Performance of the Multi-band OFDM UWB System with Time-varying Channels

Multi-band OFDM, proposed as a standard for wireless personal area network (WPAN) physical layer in [1], is a promising technology for ultra wide band (UWB) transmission, thanks to the maturity of high rate orthogonal frequency division multiplexing (OFDM) technology, and its effectiveness in combating time-dispersive channels. On the other hand, OFDM performances drop dramatically in the presence of time-varying channels, and thus it is worthwhile to evaluate the robustness of Multi-band OFDM with respect to timevarying environments. This has not been done yet in the literature, on the grounds that terminal and scatterers mobility in a WPAN is very limited, but suggestions on its implementation are given in [2], [3], [4]. We have therefore derived a suitable time-varying channel model and simulated the system performance, according to different degrees of mobility and SNR values. Our results show that system performances are consistent with the results over time-invariant channels for terminal speeds up to 10 m/s for a wide range of SNR.