IET Quantum Communication最新文献

Long-distance free space quantum key distribution based on CubeSats can be used to establish global quantum secure communication networks, with potential commercial applications benefitting from the low cost of its design and launch. Detecting single-photon level optical pulses sent from space requires highly accurate and robust timing systems to pick out signals from the noise. For such high-loss applications, we envisage a low-repetition (sub-MHz) beacon laser emitting short (ns) high-peak-power pulses from which interpolated quantum signal arrival windows can be derived. We firstly study theoretically the effects of jitter on the efficiency of gating quantum signals including all important jitter sources, and then experimentally investigated it by changing the clock jitter, and the result shows that the greater jitter will reduce the gating rate of the signal. The experimental interpolation error is tested against loss under laboratory conditions giving results close to our model. We also found that the jitter introduced by the Doppler effect can be ignored with a repetition rate larger than 1 kHz. This model can be directly used for the performance analysis and optimisation of all quantum and non-quantum systems using similar synchronisation schemes over terrestrial free space or fibre.

The evolution of Connected and Autonomous Vehicles (CAVs) promises improvements in our travel experience and the potential to enhance road safety and reduce environmental impact. This will be utilising highly diverse traffic environments that enable several advanced mobility applications. A secure, efficient, reliable, and resilient communications infrastructure is required to support developments in these CAV systems. Next generation of telecommunication networks will seamlessly integrate terrestrial, satellite, and airborne networks into a single wireless system satisfying the requirements of trustworthy future transport systems. Given the increasing importance of CAVs, coupled with their attractiveness as a cyber-attack for threat agents (e.g., disruption of transportation systems by nation states), security is paramount. Future communications systems offer an opportunity to integrate Quantum Key Distribution (QKD) into vehicular environments, protecting against advances in quantum computation that render many of the classical algorithms that underpin Public Key Infrastructure obsolete. This paper proposes a method for the integration of QKD in V2I networks to enable secure data communication. Quantum Key Distribution is used in the end-to-end path of vehicle-to-infrastructure (V2I) networks. Furthermore, an overarching Software-Defined Network, with integrated QKD, is introduced. We have investigated the security performance of QKD in a V2I network over an urban environment.

SARS-CoV-2 epidemic (severe acute respiratory corona virus 2 syndromes) has caused major impacts on a global scale. Several countries, including India, Europe, U.S.A., introduced a full state/nation lockdown to minimise the disease transmission through human interaction after the virus entered the population and to minimise the loss of human life. Millions of people have gone unemployed due to lockdown implementation, resulting in business and industry closure and leading to a national economic slowdown. Therefore, preventing the spread of the COVID-19 virus in the world while also preserving the global economy is an essential problem requiring an effective and immediate solution. Using the compartmental epidemiology S, E, I, R or D (Susceptible, Exposed, Infectious, Recovery or Death) model extended to multiple population regions, the authors predict the evolution of the SARS-CoV-2 disease and construct an optimally scheduled lockdown calendar to execute lockdown over phases, using the well-known Knapsack problem. A comparative analysis of both classical and quantum models shows that our model decreases SARS-CoV-2 active cases while retaining the average global economic factor, Gross Domestic Product, in contrast to the scenario with no lockdown.

Quantum-based technologies will provide system engineers with new capabilities for securing data communications. The UK AirQKD project has implemented a Free-Space Optical Quantum Key Distribution (QKD) system to enable the continuous generation of symmetric encryption keys. One of the use cases for the generated keys is to secure Vehicle-to-Everything (V2X) communications. V2X applications would benefit from the certificate-free security provided by QKD for a post-quantum society. How FSO-QKD could integrate into a V2X architecture is examined. An overview of V2X is provided with the role that FSO-QKD could secure V2X data though some obstacles exist. One of the issues with 6G communications is the potential line-of-sight (LOS) considerations between the V2X devices. The modelling required for LOS is examined to analyse the outage performance of the building to infrastructure links in the 6G architecture. The results from the model show that further work is required if 6G LOS communications are going to be relied upon for future safety-critical V2X applications.

The authors devised a protocol that allows two parties, who may malfunction or intentionally convey incorrect information in communication through a quantum channel, to verify each other's measurements and agree on each other's results. This has particular relevance in a modified version of the quantum coin flipping game. The key innovation of the authors’ work includes the new design of a quantum coin that excludes any advantage of cheating, by which the long-standing problem of the fair design of the game is, affirmatively, solved. Furthermore, the analysis is extended to N-parties communicating with each other, where multiple solutions for the verification of each player's measurement is proposed. The results in the N-party scenario could have particular relevance for the implementation of future quantum networks, where verification of quantum information is a necessity.

Quasi-chaotic generators are used for producing a pseudorandom behaviour that can be used for encryption/decryption and secure communications, introducing an implementation of them based on quantum technology. Namely, the authors propose a quasi-chaotic generator based on quantum modular addition and quantum modular multiplication and they prove that quantum computing allows the parallel processing of data, paving the way for a fast and robust multi-channel encryption/decryption scheme. The resulting structure is validated by means of several experiments, which assessed the performance with respect to the original VLSI solution and ascertained the desired noise-like behaviour.

As past works have shown, information-theoretically secure implementations transmitters of Y00 quantum noise randomised cypher are possible. An advance to the provably secure Y00 protocol by bridging gaps between experimental results and theoretical analyses under so-called quantum collective measurement attacks with known plaintexts is aimed. It would be the strongest attack on the Y00 protocol in the context of quantum key distribution protocols. However, recently proposed security evaluations under the attacks were too abstract to apply to experiments. Therefore, security analyses directly evaluable with the equipped Y00 transmitters under attack are offered. Thus, new security indices are proposed instead of ordinary security measures, such as the bit-error-rate guarantee between optical signals or a masking size. Contrarily, unsolved problems are also listed.

In quantum key distribution-secured optical networks (QKD-ONs), constrained network resources limit the success probability of QKD lightpath requests (QLRs). Thus, the selection of an appropriate route and the efficient utilisation of network resources for establishment of QLRs are the essential and challenging problems. This work addresses the routing and resource assignment (RRA) problem in the quantum signal channel of QKD-ONs. The RRA problem of QKD-ONs is a complex decision making problem, where appropriate solutions depend on understanding the networking environment. Motivated by the recent advances in deep reinforcement learning (DRL) for complex problems and also because of its capability to learn directly from experiences, DRL is exploited to solve the RRA problem and a DRL-based RRA scheme is proposed. The proposed scheme learns the optimal policy to select an appropriate route and assigns suitable network resources for establishment of QLRs by using deep neural networks. The performance of the proposed scheme is compared with the deep-Q network (DQN) method and two baseline schemes, namely, first-fit (FF) and random-fit (RF) for two different networks, namely The National Science Foundation Network (NSFNET) and UBN24. Simulation results indicate that the proposed scheme reduces blocking by 7.19%, 10.11%, and 33.50% for NSFNET and 2.47%, 3.20%, and 19.60% for UBN24 and improves resource utilisation up to 3.40%, 4.33%, and 7.18% for NSFNET and 1.34%, 1.96%, and 6.44% for UBN24 as compared with DQN, FF, and RF, respectively.

In this article, a protocol for information lossless teleportation using W states is proposed. Firstly, the information lossless teleportation of an unknown state with a maximally entangled W-state channel, which protects the original unknown state information even in case of teleportation failure is investigated. Next, we generalise our scheme to non-maximally entangled W-state channels. Finally, the principle of the proposed scheme is validated by performing experiments on the quantum circuit simulator Quirk. Our study shows that W states can be used to teleport any quantum state without information loss through single-qubit measurements and local unitary operations.

This paper applies a quantum machine learning technique to predict mobile users' trajectories in mobile wireless networks by using an approach called quantum reservoir computing (QRC). Mobile users' trajectories prediction belongs to the task of temporal information processing, and it is a mobility management problem that is essential for self-organising and autonomous 6G networks. Our aim is to accurately predict the future positions of mobile users in wireless networks using QRC. To do so, the authors use a real-world time series dataset to model mobile users' trajectories. The QRC approach has two components: reservoir computing (RC) and quantum computing (QC). In RC, the training is more computational-efficient than the training of simple recurrent neural networks since, in RC, only the weights of the output layer are trainable. The internal part of RC is what is called the reservoir. For the RC to perform well, the weights of the reservoir should be chosen carefully to create highly complex and non-linear dynamics. The QC is used to create such dynamical reservoir that maps the input time series into higher dimensional computational space composed of dynamical states. After obtaining the high-dimensional dynamical states, a simple linear regression is performed to train the output weights and, thus, the prediction of the mobile users' trajectories can be performed efficiently. In this study, we apply a QRC approach based on the Hamiltonian time evolution of a quantum system. The authors simulate the time evolution using IBM gate-based quantum computers, and they show in the experimental results that the use of QRC to predict the mobile users' trajectories with only a few qubits is efficient and can outperform the classical approaches such as the long short-term memory approach and the echo-state networks approach.