Incremental frequency, amplitude and phase tracker (IFAPT) for coherent demodulation over fast flat fading channels

The incremental frequency amplitude and phase tracker (IFAPT) is a recursive algorithm that estimates the parameters of piecewise-linear approximation to assumed continuous narrow-band signals. The parameters are amplitude, phase, and their respective slopes. The simple, recursive nature of IFAPT enables its direct interaction with recursive algorithms, such as the Viterbi and the BCJR in the APP SISO module, used for iteratively decoding concatenated codes. An augmented APP (A/sup 2/P/sup 2/)-module, containing IFAPT and BCJR algorithms, is here applied to iterative decoding serial concatenated convolutional codes under Rayleigh fading conditions with diversity reception. The bit-error rate under Rayleigh fading with dual diversity reception at E/sub bT//N/sub 0/=6 dB and f/sub d/T/sub s/=10/sup -2/ is 10/sup -4/, where E/sub bT/ is the total mean energy per bit in both diversity branches, f/sub d/ is the Doppler frequency, and T/sub s/ the symbol time.