Unbiased scattering function estimation during data transmission

We propose an unbiased, data-driven estimator of the scattering function of random time-varying channels satisfying the usual wide-sense stationary uncorrelated scattering (WSSUS) assumption. The estimator allows continuous on-line operation during data transmission, with segments of the data signal serving as sounding signals. A matched filterbank preprocessing stage is used to compensate for the nonideal properties of these sounding signals. The proposed estimator is well suited to fast time-varying channels, and it exploits the underspread property of typical mobile radio channels for a substantial reduction of computational complexity. The performance of the new estimator is assessed by a bias/variance analysis and simulation results