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Half Rate-Call Handover Mechanism

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  • #54633
    Student
    Guest

    Can anyone explain if a HR call can be Handed Over to a FR Channel or it has to be a HR… Take the following 2 examples:

    1) A HR Call is being Handed Over from outer zone to inner zone within a cell (single BCCH).

    2) Same as (1) except HO is inter-cell now instead of Zone HO.

    #54634
    pix
    Guest

    there are different parameters (vendor dependent, i believe) that can control this behaviour.
    The MS has a certain physical capability to handle FR and/or HR. This is known by the BSC. If a call is in HR and the MS can support both FR and HR, there is no restriction in 3GPP : a HO can be made to a HR timeslot or a FR timeslot.

    In alcatel, a MS in HR that does a HO will be sent to FR or HR depending on current load conditions in the target cell, and depending on TFO activation or not.

    #54635
    Yan
    Guest

    dear PIX
    can you please explain what is TFO stand for and what is doing

    #54636
    Michele
    Guest

    TFO is “Tandem Free Operation”.
    It permits the adaptation of the UL codec of the caller with the DL codec of the called and vice versa. In this case the transcoding on TRAU Client can be avoided. See 3GPP 28.062 specification.

    #54637
    pix
    Guest

    yes, the same codec is used from one MS to the other MS, therefore there is no “transcoding” performed in the TC. For instance, 2 MS in EFR (12.2kb/s) –> the 12.2kb/s are not coded into 64kb/s and then back to 12.2kb/s.

    The TFO can be used only during MS-MS call.

    Benefit: comparing one codec with or without TFO, you’ll notice a better voice quality with TFO.

    Constraint: specific parameters shall be tuned, in order to manage the strategy of TFO vs. AMR and TFO vs. HR codecs.

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