The standardisation of 5G is reaching its end, and the networks have started being deployed. Thus, 6G architecture is under study and design, to define the characteristics and the guidelines for its standardisation. In parallel, communications based on quantum‐mechanical principles, named quantum communications, are under design and standardisation, leading to the so‐called quantum internet. Nevertheless, these research and standardisation efforts are proceeding in parallel, without any significant interaction. Thus, it is essential to discuss an architecture and the possible protocol stack for classical‐quantum communication networks, allowing for an effective integration between quantum and classical networks. The main scope of this paper is to provide a joint architecture for quantum‐classical communication networks, considering the very recent advancements in the architectural design of 6G and the quantum internet, also defining guidelines and characteristics, which can be helpful for the ongoing standardisation efforts. For this purpose, the article discusses some of the existing main standardisation processes in classical communications and proposed protocol stacks for quantum communications. This aims at highlighting the potential points of connection and the differences that may imply future incompatible developments. The standardisation efforts on the quantum internet cannot overlook the experience gained and the existing standardisation, allowing the creation of frameworks in the classical communication context.
The standardisation of 5G is reaching its end, and the networks have started being deployed. Thus, 6G architecture is under study and design, to define the characteristics and the guidelines for its standardisation. In parallel, communications based on quantum‐mechanical principles, named quantum communications, are under design and standardisation, leading to the so‐called quantum internet. Nevertheless, these research and standardisation efforts are proceeding in parallel, without any significant interaction. Thus, it is essential to discuss an architecture and the possible protocol stack for classical‐quantum communication networks, allowing for an effective integration between quantum and classical networks. The main scope of this paper is to provide a joint architecture for quantum‐classical communication networks, considering the very recent advancements in the architectural design of 6G and the quantum internet, also defining guidelines and characteristics, which can be helpful for the ongoing standardisation efforts. For this purpose, the article discusses some of the existing main standardisation processes in classical communications and proposed protocol stacks for quantum communications. This aims at highlighting the potential points of connection and the differences that may imply future incompatible developments. The standardisation efforts on the quantum internet cannot overlook the experience gained and the existing standardisation, allowing the creation of frameworks in the classical communication context.
In the field of Internet service evolution, classical and quantum paradigms are often seen as distinct and separate research areas. Typically, the classical Internet is perceived as a foundational communications infrastructure for the emerging quantum Internet, mainly providing essential services such as synchronization, signaling, control, and feedback. Current quantum Internet research requires a radical transformation of physical layer devices, often leading to the obsolescence of existing classical infrastructures. To address this challenge, in this work we introduce a new hybrid approach for the future development of the quantum Internet. Specifically, we will delve into various mechanisms and technologies that facilitate the integration of quantum networks with future 6G networks. Our goal is to develop a complete model for a hybrid quantum-classical Internet designed for future generation 6G in order to jointly and efficiently support both quantum and classical communications. In particular, we explore an innovative hybrid datalink layer architecture that is critical for effectively managing the diverse nature of quantum and classical data traffic and security. The main advantage of our model lies in the integration of new quantum hardware at the physical layer while leveraging existing advanced classical infrastructure. Our model is proposed as a step forward in the harmonization of quantum and classical Internet technologies, paving the way for a secure and fast future 6G architecture.
While quantum communications technology evolves, the promise of a Quantum Internet becomes closer and different proposals to build it have been already proposed, addressing different aspects of what such a global network would imply. We believe a consistent reference architecture model for the Quantum Internet is required to progress in its evolution, addressing the different dimensions such a network has to consider, including the interaction with the "classical" Internet. Such a reference architecture would provide a framework for the integration of the protocols applicable to it, and enable the advance of the applications based on it. As a reference model, it should allow the proposition and analysis of different approaches and solutions, providing a framework to reason about these solutions and their interplay to achieve a global Quantum-enabled open network.Such a model has to satisfy three essential requirements: agility, enabling it to adapt to the evolution of quantum communications base technologies, sustainability, with open availability in technological and economical terms, and pliability, being able to integrate with the operations and management procedures in current networks. This paper describes the reference architecture framework currently being discussed in the QIRG (Quantum Internet Research Group) of IRTF, and intended to provide a conceptual common framework for the integration of the different technology proposals to build the Quantum Internet infrastructure and its convergence with the current Internet. The framework is based on the already extensive experience in the deployment and operation of QKD infrastructures and on recent initiatives focused on the integration of networks and services.
The emergence of quantum networks promises revolutionary advancements in secure communication, computational power, and information processing. This paper provides insights into the essential components and architecture of quantum networks. We systematically examine each layer of the quantum protocol stack, from the physical layer responsible for qubit transmission and entanglement generation to the transport layer ensuring reliable qubit communication, up to the application layer enabling quantum key distribution and quantum computing applications. In this work, we introduce the E-QNet framework, an entanglement-assisted quantum network protocol stack designed to facilitate quantum communication. Key devices such as quantum transceivers, entanglement sources, quantum memories, quantum repeaters, and quantum routers are analyzed in the context of their specific roles and functionalities. We draw parallels with classical network architecture, highlighting both the unique challenges and novel solutions inherent in quantum networking. By elucidating the interplay between hardware devices and protocol layers, this article provides a comprehensive overview of the current state and future directions in quantum network design, offering valuable insights for researchers and engineers in the field. This work aims to contribute to the foundational understanding required for the development and implementation of robust quantum networks.
Quantum communications is a promising technology that will play a fundamental role in the design of future networks. In fact, significant efforts are being undertaken by both the quantum physics and the classical communications communities on developing new architectures, solutions, and practical implementations of quantum communication networks (QCNs). Although these efforts led to various advances in today's technologies, there still exists a non-trivial gap between the research efforts of the two communities on designing and optimizing the performance of QCNs. For instance, most prior works by the classical communications community ignore important quantum physics-based constraints when designing QCNs. For example, many existing works on entanglement distribution do not account for the decoherence of qubits inside quantum memories and, thus, their designs become impractical since they assume an infinite lifetime of quantum states. In this article, we bring forth a novel analysis of the performance of QCNs in a physics-informed manner, by relying on the quantum physics principles that underly the different components of QCNs. The need for the physics-informed approach is then assessed and its fundamental role in designing practical QCNs is analyzed across various open research areas. Moreover, we identify novel physics-informed performance metrics and controls that enable QCNs to leverage the state-of-theart advancements in quantum technologies to enhance their performance. Finally, we analyze multiple pressing challenges and open research directions in QCNs that must be treated using a physics-informed approach to lead practically viable results. Ultimately, this work attempts to bridge the gap between the classical communications and the quantum physics communities in the area of QCNs to foster the development of the future communication networks toward the quantum Internet.
Quantum communications is a promising technology that will play a fundamental role in the design of future networks. In fact, significant efforts are being dedicated by both the quantum physics and the classical communications communities on developing new architectures, solutions, and practical implementations of quantum communication networks (QCNs). Although these efforts led to various advances in today's technologies, there still exists a non-trivial gap between the research efforts of the two communities on designing and optimizing the performance of QCNs. For instance, most prior works by the classical communications community ignore important quantum physics-based constraints when designing QCNs. For example, many existing works on entanglement distribution do not account for the decoherence of qubits inside quantum memories and, thus, their designs become impractical since they assume an infinite lifetime of quantum states. In this paper, we bring forth a novel analysis of the performance of QCNs in a physics-informed manner, by relying on the quantum physics principles that underly the different components of QCNs. The need of the physics-informed approach is then assessed and its fundamental role in designing practical QCNs is analyzed across various open research areas. Moreover, we identify novel physics-informed performance metrics and controls that enable QCNs to leverage the state-of-the-art advancements in quantum technologies to enhance their performance. Finally, we analyze multiple pressing challenges and open research directions in QCNs that must be treated using a physics-informed approach to lead practically viable results. Ultimately, this work attempts to bridge the gap between the classical communications and the quantum physics communities in the area of QCNs to foster the development of the future communication networks towards the quantum Internet.
Abstract Over the past four decades, quantum communication has evolved as a dynamic interdisciplinary field, advancing theoretical concepts and practical implementations. This article provides a concise overview focusing on recent progress in different aspects of secure quantum communication and quantum computation protocols, which can be applied to several real-world applications in quantum networks. These protocols guarantee unconditional security while enhancing communication rates and computation capabilities by harnessing quantum advantages. We also explore the role of non-terrestrial networks in quantum applications, with a focus on quantum technologies such as quantum key distribution and beyond, suitable for satellite-based applications. These technologies can contribute to future extensions of the quantum internet across intercontinental territories, connecting complex quantum network applications. Further, we delve into discussing the integration of quantum communication into 6G technology. The key innovation of this article lies in integrating quantum communication into 6G networks through a novel system-level simulation framework. 6G-enabled quantum networks are expected to meet the high demands on ubiquitous coverage, data rate, latency, and energy consumption. To address these issues, we design and evaluate four traffic demand scenarios using numerical simulation, illustrating how superdense coding doubles the data transmission rate and fulfills the high traffic demands on data rate, while under low traffic demand, entanglement resources can be reserved for future applications. Specifically, our investigation demonstrates how resource utilization adapts to different traffic demands, with adjustments based on available resources and practical constraints, evaluated over an ideal noise-free communication channel. The proof-of-work simulation is implemented using Python and is based on the system model we designed for varying traffic demands to pave the way for efficient quantum networks and gain deeper insights into their feasibility with available resources.