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
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
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.