Research On Application Of Distributed Fountain Codes In Deep Space Communication

Deep space communication has higher requirements in materials, volume, power,storage capacity and technology because of the rapid development of modern deepspace communication. At the same time, the requirement of reliable transmission indeep space communications technology is dramatically increasing. The conventionalerror-control transmission mechanisms, such as ARQ, HARQ adatiptive ARQ and soforth, cannot satisfy the demand of modern deep space communication, taking accountof further communication distance and no feedback in deep space. Fountain codes are arateless code that as long as the receiver receives enough data packets, the original datapackets can be recovered. Fountain codes can adapt to the various changes of thechannel and have low encoding and decoding complexity. Therefore, fountain codes arethe solution to the problem of transmission feedback and are very suitable forapplication to deep space communications.The simple point-to-point deep space communications network model can nolonger meet the needs of development, so the complex multi-source multi-relay deepspace communication network model becomes the hotspot of modern research in deepspace communication. Therefore, distributed fountain codes were proposed. Such codenot only has better performance than ordinary fountain code, but can also can usemulti-source to disperse transmission and use other communication entities as relaystations. Thereby, it enables lower complexity and further communication distance.This thesis puts emphasis on the application of distributed fountain codes in deepspace communication, and proposes several types of distributed fountain codes base onanalysis of the principles of fountain codes, and makes further analysis and discussionon the principle and performance of the distributed fountain codes. my research includes:Firstly, the basics information of the deep space communication and fountain codes areintroduced, and the summaries and simulation of the commonly used decodingalgorithm of LT codes are finished. Subsequently, distributed fountain codes, prioritizedfountain codes, prioritized distributed fountain codes and unequal error protectiondistributed fountain codes are proposed. Distributed fountain codes realize distributed transmission at the same length of multi-source data packets, and can inprove thetransmission efficiency and performance, prioritized fountain codes provide theprotection of important data packets，prioritized distributed fountain codes improve itsperformance based on prioritized fountain codes and distributed fountain codes, unequalerror protection distributed fountain codes realize error protection of distributedfountain codes that muti-source information are not equal. This thesis provides detailedanalysis and simulation of these types of distributed fountain codes base on two andfour-source single relay deep space communication models.