Equalizer complexity/performance trade-offs for high data-rate IR-UWB linear receivers in multipath channels

We investigate bit rates above 500 Mb/s rate for impulse radio ultra-wideband (IR-UWB) communications. UWB channels exhibit rich multipath leading to intersymbol interference (ISI) at these bit rates. Previous investigations studied decision feedback equalizers (DFE) for moderate bit rates (100 Mb/s and lower).We examine the effectiveness of this solution when ISI is more severe, and compare performance and complexity to that of a Viterbi algorithm (VA) equalizer with a limited (suboptimal) number of states. We consider a complete UWB link composed of a pulse transmitter, antennas, true UWB multipath channel measurements, and a linear receiver. We examine equalizer memory requirements for reliable Gb/s IR-UWB transmission for line-of-sight (LOS) channels. Non-line-of-sight (NLOS) channels are also investigated, however at lower speeds. Bit error rate (BER) simulations show that equalization is effective to varying degrees. The trade-offs in complexity vs. performance of the VA versus the DFE are discussed.