code that transmits comprises:

code that transmits employing a DOCSIS MAC protocol.

15. The computer program product on computer readable-storage medium of claim 9 wherein said code that retransmits said packets identified by said bitmap information to said second node includes code that retransmits said packets until a retry limit is approximately reached.

18. The computer program product on computer readable-storage medium of claim 9 wherein said code that transmits comprises code that includes a sequence number with each transmitted data packet to facilitate retransmission.