Order to protect the signal, the chip sequence code used is pseudo-random. (assuming no changes in the modulation or encoding techniques). To mb chips/sec can only be done if the bandwidth available is increasedīy a factor of m, making CDMA a form of spread spectrum communication Increasing the amount of information to be sent from b bits/sec = 8, if station A is assigned the chip sequence 00011011, it sends a 1 bit by To transmit a 0 bit, it sends the one'sĬomplement of its chip sequence. Is assigned a a unique m-bit chip sequence. Typically there are 64 or 128 chips per bit. In CDMA, each bit time is subdivided into m short intervalsĬalled chips. The key to CDMA is to be able toĮxtract the desired signal while rejecting everything else as random Instead, itĪssumes that multiple signals add linearly. Relaxes the assumption that colliding frames are totally garbled. Multiple simultaneous transmissions are separated using coding theory. In Code Division Multiple Access (CDMA), every communicator will be allocated the entire spectrum all of the time. Division by time, so that each pair of communicators is allocated all (or at least a large part) of the spectrum for part of the time results in Time Division Multiple Access Division by frequency, so that each pair of communicators is allocated part of the spectrum for all of the time, results in Frequency Division Multiple Access For radio systems there are two resources, frequency and time.
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