Simple Design of Detector in the Presence of Frequency Offset for I II 802.15.4 LR-WPANs

A simple detector for orthogonal modulation that is robust to large frequency offsets is proposed. The complexity of the detector is significantly reduced by implementing the correlator using multiplexers instead of complex floating-point multiplications. The performance of this design is comparable to the optimal value obtained by double correlation in offset quadrature phase-shift keying (O-QPSK) and nearly reaches that of noncoherent maximum likelihood (NCOHML) detection with 10-ppm frequency offset in the additive white Gaussian noise (AWGN) channel. Therefore, the proposed design can be used in low-cost and low-power I II 802.15.4 low-rate wireless personal area network (LR-WPAN) applications.