Time and frequency equalization for UWB systems: A comparison study

In this paper we compare the performance of time and frequency equalization for high data rate ultra-wideband communications. For time-domain equalization, we propose a joint Rake and minimum mean square error equalizer receiver. The proposed receiver combats inter-symbol interference by taking advantage of the Rake and equalizer structure. We focus our attention on the effects of the number of Rake fingers and equalizer taps on the error performance. We show that, for a MMSE equalizer operating at low to medium SNR's, the number of Rake fingers is the dominant factor to improve system performance, while, at high SNR's the number of equalizer taps plays a more significant role in reducing error rates. The performances of this structure are compared with those of a frequency-domain equalizer operating in single carrier mode. We show that the frequency domain equalizer outperforms the combined Rake-MMSE equalizer structure in all the range of studied SNR's.