Performance analysis of channel estimation algorithms for a MIMO OFDM system under digital TV channels

In 2005 the Brazilian government supported researches in order to design a new DTV standard which would employ the most recent technologies. One of the proposals for the new standard´s physical layer was named Innovative Modulation for the Brazilian Digital TV System (MI-SBTVD). This proposal employs OFDM and has an operation mode where space-time diversity at the transmitter may be employed, requiring at the receiver side a channel estimation algorithm capable of identifying the MIMO channel. This paper presents some algorithms where the estimation at pilot subcarriers is obtained through a linear combination of two received symbols, and interpolation is done to provide channel gains at data carriers. As the proposed system has the pilot subcarriers positioned in such manner to allow bi-dimensional interpolation, four possible algorithms are evaluated through computer simulations. The results for digital TV channel models are compared.