Research On Resource Control Strategy Of Centerless FDMA Satellite Communication System

With the continuous development of satellite communication technology,satellite communication systems have been widely used in many fields such as military,communications,and transportation.At present,most of the satellite communication systems adopt a centralized management method.However,in the circumstances with special application requirements,such as military war,earthquake,fire,etc.,once the central management station is destroyed or fails seriously,the satellite communication system will fall into a state of paralysis,which makes the central station,as the central center of the system,become the weakest link of the whole system.Aiming at the problem of poor survivability of the central satellite communication system,this article focuses on the centerless FDMA satellite communication system to carry out research work on efficient resource control.The main innovation points and specific research contents of this paper are as follows:(1)Aiming at the FDMA satellite communication system that is still widely used,this paper proposes a non-central resource control strategy based on its characteristics.The thesis completed the overall design of the plan including resource partitioning,logical channel partitioning,and efficient resource allocation techniques.This strategy fully considers various abnormal situations that inevitably occur in the satellite communication process(such as channel detection errors,collision caused by multi-users preemption of channel resources,and transmission of communication applications in the form of ALOHA contention on the CSC channel results in packet loss,etc.).It can effectively realize the independent access of the user station to the channel resources without the intervention of the central management station,which is closer to the engineering application requirements.At the same time,based on the proposed resource control strategy,this paper designs a centerless and robust resource control algorithm.The key technologies such as service occupancy perception and self-monitoring call control proposed in this algorithm have significantly improved the robustness of the system.(2)In order to verify the feasibility and correctness of the centerless satellite communication access control strategy and resource control algorithm,this paper proposes a simulation verification method for the centerless satellite communication system with C/S architecture.The advantage of this method is that it can effectively simulate the satellite communication channel environment in various abnormal situations,such as channel delay,signaling errors are uniformly simulated at the server end system level.The Client-side access control program can be carried out in accordance with the software framework developed by the final terminal.The core control code can be more conveniently and smoothly transplanted to the final satellite terminal product.The realization of the simulation verification method adopts N user stations and one analog satellite transponder,and the user station information is uniformly sent to the simulated channel environment to determine whether there is a collision and simulate abnormal conditions such as packet loss.At the same time,this paper builds a simulation verification platform,through the establishment of the client model,server model and service model,completes the software simulation experiment on the built platform.The experimental results show that the relationship between the call rate and the number of channels,the number of users,the average arrival time of service,the average call time of service,and the change of call rate under different conditions situation.(3)In order to provide a more realistic simulation test environment in line with the actual situation for the resource control strategy of the centerless satellite communication system,this paper proposes a semi-physical simulation system architecture,which replaces part of the user station simulated by computer software with hardware objects.The system architecture is mainly divided into three parts: the client simulated by the hardware development board,the client simulated by the computer software and the channel environment simulated by the computer software.At the same time,based on the hardware chip actually used by the satellite channel equipment,the transplantation of the access control program for centerless FDMA satellite communication was carried out on the Zynq platform and the Free RTOS operating system.Referring to the design idea of computer simulation experiment,the hardware in the loop simulation experiment is completed.