The MW_LOF is an Critical alarm indicating that the radio frame is lost.
The services are interrupted. If the system is configured with protection, protection switching may be triggered
possible cases
1- The other alarms are generated.
2- In the case of TDM radio services, the IF working modes at the local site and the opposite station are different. In the case of services, the channel bandwidth and modulation modes at the local site and the opposite station are different.
3- The operating frequency of the ODU at the local site is inconsistent with the operating frequency of the ODU at the opposite station.
4- The transmit unit of the opposite station is faulty.
5- The receive unit of the local site is faulty.
6- The receive power of the ODU is abnormal.
7- An interference event occurs.
Handling
1- The other alarms are generated.
Check whether any alarms are generated in the equipment of the local site. If yes, take priority to clear them.
The relevant alarms are as follows:
HARD_BAD"
VOLT_LOS"
IF_CABLE_OPEN"
BD_STATUS"
RADIO_RSL_LOW"
CONFIG_NOSUPPORT"
TEMP_ALARM"
2- In the case of TDM radio services, the IF working modes at the local site and the opposite station are different. In the case of services, the channel bandwidth and modulation modes at the local site and the opposite station are different.
In the case of TDM radio services, check whether the working mode of the IF board at the local site is consistent with the working mode of the IF board at the opposite station. For details, see Configuring a Single-Hop Radio Link. If not, reset the working mode of the IF board according to the network planning.
In the case of Hybrid radio services, check whether the channel bandwidth and modulation modes are the same at both ends. If not, change the channel bandwidth and modulation modes according to the network planning. For details, see Configuring a Single-Hop Radio Link.
3- The operating frequency of the ODU at the local site is inconsistent with the operating frequency of the ODU at the opposite station.
Ensure that the type of the ODU at the local site is consistent with the type of the ODU at the opposite station.
Reset the operating frequency of the ODU according to the network planning. For details, see Setting ODU Transmit Frequency Attributes.
Set the transmit frequency of the local site to the same as the receive frequency of the opposite station. Then, set the receive frequency of the local site to the same as the transmit frequency of the opposite station.
4- The transmit unit of the opposite station is faulty.
Check whether any alarms are generated in the equipment of the local site. If yes, take priority to clear them.
The relevant alarms are as follows:
HARD_BAD
BD_STATUS
VOLT_LOS
IF_CABLE_OPEN
RADIO_MUTE
RADIO_TSL_HIGH
RADIO_TSL_LOW
TEMP_ALARM
Locate the fault by looping back the opposite station.
Follow the steps:
Perform an inloop on the IF port at the opposite end. For details, see 8.4.7 Setting Loopback for the IF Board and . Check whether the fault at the opposite end is rectified after the loopback.
The fault at the opposite end is not rectified\tReplace the IF board.
The fault at the opposite end is rectified\tGo to the next step.
Check whether the cable connector is prepared according to the requirement. If any cable connector does not meet the requirement, make a new connector.
Check whether the IF cable is wet, broken, or pressed. Replace the cable that does not meet the requirement.
Then, check whether the fault at the opposite end is rectified.
The fault at the opposite end is not rectified\tReplace the ODU at the opposite end.
The fault at the opposite end is rectified\tEnd the alarm handling.
5- The receive unit of the local site is faulty.
Locate the fault by looping back the opposite station.
Follow the steps:
Perform an inloop on the IF port at the local end. For details, see 8.4.7 Setting Loopback for the IF Board and . Check whether the fault at the local end is rectified after the loopback.
The fault at the opposite end is not rectified\tReplace the IF board.
The fault at the opposite end is rectified\tGo to the next step.
Check whether the cable connector is prepared according to the requirement. If any cable connector does not meet the requirement, make a new connector.
Check whether the IF cable is wet, broken, or pressed. Replace the cable that does not meet the requirement.
Check whether the fault at the local end is rectified.
The fault at the opposite end is not rectified\tReplace the ODU at the local end.
6- The receive power of the ODU is abnormal.
At the local site, check whether the receive power of the ODU is abnormal. For details, see Browse historical performance events. If yes, determine the abnormality and take proper measures.
The RSL is lower than the receiver sensitivity
Follow the steps:
Check the installation of the antenna to ensure that the azimuth of the antenna meets the requirement.
Check the antenna direction. Check whether the received signal is from the main lobe.
If the antenna direction does not meet the requirement, adjust the antenna in a wide range.
Check whether the setting of the polarization direction of the antenna is correct. Adjust the incorrect polarization direction.
Check whether the antenna gain at both the transmit and receive ends meets the specifications. Replace the antennas that do not meet the requirement.
Check whether any mountain or building obstacle exists in the transmit direction.
If yes, contact the network planning department for proper modification of the planning design, hence preventing the block of the mountain or building obstacle.
The RSL is higher than the specified RSL of the network. The offset value is tens of decibels. The duration is from tens of seconds to several hours.
Slow up fading occurs. Follow the steps:
Check for co-channel interference. For details, see 8.1.2 Scanning Interfering Signals.
Use a spectrum analyzer to analyze the interference source.
Contact the spectrum management department to clear the interference spectrum or change plans to minimize the interference.
The RSL is lower than the specified RSL of the network. The offset value is tens of decibels. The duration is from tens of seconds to several hours.
Slow down fading occurs. Generally, the radio link may be faulty in both directions, because slow fading is imposed by the transmission path. Contact the network planning department to make the following changes:
Increase the installation height of the antenna.
Reduce the transmission distance.
Increase the antenna gain.
Increase the transmit power.
If the RSL is lower than or higher than the specified RSL of the network and if the duration is from several milliseconds to tens of seconds.
Fast fading occurs. Contact the network planning department to make the following changes:
Adjust the position of the antenna to block the reflected wave or make the reflection point fall on the ground that has a small reflection coefficient, therefore reducing the multipath fading.
Adjust the RF configuration to make the links in the 1+1 SD configuration.
If the links are configured with the 1+1 SD protection, adjust the height offset between two antennas to make the receive power of one antenna stronger than the receive power of the other antenna.
Increase the fading margin.
7- An interference event occurs.
Follow the steps:
Check for co-channel interference. For details, see 8.1.2 Scanning Interfering Signal
Use a spectrum analyzer to analyze the interference source.
Contact the spectrum management department to clear the interference spectrum or change plans to minimize the interference.
