Research And Implementation Of Rate Adaptation And Hybrid ARQ For Proximity-1 Space Communication

With the development of deep space detection task,the proximity-1 space communication has attracted widespread attention,and the related research is carried out in China due to Chang’e program and Mars exploration tasks.The efficiency and quality of a communication system are affected by the complexity and variability of deep space channel environment.Therefore,it becomes very important to design a system with adaptive technology and error control technology in the real communication system.In this paper,based on the CCSDS proximity-1 protocol,the method of rate adaptation and the mechanism of hybrid automatic repeat request(HARQ)in communication system are studied and implemented.The two technologies are combined and improved,which not only takes the application of the protocol into account,but also improves the transmission performance of the system.Firstly,this paper analyzes the characteristics of proximity-1.Based on the theory of multi-rate processing and HARQ,the overall analysis and design of the system scheme are performed.Secondly,the rate adaptation includes SNR estimation,multi-rate synchronization and adaptive switching of rate.Through the comparative analysis of the traditional methods of SNR,a joint scheme of estimation combined with DF and SNV is applied.At the same time,combined with the input-SNR and output-SNR,a rate switching criterion is designed.Furthermore,according to proximity-1 protocol,we analyze and design the scheme of the multi-rate synchronization that will affect the performance of rate adaption.And switching between different rates is achieved by using the programmable interpolation filter and the matched filter.Thirdly,HARQ is analyzed and designed,which is based on the combination of convolutional coding and Go-back-N ARQ.By analyzing and simulating the key parameters of ARQ,the recommendations on the sliding window length and the maximum number of retransmission are given.A solution is designed based on frame synchronization for solving the phase ambiguity in receiver.The scheme not only takes advantage of the characteristics of the protocol,but also has the advantages of compatible multiple modulation schemes.Finally,we design and implement the the hardware circuit of the the two pieces of content,and successfully test the whole system by both the hardware and software platform,the results and the analysis show the feasibility and correctnesss of the scheme in real protocol and system.