Different OFDM Link Level Performance Under the Presence of Co-Channel Interference and Noise

OFDM link level performance in terms of raw bit error rate (BER) versus signal-to-noise and interference ratio (SNIR) has been investigated for robust BPSK and QPSK modulation schemes in a WiMax like framework for both noise and interference limited scenarios. A fundamental difference between additive white Gaussian noise (AWGN) and co-channel interference has been observed especially under static/stationary conditions leading to a huge performance gap of several dB. The latter significantly depends on essential properties of the interference such as synchronization, modulation order as well as the received number of simultaneous interferers. Furthermore preamble based real channel estimation behaves completely different under noise and co-channel interference conditions thus considerably affecting the link level results. Real channel estimation proves to be very susceptible against co-channel interference and shows some additional degradation compared to ideal channel estimation with perfect channel state information. Moreover it has been shown that dominant co-channel interference has a strong impact on the results obtained under stationary/static conditions, whereas the statistics of a mobile fading channel significantly flattens those effects and reduces the performance gap to a rather marginal extent