An effective channel estimation method for transmit diversity systems

This paper presents a simple yet effective channel estimation method for transmit diversity systems. We propose to use the Alamoutipsilas space-time encoding scheme to create pilot symbols and insert into the transmit data symbol streams from the transmit antennas. The orthogonality of the pilot symbols from the two transmit antennas allows to eliminate the interference among transmit antennas. The proposed pilot symbol assisted (PSA) method thus does not require pilot symbol expansion as in the previous methods. We also propose to use a simple temporal average operation to process channel decision statistics to replace temporal filters or interpolators. For a 16 pilot symbols in a 100 data symbol frame transmitted using the Alamoutipsilas space-time block coding, the performance degradation of the estimated symbols is less than 0.2 dB compared with the case of perfect channel estimation.