# Optical Wireless Fronthaul-Enhanced High-Throughput FC-AE-1553 Space Networks
## 1 Introduction  
FC-AE-1553 is a real-time command/response protocol designed for avionic applications that require high reliability, fault tolerance, and deterministic behavior. It builds upon MIL-STD-1553B, extending the bandwidth, address space, and data transfer size. FC-AE-1553 serves as an upper-level protocol over Fiber Channel and is widely used in space network data processing systems due to its reliability [1, 2, 3, 4, 5]. As technology advances and the human need for space exploration becomes more urgent, the demands for in-orbit space application missions and networks are gradually increasing. However, at the same time, space information networks also face various challenges and limitations. First, there are limitations to the expansion capability of the original wired network. In the space environment, traditional wired networks are constrained by factors such as weight, volume, and power consumption, which restrict their scalability. This means that increasing the network size and connecting new devices can be difficult and limited. Second, restricted installation and access locations pose a challenge. In space, the installation and access locations of devices are typically constrained by the structure and design of space stations or satellites. This may result in network devices being unable to be flexibly installed in ideal locations, thus affecting network performance and coverage. Third, high maintenance and replacement costs are a concerning issue. Due to the extremeconditions and unique nature of the space environment, maintaining and replacing network equipment requires a significant amount of time, effort, and resources. This not only increases operational costs but can also lead to network service interruptions and delays. Last, as the volume of network services continues to grow, the network's load-bearing capacity increases as well. The diversification and complexity of application missions and network services in space place higher demands on network bandwidth, latency, and capacity. Therefore, addressing these growing network demands becomes a crucial challenge in space information networks. These challenges require us to seek innovative solutions to enhance network performance, reliability, and adaptability to meet the future needs of space exploration. Researchers have primarily focused on optimizing the FC-AE-1553 space network under the Fiber Channel architecture, considering various topologies and service scheduling. In [6], the network performance of star-topology FC-AE-1553 was evaluated in terms of packet-loss rate and bandwidth, achieving a BER lower than \(10^{-8}\). Another study [7] introduced a passive optical network FC-AE-1553 architecture and compared it with star topology and ring topology, revealing lower latency in PON FC-AE-1553. In addition to optimizing the FC-AE-1553 network architecture, several studies [8; 9; 10; 11; 12; 13] have researched dynamic bandwidth allocation strategies based on factors such as traffic type, credit, or quality of service (QoS). While these studies have contributed to improving network bandwidth and enhancing the quality of service to some extent, they have been constrained by the theoretical upper limit of the Fiber Channel network due to the limited physical channels available. In the field of mobile communications, 3 GPP is studying enhancements to sidelink operations for 5G NR in release 17. One important feature of sidelink communication is B2B communication without a base station or reduction streams passing through a base station, so the latency of communication is significantly reduced and the bandwidth of the network is utilized more efficiently. However, due to the nature of the FC-AE-1553 space network, which involves securing fiber-optic cables within the bulkheads before launching the spacecraft into orbit, repairing or retrofitting wired fiber-optic connections in space becomes challenging and expensive.