PS-CDMA: spreading signals for CDMA designed in the frequency domain using perfect sequences

In this paper are described some new approaches to the definition of CDMA spreading functions. The simplest method increases the code space up to 50%. The most sophisticated one performs a very strong rejection to the delayed replicas of the interfering signals. Several advantages have also been found in the FFT implementation of PS-CDMA transmitters and receivers, the elimination of the analog matched filter being the most attractive one. Theoretical results have been supported by computer simulations, and comparisons with the traditional DS-CDMA design of spreading functions are also included.