Oversampled Legendre basis expansion model for doubly-selective channels

In broadband wireless communication, high rate data transmission and multipath propagation results in frequency selectivity. On the other hand, high mobility contributes to time selectivity in fading channels. A finite parameter model which can be used for modeling doubly-selective channels is the basis expansion model (BEM). In this model, channel is estimated based on some basis functions which are weighted by time-invariant coefficients during a time block. In this paper, Legendre basis expansion model (LBEM) is discussed for doubly-selective fading channels and oversampled Legendre basis expansion model (OLBEM) is proposed. Simulation results show improvement in the mean square error (MSE) of our channel modeling scheme compared to that of other oversampled basis expansion models (i.e. OBEM, and oversampled polynomial basis expansion model (OPM)). In our approach the BEM coefficients are calculated using the least-squares approximation.