Design, Simulation and Hardware Implementation of a Digital Television System: STC-OFDM and Channel Estimation

In 2005 the Brazilian government supported many research consortia in order to develop an advanced digital television system employing the most recent technologies for multimedia broadcasting. One of the proposals for the physical layer of this system was entitled innovative modulation for the Brazilian digital TV system (MI-SBTVD). The MI-SBTVD project includes high performance error correcting codes, transmit spatial diversity and multi-carrier modulation. The focus of this paper is two-fold. First, we look at the transmit diversity scheme, which combines Alamouti coding and OFDM modulation. We then discuss the channel estimation algorithm that has been implemented in the proposed system. Pilot subcarriers are inserted among data subcarriers, and both unidimensional and bidimensional linear interpolation at the receiver are considered. Computer simulation results, using typical digital TV channels, show that the proposed scheme is able to perform close to the case of a perfectly known channel at the receiver