Per sub-block equalization and channel estimation for next generation handheld DVB

Orthogonal frequency division multiplexing (OFDM) systems may experience significant intercarrier interference (ICI) when used in doubly selective channels (time- and frequency-selective), particularly when large OFDM blocks are employed in order to achieve a high spectral efficiency. In this paper we recall a technique to mitigate ICI by splitting equalization at the receiver in two parts. A first pre-equalizer operates on sub-blocks of the received OFDM block with the aim of minimizing ICI, while a second, conventional equalizer adjusts phases on a per-subcarrier basis after OFDM demodulation. Moreover, we propose an estimation of channel parameters needed for equalization based on a superimposed pseudo-noise (PN) sequence method. Performance of the proposed receiver is evaluated for a possible extension of the new digital video broadcasting DVB-T2 standard to an handheld version (DVB-NGH). We show that bit error rate targets after channel decoding can be met at up to twice the speed of a conventional OFDM receiver, depending on channel dispersion.