Research On Key Techniques Of TD-SCDMA PHY Layer For High-altitude Platform Communication System

The application concerning stratosphere communication system possesses a promising prospect for its broad coverage and flexible network-construction. This thesis proposed a high-altitude stratospheric platform (HAPS) communication solution based on TD-SCDMA system with the purpose of exerting its exceptional advantages as well as avoiding unfavorable disadvantages. The thesis mainly focuses on the key technique applied in the physical layer. The main accomplishments are listed as follows,1. The stratosphere communication system scheme is proposed which is compatible effectively with the terra communication systems. The network planning and physical layer frame structure are completed. The channel model is analyzed.2. According to the key technique of semi-regeneration, the uplink synchronization process based on HAPS is designed and the uplink synchronization implementation scheme is given. Based on Continuous Wave Time-Division Multiplex (CWTDM), the complexity of signal processing on the HAPS is reduced efficiently.3. The downlink frequecy offset correction and sample timing synchronization scheme adopted in the ground gateway is described. Based on the B.Steiner channel estimation method adopted in the ground TD-SCDMA system, a post-process technique fitable for HAPS system is proposed. The simulation results of ZF-BLE and MMSE-BLE for joint detection have been compared.4. The system is divided into several modules in accordance with function. The CWTDM module in the HAPS, sample timing synchronization and the channel estimation module in the ground gateway are completed.