Keysight DOCSIS 3.1 Operation manual

Keysight DOCSIS 3.1
Configuration Wizard
Installation
& User’s Guide
Version 1.4

Notice.
© Copyright 2014-2015 Keysight Technologies, Inc.
The information contained in this document is subject to change without notice.
Keysight Technologies makes no warranty of any kind with regard to this material, including but
not limited to, the implied warranties of merchantability and fitness for a particular purpose.
Keysight Technologies shall not be liable for errors contained herein or for incidental or
consequential damages in connection with the furnishing, performance, or use of this material.
Manual Part Number
89600-90258
Edition
Edition 3, October 2015
Printed in USA
Published by:
Keysight Technologies, Inc.
1400 Fountaingrove Parkway
Santa Rosa, CA 95403

Installation & User’s Guide 89600-90258 3
DOCSIS 3.1 Configuration Wizard Installation & User’s Guide
Introduction
89600 VSA now supports DOCSIS 3.1 DS (Down Stream) & US (Up Stream) modulation
analysis with 89601B/BN-BHF Custom OFDM option. Because of complexity of OFDM signals
defined in DOCSIS 3.1 standard, this wizard tool helps to configure the OFDM signals for your
test with 89600 VSA software.
Prerequisites:
— 89600 VSA version 20.0 or later installed on your PC or PC-based instruments
— Valid licenses of 89601B/BN-200 (Basic VSA), and BHF (Custom OFDM)
How to get the DOCSIS wizard:
1. Uninstall any earlier versions (v1.3 or earlier) of the DOCSIS 3.1 configuration wizard from
your PC.
2. Go to the following URL: www.keysight.com/find/89601B
3. Select Technical Support.
4. Select the “Driver, Firmware, & Software” tab.
5. Click 89600 VSA Software DOCSIS 3.1 Configuration Wizard.
6. Click the Download button.
7. Save the zip file to your PC in default download folder or C:\Temp folder.
8. Click Save.
9. Unzip the file “Setup-DOCSIS31-Wizard_1.4.6.msi” and run the installer to use with 89600
VSA software.
10.Follow the step-by-step installation by selecting the installation folder. The program and
start icon will be created at C:\Program Files (x86)\Keysight
Technologies\DOCSIS31_Configuration_Wizard by default.

4Installation & User’s Guide 89600-90258
Figure 1 DOCSIS 3.1 Wizard Installer Menu
a. Select the Installation Folder.
If you want to change the installation folder, enter it below or click “Browse” button.
You can also specify the user of the DOCSIS 3.1 wizard as just yourself, or everyone who
accesses the PC or PC-based instruments.
Figure 2 Select Installation Folder

Installation & User’s Guide 89600-90258 5
b. Click “Next” to start the installation. After completion, a window should pop-up and
display “Installation Complete”.
Figure 3 Confirm Installation

6Installation & User’s Guide 89600-90258
How to start the DOCSIS wizard:
I. Double click the DOCSIS31ConfigWizard.exe to launch the configuration wizard.
You can also create a short-cut on your desktop with this wizard for easy access to
Docsis31ConfigWizard.exe.
II. Follow the steps below to navigate the DOCSIS wizard.
Figure 4 DOCSIS 3.1 Configuration Wizard (DS, Downstream)
How to create the DOCSIS Downstream setup files for 89600 VSA Custom
OFDM (Option BHF):
Step 1 Basic parameters
1. Select FFT mode (4096 or 8192).
2. Select guard interval (cyclic prefix) using the pull-down menu.
— 1/16 (256 * Tsd) [default]
— 3/64 (192 * Tsd)
— 1/8 (512 * Tsd)
— 3/16 (768 * Tsd)
— 1/4 (1024 * Tsd)
3. Select, or type in, a number for active subcarriers. The Up/down arrows can also be used to
select active subcarriers. Table 1 below shows typical entries for a given nominal channel
bandwidth. The actual bandwidth shown on the wizard menu means only the bandwidth of
the used (assigned) subcarriers. So it will be a few MHz less than the nominal channel
bandwidth as listed in the table 1 below. The channel bandwidth allows for some band-gap

Installation & User’s Guide 89600-90258 7
between channels.
Figure 5 Active subcarrier and guard bands
The active subcarriers are allocated to the center of the band, centered on the DC
subcarrier which is the FFT size divided by 2. The total number of subcarriers is equal to the
FFT size. Typically there are some unused subcarriers at the very left (lower frequency) and
right (upper frequency) called guard carriers. They may be called as left-guard or lower
guard, and right-guard or upper guard carriers (see in Figure 4).
The number of guard carriers is calculated using the following equation:
Nfft = NumberOfLeftGuard + NumberOfActive + NumberOfRightGuard
4. Select data modulation. This is the modulation applied to all of the data subcarriers in the
DOCSIS 3.1 downstream signal.
— BPSK, QPSK, 8PSK
— 16QAM [default], 32QAM, 64QAM, 128QAM, 256QAM, 512QAM, 1024QAM, 2048QAM,
4096QAM, 8192QAM, 16384QAM (8192QAM & 16384QAM are only available after VSA
version 18.5)
5. Select window size –
—0
— 1/128 (64 * Tsd)
— 1/64 (128 * Tsd)
— 3/128 (192 * Tsd)
— 1/32 (256 * Tsd)
6. Select a name for the setup file to be created – do this by double clicking on the text box to
the right of the label “Name of VSA setup file…” on the left side of wizard menu. File-save
dialog box will open to allow naming the output file name. The file name will have “*.setx”
extension to be recognized as 89600 VSA setup file.
Table 1 Recommended active subcarriers setting for channel bandwidth
Channel Bandwid th (MHz) FFT Mode = 4096 FFT Mode = 8192
22.5 451 901
47.5 951 1901
95 1901 3801
190 3801 7601

8Installation & User’s Guide 89600-90258
7. Select a number of the PLC Start Index. The PLC (PHY Link Channel) is a 400 kHz region
with 8 (FFT = 2048) or 16 (FFT = 4096) subcarriers. Typically the PLC is in the center of the
band, and the number to put in this box is exactly 1/2 of the FFT size. For FFT mode 4096,
the default is 2048. For FFT mode 8192, the default is 4096. (You can select a different
number here, but make sure that PLC is within the bandwidth of the active subcarriers.
There is a concept of a “PLC region” which is 6 MHz with PLC in the center. You should not
select a center position that is closer than 3 MHz from the edge of the band for active
subcarriers. You should make sure that no exclusion band subcarriers or manually entered
continuous pilot carriers are in the PLC.
8. Lower Guard Carriers is adjustable to be lower guard + upper guard + active subcarriers to
be equal to FFT size. (If you adjust lower guard carries so high, upper guards goes to 0.)
When you double-click the Lower Guard Carrier numeric box, it can center the carrier.
9. Now you can move to the center column to set exclusion bands.
Step 2 Exclusion bands (EB) setup
Exclusion bands are bands of sequential subcarriers that are not to be used by the DOCSIS 3.1
signal. This may be due to interference reasons, or because some parts of cable spectrum are
in use by some legacy service, such as a 6 MHz QAM or analog channel.
1. There is a text box to enter exclusion band information. In this text box, enter one exclusion
band per line. On each line, you should put two numbers separated by a comma. Example
“1024,1”
— The first number is the index of the first subcarrier of the exclusion band.
— The second number after a comma is the width or length of the exclusion band (how
many subcarriers)
The EB expressed as a whole number of subcarriers. The width could be as low as one
subcarrier.
2. The copy and paste operation works with this text box for EB. You can use the mouse to
select any text and copy it to some other window, or to copy from some other window into
this text box.
Key things to remember with exclusion bands (EB)
— Make sure that any excluded subcarriers are within the band of active subcarriers –
exclusion bands may not extend into the upper or lower guard regions.
— Subcarrier indexes start with subcarrier 0 as the first index in the left/lower guard region.
The last subcarrier of the right/upper guard region is index Nfft-1 (4095 or 8191).
— You should not have any exclusion band subcarriers within the 1 MHz of the PLC.
— There are some specific rules about exclusion bands in the DOCSIS specification.
The subcarrier spacing is 50 kHz for 4096 FFT and 25 kHz for 8192 FFT. This
equates to 20 or 40 subcarriers per MHz of bandwidth. Typically an EB is a 6 MHz
channel on the cable system, so for these cases an EB would normally be 120 or
240 subcarriers, with potentially a few additional ones for a band-gap as
determined by the cable plant frequency plan.

Installation & User’s Guide 89600-90258 9
— Whenever you make changes to the exclusion band information, you may want to check or
regenerate the continuous pilot positions to make sure that no continuous pilots are located
in an exclusion band (refer DOCSIS 3.1 specifications section 7.2.5 Channel Band Rules, this
was changed from previously named as 7.2.5 Exclusion Band Rules.)
Step 3 Continuous pilots
This is defined in section 7.5.15.2 of the DOCSIS 3.1 Physical Layer Specification.
1. Automatic generation – to automatically generate continuous pilot locations, select an “M”
value using the numeric control box (values from 48 to 120 are available), then press the
[Generate CP] button. Pilot positions are computed based on the parameters entered in step
1 and 2 and populated in the box of “Continuous Pilot Position(s)” on the dialog. If you want
to change these, you can just click this box and edit them. The allowed values are
determined by the FFT size (0 to 4095 for 4096 FFT, 0 to 8191 for 8192 FFT). They are
further limited by the guard bands. Do not place continuous pilots outside of the region of
active subcarriers. After you generate the continuous pilot positions and go back to step 1
or step 2 for making any changes, you may need to press [Generate CP] button again. Any
changes like FFT size, PLC start position, or exclusion bands in step 1 and/or step 2 may
affect calculations of continuous pilot positions. So you should always either check over the
continuous pilot positions, or re-generate them using the [Generate CP] button.
2. Manual entry – you can manually enter the subcarrier indexes of continuous pilots by typing
them one number per line in the provided box.
3. This text box of Continuous Pilot Position(s) also works copy and paste. You can use the
mouse to select the text and copy it to some other window, or to copy text from some other
window to paste into the box.
Advanced Mode
When you check this box, you will find a new entry field named as Symbol Modulation Pattern.
You can specifically describe the modulation types changing symbol by symbol as
100@64QAM,200@256QAM,... as you like. In this example, the first 100 symbols are 64QAM
modulation, and next 200 symbols are 256QAM, and next symbols could be different
modulation types. If your signal just contains single modulation type in data subscarries, this
setup under Advanced Mode is not required.
Step 4 Generate setup file
1. Press the [Generate setup] button on the lower right to generate the setup file. The wizard
will create a “*.setx” file to your selected folder to use with 89600 VSA with Custom OFDM
(option BHF). To load the setup file from VSA later, use the file menu as File > Recall Setup
and select the named file for DOCSIS 3.1 configuration.
Subcarrier indexes start with subcarrier 0 as the first index in the left/lower guard
region. The last subcarrier of the right/upper guard region is index Nfft-1 (4095 or
8191).

10 Installation & User’s Guide 89600-90258
Key things to know about how to use the OFDM setup file on 89600 VSA software:
The setup file is generated assuming you will be using a recording signal file with a center
frequency at 1 GHz by default on 89600 VSA software. To measure the live signal not from a
recording, use the Input menu and select Data From > Hardware instead of Recording. You
will then need to set the center frequency, bandwidth, and amplitude as appropriate for
tour signal and hardware platform connected from 89600 VSA software.
Once you have setup these measurement conditions, again use the file menu on 89600 VSA
as File > Save Setup to replace the generated setup file by the DOCSIS 3.1 wizard. Now you
can save all other settings with center frequency, bandwidth, and amplitude to actual input
signals for you to easily set up tests next time by recalling the setup file.
2. When generation is completed with no error, a “Generation Done!” message in green will
appear on lower left of the wizard.
Figure 6 DOCSIS 3.1 Configuration Wizard (setup file generation succeeded)
DOCSIS Wizard v1.3, or later, adds the menu tool bar to allow the DOCSIS 3.1
wizard setup file (*.ini) so you can easily open, save, or save as. You can load
(open), or save setting files you created with the DOCSIS wizard.