Method and apparatus for converting between byte lengths and burdened burst lengths in a broadband communication system

• US 6,928,109 B2
• Filed: 05/27/2003
• Issued: 08/09/2005
• Est. Priority Date: 01/15/1999
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Roussel, Chris, Horton, John Daniel Jr., Hollums, Scott
• Primary Examiner(s): Liu, Shuwang
• Application Number:
  US10/445,262
• Publication Number:
  US 20030196207A1
• Time in Patent Office: 805 Days
• Field of Search: 370/295, 370/350, 370/401, 370/443, 370/352, 370/335, 370/421, 370/432, 370/632, 709/236, 709/232, 375/222, 395/200.55
• US Class Current: 375/222
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9057 Arrangements for supporting packet reassembly or resequencing

Abstract

Requests are processed to transmit data packets upstream from a cable modem to a cable headend in a manner that minimizes the use of CPU operations and/or memory capacity. Data packets to be transmitted upstream are stored at the cable modem. The data packets each have a given transmission data byte length value. Burst profiles are received successively at the cable modem. Each time a new bust profile is received, a set of physical data length values corresponding to respective transmission data byte length values is calculated from the parameters of the received burst profile. The calculated set of physical data length values is stored in memory so the individual values can be retrieved from the transmission data byte length values again and again, rather than being re-calculated each time a conversion is made from transmission data byte length values to physical data length values. The same set of physical data length values is used until a new burst profile is received by the cable modem.

Claims

1. A method for transmitting data in a broadband communication system, comprising:

storing in a memory a set of byte length values corresponding to respective physical length values;

accessing said memory to retrieve a first physical length value, said first physical length value corresponding to a first byte length value of a data packet to be transmitted over a physical layer of the broadband communication system;

transmitting a request message including said first physical length value;

receiving a grant message including a second physical length value; and

accessing said memory to retrieve a second byte length value corresponding to said second physical length value, said second byte length value for determining a fragment size for transmitting a fragment of said data packet over said physical layer of the broadband communication system.

2. The method of claim 1, further comprising:

receiving a set of parameters relating to said physical layer of the broadband communication system; and

calculating said set of byte length values in response to receiving said set of parameters and prior to storing said set of byte length values in said memory.

3. The method of claim 2, further comprising:

replacing said set of byte length values in said memory with a newly-calculated set of byte length values when a new set of parameters relating to said physical layer of the broadband communication system is received.

4. The method of claim 1, wherein said storing in a memory a set of byte length values corresponding to respective physical length values comprises storing said set of byte length values in a lookup table that is addressable by said respective physical length values.

5. The method of claim 4, wherein said accessing said memory to retrieve a first physical length value corresponding to said first byte length value comprises performing a binary search of said lookup table.

6. The method of claim 4, wherein said accessing said memory to retrieve a second byte length value corresponding to said second physical length value comprises retrieving a byte length value from a location in said lookup table addressed by said second physical length value.

7. The method of claim 1, further comprising:

subtracting said second byte length value from said first byte length value to determine a difference byte length value;

accessing said memory to retrieve a third physical length value based on said difference byte length value;

transmitting said third physical length value with said fragment of said data packet.

8. A device for transmitting data packets in a broadband communication system comprising:

a memory that stores a set of byte length values corresponding to respective physical length values;

hardware configured to access said memory to retrieve a physical length value corresponding to a given byte length value and to retrieve a byte length value corresponding to a given physical length value;

wherein said hardware retrieves a first physical length value for inclusion in a request message, said first physical length value corresponding to a first byte length value of a data packet to be transmitted from the device, and

wherein said hardware retrieves a second byte length value for determining a fragment size for transmitting a fragment of said data packet from the device, said second byte length value corresponding to a second physical length value included in a grant message received by the device.

9. The device of claim 8, further comprising:

a central processing unit (CPU) configured to calculate said set of byte length values in response to receipt by the device of a set of parameters relating to a physical layer of the broadband communication system.

10. The device of claim 9, wherein said CPU is further configured to calculate a new set of byte length values corresponding to respective physical length values in response to receipt by the device of a new set of parameters relating to said physical layer of the broadband communication system and to store said newly-calculated set of byte length values in said memory.

11. The device of claim 8, wherein said memory comprises a random access memory (RAM).

12. The device of claim 8, wherein said memory stores said set of byte length values in a lookup table addressable by said respective physical length values.

13. The device of claim 12, wherein said hardware comprises search logic, said search logic configured to perform a binary search of said lookup table to retrieve a physical length value corresponding to a given byte length value.

14. The device of claim 12, wherein said hardware is configured to retrieve a byte length value from a location in said lookup table addressed by a given physical length value.

15. The device of claim 8, wherein said hardware is further configured to subtract said second byte length value from said first byte length value to determine a difference byte length value and to access said memory to retrieve a third physical length value based on said difference byte length value, said third physical length value for inclusion with said fragment of said data packet for transmission from the device.

16. A device for transmitting data packets in a broadband communication system, comprising:

a memory that stores a set of byte length values corresponding to respective physical length values;

means for accessing said memory to retrieve a physical length value corresponding to a given byte length value and to retrieve a byte length value corresponding to a given physical length value;

wherein said accessing means comprises means for retrieving a first physical length value for inclusion in a request message, said first physical length value corresponding to a first byte length value of a data packet to be transmitted from the device, and means for retrieving a second byte length value for determining a fragment size for transmitting a fragment of said data packet from the device, said second byte length value corresponding to a second physical length value included in a grant message received by the device.

17. The device of claim 16, further comprising:

means for calculating said set of byte length values in response to receipt by the device of a set of parameters relating to a physical layer of the broadband communication system.

18. The device of claim 17, wherein said means for calculating comprises means for calculating a new set of byte length values corresponding to respective physical length values in response to receipt by the device of a new set of parameters relating to said physical layer of the broadband communication system, said newly-calculated set of byte length values for storage in said memory.

19. The device of claim 16, wherein said memory comprises a random access memory (RAM).

20. The device of claim 16, wherein said memory stores said set of byte length values in a lookup table addressable by said respective physical length values.

21. The device of claim 20, wherein said accessing means comprises search means for performing a binary search of said lookup table to retrieve a physical length value corresponding to a given byte length value.

22. The device of claim 20, wherein said accessing means comprises means for retrieving a byte length value from a location in said lookup table addressed by a given physical length value.

23. The device of claim 16, wherein said accessing means comprises means for subtracting said second byte length value form said first byte length value to determine a difference byte length value and retrieving a third physical length value based on said difference byte length value, said third physical length value for inclusion with said fragment of said data packet for transmission from the device.