Study On High Altitude Platform Communication Based On Adaptive Modulations

The high altitude platform communication has attracted more and more attentions of the researchers. With the aim of real-time video transmission between high altitude communication platform and the aeroplane in flight under high dynamic circumstance, this thesis gives a communication system scheme based on the high altitude platform for increasing the performance of the system. This thesis emphasizes on the signal processing of the communication link in high altitude communication system with the three main achievements as follows:1. According to the application environment and business demand, the following tasked have been finished: designing the composition structure, choosing the duplex method, planning the channels, choosing the modulation system, the function of the channels and classifying the state of the system. And on the basis of the work, the up-down-link frame structure, information processing and modulated switching units have been designed.2. The compensation scheme and stimulation analysis on signal distortions which were caused by signal acquisition, timing synchronization and carrier tracking have been given to adjust the system's high dynamic circumstance.3. An adaptive modulation scheme on the channels' state of the system has been designed to increase the spectrum efficiency of the system. What's more, the design and stimulation analysis on estimating the system's SNR, setting the modulated switching thresholds and the adaptive modulation scheme have been achieved.