Research On Key Technologies Of Near-space Millimeter Wave High-speed Communication

With the rapid development of wireless communications,the lower frequency spectrum becomes more and more crowded,forcing us to focus on higher frequency spectrum resources,such as the millimeter wave band,especially the 60 GHz millimeter wave.Oxygen and water vapor can strongly absorb 60 GHz millimeter waves,resulting in large attenuation losses.As the elevation rises to the height of the near space,the density of oxygen and water vapor gradually decreases,and the absorption loss to the millimeter wave is greatly reduced.Due to the advantages of extremely large bandwidth and high anti-interference performance,Millimeter wave has a great application prospect in the near space.This thesis first investigates the characteristics of millimeter-wave wireless transmission at near-space height,and proposes a new method of millimeter-wave channel modeling for near space.According to the average annual global reference atmosphere in Recommendation ITU-R P.835-5 and the method for superimposing molecular resonance lines in Recommendation ITU-R P.676-10,we get millimeter wave loss curve at an altitude of 30 km in the near space,Then,we model the channel based on the principle of minimum phase system and equivalent low pass,Finally,we verifiy the minimum phase condition.Based on the idea of carrier aggregation,this thesis designs a near space 60 GHz millimeter-wave communication system,and has proved that this system can improve the average performance.This thesis uses MMSE equalization technology,and has proved that MMSE equalization technology can improve both single-channel performance and the system performance.