A new group demodulator with multi-symbol chirp Fourier transform for mobile communication systems

This paper proposes a group demodulator having a dual-parallel structure that employs the multi-symbol chirp Fourier transform and also evaluates the power consumption. The proposed group demodulator is suitable for hardware implementation and can demodulate band-limited and bit asynchronous signals with reasonably small degradation. Computer simulation results show that the bit error rate (BER) degradation of the proposed group demodulator employing 6-symbol chirp Fourier transformation is less than 0.5 dB at BER=10^-3 even when root Nyquist (α=0.6) filtered bit asynchronous FDMA signals are received. The power consumption is lower than that of conventional demodulators when many carriers are handled. The principle of the proposed scheme and a hardware implementation method are explained using an example of the INMARSAT-B system