transmission basics

Ericsson Confidential EIL NOC Presentation DTG-TX 2007-07-101

G TransmissionOverview (HMS)

Presented By: Prateek Gaur


Network Layout

RNC


Harris TX Radio.

• TIME2K


Harris TX Radio.– cont.

• TIME2K - cont



Consequences: The link can be cut off in 1+0 configuration but channels can switch for 1+1 links

Probable cause & Symptoms Corrective Actions

RFU/PRU dialogue fault

1. There can be problem with connection cable (i.e. IF cable) between RFU and PRU or functions managing PRU/RFU exchanges

Symptoms: Time 2K may show

unreachable module. RBS may be unpingable

1. Change IF cable or check connectors on both RFU/PRU

2. Perform local loop backs on PRU and/or RFU to determine faulty hardware

This alarm indicates aThis alarm indicates a failure of the communications between the RFU and PRUfailure of the communications between the RFU and PRU most likely caused by most likely caused by damage or failure of the IF cable/connectors or possibly also due to a RFU or PRU fault. Consequently, it will damage or failure of the IF cable/connectors or possibly also due to a RFU or PRU fault. Consequently, it will often result in errors or outages on the link, and can be intermittent. It indicates a problem at the end of the link often result in errors or outages on the link, and can be intermittent. It indicates a problem at the end of the link with the alarm - a fault at one site cannot cause a RFU/PRU Dialog alarm at the other end of the link.with the alarm - a fault at one site cannot cause a RFU/PRU Dialog alarm at the other end of the link.


Consequences: Receive levels may degrade at far and/or near ends

Probable cause & Symptoms Corrective Actions

Received level fault

This could be caused by the threshold settings, poor propagation/weather conditions causing attenuation, a fault on the remote transmitter, Line of sight (LOS) issues or incorrect antenna alignment- remote transmitter can be defective either at alarming end.

Symptoms T2K will show bad receive levels at near or far ends.

1. Check all alarms active on the remote station to locate the origin of the problem. Ask Bytecan to attend that site 1st which is alarming. Bytecan can check azimuthal or vertical

alignment,repan antennas if required 2. Wait for weather to clear or determine for any obstacles in the

transmission path. 3. Check if local receiver (RFU/PRU) is defective if no fault found at other

end of the link

This alarm indicates that theThis alarm indicates that the RF level being received at the RFU and reported to the PRU is lower than a RF level being received at the RFU and reported to the PRU is lower than a certain levelcertain level.. Can be a false alarm, caused by the RFU misreading the level, or the PRU misreporting the Can be a false alarm, caused by the RFU misreading the level, or the PRU misreporting the level. If there are no errors on the link coinciding with the low received level, it is most likely a false alarm. level. If there are no errors on the link coinciding with the low received level, it is most likely a false alarm. If it is a real alarm, can be caused by a If it is a real alarm, can be caused by a faulty RFUfaulty RFU at either end, at either end, poor antenna alignmentpoor antenna alignment, an , an obstruction obstruction in the in the line-of-sight between the two sites, or attenuation of the signal due to line-of-sight between the two sites, or attenuation of the signal due to heavy rainheavy rain. Once again, comparing . Once again, comparing values in each channel in a 1+1 system can be useful in isolating the fault.values in each channel in a 1+1 system can be useful in isolating the fault.



1+1 Protected terminal



HARRIS MICROWAVE CONCEPTUAL DIAGRAMS and BASIC INFORMATION

1+0 CONFIGURATION


Unprotected link


3GIS Transmission Network

• Microwave Network

1. Harris MW : Q’ty 1682 Links (3364 NE’s)

2. Siemens MW : Q’ty 496 Links (993 NE’s)

3. Siemens SMA-1K’s : 51 SDH Mux

4. 3rd Party Leased Line : around 500 E1’s

• ATM Switches

• AXD301 : Q’ty 5

• AXD305 : Q’ty 52

• RXI820 : Q’ty 32

.


Operation requirement

• System Operation Skill

1. AMS – AXD301/AXD305 management

2. TIME2K Operation – Client and Server

3. Netviewer – Siemens radio management

4. TNMSc – Siemens Mux management.

5. EMAS/ Moshell – Cello Platform management.


Network Configuration Information

• Track3G– Port information, Lease Line references, DDF records, radio equipment

parameters, commissioning reports, etc

• RBS Database– Site specific records, Path connectivity, etc.

• ATM Database– AXD/RXI port allocation, VP configuration, etc

• Connectivity Plan– Provide an overall connectivity (microwave/lease line) from hub to RBS site.


Troubleshooting Tools• Time2k Client

– Harris MDL 2000 radio equipment.

• Netviewer– Siemens SRAL, SRT1C, SRA1 radio equipment

• TNMS– Siemens SMA1k

• MOShell– RXI820, RNC, RBS

• EMAS– RXI820

• AMS– AXD305 & AXD301


Common Transmission AlarmsLOS – Loss of Signal: No incoming signal detected on Rx port. E.g. disconnection of cables, faulty Rx port, fault Tx port on the connected equipment, cable fault.

AIS – Alarm Indication Signal: Indicating connectivity exist with directly connected equipment, fault is upstream in the Rx section of the transmission path.

RDI / FERF – Remote Defect Indicator / Far End Remote Failure: Indicating Tx section of the overall transmission path is faulty.

LOF – Loss of Frame: Signal on the Rx port is detected but can’t retrieve frame alignment. E.g. loose jumper/cable, faulty DDF, faulty port.


Bit Errors• ES – Error Second: It is a one-second period in which one or more bits are in error or during

which Loss of Signal (LOS) or Alarm Indication Signal (AIS) is detected.

• SES – Severely Errored Second: It is a one-second period which has a bit error ratio ≥ 1x10–3 or during which Loss of Signal (LOS) or Alarm Indication Signal (AIS) is detected.

• Far End Block Errors (FEBE): An indication returned to a transmitting equipment that an errored block has been detected at the receiving equipment.


Loopback Testing• Loopback testing is use to identify the location of fault in the network. It

involves looping the Tx signal and send it back to the Rx end. Loopback can be software or hardware.

• If alarms and errors clears after loopback, the fault is external to the location of the loopback path.


Performing Harris Loopback1) Click on PRU or SWU and select Configuration/Activation of RC2) Select Link Loop or Line Loop on the respective channel. (Link loop is looping towards radio and Line loopback is towards tributary (jumper side).


Switching Harris Radio Channel1) Click SWU (Near End Only) and select Configure/activate RC


Switching Harris Radio Channel

2) Select Rec. Chan. X locked for switching receiving path onto channel X.

Select Em. Chan. X locked for switching transmit path onto channel X


Checking Harris RFU Rx Power• For determining possible Line of Sight issues, faulty RFU, PRU.• General rule: Rx power should be similar to commissioning values in Tx

commission report, both near end and far end should be in similar range. Typical values are -25dBm to -55dBm.

• Click on RFU and select RM..


Harris Radio Link PerformanceClick this icon to checkRadio performance


Checking Errors in AXD Port1) Select Switch Fabric -> Link and select the AXD port.


Checking Errors in AXD Port2) Click Show link statistics


Checking Errors in AXD Port3) Press Reload to see whether errors are incrementing


Common MOShell Commands• 1) List Managed Object

– lt e1|ima|atmcross

• 2) Display the loaded Managed Object– lst e1

• 3) Display current alarms– ala

• 4) Load object status e.g. E1 status (proxy no needs to be retrieved from using lst command)- lget “proxy no”

• E.g. lget 12694 where 12694 is the proxy no. retrieved from lst command.

• 5) Check errors/performance counters on an Object– pget “proxy no”


Common Type of Fault• ODU or RFU fault – Usually other end receive low (-90dBm) or rapid

variation of Rx power at the other end.• RTM or PRU fault – Usually causes bit errors or lost visibility of equipment

in Monitoring system but Rx power at the other end is still constant and active.

• PRU/RFU Dialogue Fault – IF cable or connection between PRU and RFU is faulty, could also be PRU or RFU itself.

• Line of Sight issue – Both side radio have similar power level and Rx variation is similar in time. Usually have errors present.

• Trib fault – LOS at tributary side of Harris Radio, usually jumper fault or E1 cable is not connected properly.


NET VIEWER• It is used for monitoring and testing of

Siemens microwave radio transmission.

• It shows real time links in the network along with alarms that persists on the microwave transmission.

• It also give information regarding hardware details of the equipment.


SIEMENSLINK



SIEMENS MW HUBS


ALARM WINDOW


MAJORALARM


HARDWARE DETAILS FOR MW LINK

HARDWARE DETAILS


Thank you!!Thank you!!

Any Questions??Any Questions??

Me @ [email protected]( egaupra)

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