Superimposed technique for OFDM/OQAM based digital terrestrial television broadcasting

Orthogonal frequency division multiplexing offset quadrature amplitude modulation (OFDM/OQAM) is a multi carrier modulation using staggered transmission on the I and Q axes. It uses as well an optimized non-rectangular pulse shaping. There are several advantages with respect to the conventional OFDM modulation, while the main drawback is the intrinsic intersymbol interference, hindering e.g. a proper channel estimation. In this paper to overcome the effect of the intrinsic interference we propose to estimate the channel through the superimposed correlation-based method. We propose then to exploit the superimposed sequence to achieve time synchronization as well. In particular, in this paper we show that, under the realistic conditions (e.g regarding the spectrum masks), the proposed techniques work very well and allow to achieve a significant improvement in spectral efficiency.