When does H∞ equalizer outperform H2 equalizer in multipath fading environments?

We present the BER performance for fractional-tap-spaced DFEs with adaptive a priori H_∞ filtering algorithm and with H₂ (recursive least squares, RLS) filtering algorithm in various frequency selective fading channels. Computer simulation results demonstrate the better bit error rate (BER) performance of the DFE with the adaptive a priori H_∞ filtering algorithm when the ratio of the average energy-per-bit to the white noise spectral density (E_b/N₀) and channel-fading rate (f_dT _s) is large. Therefore, it is concluded that the adaptive a priori H_∞ filtering algorithm is more robust and less sensitive to modeling error and channel parameter variation but more sensitive to input white noise