Quadrature Division Multiple Access (QDMA) is a radio protocol. The term combines two standard terms in telecommunications, CDMA and QPSK.
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Applications
QDMA is used for local area networks, usually wireless short range such as WiMax. CDMA and QDMA are especially suitable for modern communications, for example the transmission of short messages such as SMS or MMS; communication when in motion (from cars, trains, etc.); the establishment of unplanned links.
Benefits over TDMA and FDMA
The traditional TDMA and FDMA require a lot of overhead to set a link parameter with a new user, or to detect that a user left and their allocation is free to be allocated to another. In CDMA or QDMA, a new user is simply allocated a new code and is ready to go. It may impose a slight load on the spectrum, but the system is so devised as to absorb a controlled measure of collisions and continue operations at a high level of quality of service.