Deriving Binary Sequences from Chaotic Sequences Having Good Cross Correlation Properties

Set of binary sequences with good pair wise cross-correlation finds application in code division multiple access (CDMA) system. Normally in these schemes, since cross-correlation has a minimum value but not zero, if the number of users increases at a time, there is degradation in the quality of the received signal. Chaotic sequences have good correlation properties and they can be used as address sequences in spread spectrum communication. Chaotic sequences are uncorrelated when their initial values are different. In chaotic spread spectrum systems, different user may be assigned different sequences generated with different initial conditions. Chaotic functions are highly sensitive to initial condition, exhibit non-linear behavior. The investigation deals with generation of chaotic discrete and binary sequences using different chaotic maps like Logistic map, Tent map and Cubic map, study of autocorrelation and cross correlation properties of such sequences and their suitability in CDMA.