Detection and performance of weak M-ary chirp signals in class-A impulsive noise

Detection and error rate performance of weak M-ary chirp spread-spectrum (MCSS) signals in Middleton´s class-A noise are addressed. The structure of the optimal weak-signal receiver is derived and consists of a zero-memory nonlinearity (ZMNL), a function of first-order noise density, followed by Gaussian MCSS correlator receiver. Bit error rate (BER) bounds on the performance of this receiver are derived and illustrated as a function of signal-to-noise ratio (SNR), modulation and noise environment parameters, and detection sample size for MCSS modulations. Optimal 2-, 4-, 8-, and 16-ary CSS modulations are determined and their performances are examined. The results show that considerable improvement in performance can be achieved when the optimal weak-signal receiver is used for detection of MCSS signals in class-A noise.