A Spectral Analysis of M-ary Direct Sequence Spread-Spectrum Multiple Access Communication Systems

This paper presents the power spectrum of the transmitted signal in a synchronous spread-spectrum communication system in which the users\´ information symbol sequences are encoded into -ary channel symbol sequences. Furthermore, when maximal-length shift register sequences are used as the spreading code sequences of the system, the average power spectrum over all possible sets of the allowable simultaneous users is presented. It is shown that distribution of the spectrum is influenced considerably by the spreading code and the channel symbol sequences.