Channel fading estimation with unequally spaced pilot symbols

A reliable and effective method is proposed for estimating mobile channel fading with unequally spaced pilot symbols. By employing a least squares method with time-variant complex-valued-coefficient polynomials, it is proven that time-varying and frequency nonselective channel fading of each slot can be estimated by the product of a constant matrix and the fading at pilot symbol locations of the slot. The constant matrix is further optimally calculated by a least squares (off-line) training method. Simulation results indicate that our method provides very accurate estimation of channel fading