Diversity Aspects of Linear and Decision-Feedback Equalizers for Frequency-Selective Multi-Antenna Channels

The diversity-rate tradeoff was introduced by Zheng and Tse for ML reception in frequency-flat MIMO channels. Since then, some results have been obtained also for the diversity behavior of suboptimal receivers such as linear and decision-feedback equalizers for frequency-selective SIMO channels. However, these results are limited to infinite length equalizers or cyclic prefix systems. In this paper we analyze the diversity of more practical FIR equalizers. We show in particular that linear equalizers lose all frequency diversity in the classical outage-rate trade-off, except at constant rate. Decision-feedback equalizers on the other hand, even if equipped with FIR filters, allow to capture most of the spatiofrequential diversity.