OFDM and OFDMA parameters apply to DOCSIS 3.1 networks. They are available for graphing from the OFDM/A sub-tab of the Parameters tab on the Alarm Central, Analyze Network View, and Analyze Modem View screens.

On the sub-tab, these parameters are grouped according to where they are measured (OFDM—downstream or OFDMA—upstream), but the following list is organized alphabetically.

Attenuation OFDMA

Upstream RF data parameter (in dB).

The loss of upstream signal strength as it travels across the cable plant, measured as the difference in dBmV between the upstream transmit power reported by a cable modem and the upstream Rx Power for the modem as reported by the CMTS.

Average Rx Power OFDM

Downstream RF power parameter (in dBmV).

This is the power of the signal received by the cable modem on this channel, normalized to 6 MHz of spectrum.

Average Rx Power OFDMA

Upstream RF power parameter (in dBmV).

This the RF power received from the CM, normalized to 1.6 MHz of spectrum, measured at the receiver input of the CMTS, as reported by the CMTS.

Capacity

Total capacity of the channel.

CCER OFDM

Downstream RF data parameter, measured for this cable modem on this channel and profile as a number.

This is the percentage of codewords received on the channel that had correctable errors.

CCER OFDMA

Upstream RF data parameter, measured for this cable modem on this channel and IUC as a number.

This is the percentage of codewords received on the channel that had correctable errors.

CER OFDM

Downstream RF data parameter, measured for this cable modem on this channel and profile as a percentage (%).

This is the percentage of codewords received on the channel that had uncorrectable errors.

CER OFDMA

Upstream RF data parameter, measured for this cable modem on this channel and IUC as a percentage (%).

This is the percentage of codewords received on the channel that had uncorrectable errors.

CCER+CER OFDM

Downstream RF data parameter, measured for this cable modem on this channel and profile as a percentage (%).

This is the percentage of codewords received on the channel that had either correctable or uncorrectable errors.

CCER+CER OFDMA

Upstream RF data parameter, measured for this cable modem on this channel and IUC as a percentage (%).

This is the percentage of codewords received on the channel that had either correctable or uncorrectable errors.

Corrected

The number of data codewords received in the measured interval that had correctable errors.

Channel Capacity OFDM

Downstream utilization parameter (in Mbps).

This is the maximum data rate the channel can carry.

Channel Capacity OFDMA

Upstream utilization parameter (in Mbps).

This is the maximum data rate the channel can carry.

Channel CCER OFDM

Downstream RF data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had correctable errors.

Channel CCER OFDMA

Upstream RF data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had correctable errors.

Channel CCER+CER OFDM

Downstream RF data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had either correctable or uncorrectable errors.

Channel CCER+CER OFDMA

Upstream RF data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had either correctable or uncorrectable errors.

Channel CER OFDM

Downstream RF data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had uncorrectable errors.

Channel CER OFDMA

Upstream RF data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had uncorrectable errors.

Channel Device Count OFDM

Downstream device count parameter, measured on a per-channel basis as a number.

This is the number of devices on the channel as reported by the CMTS.

Channel Device Count OFDMA

Upstream device count parameter, measured on a per-channel basis as a number.

This is the number of devices on the channel as reported by the CMTS.

Channel Rate OFDM

Downstream utilization parameter measured on a per-channel basis (in Mbps).

This is the actual traffic rate the channel carried during the defined interval.

Channel Rate OFDMA

Upstream utilization parameter measured on a per-channel basis (in Mbps).

This is the actual traffic rate the channel carried during the defined interval.

Channel Utilization OFDM

Downstream utilization parameter, measured on a per-channel basis as a percentage (%).

This is the percentage of a channel's capacity that is being used.

Channel Utilization OFDMA

Upstream utilization parameter, measured on a per-channel basis as a percentage (%).

This is the percentage of a channel's capacity that is being used.

CmRxMER OFDM

Cable modem downstream error ratio parameter, measured on a per-modem, per-channel basis (in dB).

This is the MER (ratio of average power to average error power) value for each sub-carrier in the downstream channel.

CmRxPwr OFDM

Cable modem downstream receiver power parameter, measured on a per-modem, per-channel basis (in dBmV).

This is the power of the signal received by the cable modem on this channel.

CmtsRxMER OFDMA

CMTS upstream error ratio parameter, measured on a per-modem, per-channel basis (in dB).

This is the MER (ratio of average power to average error power) value for each sub-carrier in the upstream channel.

CMTS CCER OFDMA

Upstream RF data parameter, measured from the CMTS on an IUC and a channel as a percentage (%).

This is the percentage of codewords received by the CMTS that had correctable errors.

CMTS CCER+CER OFDMA

Upstream RF data parameter, measured from the CMTS on an IUC and a channel as a percentage (%).

This is the percentage of codewords received by the CMTS that had either correctable or uncorrectable errors.

CMTS CER OFDMA

Upstream RF data parameter, measured from the CMTS on an IUC and a channel as a percentage (%).

This is the percentage of all code words transmitted on this channel to the CMTS by all modems during the specified time span that contain uncorrectable errors.

CMTS Channel CCER OFDMA

Upstream RF data parameter, measured from the CMTS on a per-channel basis as a percentage (%).

This is the percentage of codewords transmitted on this channel and reported by the CMTS that had correctable errors.

CMTS Channel CCER+CER OFDMA

Upstream RF data parameter, measured from the CMTS on a per-channel basis as a percentage (%).

This is the percentage of codewords transmitted on this channel and reported by the CMTS that had either correctable or uncorrectable errors.

CMTS Channel CER OFDMA

Upstream RF data parameter, measured from the CMTS on a per-channel basis as a percentage (%).

This is the percentage of codewords transmitted on this channel and reported by the CMTS that had uncorrectable errors.

Highest IUC OFDMA

Numeric ID for a set of upstream transmission parameters.

This is the ID of the Interval Usage Code (IUC) which is the highest speed parameter set that can be used on this channel.

Highest Modulation OFDMA

Upstream data parameter, measured on a per-modem, per-channel basis and reported as a transmission modulation type.

This is the default modulation that corresponds to the IUC with the highest default modulation that the modem can use on this OFDMA channel.

Highest Profile OFDM

Downstream data parameter, measured on a per-modem, per-channel basis and reported as a profile ID.

This is ID of the highest speed profile the modem can use on this channel.

Highest Speed OFDM

Downstream data parameter measured on a per-modem. per-channel basis (in Mbps).

This is the highest speed the modem can achieve on this channel.

IUC Capacity OFDMA

Upstream utilization parameter per IUC (in Mbps).

This is the maximum data rate the channel can carry for the identified IUC.

IUC Device Count OFDMA

Upstream device count data parameter per IUC, measured as a number.

This is the number of devices on the channel for the identified IUC as reported by the CMTS.

IUC MHz Efficiency OFDMA

Upstream utilization parameter, measured on a per-modem, per-channel basis (in Mbps/MHz).

This is the actual OFDMA speed that can be obtained by a cable modem, normalized per MHz. It is an absolute value of the bandwidth anticipated for a modem per MHz allocated to the channel.

This value is obtained by dividing the product of the cable modem channel efficiency and channel capacity by the channel width.

IUC Rate OFDMA

Upstream utilization data parameter per IUC (in Mbps).

This is the actual traffic rate the channel carried per IUC during the defined interval.

IUC Usage Efficiency OFDMA

Upstream efficiency parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the ratio between the following codeword counts, represented as a percentage:

• The number of codewords required if the cable modem always uses the highest IUC defined on the OFDMA channel, and
• The number of codewords actually used to transmit the data (possibly over different IUC over time).

Fewer codewords are consumed by the cable modem when more data is transmitted over high capacity IUCs.

A modem with a low IUC usage efficiency cannot use higher speed IUCs and a modem with 100% channel efficiency always uses the best IUC defined on the channel. If the best IUC on a channel has a low capacity, a modem with 100% IUC usage efficiency also has a capacity shortage. The capacity effectively usable by the cable modem is the product of channel speed and its IUC usage efficiency.

IUC Utilization OFDMA

Upstream utilization data parameter per IUC as a percentage (%).

This is the percentage of a channel's capacity per IUC that is being used.

Mean MER OFDM

Downstream noise parameter, measured on a per-modem, per-channel basis (in dB).

This is the average modulation error ratio (MER) over all the sub-carriers in the channel. MER is an SNR measure that includes estimated error when performing QAM demodulation.

Mean MER OFDMA

Upstream noise parameter, measured on a per-modem, per-channel basis (in dB).

This is the average MER over all the sub-carriers in the channel.

MER Deviation OFDM

Downstream noise parameter, measured on a per-modem, per-channel basis (in dB).

This is the standard deviation between the MER of the sub-carriers in the channel.

MER Deviation OFDMA

Upstream noise parameter, measured on a per-modem, per-channel basis (in dB).

This is the standard deviation between the MER of the sub-carriers in the channel.

MER Percentile OFDM

Downstream noise parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentile number to report MER for on this channel. The default value is 2, which results in the 2nd percentile.

MER Percentile OFDMA

Upstream noise parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentile number to report MER for on this channel. The default value is 2, which results in the 2nd percentile.

MER Percentile Value OFDM

Downstream RF noise parameter, measured on a per-modem, per-channel basis (in dB).

This is the MER at the designated percentile among the MER of the sub-carriers in the channel.

MER Percentile Value OFDMA

Upstream RF noise parameter, measured on a per-modem, per-channel basis (in dB).

This is the MER at the designated percentile among the MER of the sub-carriers in the channel.

Minislot Utilization OFDMA

Upstream utilization parameter, measure as a percentage (%).

The number of minislots the CMTS allocated to modems for transmission on a channel, as a percentage of the total it could have allocated.

NPC CER OFDM

Downstream data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had uncorrectable errors.

NCP CRC Failures

Cyclic redundancy check (CRC) is a code appended to a data field (NCP) to allow checking for corruption of data by the receiver.

NCP Total

Total number of NCP fields received in the measured interval.

PLC CER OFDM

Downstream data parameter, measured on a per-modem, per-channel basis as a percentage (%).

This is the percentage of codewords received on the channel that had uncorrectable errors.

PLC Total

The total number of PLC codewords received in the measured interval. The PLC CER is the ratio of PLC Unreliable over PLC Total as a percentage.

PLC Unreliable

Number of unreliable PLC codewords received in the measured interval.

Profile Capacity OFDM

Downstream utilization parameter, measured per profile (in Mbps).

This is the maximum data rate the channel can carry using this profile.

Profile Device Count OFDM

A downstream device count parameter, measured per profile as a number.

This is the number of devices on this channel using this profile.

Profile Rate OFDM

A downstream utilization parameter, measured per profile (in Mbps).

This is the average traffic rate the channel carried during the defined interval using this profile.

Profile Utilization OFDM

A downstream utilization parameter, measured per profile as a percentage (%).

This is the percentage of a channel's capacity that is being used with this profile.

Subcarrier Spacing

The frequency width of each sub-carrier across the OFDM/A channel.

T3 Errors OFDMA

An upstream timeout parameter, measured on a per-modem, per-channel basis as a number.

This is the number of T3 timeouts reported by the cable modem for each discrete upstream channel during the selected period. A T3 timeout indicates a timeout waiting for a ranging response.

T4 Errors OFDMA

An upstream RF power parameter, measured on a per-modem, per-channel basis as a number.

This is the number of T4 timeouts reported by the cable modem for each discrete upstream channel during the selected period. A T4 timeout indicates a timeout occurred while waiting for a periodic ranging opportunity.

Timing Offset

A measure of the time required for a signal to propagate in the network between the CMTS and cable modem.

Total Codewords

The total number of data codewords received in the measured interval.

Tx Power OFDMA

An upstream RF power parameter, measured on a per-modem, per-channel basis (in dBmV).

This is the RF power normalized to 1.6 MHz of spectrum on this channel, set by the transmitter at the output of the cable modem, as reported by the cable modem.

Uncorrectables

The number of data codewords received in the measured interval that had uncorrectable errors.

Utilization (%)

Measure of how close the cable modem - to - CMTS (upstream) or CMTS - to - cable modem (downstream) channel is to its full data carrying capacity. Very high utilization, typically 80% or more, may result in performance degradation for the subscriber.