Advanced Channel Estimation for MIMO-OFDM in Realistic Channel Conditions

An advanced decision-directed channel estimation scheme is proposed, which is suitable for employment in a wide range of multi-antenna multi-carrier systems as well as for communications over the entire range of practical channel conditions. In particular, we consider a MIMO-OFDM system operating in a mobile wireless multipath channel, which exhibits frequency-selective Rayleigh fading and is characterized by a time-variant power delay profile. Both the mean square error as well as the bit error rate performances achieved by the proposed system are documented. Specifically, we report a virtually error- free performance of a rate 1/2 turbo-coded 8times8-QPSK-OFDM system, exhibiting an effective throughput of 8middot2middot1/2=8 bits/sec/Hz, while having a pilot overhead of only 10%, at an SNR of lOdB and an OFDM-symbol-normalized Doppler frequency of 0.003, which corresponds to the mobile terminal speed of about 65 km/h.