Analyzing First Generation Quantum Key Distribution Protocols in Low Earth Orbit Satellite Networks
University of West Hungary
Our aim is to analyze the quantum-based space communication in optical satellite communication. The quantum communication is based on the laws of quantum mechanics, and utilizes different quantum-based algorithms and protocols. Comparing with classical algorithms, which are used in classical computation, the advantages of quantum algorithms are the quickness, the factorization and encryption. The base unit of the quantum computing is the quantum bit (qubit), which can be represented by different polarization states of a photon. The state of a classical bit can be represented by only one of the 0 and 1 values, but the qubit can be an in arbitrary superposition of 0 and 1.
There are two groups of the currently used quantum key distribution (QKD) solutions. The first generation protocols use singe-photon sources, while coherent laser is used and the wave properties of light is exploited in the second generation protocols. This first approach is named as Discrete Variable QKD (DV-QKD), the second one is named as Continuous Variable QKD (CV-QKD).
The quantum-based satellite communications offers revolutionary solutions for the near future. A complex, satellite-based network could enable a global quantum key exchange service. Due to the nature of quantum-based protocols, the noise of the channels need to be estimated since the errors introduced by an eavesdropper could be masked by the natural noise of the channel. With our model based on the behavior of single-photon sources, we are able to analyze the effects of losses originated from beam spreading and pointing error on the first generation QKD protocols.
In our research, we dealt with different types of channels, including Earth-satellite, satellite-satellite and satellite-Earth channels and analyzed different types of QKD protocols, e.g., BB84, B92, S09. After the evaluation of the communication channels, a simulation platform was developed which handles different ground stations on the Earth, satellites on different orbits, and communication channels with different kind of transmission errors. We analyzed and evaluated the performance characteristics of such satellite network.
The research was supported by the Hungarian Scientific Research Fund – OTKA PD-112529.