M-ary chirp modulation for coherent and non-coherent data transmission

M-ary chirp modulated signals are described and illustrated as a function of modulation parameters-h, the peak-to-peak frequency deviation divided by the symbol rate; and w, the frequency sweep width divided by the symbol rate. The detection of these signals in AWGN channel is addressed and optimum receiver structures for both coherent and non-coherent cases are derived. Closed-form expressions for symbol error probabilities for these receivers have been obtained. Optimum 2-, 4-, and 8-ary coherent chirp systems that minimize symbol error rate have been determined. The performances of both coherent and non-coherent M-ary chirp systems are compared with respective conventional M-ary digital modulations.