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problem between 900 and 1800 siemens

Viewing 5 posts - 1 through 5 (of 5 total)
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  • #46248

    you guide me about pl in 1800 bts siemen and tel it must be 5 so i have another question and a serios problem .
    what is the value of pl in 900 band siemens bts ?and my problem :
    we have a 1800 bts and 900 bts in a same location in the my city center .during the day both bts serves the sub but in the evening and during the night more time we can not dial by 1800 frequencys and when we dial we have not any anten and we dont succes to connect but when lock the 1800 bts allthing willbe normal .
    pleas help me .


    Hi parsa79 ,
    I m not sure, what is the problem.
    But from your description: Is it blocking for 1800 band or not sufficient coverage??? Please specific problem in detail.

    But in principle: 900 and 1800 on the same site (same antenna ditection). 900 for coverage and 1800 for capacity. For 1800 PL=5 and for 900 PL = 10. You must set correct PLNC. You should to set in proper way also RXLEAMI, CRESPARI, CRESOFF and HOLTHLVDL/UL for 1800 band. But from your description


    Try to lock trx by trx. Possible one of trx (conection)failed.


    Hi Parsa79,
    for 1800band you should set RXLEVAMI=15 (or12). And also to set RXLEVMIN (for handover). I thing that it is the reason, why you could not setup call and your mobile missed paging.
    Your problem probably is, that you don’t have Path balance (Uplink-Downlink). Your mobile could listen BCCH, but BTS don’t.
    It is wrong to set same RXLEVAMI for both band, if you have sufficient capacity in 900 layer.


    I sopose that your 1800MHz sektor curring only HO traffic.(HO from 900 to 1800)Could you see in stats that you have some some sdcch trafiks on 1800?
    a)check if you have SDCCH configured on 1800MHz.
    b)check LB , but if during daytime there is a traffic , than it can not be a problem. anyway chack
    c)check the BTS parameter – “not allowed access class”. May be a mistake.
    d)If you are playing with C2 criteria on 1800MHz, then there is possible situation when C1 neigbour C2 (in your case 900 sector), then MS need some time for reselection.During this time the mobile not reacheble because of C1

Viewing 5 posts - 1 through 5 (of 5 total)
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