Carrier for DOCSIS 3.1 Upstream

1. Basic

State

Double-click or use the drop-down menu to control the operating state of the carrier.

Format

The format of the carrier.

Frequency Offset

Range: Depends on instrument and waveform settings

Set the frequency offset for the carrier relative to the signal generator’s frequency setting. Note: according to signal's bandwidth, the max frequency offset of each format will less than 80MHz

The valid range will be different for every format with various oversampling ratio.

Initial Phase

Range: 0 to 359 degrees

Set the initial phase of the carrier.

Power

Range: -50 to 0 dB

Sets the power level in dB for the selected carrier in a multiple carrier configuration, relative to the power settings defined for the other carriers in the configuration.

You can ignore this parameter for single carrier configurations. In single carrier configurations, the amplitude of the signal is determined by the Amplitude setting in the Signal Generator node.

2. Channel Settings

Multi-path Channel

Click in the right side of the cell to open theMulti-path Channel configuration window. The default is OFF and you can change Multi-path Parameter” to User Defined and set the paths in the table.

User Defined provides a more flexible way configuring each path's attenuation ρ, relative delay τ and phase shift from scattering θ.

You can edit the parameters values in the table directly. Alternatively, click on the Open button, and select a fading file (*.fading) previously configured.

When you finished editing the user defined parameter configuration, click on Save button to make a copy.

Attenuation (ρ)

Display the attenuation of the i'th path.

If Attenuation of all paths are zero, there will be an error when you click OK to close this dialog.

Delay (τ)

Displays the ralative delay of the i'th path.

When this valus is too large, there will be an out-of-memory exception that ask you to decrease it.

Phase (θ)

Displays the phase shift of the i'th path.

This is a radian value, so 2*pi has the same meaning with 0.

Tilted Channel

Choice: On | Off

Default: Off

Coupling: When Tilted Channel is off (default), the Tilt per Subcarrier will not be activated.

Get/Set whether tilted channel is enabled.

Tilt per Subcarrier

Range: -1dB to 1dB

Resolution of tilt: 0.0001dB

Default: 0 dB

Coupling: When Tilted Channel is off (default), the Tilt per Subcarrier will not be activated.

Get/Set the tilt amplitude per subcarrier in dB.

Exclusion Bands

Gets or sets the exclusion bands. The bands are separated by "," and surrounded by "[" and "]". For example, [0,799],[1428,2047] means 2 bands, one is from subcarrier 0 to subcarrier 799, the other is from subcarrier 1428 to subcarrier 2047.The number of continuous subcarriers which are not excluded should contain integer minislots.

For FFT Size is 2048, some exclusion bands for typical bandwidths are:

24MHz: [0,799],[1248,2047]

48MHz: [0,553],[1498,2047]

96MHz: [0,73],[1970,2047]

For FFT Size is 4096, some exclusion bands for typical bandwidths are:

24MHz: [0,1573],[2518,4095]

48MHz: [0,1107],[2980,4095]

96MHz: [0,147],[3940,4095]

Number of Active Subcarriers

Gets the number of active subcarriers of DOCSIS3.1 Upstream carrier. Active means not in the exclusion bands.

This is always read-only and determined by Exclusion Bands.

Number of Minislots per Frame

Gets the maximum number of minislots per frame of DOCSIS3.1 Upstream carrier. This is always read-only and determined by exclusion bands and FFT size.

Active Signal Bandwidth

Gets the active signal bandwidth of DOCSIS3.1 Upstream carrier. This parameter is always read-only and determined by Exclusion Bands.

3. Modulation Settings

FFT Size

Choices: 2048 | 4096

Default: 2048

Double-click or use the drop-down menu to select the FFT size for the OFDM signal.

For multi-carrier case, this parameter is read-only and determined by the first carrier.

Subcarrier Spacing

Choices: 50kHz | 25kHz

Default: 50kHz

Gets the subcarrier spacing for the OFDM. This parameter is always read-only and determined by FFT Size.

Number of Subcarriers per Minislot

Choices: 8 | 16

Default: 8

Gets the number of subcarriers per minislot. This parameter is always read-only and determined by FFT Size.

Symbols per Frame (K)

Range: 6 to 36

Default: 16

Gets or sets the number of symbol periods per frame.

Cyclic Prefix

Default: 0.9375 us (96*Tsd)

Double-click or use the drop-down menu to select the cyclic prefix time (points) for the OFDM signal.

For multi-carrier case, this parameter is read-only and determined by the first carrier.

Windowing

Default: 0.625 us (64*Tsd)

Double-click or use the drop-down menu to select the windowing roll-off time (points) for the OFDM signal.

Randomizer Seed

Gets or sets the randomization seed in the format of Hex. This is a string composed of "0" to "9" and "A" to "F".

4. Data Settings

Number of Grants

Gets the number of grants. This parameter is always read-only and determined by the added grants.

Number of Frames

Range: 1 to 20

Default: 1

Gets or sets the number of frames to be generated.

Number of Idle Symbols

Range: 1 to 36

Default: 16

Gets or sets the number of idle symbols without data modulated. These symbols will be added behind the generated frames.