Network failure detection and MW failure disposition

1. Network failure detection and MW failure disposition Provided by BEIJING DG TELECOMMUNICATIONS EQUIPMENT CO.LTD

2. Network failure detection

3. Failure detection • After receiving the report that the site is offline, FOPS O&M engineer contact the DG maintenance engineer and detect the failure according to the network map. • Many sites are offline or single site is offline; • If many sites are offline , is there same upper site for these sites? • The disposition for scattered sites is same as single site.

4. The disposition for the offline sites which have same upper site • The upper sites is PDH MW • The upper site is SDH MW(HUBSITE) • The upper site has optical transmission equipment.

5. Upper site is PDH MW • First check the upper site whether there is no AC Powerby OMC. • If there has noAC Power , please arrange the generator by ZTE. • FOPS O&M engineer do the loopback test at BSC. • If the BSC is ok, DG would arrange maintenance engineer to check mw equipment.

6. Upper site has optical transmission equipment • When several links which belong to one WATEEN site are offline at the same time, ZTE maintenance engineer should do the loopback test at BSC side first. • If the BSC is ok, ZTE engineer should do the loopback test on the WATEEN site.

7. Upper site is SDH MW • When all sites which belong to SDH MW are offline, ZTE maintenance engineer would check whether there is power at the HUBSITE. • If power is available there, DG engineer would go to check SDH MW.

8. Single site is offline • First confirm whether there is down site. • If there is but it is online: The mw link is ok in this case, first check whether there has AC Power. If there AC Poweris available, do the loopback test at BSC side first. If BSC is ok, the E1 patching may have caused this problem ,the maintenance engineer would go to check.

9. Single site is offline If there has no down site of the site: ZTE maintenance engineer should check whether there has AC Power by OMC firstly. Then check the mw equipment by mw NMS. If there is problem of the mw equipment, DG maintenance engineer would go to check the mw equipment. If there is AC Powerand the mw is ok too, do the loopback test at BSC side. If the BSC is ok, the E1 patching might have caused this problem, maintenance engineer should go to check it.

10. DG SUPERSTAR MW TESTING Equipment problem

11. DG SUPERSTAR MW FAILURE TESTING • Mw failures are classified by equipment problem and system problem. • Equipment problem means the problem of IDU and ODU, these can be detected by Indicator light/AIS/LOOPBACK easily. • System problem means the equipment is ok, but the system not, generally speaking, this kind of problems is difficult to detect and solve.

12. MW equipment failure • Detect the failure by indicator light 1,Power light is not on: the power module of IDU is broken, replace it. 2,Cable light is not on: IF cable or ODU problem. 3,ODU light is red: replace ODU. 4,Run light is not blink: restart IDU, if the problem is same as before, then replace IDU.

13. MW equipment failure • Login to the IDU to solve failure Use the cat-5 cable to connect the NMS interface of IDU and the network port of laptop, then open the IE ,input the local ip address which is showed on the IDU (Detail instruction is in the 5.2-USING WEB of guide instruction) Check the technical parameter on the homepage.

14. Detect equipment failure by laptop One: Whether IDU is connected with ODU. When it is not , the homepage shows :NO DATA FROM ODU RF POWER=OFF , so we can know there is problem of the IDU or ODU: 1，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 broken 2，If the output voltage of IDU is normal, check the connection wire 3，If the above two items are all ok, use multimeter to test N connector of ODU ,Switch to LED, when the direct test is high impedance, the value of reverse test is around 542, the IDU is broken otherwise the ODU is broken.

15. Detect equipment failure by laptop Two: Check the RXL of equipment check RXLEV=? on the homepage the operation range: 16E1:-20~-79dBm 8E1 :-20~-81dBm 4E1 :-20~-83dBm If the RXL is less than the RXL alarm threshold, the equipment can’t work normally, continue checking the equipment to recover the normal RXL. Normally the RXL is larger than-50dBm. If the actual RXL is less than -50dBm,we should increase the RXL by increasing the TX power or align dish. The best RXL range for equipment is -30~-35dBm

16. Detect equipment failure by laptop Three: Check the TX power Check the TX POWER=? On the homepage If it shows TX power=OFF, the equipment won’t work, we can switch the TX power to solve this issue. The method is click the LINK CONFIG, then type the username: sstar, password: test, choose the available value at the drop-down menu of TX power(-10~20dBm), then click OK. Finally click SAVE CONFIG to finish adjusting the TX power of ODU. After adjusting the TX power, check the RX power of far end site. Find the best RX power value by increase/decrease TX power

17. Detect equipment failure by laptop • Four: Check whether the TX frequency is matching The TX frequency of local site must be equal to the RX frequency of far end site, and the RX frequency of the local site must be equal to the TX frequency of far end site. Check TX=?RX=? on the homepage, compare this with far end sites, If it does not match, modify the frequency. The method is :click LINK CONFIG, type username: SSTAR, password: TEST, choose available value on the drop-down menu of chan, click SET, finally click SAVE CONFIG to finish the modification. After modify the frequency check it on the homepage to confirm it’s modified correctly.

18. Detect equipment failure by laptop • Five: Check the capacity • The equipment capacity must be same on both sites. Click WEST TRIB CONFIG to check the equipment capacity, if it’s different from remote site, we should modify it. The method is: choose the correct capacity on the drop-down menu of capacity(8MB,16MB,34MB),click Ok, then save the configuration.

19. Detect equipment failure by laptop • Six: detect the failure by loopback function 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 site problem also we can know it’s IDU or ODU problem. Method is: Click LINKCONFIG, type the username and password, choose “on”on the 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 off, it means the local site equipment is ok and the far end site equipment is broken .Unlock the RF loopback after the loopback test. Notice: 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 test.

20. DG SUPERSTAR MW FAILURE TEST SYSTEM PROBLEM

21. System problem • System problem means the mw equipment of both sites are ok( confirmed by loopback) but the transmission is down.. • System problem may be caused by the change of communication environment because of natural or man-made activity. • System problem include: frequency interference, deviation of mw dish, block by construction, multipath interference, waterish dish/IF cable system and etc.

22. Frequency interference • The frequency resource is limited in Pakistan because many MW are used. So the mw may encounter frequency interference. • Reason: The distance between two hops mw which use same or adjacent channel is short and the direction is same. • Symptom: The mw equipment is ok and the RX power is good on both sites but there is high BER at one site. • Testing: Switch one site’s equipment off, but there is still intensive RX power larger than -60dBm for example. • Solution: If there is frequency interference at local site, switch off far end site’s equipment, then adjust the frequency of local site’s equipment, take the frequency point which get the minimum interference and make record.

23. Deviation of MW dish • Reason: The mw dish is not fixed, the mw dish deviate from transmission direction under inclement weather. • Symptom : The RX power is very low on both sits, and the mw equipment is ok, the problem occur with the inclement weather, check whether the mw dish deviate. • Solution :Align the mw dish, get the maximum RX power. • Notice: The deviation of mw dish caused by natural activity is just in the horizontal direction, it will not happen in the vertical direction, so just do the alignment in the horizontal direction.

24. Obstruction by construction • This case almost happens in the downtown • Reason: The transmission is down caused by the high construction which block the transmission of Electromagnetic wave. • Symptom : The RX power is low on both site, it takes long time from the worse of communication quality to the communication is definitely down, the rx power decrease gradually. • Testing : There is block in front of the mw dish. • Solution: Increase the height of dish when it’s possible, if the tower is not high enough, we can change the upper site, when the --route can’t be changed, we can use the obstruction as relay transmission.

25. Multipath interference • Multipath interference occurs at the river, lake, sea, paddy field, smooth ice surface, smooth gobi and etc. • Reason : The phase in different between interference signal and normal signal. • Symptom : Because the interference signal is unstable, the rx power fluctuates between -30dBm~-60dBm. • Solution :SD is the best way to solve this issue, but if it’s not available we can sacrifice the RX power to solve this but the disadvantage is that the fade margin is not enough, so it’s not suggested.

26. Waterish Dish/IF cable • Reason :Dish/If cable is destroyed by man-made activity. Dish/If cable aging. The waterproof is poor, the dish and If cable would get waterish when it rains, then the communication will be down. • Symptom :When the If cable is waterish, check the N type connector by multimeter it’s short circuit. When the feed horn is waterish, there is aeruginous rust at the hole of feed horn The inside of the feeder horn is damp. • Solution: Replace the feed horn or IF cable.

27. Thanks!