Network failure Network failure detection and MW detection and MW failure dispositionfailure disposition

Provided by BEIJING DG TELECOMMUNICATIONProvided by BEIJING DG TELECOMMUNICATION

S EQUIPMENT CO.LTDS EQUIPMENT CO.LTD

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Network failure detectionNetwork failure detection

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Failure detectionFailure detection After receiving the report that the site is After receiving the report that the site is

offline, FOPS O&M engineer contact the offline, FOPS O&M engineer contact the DG maintenance engineer and detect the DG maintenance engineer and detect the failure according to the network map.failure according to the network map.

Many sites are offline or single site is Many sites are offline or single site is offline;offline;

If many sites are offline , is there same If many sites are offline , is there same upper site for these sites?upper site for these sites?

The disposition for scattered sites is The disposition for scattered sites is same as single site.same as single site.

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The disposition for the The disposition for the offline sites which have offline sites which have

same upper sitesame upper site The upper sites is PDH MWThe upper sites is PDH MW The upper site is SDH The upper site is SDH

MW(HUBSITE)MW(HUBSITE) The upper site has optical The upper site has optical

transmission equipment.transmission equipment.

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Upper site is PDH Upper site is PDH MWMW

First check the upper site whether First check the upper site whether there is no AC Powerthere is no AC Power by OMC.by OMC.

If there has noIf there has no AC Power , please AC Power , please arrange the generator by ZTE.arrange the generator by ZTE.

FOPS O&M engineer do the loopback FOPS O&M engineer do the loopback test at BSC.test at BSC.

If the BSC is ok, DG would arrange If the BSC is ok, DG would arrange maintenance engineer to check mw maintenance engineer to check mw equipment.equipment.

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Upper site has optical Upper site has optical transmission equipmenttransmission equipment

When several links which belong to onWhen several links which belong to one WATEEN site are offline at the same e WATEEN site are offline at the same time, ZTE time, ZTE maintenancemaintenance engineer sho engineer should do the loopback test at BSC side firuld do the loopback test at BSC side first.st.

If the BSC is ok, ZTE engineer should dIf the BSC is ok, ZTE engineer should do the loopback test on the WATEEN sito the loopback test on the WATEEN site.e.

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Upper site is SDH MWUpper site is SDH MW

When all sites which belong to SDH When all sites which belong to SDH MW are offline, ZTE maintenance MW are offline, ZTE maintenance engineer would check whether there engineer would check whether there is power at the HUBSITE.is power at the HUBSITE.

If power is available there, DG If power is available there, DG engineer would go to check SDH engineer would go to check SDH MW.MW.

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Single site is offlineSingle site is offline

First confirm whether there is down First confirm whether there is down site.site.

If there is but it is online:If there is but it is online:The mw link is ok in this case, first check The mw link is ok in this case, first check

whether there has AC Powerwhether there has AC Power .. If there AC PowerIf there AC Power is available, do the is available, do the

loopback test at BSC side first.loopback test at BSC side first. If BSC is ok, the E1 patching may have If BSC is ok, the E1 patching may have

caused this problem ,the maintenance caused this problem ,the maintenance engineer would go to check.engineer would go to check.

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Single site is offlineSingle site is offlineIf there has no down site of the site:If there has no down site of the site: ZTE maintenance engineer should check ZTE maintenance engineer should check

whether there has AC Power by OMC whether there has AC Power by OMC firstly. Then check the mw equipment by firstly. Then check the mw equipment by mw NMS. If there is problem of the mw mw NMS. If there is problem of the mw equipment, DG maintenance engineer equipment, DG maintenance engineer would go to check the mw equipment.would go to check the mw equipment.

If there is AC PowerIf there is AC Power and the mw is ok too, do and the mw is ok too, do the loopback test at BSC side.the loopback test at BSC side.

If the BSC is ok, the E1 patching might have If the BSC is ok, the E1 patching might have caused this problem, maintenance engineer caused this problem, maintenance engineer should go to check it.should go to check it.

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DG SUPERSTAR DG SUPERSTAR MW TESTINGMW TESTING

Equipment problemEquipment problem

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DG SUPERSTAR MW DG SUPERSTAR MW FAILURE TESTINGFAILURE TESTING

Mw failures are classified by equipment Mw failures are classified by equipment problem and system problem.problem and system problem.

Equipment problem means the problem Equipment problem means the problem of IDU and ODU, these can be detected of IDU and ODU, these can be detected by Indicator light/AIS/LOOPBACK easily.by Indicator light/AIS/LOOPBACK easily.

System problem means the equipment is System problem means the equipment is ok, but the system not, generally ok, but the system not, generally speaking, this kind of problems is speaking, this kind of problems is difficult to detect and solve.difficult to detect and solve.

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MW equipment failureMW equipment failure

Detect the failure by indicator lightDetect the failure by indicator light

1,Power light is not on: the power 1,Power light is not on: the power module of IDU is broken, replace it.module of IDU is broken, replace it.

2,Cable light is not on: IF cable or ODU 2,Cable light is not on: IF cable or ODU problem.problem.

3,ODU light is red: replace ODU.3,ODU light is red: replace ODU.

4,Run light is not blink: restart IDU, if 4,Run light is not blink: restart IDU, if the problem is same as before, then the problem is same as before, then replace IDU.replace IDU.

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MW equipment MW equipment failurefailure

Login to the IDU to solve failureLogin to the IDU to solve failure

Use the cat-5 cable to connect the Use the cat-5 cable to connect the NMS interface of IDU and the network NMS interface of IDU and the network port of laptop, then open the IE ,input port of laptop, then open the IE ,input the local ip address which is showed the local ip address which is showed on the IDU (Detail instruction is in the on the IDU (Detail instruction is in the 5.2-USING WEB of guide instruction)5.2-USING WEB of guide instruction)

Check the technical parameter on the Check the technical parameter on the homepage.homepage.

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Detect equipment failure by Detect equipment failure by laptoplaptop

One: Whether IDU is connected with ODU.One: Whether IDU is connected with ODU. When it is not , the homepage shows :NO DATA FROM ODU RWhen it is not , the homepage shows :NO DATA FROM ODU R

F POWER=OFF , so we can know there is problem of the IDU oF POWER=OFF , so we can know there is problem of the IDU or ODU:r ODU:

11，， Check whether the output voltage at the N interface of IDU is Check whether the output voltage at the N interface of IDU is normal, the normal value is +24V, if it is not, the IDU is brokenormal, the normal value is +24V, if it is not, the IDU is brokenn

22，， If the output voltage of IDU is normal, check the connection If the output voltage of IDU is normal, check the connection wirewire

33，， If the above two items are all ok, use multimeter to test N coIf the above two items are all ok, use multimeter to test N connector of ODU ,Switch to LED, when the direct test is high nnector of ODU ,Switch to LED, when the direct test is high impedance, the value of reverse test is aroundimpedance, the value of reverse test is around 542, 542, the IDU the IDU

is broken otherwise the ODU is broken.is broken otherwise the ODU is broken.

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Detect equipment failure by Detect equipment failure by laptoplaptop

Two: Check the RXL of equipmentTwo: Check the RXL of equipment check RXLEV=? on the homepagecheck RXLEV=? on the homepage the operation range:the operation range: 16E1:-20~-79dBm16E1:-20~-79dBm 8E1 :-20~-81dBm8E1 :-20~-81dBm 4E1 :-20~-83dBm4E1 :-20~-83dBm If the RXL is less than the RXL alarm threshold, If the RXL is less than the RXL alarm threshold,

the equipment can’t work normally, continue the equipment can’t work normally, continue checking the equipment to recover the normal RXL.checking the equipment to recover the normal RXL.

Normally the RXL is larger than-50dBm. If the Normally the RXL is larger than-50dBm. If the actual RXL is less than -50dBm,we should increase actual RXL is less than -50dBm,we should increase the RXL by increasing the TX power or align dish. the RXL by increasing the TX power or align dish. The best RXL range for equipment is -30~-35dBmThe best RXL range for equipment is -30~-35dBm

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Detect equipment failure by Detect equipment failure by laptoplaptop

Three: Check the TX powerThree: Check the TX power Check the TX POWER=? On the homepageCheck the TX POWER=? On the homepage If it shows TX power=OFF, the equipment If it shows TX power=OFF, the equipment

won’t work, we can switch the TX power to won’t work, we can switch the TX power to solve this issue. The method is click the LINK solve this issue. The method is click the LINK CONFIG, then type the username: sstar, CONFIG, then type the username: sstar, password: test, choose the available value at password: test, choose the available value at the drop-down menu of TX power(the drop-down menu of TX power(--10~20dBm), then click OK. Finally click SAVE 10~20dBm), then click OK. Finally click SAVE CONFIG to finish adjusting the TX power of CONFIG to finish adjusting the TX power of ODU.ODU.

After adjusting the TX power, check the RX After adjusting the TX power, check the RX power of far end site. Find the best RX power power of far end site. Find the best RX power value by increase/decrease TX powervalue by increase/decrease TX power

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Detect equipment failure by Detect equipment failure by laptoplaptop

Four: Check whether the TX frequency is matchingFour: Check whether the TX frequency is matching The TX frequency of local site must be equal to the RThe TX frequency of local site must be equal to the R

X frequency of far end site, and the RX frequency of X frequency of far end site, and the RX frequency of the local site must be equal to the TX frequency of fthe local site must be equal to the TX frequency of far end site.ar end site.

Check TX=?RX=? on the homepage, compare this witCheck TX=?RX=? on the homepage, compare this with far end sites, If it does not match, modify the freqh far end sites, If it does not match, modify the frequency. The method is :click LINK CONFIG, type useuency. The method is :click LINK CONFIG, type username: SSTAR, password: TEST, choose available varname: SSTAR, password: TEST, choose available value on the drop-down menu of chan, click SET, finallue on the drop-down menu of chan, click SET, finally click SAVE CONFIG to finish the modification.ly click SAVE CONFIG to finish the modification.

After modify the frequency check it on the homepagAfter modify the frequency check it on the homepage to confirm it’s modified correctly.e to confirm it’s modified correctly.

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Detect equipment failure by Detect equipment failure by laptoplaptop

Five: Check the capacityFive: Check the capacity The equipment capacity must be same The equipment capacity must be same

on both sites.on both sites. Click WEST TRIB CONFIG to check the Click WEST TRIB CONFIG to check the

equipment capacity, if it’s different equipment capacity, if it’s different from remote site, we should modify it. from remote site, we should modify it. The method is: choose the correct The method is: choose the correct capacity on the drop-down menu of capacity on the drop-down menu of capacity(8MB,16MB,34MB),click Ok, capacity(8MB,16MB,34MB),click Ok, then save the configuration.then save the configuration.

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Detect equipment failure by Detect equipment failure by laptoplaptop

Six: detect the failure by loopback functionSix: detect the failure by loopback function If the configuration, power, and frequency are all ok, but the transmission If the configuration, power, and frequency are all ok, but the transmission

is down, By the loopback function we can know it’s local site or far end siis down, By the loopback function we can know it’s local site or far end site problem also we can know it’s IDU or ODU problem. Method is:te problem also we can know it’s IDU or ODU problem. Method is:

Click LINKCONFIG, type the username and password, choose “on”on thClick LINKCONFIG, type the username and password, choose “on”on the drop-down menu of loopback, then back to homepage, check the rxlev. If e drop-down menu of loopback, then back to homepage, check the rxlev. If it’s larger than -65, and the indicator light of IDU,ODU and RA are all it’s larger than -65, and the indicator light of IDU,ODU and RA are all offoff,, it means the local site equipment is ok and the far end site equipment is br it means the local site equipment is ok and the far end site equipment is broken .Unlock the RF loopback after the loopback test.oken .Unlock the RF loopback after the loopback test.

Notice: On the TX- High side, use the lower frequency when do the RF looNotice: On the TX- High side, use the lower frequency when do the RF loopback, at the TX –LOW side, use the higher frequency when do the RF loopback, at the TX –LOW side, use the higher frequency when do the RF loopback test.pback test.

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DG SUPERSTAR DG SUPERSTAR MW FAILURE MW FAILURE

TESTTEST

SYSTEM PROBLEMSYSTEM PROBLEM

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System problemSystem problem

System problem means the mw equipment System problem means the mw equipment of both sites are ok( confirmed by of both sites are ok( confirmed by loopback) but the transmission is down..loopback) but the transmission is down..

System problem may be caused by the System problem may be caused by the change of communication environment change of communication environment because of natural or man-made activity.because of natural or man-made activity.

System problem include: frequency System problem include: frequency interference, deviation of mw dish, block interference, deviation of mw dish, block by construction, multipath interference, by construction, multipath interference, waterish dish/IF cable system and etc.waterish dish/IF cable system and etc.

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Frequency Frequency interferenceinterference

The frequency resource is limited in Pakistan because The frequency resource is limited in Pakistan because many MW are used. So the mw may encounter frequency many MW are used. So the mw may encounter frequency interference.interference.

Reason: The distance between two hops mw which use Reason: The distance between two hops mw which use same or adjacent channel is short and the direction is same or adjacent channel is short and the direction is same.same.

Symptom: The mw equipment is ok and the RX power is Symptom: The mw equipment is ok and the RX power is good on both sites but there is high BER at one site.good on both sites but there is high BER at one site.

Testing: Switch one site’s equipment off, but there is still Testing: Switch one site’s equipment off, but there is still intensive RX power larger than -60dBm for example.intensive RX power larger than -60dBm for example.

Solution: If there is frequency interference at local site, Solution: If there is frequency interference at local site, switch off far end site’s equipment, then adjust the switch off far end site’s equipment, then adjust the frequency of local site’s equipment, take the frequency frequency of local site’s equipment, take the frequency point which get the minimum interference and make point which get the minimum interference and make record.record.

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Deviation of MW dishDeviation of MW dish Reason: The mw dish is not fixed, the mw dish Reason: The mw dish is not fixed, the mw dish

deviate from transmission direction under deviate from transmission direction under inclement weather.inclement weather.

Symptom : The RX power is very low on both Symptom : The RX power is very low on both sits, and the mw equipment is ok, the problem sits, and the mw equipment is ok, the problem occur with the inclement weather, check occur with the inclement weather, check whether the mw dish deviate.whether the mw dish deviate.

Solution :Align the mw dish, get the maximum Solution :Align the mw dish, get the maximum RX power.RX power.

Notice: The deviation of mw dish caused by Notice: The deviation of mw dish caused by natural activity is just in the horizontal natural activity is just in the horizontal direction, it will not happen in the vertical direction, it will not happen in the vertical direction, so just do the alignment in the direction, so just do the alignment in the horizontal direction.horizontal direction.

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Obstruction by Obstruction by constructionconstruction

This case almost happens in the downtownThis case almost happens in the downtown Reason: The transmission is down caused by the higReason: The transmission is down caused by the hig

h construction which block the transmission of Eleh construction which block the transmission of Electromagnetic wave.ctromagnetic wave.

Symptom : The RX power is low on both site, it takeSymptom : The RX power is low on both site, it takes long time from the worse of communication qualits long time from the worse of communication quality to the communication is definitely down, the rx py to the communication is definitely down, the rx power decrease gradually.ower decrease gradually.

Testing : There is block in front of the mw dish.Testing : There is block in front of the mw dish. Solution: Increase the height of dish when it’s posSolution: Increase the height of dish when it’s pos

siblesible,, if the tower is not high enough, we can chang if the tower is not high enough, we can change the upper site, when thee the upper site, when the -- --route can’t be changeroute can’t be changed, we can use the obstruction as relay transmission. d, we can use the obstruction as relay transmission.

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Multipath Multipath interferenceinterference

Multipath interference occurs at the river, lake, sMultipath interference occurs at the river, lake, sea, ea, paddy field, smooth ice surface, smooth paddy field, smooth ice surface, smooth gobi and etc.gobi and etc.

Reason : The phase in different between interferReason : The phase in different between interference signal and normal signal.ence signal and normal signal.

Symptom : Because the interference signal is unsSymptom : Because the interference signal is unstable, the rx power fluctuates between -30dBm~-table, the rx power fluctuates between -30dBm~-60dBm.60dBm.

Solution :SD is the best way to solve this issue, buSolution :SD is the best way to solve this issue, but if it’s not available we can sacrifice the RX pot if it’s not available we can sacrifice the RX power to solve this but the disadvantage is that the fwer to solve this but the disadvantage is that the fade margin is not enough, so it’s not suggested.ade margin is not enough, so it’s not suggested.

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Waterish Dish/IF Waterish Dish/IF cablecable

Reason :Dish/If cable is destroyed by man-made Reason :Dish/If cable is destroyed by man-made activity. Dish/If cable aging. The waterproof is pactivity. Dish/If cable aging. The waterproof is poor, the dish and If cable would get waterish whoor, the dish and If cable would get waterish when it rains, then the communication will be dowen it rains, then the communication will be down.n.

Symptom :When the If cable is waterish, check Symptom :When the If cable is waterish, check the N type connector by multimeter it’s short cthe N type connector by multimeter it’s short circuit. When the feed horn is waterish, there is ircuit. When the feed horn is waterish, there is aeruginous rust at the hole of feed horn The insiaeruginous rust at the hole of feed horn The inside of the feeder horn is damp. de of the feeder horn is damp.

Solution: Replace the feed horn or IF cable.Solution: Replace the feed horn or IF cable.

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Thanks!Thanks!

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