Higher-order cyclostationarity properties of coded communication signals

Results on the higher-order cyclostationarity of digital communication signals currently presume for the sake of simplicity that the symbol stream is stationary and white. Thus, these results focus on the periodicities induced within the modulator which takes as its input the discrete-time sequence of symbols to be sent and produces as its output a continuous-time signal suitable for transmission. In this paper, we characterize the higher-order cyclostationarity (HOCS) induced by the periodically time-variant nonlinear (in R) operations in linear (in GF(2)) block coders operating on stationary binary-valued input sequences. The fundamental result of this paper is that the HOCS properties of the coder output are characterized completely by the parity-check matrix of the coder.