Method and apparatus for performing periodic ranging for cable modems

• US 6,453,472 B1
• Filed: 06/02/1999
• Issued: 09/17/2002
• Est. Priority Date: 06/02/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Leano, Chrisanto D., Roeck, Guenter E., Millet, Mark E.
• Primary Examiner(s): Faile, Andrew
• Assistant Examiner(s): Tran, Hai V.
• Application Number:
  US09/324,358
• Time in Patent Office: 1,203 Days
• Field of Search: 375/222, 455/3.1, 455/5.1, 455/69, 455/14, 340/310, 348/609, 330/149, 370/395, 725/111, 725/117
• US Class Current: 725/111
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04N 21/42676 for modulating an analogue carrier signal to encode digital information or demodulating it to decode digital information, e.g. ADSL or cable modem
• CPC Class Codes: H04N 7/17309 Transmission or handling of upstream communications

Abstract

Disclosed are a method apparatus for performing periodic ranging with a cable modem. It is determined whether an actual power level of the cable modem requires adjustment to a desired power level and it is indicated to the cable modem that it should adjust the actual power level to an adjusted power level that differs from the actual power level of the cable modem by less than or equal to a first dynamic range associated with the cable modem. In one extension of this method, the first dynamic range represents a difference between a modem dynamic range of the actual power level output by the cable modem and a head end dynamic range for recognizing the actual power level output by the cable modem.

Claims

1. A method for dynamically adjusting a power level of a cable modem, the method comprising:

performing initial periodic ranging with a cable modem to determine a dynamic range of power levels of the cable modem that are recognized by a cable termination system (CMTS); and

performing periodic ranging with the cable modem to dynamically adjust the cable modem'"'"'s power level so that it substantially matches a desired power level, wherein the adjustments include incrementally increasing or decreasing the cable modem'"'"'s power level based on the determined dynamic range of the cable modem.

2. A method as recited in claim 1, further comprising receiving a new desired power level for the cable modem, wherein the periodic ranging is performed to dynamically adjust the cable modem'"'"'s power level so that it substantially matches the new desired power level, wherein the adjustments include incrementally increasing or decreasing the cable modem'"'"'s power level based on the determined dynamic range of the cable modem.

3. A method as recited in claim 1, wherein the cable modem'"'"'s power level is incremented or decremented no more than the determined dynamic range of the cable modem.

4. A method as recited in claim 1, further comprising:

performing initial periodic ranging with a second cable modem to determine a second dynamic range of power levels of the second cable modem that are recognized by the CMTS, wherein the second dynamic range differs from the first dynamic range; and

performing periodic ranging with the second cable modem to dynamically adjust the second cable modem'"'"'s power level so that it substantially matches the desired power level, wherein the adjustments include incrementally increasing or decreasing the second cable modem'"'"'s power level based on the determined second dynamic range of the second cable modem.

5. A method as recited in claim 4, wherein the second cable modem'"'"'s power level is incremented or decremented no more than the determined second dynamic range of the second cable modem.

6. A method as recited in claim 1, further comprising determining whether an adjustment flag associated with the cable modem indicates adjustment is to be performed, wherein the periodic ranging is only performed when it is determined that the adjustment flag associated with the cable modem indicates adjustment is to be performed.

7. A method as recited in claim 6, further comprising setting the adjustment flag to indicate adjustment is to be performed when a user specifies the desired power level.

8. A method as recited in claim 1, wherein the periodic ranging is performed on a plurality of cable modems associated with a same upstream channel, the periodic ranging comprising:

ranging the cable modems to a first set of incremental or decremental adjustments to their respective power levels;

tracking whether the cable modems have successfully ranged to the first set of incremental or decremental adjustments to the cable modems'"'"'power levels; and

ranging the cable modems to a second set of incremental or decremental adjustments to the cable modems'"'"' power levels after the cable modems have all successfully ranged to the first adjustment to the cable modems'"'"' power level.

9. A method as recited in claim 1, wherein the determined dynamic range represents a difference between a modem dynamic range of the actual power level output by the cable modem and a CMTS dynamic range for the CMTS recognizing the actual power level output by the cable modem.

10. A cable modem termination system (CMTS), the CMTS capable of dynamically adjusting a power level of a cable modem comprising:

an upstream receiver and demodulator capable of receiving an upstream signal at an input power level from the cable modem;

a downstream transmitter and modulator capable of transmitting a downstream signal to the cable modem; and

a processor arranged to perform initial periodic ranging with a cable modem to determine a dynamic range of power levels of the cable modem that are recognized by the cable termination system (CMTS) and perform periodic ranging with the cable modem to dynamically adjust the cable modem'"'"'s power level so that it substantially matches a desired power level, wherein the adjustments include incrementally increasing or decreasing the cable modem'"'"'s power level based on the determined dynamic range of the cable modem.

11. A CMTS as recited in claim 10, the processor being further arranged to receive a new desired power level for the cable modem, wherein the periodic ranging is performed to dynamically adjust the cable modem'"'"'s power level so that it substantially matches the new desired power level, wherein the adjustments include incrementally increasing or decreasing the cable modem'"'"'s power level based on the determined dynamic range of the cable modem.

12. A CMTS as recited in claim 10, wherein the cable modem'"'"'s power level is incremented or decremented no more than the determined dynamic range of the cable modem.

13. A CMTS as recited in claim 10, the processor being further arranged to:

perform initial periodic ranging with a second cable modem to determine a second dynamic range of power levels of the second cable modem that are recognized by the CMTS, wherein the second dynamic range differs from the first dynamic range; and

perform periodic ranging with the second cable modem to dynamically adjust the second cable modem'"'"'s power level so that it substantially matches the desired power level, wherein the adjustments include incrementally increasing or decreasing the second cable modem'"'"'s power level based on the determined second dynamic range of the second cable modem.

14. A CMTS as recited in claim 13, wherein the second cable modem'"'"'s power level is incremented or decremented no more than the determined second dynamic range of the second cable modem.

15. A CMTS as recited in claim 10, the processor being further arranged to determine whether an adjustment flag associated with the cable modem indicates adjustment is to be performed, wherein the periodic ranging is only performed when it is determined that the adjustment flag associated with the cable modem indicates adjustment is to be performed.

16. A CMTS as recited in claim 15, the processor being further arranged to set the adjustment flag to indicate adjustment is to be performed when a user specifies the desired power level.

17. A CMTS as recited in claim 10, wherein the periodic ranging is performed on a plurality of cable modems associated with a same upstream channel, the periodic ranging comprising:

ranging the cable modems to a first set of incremental or decremental adjustments to their respective power levels;

tracking whether the cable modems have successfully ranged to the first set of incremental or decremental adjustments to the cable modems'"'"' power levels; and

ranging the cable modems to a second set of incremental or decremental adjustments to the cable modems'"'"' power levels after the cable modems have all successfully ranged to the first adjustment to the cable modems'"'"' power level.

18. A CMTS as recited in claim 10, wherein the determined dynamic range represents a difference between a modem dynamic range of the actual power level output by the cable modem and a CMTS dynamic range for the CMTS recognizing the actual power level output by the cable modem.

19. A computer readable medium containing program instructions for dynamically adjusting a power level of a cable modem, the computer readable medium comprising:

computer readable code for performing initial periodic ranging with a cable modem to determine a dynamic range of power levels of the cable modem that are recognized by a cable termination system (CMTS); and

computer readable code for performing periodic ranging with the cable modem to dynamically adjust the cable modem'"'"'s power level so that it substantially matches a desired power level, wherein the adjustments include incrementally increasing or decreasing the cable modem'"'"'s power level based on the determined dynamic range of the cable modem.

20. An apparatus for dynamically adjusting a power level of a cable modem, the apparatus comprising:

means for performing initial periodic ranging with a cable modem to determine a dynamic range of power levels of the cable modem that are recognized by a cable termination system (CMTS);

means for performing periodic ranging with the cable modem to dynamically adjust the cable modem'"'"'s power level so that it substantially matches a desired power level, wherein the adjustments include incrementally increasing or decreasing the cable modem'"'"'s power level based on the determined dynamic range of the cable modem.

21. An apparatus as recited in claim 20, further comprising means for receiving a new desired power level for the cable modem, wherein the periodic ranging is performed to dynamically adjust the cable modem'"'"'s power level so that it substantially matches the new desired power level, wherein the adjustments include incrementally increasing or decreasing the cable modem'"'"'s power level based on the determined dynamic range of the cable modem.

22. An apparatus as recited in claim 20, wherein the cable modem'"'"'s power level is incremented or decremented no more than the determined dynamic range of the cable modem.

23. An apparatus as recited in claims 20, further comprising:

means for performing initial periodic ranging with a second cable modem to determine a second dynamic range of power levels of the second cable modem that are recognized by the CMTS, wherein the second dynamic range differs from the first dynamic range; and

means for performing periodic ranging with the second cable modem to dynamically adjust the second cable modem'"'"'s power level so that it substantially matches the desired power level, wherein the adjustments include incrementally increasing or decreasing the second cable modem'"'"'s power level based on the determined second dynamic range of the second cable modem.

24. An apparatus as recited in claim 23, wherein the second cable modem'"'"'s power level is incremented or decremented no more than the determined second dynamic range of the second cable modem.

25. An apparatus as recited in claim 20, further comprising means for determining whether an adjustment flag associated with the cable modem indicates adjustment is to be performed, wherein the periodic ranging is only performed when it is determined that the adjustment flag associated with the cable modem indicates adjustment is to be performed.

26. An apparatus as recited in claim 25, further comprising means for setting the adjustment flag to indicate adjustment is to be performed when a user specifies the desired power level.

27. An apparatus as recited in claim 20, wherein the periodic ranging is performed on a plurality of cable modems associated with a same upstream channel, the periodic ranging comprising:

means for ranging the cable modems to a first set of incremental or decremental adjustments to their respective power levels;

means for tracking whether the cable modems have successfully ranged to the first set of incremental or decremental adjustments to the cable modems'"'"' power levels; and

means for ranging the cable modems to a second set of incremental or decremental adjustments to the cable modems'"'"' power levels after the cable modems have all successfully ranged to the first adjustment to the cable modems'"'"' power level.

28. An apparatus as recited in claim 20, wherein the determined dynamic range represents a difference between a modem dynamic range of the actual power level output by the cable modem and a CMTS dynamic range for the CMTS recognizing the actual power level output by the cable modem.