Blind Bluetooth interference detection and suppression for OFDM transmission in the ISM band

The performance of an OFDM-based transmission system according to IEEE 802.11g can severely suffer from interfering Bluetooth packets. Therefore, we propose two new approaches for narrow-band interference suppression as countermeasure. At first, the presence and frequency position of interference is blindly estimated by evaluating either the magnitude variance of the received symbols or the noise power on each subchannel. For that purpose, we present one algorithm based on differentiation in frequency direction, and another one making use of the median filter. After detection, an interference suppression by modifying the softbit magnitudes at the input of the channel decoder leads to a significant improvement of the system performance, as we will show by simulations.