Testing your LTE / FTTA Deployment

Mobile network providers are increasingly deploying Fibre To The Antenna (FTTA) technology solutions in order to minimise the deployment time for their RAN expansions.

FTTA replaces the traditional coax cable that ran to the top of the tower with optical fibre, and repositions components such as the Remote Radio Unit (RRU) to the top of the tower. The fibre connecting the RRU is run to a baseband unit that can either be deployed at the bottom of the tower or can be remotely located, allowing a single BBU to connect to multiple towers in a distributed manner.

Only the short distance between the RRU and the antenna are left using coax cable.

This change in the architecture of the tower means that new tools and methods are required to turnup new tower locations.

FTTA Test Location and Method

Connector cleaning

Clean patch cord and bulkhead fibre end faces using the included fibre cleaning tools.

Connector inspection

Inspect and test the connector end faces in accordance with IEC 61300-3-35. Verify that each connector passes the automated analysis.

Optical power measurement

Perform channel insertion loss measurements with that include optical light source (OLS), optical power metre (OPM) and loopbacks.

Visual fault location

Where there is no connection between FTTA components use the VFL to check fibre continuity and that the correct fibre is being tested.

Reference Setup

  1. Clean, and then inspect the optical connector on the light source.
  2. Clean and inspect  end A of patch cord #1.
  3. Connect end A of patch cord #1 to the light source port.
  4. Clean and inspect end A of patch cord #2.
  5. Connect end A of patch cord #2 to the power meter.
  6. Clean and inspect end B of patch cord #1 and end B of patch cord #2.
  7. Connect end B of both patchcords to one side of a duplex LC adapter (if using dual LC connectors).
  8. Clean and inspect the loopback device.
  9. Insert the loopback into the duplex LC adapter.
  10. Select 850 nm on the light source.
  11. Select 850 nm on the power metre (CW mode; output should be -5 dBm).
  12. Switch on the light source and turn on the the ouput signal.
  13. Ensure the reading on the power metre is approximately–7 to -8dB. If the recorded power is lower than expected the connectors should be be cleaned and inspected again. If this does not resovle the problem the patch cords/loopback should be replaced.
  14. Press Ref on the power meter; the reading should be 0.00 dB and should not vary by more than .2 dB as the fiber is moved around.
  15. Disconnect the loopback and LC adaptor from test leads and protect end faces using caps.
  16. Move the loopback and LC duplex adaptor to the top of the junction box or RRU unit. Note: Fibre cleaning and inspection will also be required at the remote end prior to connection of the loopback.

Inspection and Test at Base Junction Box

  1. Connect the required trunk pair into the duplex LC adapter on the patch- cord microscope.
  2. Inspect and test connector #1.
  3. If test fails, clean the connection again and retest.
  4. Save the test result with the naming convention Trunk# – Fibre# – Pair#.
  5. Repeat for connector #2 and slide the duplex adapter across.
  6. Save the test result with the naming convention Trunk# – Fibre# – Pair#.
  7. Plug the trunk pair into the duplex adapter in the junction box.
  8. Proceed to loss measurement.

Loss Measurement

  1. At base junction box, clean and connect end B of test leads to the required trunk pair ports (end A is connected to the light source and the power metre).
  2. At the top of the tower, clean the end of the jumper cable at the RRU end, clean the loopback, and connect the jumper cable to the loopback with the LC duplex adapter
  3. Record the loss value on the optical power metre (the value should be <=3 dB) by pressing the Save button. This will link automatically to the last inspection report saved
  4. Move test fibres to next fibre pair in the base junction box
  5. Move the loopback on the duplex LC adapter to the next jumper pair. 6. Move to Inspection Step 1.

Your Frame FTTA Toolkit

VF10 Visual Fault Locator

AE210 Optical Power Meter

LS310 Light Source

FOD6003 Inspection Screwdriver

Fibre Connector Cleaner

Order your FTTA deplyment toolkit now

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