Adaptive Coding And Modulation Technique For Aircrafts Networking Based On LDPC

As the requirements for collaborations of the aircrafts are in great urgency, thesolutions for the networking among aircrafts are pressing. When the aircrafts are incommunication, the channel is of complete complication. There are large-scale fadingand small-scale fading at the same time. It is impossible for fixed coding andmodulation scheme to enhance the spectral efficiency as to secure the communicationquality meanwhile. Adaptive coding and modulation (ACM) is an advanced way tobalance both the quality and efficiency in communication. Accordingly, an ACM basedon LDPC for the aircrafts networking is researched in this paper. It is an important andsupportive method that adjusts the aircrafts communication networking to thecomplicated channel.First of all, LDPC, which is the basis technique of the aircrafts networking, isexplored. The theories, construct and decoding methods of LDPC is elaborated in thispaper. Then the BER performance of LDPC under the modulation of M-QPSK andM-QAM is simulated. The results of the LDPC BER performance are analyzed later on.These are all prepared for the optional modes of coding and modulation for the ACMtechnique. Secondly, the channel model about the aircrafts communication is deeplyresearched. There are two categories of the channels, one is the channel between theaircrafts and the other is the channel between the aircraft and the ground station. Linkaccounts and analysis have been done to the two of the channels. Signal-time-seriesmodel is built based on the Link accounts for the purpose of the following-up research.Thirdly, the integrated ACM technique of aircrafts networking is designed, includingcoding, modulation, channel estimation, demodulation, decoding and adaptive control.There are five modes for the ACM optional mode-scheme. The M2M4and DA-MLchannel estimations are investigated in this paper as well. After doing research to thethreshold shift method, a Schmidt-ACM mode switching method is proposed. Thisimproved method is well researched as the threshold shift method. At last, throughcomplete simulation, the superior performance of the Schmidt-ACM mode switchingmethod is proved. It is better than the threshold shift method in switching times andBER performance.