Dtn and non-dtn routing protocols for inter-cubesat communications: A comprehensive survey

CubeSats, which are limited by size and mass, have limited functionality. These miniaturised satellites suffer from a low power budget, short radio range, low transmission speeds, and limited data storage capacity. Regardless of these limitations, CubeSats have been deployed to carry out many research missions, such as gravity mapping and the tracking of forest fires. One method of increasing their functionality and reducing their limitations is to form CubeSat networks, or swarms, where many CubeSats work together to carry out a mission. Nevertheless, the network might have intermittent connectivity and, accordingly, data communication becomes challenging in such a disjointed network where there is no contemporaneous path between source and destination due to satellites’ mobility pattern and given the limitations of range. In this survey, various inter-satellite routing protocols that are Delay Tolerant (DTN) and Non Delay Tolerant (Non-DTN) are considered. DTN routing protocols are considered for the scenarios where the network is disjointed with no contemporaneous path between a source and a destination. We qualitatively compare all of the above routing protocols to highlight the positive and negative points under different network constraints. We conclude that the performance of routing protocols used in aerospace communications is highly dependent on the evolving topology of the network over time. Additionally, the Non-DTN routing protocols will work efficiently if the network is dense enough to establish reliable links between CubeSats. Emphasis is also given to network capacity in terms of how buffer, energy, bandwidth, and contact duration influence the performance of DTN routing protocols, where, for example, flooding-based DTN protocols can provide superior performance in terms of maximizing delivery ratio and minimizing a delivery delay. However, such protocols are not suitable for CubeSat networks, as they harvest the limited resources of these tiny satellites and they are contrasted with forwarding-based DTN routing protocols, which are resource-friendly and produce minimum overheads on the cost of degraded delivery probability. From the literature, we found that quota-based DTN routing protocols can provide the necessary balance between delivery delay and overhead costs in many CubeSat missions

Energy-Aware Routing for CubeSat Swarms

CubeSats operating in a swarm are characterized by a mix of scheduled intermittent connectivity, high delays, and high failure rates. Each CubeSat is limited in size, usually has low data rates and has a low mass. Consequently, they have limited space for solar panels, and thus limit their available energy. Profitably, CubeSats can function in swarms using inter-CubeSat links as well as ground links. Accordingly, any routing protocols developed for CubeSats must be energy aware. We propose two novel Shortest and Energy Reliable Path (SERP) routing protocols; namely, SERP- Breadth-First Search (SERP-BFS) and SERP-Dijkstra. Both algorithms aim to minimize the overall energy cost and maintain connectivity over time. Both choose shortest paths that have CubeSats energy levels higher than or equal to an energy reliability threshold. We have compared our SERP algorithms with Epidemic algorithm. The results show the outperformance of our proposed algorithms in terms of saving the overall energy cost

Routing in CubeSat Networks: Protocols, Architectures and Standards

CubeSats, limited by size and mass, have limited functionality. These miniaturised satellites suffer from a low power budget, short radio range, low transmission speeds and limited data storage capacity. Regardless of these limitations, however, CubeSats have been deployed to carry out many research missions, for instance, gravity mapping and tracking air and marine navigation. One method of increasing their functionality and reducing their limitations is to form CubeSat networks, or swarms, where many CubeSats work together to carry out a mission. Nevertheless, due to given limitations of range, the network may still have intermittent connectivity and, accordingly, data communication becomes challenging in such a disjointed network where there is no contemporaneous path between source and destination. When the network is disjointed, the rate of dropped packets increases making the performance of traditional TCP/IP protocols inefficient