OFDM Channel Power Profile

The OFDM Channel Power Profile feature helps in adjusting the power-level of 6 MHz bands in a DOCSIS 3.1 downstream OFDM channel.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/. An account on http://www.cisco.com/ is not required.

Hardware Compatibility Matrix for Cisco cBR Series Routers


Note

The hardware components introduced in a given Cisco IOS-XE Release are supported in all subsequent releases unless otherwise specified.

Table 1. Hardware Compatibility Matrix for the Cisco cBR Series Routers

Cisco CMTS Platform

Processor Engine

Interface Cards

Cisco cBR-8 Converged Broadband Router

Cisco IOS-XE Release 16.5.1 and Later Releases

Cisco cBR-8 Supervisor :

  • PID—CBR-CCAP-SUP-160G

  • PID—CBR-CCAP-SUP-60G

  • PID—CBR-SUP-8X10G-PIC

Cisco IOS-XE Release 16.5.1 and Later Releases

Cisco cBR-8 CCAP Line Cards:

  • PID—CBR-LC-8D30-16U30

  • PID—CBR-LC-8D31-16U30

  • PID—CBR-RF-PIC

  • PID—CBR-RF-PROT-PIC

  • PID—CBR-CCAP-LC-40G-R

Cisco cBR-8 Downstream PHY Modules:

  • PID—CBR-D30-DS-MOD

  • PID—CBR-D31-DS-MOD

Cisco cBR-8 Upstream PHY Modules:

  • PID—CBR-D30-US-MOD

Information About OFDM Channel Power Profile

The OFDM power profile provides a better, consistent power-level output at the cable modem, compensating the power levels at a finer granularity. It reduces the differing amounts of cable-loss over the bandwidth of OFDM channel.

This feature enables the Cisco cBR Series Converged Broadband Router to correct the transmission loss due to the cable in the plant.

The OFDM power profile (ofdm-power-profile) adjusts the transmission power level of each 6 MHz in an OFDM channel. The OFDM channel width can range from 24 MHz to 192 MHz, resulting in band-counts between 4 and 32 for the profile.

Each 6 MHz band is referenced by a band index (band-index) that is zero-based, with a maximum band range of 192 MHz OFDM channel being 0 to 31. Each band within the OFDM channel can have a unique power level setting. The OFDM power profile allows a total band adjustment range of 8 dB. Under some specific conditions, if the OFDM channel's downstream controller's base channel power is set to exceed the maximum DRFI specification power level, the OFDM power profile adjustment range can become as high as 9 dB.

In a power profile, you can set the power level (power-adjust-default) to a default value. This default value is applied to any band that is not configured through any other means.

You can configure band power levels in two methods: through the power tilt config (power-tilt-linear) or by configuring the power level for a band or range of bands (band-index). You can use both methods for configuring the band power levels simultaneously within an OFDM power profile.

The power tilt configuration applies a linear power-adjust value between the power-adjust-default value applied to the band index 0, and the power-tilt-linear adjust value applied to the highest band index of the profile. For example, an OFDM Power Profile of 96 MHz, with a power-tilt-linear of 4 dB, and power-adjust-default of 0 dB, has16 bands numbered 0 to 15, band index 0 is +0 dB, band index 15 is +4 dB, and bands 1 to 14 contain the linear power level setting based on the slope of the line between the band 0 and band 15 to the nearest 1/10th dB.

The band-index configuration applies a specified value to the indicated bands. The band-index configuration can specify a single band or a range of bands. A power-adjust configuration is used to specify the power level for the bands to the nearest 1/10th dB.

You can simultaneously use both power tilt and band index, where band-index is applied last. When you use both, the power-tilt-linear values can be overridden using the band-index power-adjust values.

A maximum of 64 OFDM power profiles can be configured on the Cisco cBR routers, numbered from 1 to 64. You can apply a single OFDM power profile to multiple controller OFDM channels, across line cards, as long as all validity checks pass during configuration. The router console displays an error message explaining any configuration errors or warnings.

Restrictions for Configuring OFDM Power Profile

The following restrictions are applicable for configuring an OFDM power profile:

  • OFDM power profile can be configured only on DOCSIS 3.1 system

  • The power profile can be applied only to downstream controller OFDM channels (RF-channels 158 to 162)

How to Configure the OFDM Channel Power Profile

Configuring OFDM Power Profile Using Band-index

Use the following commands along with the band-index configuration to configure OFDM Power Profile, where the band-index values act as an override.
enable
configure terminal
cable downstream ofdm-power-profile <profile_id>
  power-adjust-default -2.1
  band-index 0 7
    power-adjust -1.0
  band-index 8 15
    power-adjust -0.5
  band-index 16 23
    power-adjust 0.5
  band-index 24 31
    power-adjust 1.5

controller Integrated-Cable {slot}/{subslot}/{port}
rf-channel {158 - 162 }
power-profile {ofdm-power-profile-id}

Verifying the Power Profile Configuration

To display the power profile configuration details, use the show cable ofdm-power-profile command as given in the following example. This command also displays the actual power-band power levels as set by the profile.
Router> show cable ofdm-power-profile 3
OFDM Power Profile 3

Power-Adjust-Default(*): -2.1

Power-Band:
[00-07]   -1.0   -1.0   -1.0   -1.0   -1.0   -1.0   -1.0   -1.0
[08-15]   -0.5   -0.5   -0.5   -0.5   -0.5   -0.5   -0.5   -0.5
[16-23]    0.5    0.5    0.5    0.5    0.5    0.5    0.5    0.5
[24-31]    1.5    1.5    1.5    1.5    1.5    1.5    1.5    1.5

  +4 .0 |                                                                 
        |                                                                 
  +3 .0 |                                                                 
        |                                                                 
  +2 .0 |                                                                 
        |                                                 * * * * * * * * 
  +1 .0 |                                                                 
        |                                 * * * * * * * *                 
  +0 .0 | ----------------------------------------------------------------
        |                 * * * * * * * *                                 
  -1 .0 | * * * * * * * *                                                 
        |                                                                 
  -2 .0 |                                                                 
        |                                                                 
  -3 .0 |                                                                 
        |                                                                 
  (dB)    0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 
          0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
                               band-index

Configuring OFDM Power Profile with Linear Power-tilt

Use the following commands to configure the OFDM power profile with a linear power-tilt and the band-index override. 
enable
configure terminal
cable downstream ofdm-power-profile <profile_id>
  power-adjust-default 0.0
  power-tilt-linear 3.5
  band-index 0
  power-adjust 4.0

Verifying the Power Profile Using show controller Command

Use the show controller command to display the absolute power-band levels as set by the power profile. When the power-profile is applied to the controller, the power level displayed is the actual transmit power level in dBmV. 
Router>show controller Integrated-Cable 3/0/0 rf-channel 158 verbose
Chan State Admin Mod-Type  Start  Width     PLC        Profile-ID    dcid  power  output
                           Frequency                                      
 158   UP   UP   OFDM      849000000   96000000  856000000       20       159   33.0   NORMAL
 Resource status:   OK
 License: granted <09:23:14 EDT Aug 1 2016>
 OFDM channel license spectrum width: 92200000
 OFDM config state: Configured

 OFDM Power Profile: 3
Power-Band:
[00-07]   32.0   32.0   32.0   32.0   32.0   32.0   32.0   32.0
[08-15]   32.5   32.5   32.5   32.5   32.5   32.5   32.5   32.5
[16-23]   33.5   33.5   33.5   33.5   33.5   33.5   33.5   33.5
[24-31]   34.5   34.5   34.5   34.5   34.5   34.5   34.5   34.5

OFDM channel details: [3/0/0:158]
------------------------------------------

Configuration Example for OFDM Power Profile

This section provides example for the OFDM Power Profile configuration.

Example: OFDM Power Profile with Linear Power-tilt Configuration

enable
configure terminal
cable downstream ofdm-power-profile 3
  power-adjust-default 0.0
  power-tilt-linear 3.5
  band-index 0
  power-adjust 4.0

Feature Information for OFDM Channel Power Profile

Use Cisco Feature Navigator to find information about the platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to the www.cisco.com/go/cfn link. An account on the Cisco.com page is not required.


Note

The following table lists the software release in which a given feature is introduced. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Table 2. Feature Information for OFDM Channel Power Profile

Feature Name

Releases

Feature Information

OFDM Channel Power Profile

Cisco IOS-XE Release 16.5.1

This feature was introduced on the Cisco cBR Series Converged Broadband Router s.