OFDM Receiver Structure for a Subband-Selective Mitigation of Time-Variant Interference

Abstract— System performance of orthogonal frequency-division multiplexing (OFDM) degrades in the presence of time-variant frequency-selective interference. In the literature, several pulse-blanking concepts have been introduced over the past few years, which are promising ways to mitigate impulsive interference for OFDM reception. However, blanking yields an attenuation of the signal and intercarrier interference (ICI). A receiver structure is proposed, which consists of a frequency-selective pulse-blanking unit, a blanking mitigation
unit, and an iterative ICI cancelation unit. The L-band Digital Aeronautical Communication System 1 (L-DACS 1) is regarded as an application that suffers from interference from the impulsive Distance Measuring Equipment (DME) system whose frequency bands partly overlap. It is shown that, by using the proposed mitigation scheme for impulsive interference, a reliable reception is possible, even in strong interference situations. OFDM is beneficial in situations where impulsive interference with moderate energy is present because its energy is spread over many subcarriers. overlapping frequency responses of the filter-bank subband filters with suitable filter types to increase the time selectivity of the blanking process. Furthermore, we introduce an MMSE-based soft blanking approach, which makes use of a subband-selective interference detection scheme. In particular, we address a proposal for the detection of the DME power in the subbands to apply soft blanking. < final year projects >