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signakl strength

  • This topic has 19 replies, 1 voice, and was last updated 15 years ago by Da Architect.
Viewing 15 posts - 1 through 15 (of 20 total)
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  • #47965 Reply

    On gsm 1800MHz network ericsson cell site, antennas are at 19metres, and transmitter power is 26.235 dBW propagting to rural terrain would it be expected to find signal strength at test handset of 71dBm where mobile is located some 2.2km from mast?

    #47966 Reply

    forgot to add line of sight below.

    #47967 Reply

    19m. is not so high, but in line of sight, it doesn’t sound like a crazy value. -71dBm sounds OK… why ? does it seem too low to you ?

    #47968 Reply

    Hi Pix, you right it does sound too low.

    From surveys I usually see that value of signal strength about 1Km from mast, on average usually at 2Km I usually see about -90dBm

    #47969 Reply

    hi pix
    we have a provlem in our network
    some time in some where singal strength go up and again go down ,while we are sure which we havnt any problem with radio .coild you please advice us about that ,and another question we have many call end with any reasone which that confused do u have any oponion or any expriment about that .
    thank you for yor reply

    #47970 Reply
    Da Architect

    Dear Hashem,

    I hope pix agree with me, concerning the signal stregth, check these three things:
    VSWR, that NMC didn’t report, may be they thought it is minor!
    Second, check your transceiver TRX,and corresponding combiner. it might be software or hardware problems, you may refresh the TRX or Combiner, or even replace them and check!
    Third, which is most important, check the power control parameters, perhaps the thresholds and offsetes on this power control window require adjustemnts.

    Is this cell a concentric cell with 900 and 1800 (UL and OL), if so it may explain a lot of things too!

    concerning the call end issue it might be related to NSS, i need to describe more this call end and what do you mean with any response? check layer three messages during drive test, you might find your answer in these messages.

    #47971 Reply

    Hi Da Architect ! i always agree with your good practical sense ๐Ÿ˜‰

    Hashem, your problem lacks details. you must spend more time collecting clues…
    when you say “signal strength goes up & down”, and then you say “we’re sure we don’t have a problem on the radio”.
    well, you MUST have a problem on the radio, obviously.

    perhaps, check for sector crossing, or TRX crossing…

    problem 1 : are you connected on one cell or is the difference of rxlev due to the MS changing cells quickly ? Is it during idle mode or dedicated mode ?

    problem 2 : call end = call drop ? check qos stats : what is the highest cause of drops on this cell ? perform a trace : what is the reason of the call release ?

    give us more data, if you want help ๐Ÿ™‚

    best regards

    #47972 Reply

    hi pix and da architect
    thank you so much for your reply and your help in first
    dear da architect ,we have this problem in band 900 (UL,DL)
    dear pix ,when my colleague did drivetest ,i checkd all data and messages but didnt seen any doubtful things but when i have good singnal and have not any interferece,and my speech quality its ok and prefect ok how can i said i have vswr problem or trx problem ,and this promale made during call setup ,second we change another subscriber place by made a drive test there but we havent any thing and any problem ,
    but just like normal call end ,in drive test time this accured .
    dear pix and dear da architect could you please give me your mail and send image which captured and data message and to contact more
    thank you so much

    #47973 Reply


    I read your post 3 times, but I can’t make any sense out of it !! I don’t understand what you’re saying.

    here is my email :
    pix_erlang **at **

    #47974 Reply

    dear pix
    i sent you my question to yourmail but i had failure notice with this sending
    which one its yourmail
    and by the way this is my mail
    thank you

    #47975 Reply

    I received your mail but again, i’m really sorry about this, but i don’t understand your problem.

    and i have no doc about tems.
    and i will not send any doc about optimization or drivetest investigations. There are plenty of books available on the market, and all specs are available at 3GPP…

    good luck…

    #47976 Reply

    i expected you to send to screen capture of tems, or something… not repeat what you just said before ๐Ÿ™‚

    #47977 Reply

    Iam having ping pongs on some rural sites due to low signal strength in the uplink.How do i counter that.

    Iam also having tch drops due to sudden connection loss.How do i counter that as well.

    #47978 Reply

    nachi :

    problem 1
    if there is HO due to low level in the UL, is there really a bad signal in the UL ?

    – check the UL power control :
    L_RXLEV_UL_P = L_RXLEV_UL_H +10 ?

    – check the UL level HO threshold
    L_RXLEV_UL_H < -100dBm - check that you select a cell with a better level: HO_MARGIN_LEV(0,n) > 2dB
    (increase this value to avoid ping pong, but it can be a little risky. check the HO PREPARATION algorithm, power budget filtering)

    problem 2 :
    call drop due to sudden connectio loss ? is that a counter ?
    if yes, what is the triggering message ?
    if no, what is the qos counter associated ? what are the QoS stats for this cell ?

    causes can be : Abis failures, TRX failures, BSC failures, NSS failures …

    check if one trx is having a higher CDR than the others.


    #47979 Reply

    Hi Pix,
    The ping pongs are happening in an island site such that it only has the other two sectors of the 3 sectors of the site as neighbours.What i was expecting are droppped calls due to low signal when a MS moves away from good coverage but they are ping ponging between two sectors.

    On the call drops from errcson,one can get to the cause of the drops,some of them being bad quality,low signal strength and like in my case,sudden loss of connection.i will check at what level the connection is lost

Viewing 15 posts - 1 through 15 (of 20 total)
Reply To: signakl strength
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