Multi-Relay Cooperative Diversity Based Rain Attenuation Mitigation Technology In HAPS

With the progress of the times,communication technologies change with each passing day.The current terrestrial communication system is gradually unable to meet the needs of human beings.High altitude platform stations usually work at a quasi static height between 20 to 25 km,with such advantages as low construction cost,easy deployment,wide coverage area,and low propogation delay.During the transmission process,the signal will go through a va riety of fading,among which the rain attenuation is one of the main reasons for poor communication performance of HAPS system working on Ka frequency band.Due to the limited energy of the high altitude platform and the limited area of the platform,traditional technologies cannot mitigate the impact of rain attenuation on the HAPS system effectively.In this paper,I use cooperative diversity technology to assist the communication between HAPS and users.Through cooperative diversity technology,the communication link quality between transmitter and receiver can be enhanced and the communication quality of the system can be improved by utilizing the information forwarded by other users in the communication environment.Firstly,the characteristics of wireless propogation environment in HAPS communication system are investigated.Secondly,we introduce the transmission strategies,merging algorithms of cooperative diversity.Then the system model and transimission process of the HAPS are illustrated detailedly.Fianlly,the multiple-relay selection scheme based on backtracking algorithm is proposed to select suitable cooperative users,and the performance of the proposed multi-relay selection scheme is verified by Matlab.