Impact of electromagnetic noises from PCs on the performance of MB-OFDM UWB systems

The impact of electromagnetic noises from a PC on the bit error rate (BER) performance of a multiband orthogonal frequency division multiplexing (MB-OFDM) ultra wideband (UWB) communication system equipped on the PC is analyzed. The results of numerical simulation indicate that the PC noise consisting of the harmonic components of the PC clock causes considerable bit error rate (BER) degradation in the UWB system particularly those systems operated in high data-rate communication modes. It is also found that the frequency modulation of a PC clock signal, the so-called spread spectrum clocking (SSC), has no effect on mitigating BER degradation, although SSC techniques are commonly used in PCs for reducing the power spectral density of radiated noise. An interference mitigation scheme using Viterbi decoding with channel state information (CSI) is proposed on the basis of a novel receiver structure in which a reference PC clock signal is fed into the UWB receiver by the PC in order to accurately estimate the instantaneous frequency of interfering clock harmonics.