BER analysis of dual-carrier modulation (DCM) over Rayleigh fading channel

In this paper, we consider a dual carrier modulation (DCM) which is employed in multi-band orthogonal frequency multiplexing (OFDM) ultra wide-band (UWB) system. DCM transforms two QPSK symbols to two 16-QAM symbols with different bit-to-symbol mappings. We find that the basic idea of DCM is the same as that of the rotation code. More specifically, both the rotation code and DCM can provide not only diversity gain by symbol repetition in the time or frequency domain, respectively but also coding gain by constellation rearrangement. We find that these features allow to derive the tight upper bound on the bit error rate (BER) of DCM over the Rayleigh fading channel. We show that our analysis is virtually identical to simulation results over the acceptable range of E_b/N_o, e.g., higher than 4dB.