| L-Band Digital Aeronautical Communication System1(L-DACS1), which will provide communication service for Air Traffic Services(ATS) and Aviation Operation Control(AOC) in the future, is a candidate technology for aeronautical mobile communication system proposed by International Civil Aviation Organization(ICAO). The deployment option for L-DACS1 as an inlay concept was approved that allows the utilization of frequency gaps between two adjacent channels of distance measure equipment(DME) system in the aeronautical radio navigation band at the World Radio Conference in 2007.To mitigate the deleterious influence of DME interference on the transmission link of L-DACS1 operating as an inlay system, the main research contents of this paper are as follows:Firstly,conventional pulse interference suppression methods of OFDM receiver are researched, including pulse blanking,pulse clipping and joint pulse blanking and clipping. Furthermore,to mitigate the influence of Inter Carrier Interference(ICI) caused by pulse blanking, an iterative pulse interference mitigation method based on hard-decision is introduced. Finally, the bit error rate(BER) of four conventional pulse interference suppression methods is compared by simulation.Secondly, an iterative pulse interference mitigation method based on soft-symbol reconstruction is proposed. Firstly, the soft-symbols are calculated based on the interleaved codeword bit soft-information of the codeword bit from soft-decoder. Then, the received signal is reconstructed with the soft-symbols and the frequency response of channel. At last, the blanked samples are compensated with the reconstructed received signal and the position information of the blanked samples. Simulation results show that the proposed method can effectively suppress DME interference and improve the reliability of the OFDM receiver. |
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