XPIC Commissioning Tests Individual Link Verification Before operating in XPIC configuration, each of the links (V and H) should be commissioned individually in order to verify its proper operation. 1 Power up only drawer V at both ends and verify its frequency channel and Tx power configuration. 2 Verify that the RSL is no more than +/-4 dB from the expected level. 3 Run BER stability test on the link for at least 15 minutes to ensure error-free operation. 4 Power up only drawer H at both ends and verify its frequency channel and Tx power configuration. 5 Verify that the RSL is no more than +/-4 dB from the expected level. 6 Run BER stability test on the link for at least 15 minutes to ensure error-free operation. XPIC Configuration Verification 1 Using the XPIC cable, connect the two ODUs at each end to the TNC connectors. Make sure the cable is no longer than 3 meters. 2 Configure the drawers to work in XPIC mode. 3 Verify that the RSL at all four ODUs is no more than +/-4 dB from the expected level. 4 Verify that no alarms exist (if a 155 Mbps line is connected). 5 Run BER stability test on each of the 155 Mbps links for at least 1 hour to ensure error-free operation. Note: In a 2+2 configuration, repeat each step above for each of the four coupled ODU combinations. XPIC Recovery Verification In order to verify XPIC operation, simulate the faults described below. 1 Disconnect the IDU-ODU cable for each of the drawers (one at a time), and verify that the other link is operating. 2 Disconnect the XPIC cable and check that the relevant alarms are generated. 3 Power down each of the drawers and verify that the other link is operating. 4 Swap the V and H cables and check that the relevant alarm is generated. 5 Mute and then un-mute one ODU at a time and verify that the other link is operating. Note: In a 2+2 configuration, repeat each step above for each of the four coupled ODUs connected to the two standby IDUs.
This is a simple document to help on the antennas alignment with XPIC, here are the steps for a simple and quick way, as well alerting for the most common problems: -Installation verification Verify if the installed hardware is according with the link frequency In e.g. Sometimes installed waveguides not mach the RAU or antenna frequency. -Antenna Product Name The antenna product name is structured in the following way: ANTa b c d (e.g. ANT0 1.2 10/11 HPX) a 0 – Antenna for separate installation 1 – Integrated antenna for RAU1 2 – Integrated antenna for RAU2 b Antenna size (in meters) c Frequency band (in GHz) d HP – High performance, single polarised STD – Standard performance, single polarised HPX – High performance, dual polarized
-Check the waveguides if during alignment the RX level is different between both polarities it means that one of the waveguides may be damaged. -Setting feeders at 0º. Use a digital level tool; this must be done both at near end and far end. -Verify the LOS (Line Of Sight) E.g. Obstruction: Cranes, new buildings, power lines and vegetations. -NE Setup Parameters Purpose: To verify that the correct parameters are used. Check, by using a PC with LCT software, that all setup parameters are set according to the Site Installation Documentation (SID), which is provided by the design department. -Interference Test. Purpose: To verify that there are no interfering signals, which can degrade the performance. Access the far-end terminal through the MSM program and switch the far-end transmitter off. Note: In a 1+1 system both transmitters must be switched off. Read the received RF input level and record the value in the test record. If the level exceeds -90 dBm, consult the design department. After the test has been performed, activate the transmitters again and restore the communication over the hop. -Alignement Mechanical optimization 1. Make sure the function Automatic Transmitter Power Control (ATPC) is turned off during alignment 2. Adjust the antenna horizontally for maximum alignment value. 3. Tighten the locking screw when maximum value is achieved 4. Adjust the antenna in the vertical plane for maximum alignment value 5. Tighten the locking screws when maximum value is achieved. 6. Repeat steps 2 to 5 until the maximum alignment value is achieved. 7. Measure the alignment level and record the value. 8. Verify if the RX level is according the SID 9. Make sure all screws are tightened when the alignment procedure is finished -Check Cross Polarization Discrimination Optimization (XPD) Minimum XPD within the 1 dB co-polarized contour: 06 – 13 GHz 30 dB 15 – 38 GHz 27 dB 1. Turn on the transmitter on far end, using vertical polarization 2. Measure with a voltmeter at near end on the RAU with horizontal polarization 3. Rotate the feeder until the worst voltage value found. The rotation is performed to minimize the leakage between the two polarizations, that is, to maximize the cross polarization discrimination. 4. Verify the RX Level at near end in horizontal polarization and record the measured value. 5. Verify the RX level at near end in vertical polarization and record the value. 6. A cross polarization discrimination of at least 27 dB (AGC 0.675 V) must be reached. The value is the difference between the signals measured on the two radios. 7. If the reached value is less than 27 dB, perform step 2 to 5 again 8. If the reached value is less than 27 dB, after repeating steps 2 to 5, verify again the hardware installation, then the mechanical optimization and then the Cross Polarization Discrimination Optimization. 9. Tighten the feeder screws when maximum discrimination is found
