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    What is a spreading factor in UMTS?

    what is spreading factor in UMTS?

    •   Alt27th July 2006, 07:03

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  2. #2
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    relation between spreading factor & bit rate

    The spreading factor is the concept of CDMA used in UMTS.As after spreading the user data the a single bit is called the chip.The spreading factor is the ratio of chip rate to bit rate.In UMTS you have spreading factor limit of 4to512.



    •   Alt27th July 2006, 07:09

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    Re: spreading factor

    The spreading factor, is how much the signal is spreaded, and it is calculated as the bit duration over the chip duration.
    Best Wishes
    Nidhal



    •   Alt27th July 2006, 07:10

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  4. #4
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    Re: spreading factor

    Each user has its own spreading code. The identical code is used in both
    transformations on each end of the radio channel, spreading the original signal
    to produce a wideband signal, and despreading the wideband signal back
    to the original narrowband signal . The ratio between the
    transmission bandwidth and the original bandwidth is called the processing
    gain (also known as the spreading factor). Note that this ratio simply means
    how many chips are used to spread one data symbol. In the UTRAN, the
    spreading-factor values can be between 4 and 512 (however, in the TDD
    mode also SF=1 is allowed). The lower the spreading factor, the more payload
    data a signal can convey on the radio interface.

    Spreading Factor = chip rate/bit rate



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