Aeronautical Communications Technology Research Based On Soft-information-forwarding Scheme

In the aeronautical radio communications, the communications will suffer the shadoweffect, multipath fading and Doppler shift during information transmission which maydamage the communication quality. In addition, the Earth’s curvature will restrict the radius ofaeronautical communications. With the rapid development of the aviation industry, theaeronautical radio communications nowadays need higher date rate and better transmissionquality. As an effective way to combat shadow and multipath fading effects in wirelesschannels, cooperative communications can generate independent links between the sourcenode and the destination node by introducing relay channel to provide independent links andassist the communications between the source node and the destination node. Through theimplementation of appropriate signal processing algorithms at the relay node, the informationbroadcasted from the relays is subsequently combined to produce spatial diversity at thedestination node. The relay channel between aircraft and ground control tower, can effectivelyincrease the radius of aeronautical communications and increase the coverage area ofaeronautical communications.This paper focuses on studying the forwarding scheme of cooperative communication inaeronautical communications. We proposed two soft information forwarding scheme for atwo-hop parallel relay wireless network in Rayleigh fading channels and aeronauticalchannels, gave an in-depth analysis of the key factors affecting these two scheme andconstraints, and compared the bit error rate performance of two soft information forwardingschemes with the amplify forwarding scheme and detect forwarding scheme. The proposedscheme can effectively extend the radius of aeronautical communications, overcome the effectof amplified noise in the amplify forwarding scheme and the error propagation problems inthe detect forwarding scheme, and equilibrate the efficiency and reliability of aeronauticalcommunications to gain higher date rate at the sacrifice of the reliability. The main points ofthe paper work and innovation are as follows:(1) We proposed the multiple phase shift keying symbol-based estimate forwarding scheme inRayleigh channels and aeronautical channel, respectively.(2) We proposed the multiple phase shift keying symbol-based mutual-information- forwarding in Rayleigh channels and aeronautical channel, respectively.The simulation results show that the data rate gradually increased and the reliability willbe obviously reduced with the increase of the modulation order with the samesignal-to-noise ratio and number of relay nodes. However, the bit error rate performance ofsoft information forwarding scheme is always superior to that of the amplify-and-forwardscheme and the detect-and-forward scheme in the low signal-to-noise region. In addition, themodulation order should not be too large as to guarantee the validity and reliability of datatransmission. Furthermore, it shows that the impact of channel estimation error on thesoft-information-forwarding scheme based on multiple phase shift keying modulationincreases as the accuracy of the channel state information estimation decreases.