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Rx levels change all of a sudden

Viewing 15 posts - 1 through 15 (of 21 total)
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  • #42806 Reply
    Aadil Shafi
    Guest

    Hi All,

    I am a new entrant to this forum and hope to get all the support from guys out here. Well, i am facing a typical problem out here. We are here having Nokia Ultrasite BTS’s. Prior we were having Ericsson 2206 bts’s. The problem is that at a particular site, the Rx level changes all of a sudden from about -70dbm to about -100 dbm. This happens only for a particular sector, and not for the site as a whole. After a few minutes the level come to normal again. A timely response will be appreciated.

    #42807 Reply
    alexander
    Guest

    Hi, Aadil !
    Which way you measure RX level? By netmonitor on your mobile? Or by special equipment? Ask your BSC guys to check from BSC, what is uplink/downlink level and balance between them !!! by E01_BXSX application… may be your “measurement equipment” are not perfect, always check uplink/downlink level and balance from BSC !!!
    Alex
    http://www.dx200.biz

    #42808 Reply
    Boko
    Guest

    Hi,

    Do measure in Idle mode or in Dedicated. If in dedicated if you are using DTX you should go for the RxLevSub values becaus RxLevFull values are not correct (show a lot lower levels). Also for dedicated check power control settings.

    Regards,
    Boko

    #42809 Reply
    Aadil Shafi
    Guest

    Hi Alex and Boko,

    I have measuring the level using the Sagem OT mobile which is specifically used for this purpose. I have checked in idle mode as well as in dedicated mode. The same problem exists in both scenes.In idle mode, the level varies from -70 dbm to -90dbm all of a sudden and hence makes things worse.

    Additionally, can anyone help me on the following two alarms in Nokia BSC’s :
    1. 7743 MEAN HOLDING TIME BELOW DEFINED THRESHOLD
    00 00 00 00 01 01 00 00 05 02 4d
    and
    2. 7746 CH CONGESTION IN BTS ABOVE DEFINED THRESHOLD
    02 1127 9225d 30d 100d 19d

    #42810 Reply
    alexander
    Guest

    Aadil, give me your email, I’ll explain you the meaning of those alarms, or write me email to: alex at dx200.biz
    Alex
    http://www.dx200.biz

    #42811 Reply
    alexander
    Guest

    aadil, check the RX level from BSC!!!!! Nokia BSC has correct measurement results, it’s much more correct equipment than your Sagem!!! Ask your BSC gyus to check RX level. It’s the only 100% reliable way to measure actual level!!!
    Alex
    http://www.dx200.biz

    #42812 Reply
    Boko
    Guest

    Hi,

    If you experience such sudden level change in idle mode, there should be some equipment/hardware failure. Maybe Alex will help you more with Nokia experience. Nevertheless we have some Sagem OT190 phones and measure Siemens with Kathrein antennas and does not experience such problem.

    Regards,
    boko

    #42813 Reply
    samwel
    Guest

    if am using netmonitor phone. What could be the reason.Am experiencing the same right here with this phone. Tell me what is really happening putting aside measurements taken form BSC?

    #42814 Reply
    alexander
    Guest

    samwel, netwonitor is not a professional tool to measure RX level, professional measurement equipment is very expensive, dozens of thousands of US dollars, so nobody belive that $100 mobile phone shows same accuracy like $10000 professional RF measurement tool…. Nokia BSC have actual results of RX level, I never see any “bug” in BSC measurements which is done by E01_BXSX application, you may 100% rely on it
    Alex
    http://www.dx200.biz

    #42815 Reply
    Garry !!
    Guest

    Hi Aadil,

    Well, there could be many causes for a particular problem. The best way is to isolate them one-by-one.

    Regarding your rx_lev changes:
    1.Have you checked the path balance of the cell ? It should be checkec per TRX wise.

    2. Is that problem is on particular TRX or in the entire cell ?

    3. Do let me know this, then may be I can suggest you some more solutions.

    If it is cell specific problem, BSC level settings would hardly matter at times.

    Regarding your 7743 & 7746 alarms:

    1.In BSC settings you must have defined some threshold for this alarms, check whether is it a network wide problem or cell specific problem.

    Revert incase of case of any clarifications if required.

    Best regards,

    Garry !!

    #42816 Reply
    Aadil Shafi
    Guest

    Hi Alex and Garry,

    Firstly my email is aadilshafi@gmail.com.

    Secondly,we have checked the Rx levels in the BSC, its ok, but in the field situation is different, all of a sudden the rx level drops to such a level that the other signals dominate.and as expected the call drops.
    Sometimes, level of a particular cell varies only and the other two cells dominate.In some cases however, the Rx level of the whole site varies and is retored after few seconds to few minutes.Be it in idle mode or in dedicated mode, the level varies.

    Regarding the hardware, we are using Nokia with Katherine antennas and max of these sites are having this prob.

    But one observation i have had is that the sites having this problem mainly have the alrms i have mentioned.

    Garry, Regarding the 7743 & 7746 alarms, definitely every alarm has a threshold defined in BSC, but each alarm means something. These are the alarms i am getting in those sites having RX level variation. thats why i wanted info regarding these alarms.

    #42817 Reply
    Garry
    Guest

    Aadil,

    Move the SDCCH TS on to other TRXs and lock that particular TRX, and see that alarm goes off or not ?

    I guess it would solve the problem.

    Best regards,

    Garry !!

    #42818 Reply
    Garry
    Guest

    Aadil,

    Cut&Paste both the alarms with all the description (bit patterns).

    Garry !!

    #42819 Reply
    Aadil
    Guest

    Hi Gary,

    I am pasting the alarms for your reference. Hope they suffice.I have taken the alarms randomnly.

    1.
    BSRN1 BCF-005 BTS-013 QUAL 2005-09-26 13:29:52.70
    ** ALARM TRX -004 NJKSRP3SRR023A
    DISABLED
    (16555) 7743 MEAN HOLDING TIME BELOW DEFINED THRESHOLD
    00 00 01 00 00 01 00 00 05 02 10d

    2.
    BSRN1 BCF-005 BTS-014 QUAL 2005-09-26 13:29:52.94
    ** ALARM TRX -008 NJKSRP3SRR023B
    DISABLED
    (16590) 7745 CHANNEL FAILURE RATE ABOVE DEFINED THRESHOLD
    01 00 00 00 00 00 01 00 00 05 02 20d

    Regards,

    Aadil

    #42820 Reply
    patrick
    Guest

    is it a city talk?

    I explain with city talk:

    7745 CHANNEL FAILURE RATE ABOVE DEFINED THRESHOLD
    01 00 00 00 00 00 01 00 00 05 02 20d

    20D is a pourcent of failure.

    20 is not very important. When you have 70D or more it is a really problem.

    7745 + 7743, I think you have a problem on the feeder link or TRX is begin to broken. (LNA, antenna, water on câble, …)

    You can test TRX on loop test. selected both separetly.

    IF rx path1 is different of Rx path2 (>4) change your TRX.

Viewing 15 posts - 1 through 15 (of 21 total)
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