Adaptive Threshold Optimization for a Blanking Nonlinearity in OFDM Receivers

Kurzfassung

The application of a blanking nonlinearity to cope with impulsive interference is a common approach in OFDM systems. The choice of the amplitude threshold to decide whether a received sample is blanked heavily affects the performance of the entire transmission. Unfortunately, the perfect blanking threshold strongly depends on the characteristics of the interference. In previous publications this perfect threshold has been derived, given knowledge about the interference statistics. However, in general no reliable information about the interference statistics is known at the receiver side. In this paper a practical method for calculating an adaptive blanking threshold to maximize the signal-to-interference-and-noise ratio after the blanking nonlinearity is proposed. The calculation is based on the distribution of the amplitude of the received signal at the OFDM receiver. Simulation results show only a negligible performance degradation when comparing the proposed method to the case where the theoretically derived perfect threshold is applied for blanking.