A new group demodulator for mobile communication systems

This paper proposes a group demodulator having a dual-parallel structure that employs multisymbol chirp Fourier transform to demodulate band-limited and bit asynchronous signals; the demodulator is sufficiently feasible for practical use unlike conventional group demodulators based on the chirp Fourier transform. Moreover, a new symbol timing offset detection scheme is also proposed to realize the aforementioned group demodulator, and the power consumption of the proposed group demodulator including the symbol timing offset detector is also evaluated. Computer simulation results show that the overall bit error rate (BER) degradation of the proposed group demodulator employing six-symbol chirp Fourier transform is less than 0.5 dB at BER=10^-3 even when a root Nyquist (α=0.6) filter is used as the transmission band-limiting filter and symbol timing offset between the desired channel and the chirp sweep exists. The power consumption is lower than that of conventional demodulators when more than 120 carriers are handled