On frequency selective multipath channels

The energy detection of continuous phase frequency shift keying (CP-FSK) signals is the optimum noncoherent detection technique yielding a minimum bit error rate (BER) on the additive white Gaussian noise (AWGN) channel. This scheme is usually used when carrier phase estimation is difficult. When a CP-FSK signal is passed through a frequency selective multipath fading channel, inter-symbol interference (ISI) is introduced which distorts the received signal waveform. However, this ISI can be compensated and the BER improved by use of sequence estimation at the output of the energy detectors. In this paper, we derive an analytical upper bound as well as a lower bound on the BER for this scheme on the multipath fading channels and compare the results with the computer simulation to show the effectiveness of the technique