Improving channel estimation using a modified root selection algorithm with model order estimation in OFDM systems

In this paper a new algorithm for blind channel estimation in orthogonal frequency division multiplexing (OFDM) systems is described. The proposed algorithm uses a modification to the root-selection algorithm for channel estimation and a generalized Akaike information criterion to estimate the channel length. The new algorithm is termed, the modified root-selection (MRS) algorithm. This algorithm together with the channel order estimation effectively reduces the signal space of the estimator, and hence improves the estimation performance as demonstrated using computer simulations. The proposed MRS with channel estimation algorithm has a 5 dB lower mean square error in channel estimation when compared to the conventional RS approach which translates to approximately 0.5 dB improvement in SNR at receiver. In addition, the proposed modification to the RS algorithm results in a more computationally efficient algorithm. It is applicable not only to standard OFDM transmitters with cyclic prefix, but also to the recently proposed zero padded OFDM transmissions