Research On The Downlink Key Techniques Of High-altitude Platform Based Broadband Mobile Communication System

High-altitude platform based(HAP based)communication system has a good prospect of application for its wide coverage and deploying flexiblity This thesis analyses the system architecture, frame structure and frequency plan of HAP based broadband mobile communication system, with emphasis on the system architecture and downlink key techniques. The main contributions are as follows:1. The system architecture of HAP based broadband mobile communication system is described with emphasis on the frame format. Then the downlink transmiter and receiver for the aforementioned system are designed.2. In order to meet the synchronization precision requirement, a sample timing synchronization scheme based on multiphase filter banks re-sampling technique is presented. Simulation results show that the proposed scheme achieves a good synchronization precision.3. The deleterious impact of carrier frequency offset is analyzed and a carrier-tracking scheme is given. Simulation results show its good performance.4. An adaptive equalization scheme based on LMS algorithm is presented for the ground receivers and the simulation results show that the scheme can eliminate inter-symbol interference well.