Research On Polar Coding Techniques For High Throughput Aerospace Communications

Aerospace communication is a combination of new generation wireless communication technologies and the cutting-edge fields of space science and technology.The development trends of aerospace communication can be summarized as the broadband satellites with high capacity,the networking of satellites in different orbits,and the heterogeneous integration of satellite-terrestrial network.With the development of aerospace communications,the information transmissions face the problems such as increasing environmental fading,dynamic time-varying links,and complex and diverse services and scenarios.Channel coding technology is the key underlying technology of communication systems,which needs to support for the reliability of information transmission in the entire process of high-throughput aerospace communication.However,under the constraints of aerospace communication characteristics,traditional coding techniques become not applicable.They are difficult to guarantee continuous and reliable transmissions under large attenuation and time-varying links,and they are also difficult to accurately support complex services and scenarios with different characteristics and requirements.Therefore,it is urgent to carry out innovative research on reliable coding technology for high-throughput aerospace communications.Focusing on the reliablility requirement of high-throughput aerospace information transmissions,the dissertation aims to improve the coding applicability under the constraints of aerospace characteristics.Based on polar coding,the dissertation carries out novel research on the channel coding theory and technology for high-throughput aerospace communications.The core technical requirement is to improve gain ability,adaptability and practical ability of the coding.Therefore,the dissertation mainly focuses on exploring methods to obtain high coding gains with a small amount of computational and storage overhead,designing coding transmission strategies suitable for time-varying channels,and proposing practical concatenated coding schemes for typical services and scenarios.Thus,the reliability of coding technology under high-throughput aerospace communications can be guaranteed.Specific research on the following aspects.Firstly,the encoding and decoding algorithms of polar code are studied and the decoding resource cost is optimized.The encoding and decoding principles of polar code are studied,and the resource cost optimizations of high-gain decoding methods are the key points.Based on the theoretical analysis of the decoding process,the decoding complexity optimization strategy is formulated to minimize the decoding computation and storage resource cost while ensuring the bit error performance as much as possible.This work makes the high-gain decoding methods of polar code suitable for the aerospace communication nodes with limited resources,and improves the cost-effectiveness of the coding gain.Secondly,a rateless polar coding scheme is designed for the time-varying links in aerospace communications.According to the characteristics of time-varying channel and the requirement of reducing retransmission,the rateless polar coding scheme is designed based on the analyses of the design principles.Aiming at the requirement of continuous coded transmissions in time-varying channels,an adaptive rateless polar coding scheme is designed with the goal of improving efficiency.This work makes the polar coding suitable for the dynamic time-varying aerospace links,and improves the adaptability of the coded transmissions in aerospace communications.Thirdly,aiming at high-speed stream transmission,which is a typical service in aerospace communication,the staircase concatenated polar coding scheme is designed,and the time dimension coding is applied to ensure the reliability through concatenations and interleaving.According to the requirements of concatenated coding,the iterative soft input and soft output high-gain decoding is designed and simplified,and then the decoding of staircase concatenated polar codes is comprehensively designed.Considering the transmission requirements of high-speed streaming services in time-varying links,a rateless staircase concatenated polar coding scheme is also designed.This work provides a new high-reliability polar coding scheme for high-speed stream services of aerospace communication,and supports the precise matching of coding schemes to services in aerospace communications.Finally,concatenated polar coding schemes for single-user and multi-user are carried out for the important satellite-terrestrial transmission scenarios.In order to improve the transmission reliability and based on multi-antenna diversity gain,a concatenation of polar codes and space-time codes is provided with fully considering the antenna correlations in aerospace communication scenarios.For satellite-terrestrial multi-user access,considering the link characteristics of scenarios,the concatenation of polar codes and SCMA is designed.The process of estimation,detection and decoding is also comprehensively considered to improve the transmission performance.This work provides new concatenated polar coding solutions for satellite-terrestrial transmissions,and improves the reliability of the transmissions.