Research On The Self-adaptive Mechanism Of Generation Coding Transmission In Space Networks

Traditional TCP protocol has many applied problems,such as the increases of packet error rate and the drops of throughput,etc,when it is used in the complicated space network environment.Accordingly,how to design and implement a reliable transport protocol for space network is an important research topic.In this paper,the adaptive generation encoding mechanisms is researched.Further more,space-oriented network transport protocol of generation coding is designed and implemented.The main contents of this paper are as follows:First,in this paper,we discuss several improved schemes for improving transmission performance in space network,and the related theoretical and applied research of network coding technology.The improved schemes include end-to-end scheme,link layer scheme,spilt connection scheme,and network coding scheme that the different advantages and disadvantages of these schemes are analyzed and researched.Then we discuss two generation-coded transport mechanisms: SG-NC coding scheme and MGM-NC coding scheme.Considered the two coding schemes,two typical coding transport protocols named TCP / NC protocol and CTCP protocol are introduced,farther,the advantages and disadvantages of two coded transport protocols are discussed and researched.Second,in order to resolve the problem of the self-adaptive generation coding size for transport protocol,the transport mechanism of generation coding is discussed,and a self-adaptive adjustment algorithm of coding generation size named GCA is designed and implemented.The main contents of the algorithm are as follows: the resources of space network environment are relatively scarce,choosing the simple and effective generation coding mechanism is more reasonable;discussed the packet coding within generation messages,we propose an improved scheme of packet coding within generation which can self-adaptive adjust redundancy factor according as the packet loss rate;in order to resolve the problem of the size of the adjustment generation(the original packet coding),we propose that the coding generation size is self-adaptive adjusted according as the factors of network bandwidth and latency;at last,we complete interaction issues between network coding algorithm and congestion control.Third,considered the combination of TCP / NC protocol and CTCP protocol,we design and implement a space-oriented generation coding transport protocol named GCTP.The general framework of GCTP protocol,packet format and network parameter estimation all are introduced.Design and implementation of the sender and receiver modules are discussed,and some key data structures and functions about GCTP are mention in this paper.Fourth,we design a test scenario in order to verify the effectiveness and improvement of the algorithm GCA and the GCTP protocol.The results showed that,the algorithm GCA can effectively improve transmission performance GCTP protocol at the environment of high packet loss and long delay,also can significantly improve the ability of self-adaptive bandwidth of GCTP protocol.