Constant amplitude zero autocorrelation waveform
In signal processing, a constant amplitude zero autoCorrelation waveform (CAZAC) is a periodic complex-valued signal with modulus one and out-of-phase periodic (cyclic) autocorrelation equal to zero. CAZAC sequences find application in wireless communication systems, for example in 3GPP Long Term Evolution for synchronisation of mobile phones with base stations. Zadoff–Chu sequences are well-known CAZAC sequences with special properties.
In wireless CDMA technology, the given data encoded and in transmitter side number users assign to unique codes with help command codes (ex. PN sequences, pseudorandom noise). In CDMA technology, data transmitted under same range of frequency but the users are identified by the unique number, the codes are matched between the particular users than data will transmitted.
The matching between the users is called synchronous CDMA. The coded data sending with constant amplitude and zero auto correlation. The constant amplitude means the sending and receiving easily without any correction. Zero auto correlation means the correlative variance between the users is zero, so no interaction or interference between the users.