Robust CSI-Based Soft Decision for COFDM Systems with Co-Channel Interference

In this paper, we propose a robust soft decision method based on channel state information (CSI) for coded orthogonal frequency division multiplexing (COFDM) systems. In the presence of co-channel interference (CCI), conventional soft decision decoding is performed by a simple erasing method for frequency selective CCI. But the conventional method cannot obtain sufficient performance gain because the CCI power varies and a considerable number of bits are affected by the CCI. For this reason, we consider a novel weighting method based on the specific CSI such as statistical location and instantaneous power of the CCI as well as typical frequency-selective fading channel. Simulation results verify that the proposed CSI estimation is sufficiently reliable for digital video broadcasting-terrestrial (DVB-T) system with analog TV signals as the CCI. In addition, the proposed soft decision method guarantees superior coded bit error rate (BER) performance compared to the conventional method.