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BTS

Viewing 9 posts - 16 through 24 (of 24 total)
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  • #44048 Reply
    patrick.fr
    Guest

    Uplink and downlink signalling
    In the uplink path, the BTS receives signals from the MS. In the downlink path, the BTS sends signals to the MS. Uplink and downlink signals travel through the Air interface on different frequencies, with the higher frequency carrying downlink signals.

    The uplink signal path involves the following actions:

    The antenna picks up a signal from the MS through the Air interface.

    The antenna passes the signal to the optional Masthead Amplifier (MNxx) and Bias Tee (BPxx) units or to the optional Dual Band Diplex Filter (DU2A) unit.

    The signal passes through either the Dual Variable Gain Duplex Filter (DVxx) or Remote Tune Combiner (RTxx) unit to the Receiver Multicoupler (M2xA or M6xA) and Transceiver RF (TSxx) units.

    The Transceiver module (TRX) on the TSxx unit converts the received signal to Intermediate Frequency (IF) levels and filters the signal.

    The TSxx unit then sends the signal to the Transceiver Baseband (BB2x) unit for digital signal processing.

    The BB2x unit sends the processed signal to the Transmission (VXxx) unit, which transmits the signal to the BSC utilizing standard transmission technologies.

    The downlink signal path involves the following actions:

    The BSC receives a signal from the core network and sends the signal to the VXxx unit utilizing standard transmission technologies.

    The VXxx passes the signal to the BB2x unit for digital signal processing.

    The BB2x unit sends the processed signal to the TSxx unit.

    The TRX module on the TSxx unit filters the signal, raises it to the carrier frequency, and amplifies it.

    The TSxx unit then sends the signal either to the RTxx unit or through the optional Wideband Combiner (WCxA) unit to the DVxx unit.

    The DVxx or RTxx unit sends the signal through either the optional DU2A unit or the BPxx and MNxx units to the antenna, which passes the signal through the Air interface to the MS.

    #44049 Reply
    Ibrahim F Jasim
    Guest

    Hi to all, I am working on Huawei BTS’s. I kindly ask if any one can tell me how to calibrate the Huawei TRX power.

    #44050 Reply
    sharafany
    Guest

    hi to all please can you tell me the function of ETC5 card with my respect.bye

    #44051 Reply
    sairam
    Guest

    hello mr.partik,
    can u plz describe the function of BB2x ,ML2X,COMBINER in detail.
    and another thing -i hv nver used EDAP where we exactly use that signal and how to use?
    why we use DAC value?
    whts the use of Rx clock and Internal timing?
    can v use 2 or three power cards for 1+1+1 configuration? if no why?

    plz answer me….

    thanks

    #44052 Reply
    patrick.fr
    Guest

    Function
    The BB2x unit is a digital signal processing board, consisting of two independent baseband modules. Each module functions independently for its own TSxx unit. The BB2x unit also controls frequency hopping.

    Externally all the units are alike except for the model number on the face of each. Internally, the major difference is the additional EDGE capability provided by the BB2E and BB2Funits. BB2A units can only be used with GSM (TSxA) transceiver units. The BB2E and BB2F may be used with or can replace the BB2A and supports GSM (TSxA) and GSM/EDGE (TSxB) transceiver units. EDGE operation is only possible when BB2E or BB2F units are used in conjunction with TSxB transceiver units.

    The front panel of the BB2x unit is grounded to handle electrostatic discharges.

    The BB2x units of Nokia UltraSite EDGE Base Station have the following main functions:

    Process digital speech and data channels signals

    Manage all speech function signalling

    Uses software downloaded from the Base Operations and Interfaces (BOIx) unit

    Sets internal timing according to clock references from the BOIx unit

    Supports synthesised radio frequency (RF) and baseband (BB) frequencyhopping

    #44053 Reply
    patrick.fr
    Guest

    and another thing -i hv nver used EDAP where we exactly use that signal and how to use?

    EDAP = trame EDGE

    It is recommended that the same timeslot allocation be used for the BSC and BTS. If required, the first EDAP timeslot at the BSC can be different than the first EDAP timeslot at the BTS. Cross connections are allowed, but it is recommended that the whole PCM frame or the n*64 cross connection complies with the ITU-T G.796 (Characteristics of a 64 kbit/s Cross-Connect Equipment with 2048 kbit/s Access Ports, Chapter 2.1) standard in respect to maintaining octet sequence integrity of signals being cross connected. The following precautions help to maximise the EDGE performance:

    EDAP and the TRXs that are tied to the EDAP (including traffic/master and signaling channels) must share the same physical Abis connection route. It is also recommended that PCM frames have octet sequence integrity, which can be achieved using one of the following methods:

    Using 1-3 PCM lines that perform according to G.796. If BTS capacity requires several PCM lines, a normal network delay variance between the PCM lines does not impact EDGE performance. EDAP pool and the TRXs tied to it, have to locate on a single PCM. Example 4+4+4 configuration: TRX 1-4 and their EDAP(s) on PCM1, TRX 5-8 and their EDAP(s) on PCM2, TRX 9-12 and their EDAP(s) on PCM3.

    Using fractional E1, n*64k connection that complies with G.796.

    The EDAP pool and TRXs tied to it must have a connection made within a single PCM or a single or multiple n*64k connection inside one PCM that comply with the G.796 in the respect of octet sequence integrity. This structure must be maintained throughout the network.

    If the PCM line does not fulfill the octet sequence integrity requirement as specified in ITU-T G.796, a maximum of +/- three PCM frame delay between timeslots is tolerated when BSC software S10.5 ED CD1.2 or newer is used.

    #44054 Reply
    patrick.fr
    Guest

    why we use DAC value?

    DAC value = 13 Mhz clock of BOIA (BCF)

    Connect the frequency counter to the 13 MHz test connector on the BOIx front panel with an appropriate test cable.
    Check the current and permanent DAC value with the BTS Manager.
    Adjust the trigger level on the counter to produce a frequency reading.

    Set the measuring period to one second for the first adjustment.
    Adjust the current DAC value to 13 000 000.0 Hz with the BTS Manager.

    Click the Set as current button.

    Note
    When searching for the 13 000 000.0 Hz frequency, it is useful to know that 40.8 DAC steps equals one Hz.
    Save the current DAC value as the permanent DAC value with the BTS Manager.

    When adjustments are complete, click the Save Current Permanently button.

    Adjust the maximum measuring period to achieve the required sampling accuracy.
    Re-check the displayed frequency.
    If you must make more adjustments.

    #44055 Reply
    patrick.fr
    Guest

    whts the use of Rx clock and Internal timing?

    In your transmission card (fxc, fxc rri, …)

    1st priority = PCM E1/T1
    2nd priority = internal timming

    all transmission card take synchronisation on BSC signal (ET)

    #44056 Reply
    patrick.fr
    Guest

    can v use 2 or three power cards for 1+1+1 configuration? if no why?

    PWSA
    2250 W
    PWSB
    600 W
    PWSC
    2500 W

    Cabinet/Unit power consumption
    Value
    CRMA with 11 unit fans
    110 W
    CRMC with 7 unit fans
    70 W
    BOIA
    10 W
    TSxA
    230 W
    TSxB
    265 W
    BB2A
    10 W
    BB2E
    15 W
    BB2F
    10W
    DVxx
    25 W
    RTxx
    40 W
    MNxx
    15 W
    E1/T1 Transmission unit
    10 W
    Radio Transmission
    60 W

    Do the calcul but 1+1+1 = 1PWSB.

Viewing 9 posts - 16 through 24 (of 24 total)
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