In satellite communications, it is often necessary to broadcast large data to terrestrial users. Because the satellite channel is a typical fading channel, packets can’t be correctly received. Therefore, retransmission is necessary. This paper proposes a network-coding-based broadcasting retransmission approach, whose key idea is to combine different lost packets with network coding to achieve minimum number of retransmission. Simulation results indicate that compared with existing approaches, network-coding-based broadcasting retransmission approach can effectively reduce average number of transmissions.

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Fractionated Spacecraft is a concept which transforms a traditional monolithic spacecraft into a network of elements where a free-flying payload module is supported by nearby free-flying infrastructure modules. In this paper, we propose a novel concept named as Payload-Distributed GEO Communication Satellite System (PD-GEO) which divides the traditional GEO communication satellite into several modules. Those modules can be reconfigured, added, or exchanged independently from the others, and be reused over several missions. Then, for the purpose of reliable and high-efficient data transmission in this system, an opportunistic network coding based cooperative information exchange (ONC2IE) scheme was presented. Qualitative analysis and extensive simulations demonstrate the effectiveness and efficiency of ONC2IE.

According to satellite communication, a novel parameter estimation method based on spectrum feature analysis is proposed. For the satellite communication signals shaped by raised cosine, the scheme enhance the efficiency of power spectrum and the square power spectrum of signals. The proposed method can estimate symbol rate and carrier frequency exactly in the satellite channel without any prior knowledge.

It is significant to develop a method to realize efficient broadcast transmission in wireless networks. Network coding is a promising technique in this scenario. In this paper, a multicast constellation design scheme using combination network coding (CNC) is proposed. This scheme employs CNC to guide the constellation design, under multi-objective such as multicast throughput and coverage performance. Through the analysis and simulation results, the design result can completely meet the design requirement.