Viavi T-BERD 5800 User manual

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Viavi T-BERD 5800
CPRI Testing Guide with ALU BBU
Emulation
Version 4
January 2018
Firmware 26.0.0.6c1973b or Later REQUIRED!
Scope
This document describes Common Public Radio Interface (CPRI) testing procedures. This document
is intended to be a method of procedure (MOP) for configuring CPRI test setups, running tests,
analyzing results, and creating reports with the Viavi T-BERD 5800v2. This document is not intended
to be a user guide. This MOP should be used in conjunction with T-BERD User’s Guides for detailed
explanation of all testing options.
This document describes three test applications for the CPRI Check test: Verifying provisioning and
operation of CPRI Radio Equipment such as a Remote Radio Unit (RRU) unit

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1. Optical Time Domain Reflectometry (OTDR)
An OTDR sends thousands of very short pulses of light at designated wavelengths into the fiber under
test. It detects the amplitude and time delay of both the scattering and the reflection of the light as it
returns to the same interface. Through computations, an OTDR builds a picture of the loss
characteristics of the fiber throughout its path. It then asserts the location and nature of events such as
splices, bends, breaks, connectors and the fiber end. It also provides the aggregate loss of the fiber
from start to end.
An Insertion Loss test can tell you if a fiber run is performing acceptably. If it fails your threshold,
you do not know where the problem or problems are. An OTDR will tell you each and every
contributor to the losses incurred in the fiber system. Thresholds can be set not just for total loss (dB)
but for each contributing element.
Follow this procedure to set up a T-BERD 5800 to run the Optical Time Domain Reflectometer
(OTDR). The picture below is of a TBERD 5800v2 with a Single Mode OTDR module attached. The
post of the OTDR module is covered with a green dust protector indicating that an Angled Physical
Contact (APC) connector is used on the port.
USEFUL INFORMATION: It is important to know the fiber distance from the BBU connection to the
RRU connection. This is typically the length of the hybrid plus any jumpers. These parts are typically
purchased at some standard length. When you run the OTDR test, you want to see the Test Set declare
“End of Fiber” at a distance that correlates to the “as built” information for the system under test. A
declaration of “End of Fiber” before that length indicates a connection is still open or there is a fiber
break.
1.1 Test Setup
Step Action Details
1. Power On Press and hold the ON/OFF button to turn on the T-BERD 5800v2.
2. Select Test Select the Fiber Optics Tab at the top of the screen

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From the Home Screen , select FTTA OTDR (turns
Yellow)
Select the test tab and then the Setup button , then Load
Config in the lower right corner.
Select FTTA_RRU_ConstrLoop.SM-OTDR and Load as FTTA
Config
3. Clean & Inspect (IBYC) Ensure all test jumpers, the hybrid cable and the OTDR port are
clean using a Fiber Inspection probe and cleaning supplies. The
technician at the tower top should do the same with all connections
including the loopback cable.
4. Ensure continuity The VFL Continuity test should have been completed earlier and the 10-
meter loopback fiber left in place at the tower top.
5. Connect Connect the 10 meter SC-APC to LC-PC launch cable from the TB5800
OTDR port to the fiber pair under test using a duplex LC coupler. Also
connect a 10-meter “receive cable” to the other port on the duplex
coupler. This receive or run out cable will give the OTDR visibility to
the last connection that will part of the system. Optionally, place a non-
reflective terminator at the end of the receive cable. If you do not have
such, just make sure that the end of the fiber will be pointed safely away
so that there is no chance that the laser light could reach anyone’s eyes
either directly or by reflecting off a surface.

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6. Run the Test Touch the Start/Stop green button
The OTDR will take about 45 seconds to run a test at 1310 nm and
another at 1550 nm.
7. Interpretation Much like a sweep test on coaxial cable, the OTDR is looking for
reflective events along the path. It also detects Raleigh scattering along
the entire fiber which allows it to detect non-reflective events as well. It
presents the results in a graph and in a graphical form. Each connector
as well as the end of the fiber will be detected. Bends or kinks in the
fiber will show up as well. A broken or cut will be declared as “End of
Fiber”. Any events that exceed the thresholds should be investigated.
An “End of Fiber” that is clearly short of the “as built” records for this
site is actually a broken fiber that needs to be swapped or replaced.
Below is an example of a traditional Trace View. Each event is a peak
on the graph. Events that surpass a threshold will have RED values in
the table below.
The schematic on
the left shows the
path up and down
the tower
independently, but
the up/down paths
are really the 2
fibers in a fiber
pair with the
connectors aligned
side by side.

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The screen shot below is the same test result, but presented in a graphical
form instead of the traditional “trace” view.
Values in black are unjudged results
Values in Green have been assessed against a threshold and they Pass
Values in Red (none shown) have been assessed against a threshold and
they failed. Investigate any values in red. If it is a connector, re-inspect
and clean if necessary and re-run the test.
Note the symmetry in the Trace View. There is 10 meters of launch and
receive cable at the 2 ends. The Hybrid cable was 25 Meters long. The
jumper from the end of the Hybrid to the RRU was 10 meters. The
loopback cable that loops the end of the RRU jumper is also 10 meters.
Every successful test should look similar to this one. The main
differences might be that the Hybrid and/or RRU jumper is different
from the previous.

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2. Verifying provisioning of an RRU with RF over CPRI Spectrum
Analysis
Follow this procedure to set up a T-BERD and test a CPRI link and RRU, and perform RF over CPRI
Spectrum Analysis for PIM detection and Diversity Imbalance. The test may be run on dark fiber or
through Layer 1 network elements such as transponders and multiplexors. The CPRI Radio Equipment
should be installed at the far end on the link before testing.
Note: This is a dual port application. Port 1 is used by default
Step Action Details
1. Power On Press the ON/OFF button to turn on the T-BERD.
2. Insert SFP Insert an SFP or SFP+ that supports the Wavelength, CPRI rate and
range of the line under test into the T-BERD 5800v2’s Port 1 SFP+ slot.
Note: All SFPs do not support CPRI. Use a Viavi approved CPRI
SFP (see Appendix A) or one approved by your CPRI network
equipment manufacturer.
3. Clean & Inspect Ensure that fiber and connectors are clean using a Fiber Inspection
probe.
4. Connect Connect the SFP or SFP+ to the CPRI port under test using
yellow Single Mode Fiber jumper cables (LC-LC).
You may need to attenuate the signals if you are using a
long range SFP/SFP+.

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5. Test Menu Press the button to access the BBU Test
6. Launch Test Select the CPRI Check ALU BBU Emulation test for the proper rate
(usually 4915.2M)
7. Manual Launch If the above tests are not loaded on the 5800 follow the next steps to
launch the CPRI Check for ALU BBU Emulation.
From the menu, select CPRI>>RATE>>CPRI
Check>>P1 Terminate
8. NOTE: The test will launch on PORT 1 UNLESS there is already a test running
Verify the port in the upper right-hand corner of the screen
If needed move the SFP to port 2 as shown on the previous page

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4. Creating a New RRH Configuration
Step Action Details
1. Select Tests Press the button to Start a new Configuration
Select ALU for the “Far-end Device” (default) and check to test needed
for BBU Emulation
Press the button to advance to the Link page
2. Link values Set the test duration and SFP power if desired
Press the button to advance to the RRH page
3. RRH Settings Click the RRH Bandwidth drop down box and
select the Bandwidth needed

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4. Antenna Test Select the Transmit Antenna to test
5. Waveform Set the Waveform to LTE-FDD TM3.1 (NOTE TM3.1 is required for
FULL OCNS channels to test VSWR and PIM)
6. Return Press the button to proceed to the Save Profile screen
7. Save Profile To save the configuration in the Save Profiles screen, enter a Filename,
and tap , tap , and tap twice.
8. Continue After saving the profile Press the press the arrow to
advance to the test screen
GOTO Section 2 BBU Emulation
Loading a saved Configuration
1. Run Wizard Load a save configuration by pressing the button under the “Load
Configuration from a Profile” area
NOTE: If a configuration for the RRH does NOT exist, proceed Section
4 Creating a New RRH Configuration
Select the configuration and press the button
Press the button to accept the configuration
Press the button to advance to the next screen
GOTO Section 2 BBU Emulation (Next page)

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2. BBU Emulation
Running the Test
Step Action Details
1. Launch Press the button to start the test
2. SFP Verification In the Local SFP Verification screen, verify that the SFP meets the
requirements of the line under test.
If the SFP was purchased from or approved by Viavi, and supports the
selected CPRI line rate, the following screen will be displayed:
Tap to proceed to step 5.
If the SFP was sourced from your CPRI Network Equipment
Manufactured and has not been tested and approved by Viavi, the
following screen will be displayed:
Check that the SFP Wavelength, SFP Vendor, and SFP Part Number are
approved for this CPRI line rate. Tap to proceed.

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3. Run Tests Tap . The T-BERD will run all configured tests.
The first 5 tests (SFP Check, Interface, Start-up Sequence, RTD) will run
simultaneously for the time specified in the setup screen (usually 30
seconds). Once completed, the RRH Identification test will run.
4.View Details Press the button for RRH Identification to view the details
about the connected RRH
5. Return Press the button to return to the test screen
6. RF Tests RET, VSWR, Diversity Imbalance, and PIM testing require specific
information for the RRU under test.

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7. RET Press the button to enter the RET Test
8. RET Info Select the ALD (RET Controller) from the list and check the Alarm state
9. Return Press the button to return to the test screen
10. Continue Pres the button to continue to the next test.
11. VSWR Press the button to enter the VSWR Test
12. RRH Configuration The VSWR test requires the RRH to be configured with specific data to
transmit at full power. The data entered will be the same for Band 13
(700MHz) but will vary for AWS and PCS RRHs. The data below is
for Band 13(700MHz) RRHs
13. Configure Select the link and enter the following information:
Bandwidth
Bandwidth of LTE signal
10 MHz
Tx Frequency
Downlink Frequency
751MHz
Rx Frequency
Uplink Frequency
782MHz

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14. Enable Press the button to Set the RRH. Once completed the Carrier
State will show ENABLE
a. NOTE –If the data was entered incorrectly the Tx and Rx
frequencies will how “0” and are invalid and the Carrier State
will be DISABLED
15. Return Press the button to return to the VSWR screen
16. Run VSWR Press the button to run the VSWR test
17. Return Press the button to return to the test screen
18. Continue Press the button to continue to the next test.

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19. Diversity Press the button to enter the Diversity Imbalance Test
The Diversity Imbalabnce test requires the RRH to be configured with
specific data to transmit at full power. Please refer to step 13 if the
VSWR test was not run
20. Diversity Press the button to RUN the Diversity Test
21. Spectrum Optional - Press the button to view the Diversity Screen
22. Return Press the button to return to the Diversity Imbalance test screen
23. Continue Press the button to continue to the next test.
24. PIM Press the button to enter the PIM Test
The PIM test requires the RRH to be configured with specific data to
transmit at full power. Please refer to step 13 if the VSWR test was not
run

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25. PIM Press the button to RUN the PIM Test
26. Spectrum Optional - Press the button to view the PIM trace
27. Return Press the button to return to the PIM test screen
28. Return Press the button again to return to the test screen
29. Continue Pres the button to Complete the tests.
At the conclusion of the test, Pass/Fail status for each test will be
indicated by green checkmark, , or red x, . Test for which no
pass/fail threshold was specified will have a blue checkmark, .
Detailed results for each test can be viewed by tapping .
30. Results Press the button to create a report or to Exit the CPRI
Check

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3. Creating a Report
Step Action Details
1. Report Press the button to Create a report
2. Information Enter the Job information
31. Format Press the button to proceed to the next screen
32. Save Name the File and press the button to Create a report
33. Repeat Press the button to proceed to the Test section. All test
can be repeated on other RRHs without the need for Setup.
END OF TESTING