Optimum and suboptimum 2D channel estimation for UTRA LTE and LTE-advanced

In this work a space-frequency block coding (SFBC) system is considered, which is compliant to the Long-Term-Evolution (LTE) specification. The uncoded bit error ratio (BER) of the linear Alamouti SFBC detector with BPSK modulation in the presence of 2-dimensional (2D) channel estimation is analyzed. The work in this paper comprises frequency-selective and Doppler fading. The quality of robust and optimum channel estimation is investigated by derivation of the Cramer-Rao Lower Bound (CRLB) for the complex-valued channel estimates. The BER performance of the LTE SFBC receiver is studied considering channel estimation with robust and optimum Wiener intepolation. The paper shows the effect of key system parameters on the SFBC performance, such as the anticipated power delay profile and Doppler spectrum at the channel estimator, the actual, i.e. true, power delay and Doppler spectrum, the pilot spacing and the Wiener filter length.