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CMDA vs TDMA

  1. Apr 14, 2003 #1
    [SOLVED] CMDA vs TDMA

    These are the two cellphone architectures... Sprint uses CDMA (code-division multiplexing) and everyone else uses TDMA (time-division), including the international GSM standard.

    My question is, doesn anyone know what the technical difference between the two is? How do they stack up? Can you give any good refs/links? Thanks,

    damgo
     
  2. jcsd
  3. Apr 14, 2003 #2
    CDMA (Or "spread spectrum") A form of multiplexing where the transmitter encodes the signal using a pseudo-random sequence which the receiver also knows and can use to decode the received signal. Each different random sequence corresponds to a different communication channel.
    Taken from; http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?code+division+multiplexing


    TDM A type of multiplexing where two or more channels of information are transmitted over the same link by allocating a different time interval ("slot" or "slice") for the transmission of each channel. I.e. the channels take turns to use the link. Some kind of periodic synchronising signal or distinguishing identifier is usually required so that the receiver can tell which channel is which.

    TDM becomes inefficient when traffic is intermittent because the time slot is still allocated even when the channel has no data to transmit. Statistical time division multiplexing was developed to overcome this problem.
    Taken from; http://wombat.doc.ic.ac.uk/foldoc/foldoc.cgi?time+division+multiplexing

    Here is a rather lengthy PDF (over 100 pages) that has a few pages you might find interesting (In chapter two, I believe);

    http://scholar.lib.vt.edu/theses/available/etd-05022000-15590055/unrestricted/CDM_FO_MEMS.pdf
     
  4. Apr 16, 2003 #3
    i think verizon uses cdma too.

    but that doesnt mean that there cross compatable bacause there not.
     
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