Optimization of multiple access mode for large-scale constellation networking communication

大规模星座组网通信的多址接入方式优化

¹ Micro-satellite Research Center, Zhejiang University, Hangzhou 310027, China
² Huanjiang Laboratory, Zhuji 311899, China
³ Key Laboratory of Micro-satellite Research of Zhejiang Province, Hangzhou 310027, China

Received: 25 September 2022

Abstract

In the large-scale satellite constellation technology, the establishment of satellite internal network is the top priority. As the network capacity of the constellation continues to expand and the number of satellite nodes continues to increase, the previous multiple access technology can no longer meet the network capacity requirements of large-scale constellations. In order to meet the requirements of massive connections of satellite nodes in large-scale constellation for new networking communication methods, this paper establishes a sparse spread spectrum inter-satellite communication system with sparse code multiple access (SCMA) as the core. At the same time, the channel characteristics of large-scale constellation are analyzed and the corresponding inter satellite channel model is established in MATLAB. Based on this channel model, the performance of the system is simulated. The simulation results show that under the same signal energy to noise ratio, the sparse spread spectrum inter-satellite communication system established in this paper has better BER characteristics compared with orthogonal frequency division multiple access (OFDMA) and code division multiple access (CDMA). In addition, the threshold signal energy to noise ratio of the system is more than 2 dB better than that of CDMA technology, and the utilization rate of time-frequency resources is 50% higher than that of OFDMA technology.

摘要

在大规模卫星星座技术中, 卫星内部网络的建立是重中之重, 而随着星座的网络容量不断扩大、卫星节点的不断增多, 以往的卫星多址接入技术已经不能满足超大规模星座的网络容量需求。针对大规模星座中卫星节点的海量连接对组网通信新方式的需求, 以稀疏码分多址技术(sparse code multiple access, SCMA)为基础建立星间稀疏扩频通信系统, 提出了利用枚举遍历算法进行码本设计、迭代矫正算法完成接收端的信道估计等核心技术, 同时对大规模星座的信道特点进行分析并在MATLAB中建立了对应星间信道模型, 在该信道模型基础上对系统进行性能仿真。仿真结果表明在同等能噪比条件下, 所建稀疏扩频星间通信系统与正交频分多址技术(orthogonal frequency division multiple access, OFDMA)、码分多址技术(code division multiple access, CDMA)相比取得了更优的误码率特性, 并且, 该系统相对于CDMA技术其门限能噪比有2 dB以上的性能优化, 相对于OFDMA技术则有着50%的时频资源利用率提升。