Transmit diversity based on subcarrier diversity for OFDM broadcasting systems

This paper investigates the utilization of subcarrier diversity (SD) in modern broadcasting systems to achieve transmit diversity. SD takes advantage of orthogonal frequency division multiplexing (OFDM) and robust forward error correction (FEC) to exploit the space diversity of multiple transmit antennas. In particular, we focus on a variant of SD that we call transmit antenna switching (TxAS) in which each antenna transmits only in one contiguous portion of the spectrum. This way, it is possible to achieve a higher diversity than single transmit antenna configurations with no significant increase in terms of complexity or pilot density. As a result, the utilization of TxAS can outperform more complex space-frequency block codes (SFBC) like Alamouti if the transmission of pilots is taken into account. We evaluate the performance of the proposed technique by means of physical layer simulations in the context of DVB NGH (Digital Video Broadcasting Next Generation Handheld), the future broadcasting DVB system for the provision of mobile services to handheld devices.