Ultrawideband (UWB) radio is a promising solution for high-rate wireless communications over short ranges. In this paper, the performance of multiband orthogonal frequency division multiplexing (MB-OFDM) UWB systems is analyzed using the Saleh-Valenzuela channel model in terms of the packet error rate and the transmission range for indoor environments. The performance improvements resulting from the use of linear precoding and multiple antenna techniques are also analyzed and compared. It is shown both by theory and computer simulations that the two methods can effectively enlarge the transmission range of UWB devices.