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  • #40570 Reply


    Can anyone tell me why STM-1 is used in GSM? how it differs from E1 links? I know that STM-1 is an optical link,,,but could some on tell about it in detail…regards..

    #40571 Reply

    E1 (2Mbps) is PDH, STM-1 (155Mbps) is SDH. To transmit a big (I mean BIG) traffic it will be more effective to multiplex several E1 to form STM1 then transmit it over a single optical link and demux it on the other end. There are also STM-4, 16, 64.

    #40572 Reply
    ernest .nigeria

    E1 is a primary rate in the PDH system.approximately 63 E1(2Mbps) make up an STM-I which is the 1st data rate for an SDH system.
    basically in a GSM network, STM-1 155Mbps is used to interlink the BTS and BSC or BSC to MSC as the case may be.and act as backbone link for the network.
    becourse of it high capacity rate,the full trunk/traffic could be transmitted through this medium to the switching center, and it can.
    1. allow a simplified add and drop at any BTS or BSC.for any of it E1 it carrying.
    2.since is an SDH stardard, new protocols, ATM,FRAME-RELAY,ETHERNET 100Mbps,etc can be transmitted over it
    3.fully scallable and be administar at remote.
    finally,the cost of equipment ar lesser compare to PDH system and not as bogus as PDH which entails each site demultiplexing.
    at higher level of STM-4, 16, 64. fibre is the only medium, why STM-1 can take both medium radio and fibre

    #40573 Reply

    thnks a lot guys, u were a great help..

    Is the data on the STM-1 only transmitted fiber optic link, or by microwave as well..for example, in a BTS, microwave antenna is used to transmit E1 data. I have heard that microwave antenna can also be used to tranmit STM-1 data. Please calrify…furthermore, if microwave can be used as STM-1 link, how it differs from normal Abis-link (E1).


    #40574 Reply

    Hi Weber,

    It seems you are refering to Inilink which is mostly used in ERICSSON Cell Sites.

    This is shorter distance ( Higher Freq MW Links )and has a capcity of MAX-16 PCMs..

    Called as PDH.

    SDH – Technology can be used in MICROWAVE or OPTICAL.If it is MW used in ( Lower MW Fre Link ) for Longer Distance.Mostly for Ntework Backbone Network like OPTICAL.Normally OPTICAL has more good stability compare to SDH.But SDH is easy to deploy and start operation.

    And additionaly…

    In ERICSSON-AXE810 you can get STM-1 ( 63 PCMs) Output either as Optical/Electrical for MW Links directly from SWICTH MSC/BSC.

    This is new…..

    #40575 Reply

    STM 1 contains 155 Mbps (63 E1) .For BSC -MSC or MSC-MSC connectivity STM 1 or higher order STMs i.e. STM4/STM 16 are used

    #40576 Reply
    Amrut Barde

    Does STM 1 has 155Mbps upload and download seprate or total is 155Mbps?

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