Cable modem with dual automatic attenuation

• US 9,282,281 B2
• Filed: 12/27/2010
• Issued: 03/08/2016
• Est. Priority Date: 12/27/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Ericsson Wifi Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Williams, Chris, Smith, Roland, Zaniewski, Jarek, Chenier, Marcel, Rayment, Stephen
• Primary Examiner(s): Acolatse, Kodzovi
• Application Number:
  US12/978,684
• Publication Number:
  US 20120163201A1
• Time in Patent Office: 1,898 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04N 7/102 Circuits therefor, e.g. noise reducers, equalisers, amplifiers H04N7/108 takes precedence

Abstract

Described herein are a number of steps, methods and/or solutions that can be applied to greatly improve attenuation control of RF signals in cable plant. The present disclosure is directed to a cable modem auto-attenuation system or any other signal transferring system. The system may be capable of taking a high-power signal from the cable plant'"'"'s service line, dropping the power value down to a usable level and transmitting the signal to a cable modem while eliminating the need for rigorous manual adjustments that a normal cable modem often requires. In certain embodiments, the system may be integrated into a separate device connected between the modem and the cable company service line and configured to handle upstream and downstream attenuation separately or jointly.

Claims

1. A device for attenuating an input signal, comprising:

a duplexer for splitting the input signal into an upstream signal and a downstream signal;

an upstream attenuator, configured to attenuate said upstream signal independently of said downstream signal; and

at least one control processor configured to;

determine that a cable modem is not synchronized with a Cable Modem Termination System (CMTS) when the upstream signal level is not within a first range for the upstream signal;

adjust the upstream attenuator until the upstream signal level is within the first range, to synchronize the cable modem with the CMTS; and

when the cable modem is synchronized with the CMTS, adjust the upstream attenuator until the upstream signal level is within a second range for the upstream signal, narrower than the first range;

wherein to adjust the upstream attenuator until the upstream signal is within a second range, the at least one control processor is further configured to adjust a current attenuation of the upstream attenuator based on a target value for the upstream signal.

2. The device of claim 1, wherein to adjust the upstream attenuator until the upstream signal level is within the first range, the at least one control processor is further configured to adjust the upstream attenuator to one of a minimum and a maximum upstream attenuation value.

3. The device according to claim 1, wherein to adjust the upstream attenuator until the upstream signal is within the first range, the at least one control processor is further configured to adjust the upstream attenuator by alternating the upstream attenuation between a minimum and a maximum value.

4. The device according to claim 1, further comprising a downstream attenuator configured to attenuate the downstream signal independently of the upstream signal, and wherein the at least one control processor is further configured to:

determine that the cable modem is not synchronized with the CMTS when the downstream signal level is not within a first range for the downstream signal;

adjust the downstream attenuator until the downstream signal level is within the first range, to synchronize the cable modem with the CMTS; and

when the cable modem is synchronized with the CMTS, adjust the downstream attenuator until the downstream signal level is within a second range for the downstream signal, narrower than the first range.

5. The device of claim 4, wherein to adjust the downstream attenuator until the downstream signal is within the first range for the downstream signal, the at least one control processor is further configured to adjust the downstream attenuator to one of a minimum and a maximum downstream attenuation value.

6. The device of claim 4, wherein to adjust the downstream attenuator until the downstream signal is within the first range for the downstream signal, the at least one control processor is further configured to adjust the downstream attenuator by alternating the downstream attenuation between a minimum and a maximum value.

7. The device of claim 4, wherein to adjust the downstream attenuator until the downstream signal is within the second range for the downstream signal, the at least one control processor is further configured to adjust a current attenuation of the downstream attenuator based on a target value for the downstream signal.

8. The device of claim 4, wherein the first and second ranges for the upstream signal are respectively different from the first and second ranges for the downstream signal.

9. The device of claim 4, wherein the at least one control processor is configured to adjust the downstream attenuator to minimize a receive error rate (BER or CER).

10. The device of claim 1, wherein the at least one control processor is configured to receive independent upstream level control requests from the CMTS.

11. The device of claim 1, wherein the at least one control processor is configured to adjust the upstream attenuator to enable the cable modem to operate at a maximum Signal-to-Noise Ratio (SNR).

12. The device of claim 1, wherein the device is integrated in the cable modem.

13. The device of claim 1, wherein the cable modem is integrated in a strand-mounted wireless access point comprising an access radio coupled to an access antenna.

14. A method for a device for attenuating an input signal comprising:

splitting the input signal into an upstream signal and a downstream signal;

determining that a cable modem is not synchronized with a Cable Modem Termination System (CMTS) when the upstream signal level is not within a first range for the upstream signal;

adjusting an upstream attenuator configured to attenuate the upstream signal independently of said downstream signal, until the upstream signal level is within the first range, to synchronize the cable modem with the CMTS; and

when the cable modem is synchronized with the CMTS, adjusting the upstream attenuator until the upstream signal level is within a second range for the upstream signal, narrower than the first range;

wherein to adjust the upstream attenuator until the upstream signal is within a second range for the upstream signal, the method further comprises adjusting a current attenuation of the upstream attenuator based on a target value for the upstream signal.

15. The method of claim 14, wherein to adjust the upstream attenuator until the upstream signal level is within the first range, the method further comprises adjusting the upstream attenuator to one of a minimum and a maximum upstream attenuation value.

16. The method of claim 14, wherein to adjust the upstream attenuator until the upstream signal is within the first range, the method further comprises adjusting upstream attenuator by alternating the upstream attenuation between a minimum and a maximum value.

17. The method of claim 14, further comprising:

determining that the cable modem is not synchronized with the CMTS when the downstream signal level is not within a first range for the downstream signal;

adjust a downstream attenuator configured to attenuate the downstream signal independently of the upstream signal, until the downstream signal level is within the first range, to synchronize the cable modem with the CMTS; and

when the cable modem is synchronized with the CMTS, adjust the downstream attenuator until the downstream signal level is within a second range for the downstream signal, narrower than the first range.

18. The method of claim 17, wherein to adjust the downstream attenuator until the downstream signal is within the first range for the downstream signal, the method further comprises adjusting the downstream attenuator to one of a minimum and a maximum downstream attenuation value.

19. The method of claim 17, wherein to adjust the downstream attenuator until the downstream signal is within the first range for the downstream signal, the method further comprises adjusting the downstream attenuator by alternating the downstream attenuation between a minimum and a maximum value.

20. The method of claim 17, wherein to adjust the downstream attenuator until the downstream signal is within the second range for the downstream signal, the method further comprises adjusting a current attenuation of the downstream attenuator based on a target value for the downstream signal.

21. The method of claim 17, wherein the first and second ranges for the upstream signal are respectively different from the first and second ranges for the downstream signal.

22. The method of claim 17, wherein adjusting the downstream attenuator is to minimize a receive error rate (BER or CER).

23. The method of claim 14, further comprising receiving independent upstream level control requests from the CMTS.

24. The method of claim 14, wherein adjusting the upstream attenuator is to enable the cable modem to operate at a maximum Signal-to-Noise Ratio (SNR).

25. The method of claim 14, wherein the device is integrated in the cable modem.

26. The method of claim 14, wherein the cable modem is integrated in a strand-mounted wireless access point comprising an access radio coupled to an access antenna.