Bit loading for wavelet packet modulation using time-domain equalization

Wavelet Packet Modulation (WPM) has been considered as an alternative to Orthogonal Frequency Division Multiplexing (OFDM) since it provides higher flexibility in terms of time-frequency resolution and can reduce the computational complexity as the transform size varies. This research investigates how to perform equalization and bit loading for WPM, which remains open in comparison to OFDM. The considered technique employs linear Minimum Mean-Square Error (MMSE) time-domain equalization and bit loading based on water-filling corresponding to the equalization filter. The combination of linear MMSE equalization and bit loading for WPM is introduced in this paper, and has not yet been reported. Numerical results from computer simulations show that bit loading along with time domain equalization provides significant improvement in the Bit Error Rate (BER) performance when the channel is highly dispersive.