In this paper, we propose an approach for constructing a multi-layer multi-orbit space information network (SIN) to provide high-speed continuous broadband connectivity for space missions (nanosatellite terminals) from the emerging space-based Internet providers. This notion has been motivated by the rapid developments in satellite technologies in terms of satellite miniaturization and reusable rocket launch, as well as the increased number of nanosatellite constellations in lower orbits for space downstream applications, such as earth observation, remote sensing, and Internet of Things (IoT) data collection. Specifically, space-based Internet providers, such as Starlink, OneWeb, and SES O3b, can be utilized for broadband connectivity directly to/from the nanosatellites, which allows a larger degree of connectivity in space network topologies. Besides, this kind of establishment is more economically efficient and eliminates the need for an excessive number of ground stations while achieving real-time and reliable space communications. This objective necessitates developing suitable radio access schemes and efficient scalable space backhauling using inter-satellite links (ISLs) and inter-orbit links (IOLs). Particularly, service-oriented radio access methods in addition to software-defined networking (SDN)-based architecture employing optimal routing mechanisms over multiple ISLs and IOLs are the most essential enablers for this novel concept. Thus, developing this symbiotic interaction between versatile satellite nodes across different orbits will lead to a breakthrough in the way that future downstream space missions and satellite networks are designed and operated.

6G networks are expected to meet ambitious performance parameters of coverage, data rates, latency, etc. To fulfill these objectives, the implementation of non-GEO satellite constellations is expected to improve coverage, capacity, resilience, etc. as well as the implementation of new advanced network virtualization algorithms in order to optimize network resources. However, the integration of these technologies represents new challenges, such as the execution of network slicing schemes in highly dynamic environments and network awareness requirements. In this regard, Software Defined Networking (SDN) is seen as a required 6G technology enabler in order to provide better satellite-terrestrial integration approaches and Virtual Network (VN) implementation solutions. In this paper, we present an experimental testbed for non-GEO satellite constellations integration solution and VNE algorithms implementation adapted to highly variable network conditions that builds upon SDN. A laboratory testbed has been developed and validated, consisting in SDN-based satellite-terrestrial dynamic substrate network emulated in Mininet, a Ryu SDN controller with an End-to-End (E2E) Traffic Engineering (TE) application for the VNs establishment and a Virtual Network Embedding (VNE) algorithm implemented in Matlab.

The integrated terrestrial and non-terrestrial networks in 5G and beyond 5G are envisioned to support dynamic, seamless, and differentiated services for emerging use cases with stringent requirements. Such service heterogeneity and rapid growth in network complexity pose difficulties to network management and resource orchestration. Network slicing paves the way for delivering highly customized services and enabling service-oriented resource allocation. In this context, artificial intelligence (AI) becomes a key enabler for network slicing management. However, AI-based approaches encounter critical challenges in adapting to dynamic and complex wireless environments. In this article, firstly, we aim at providing a comprehensive understanding of these challenges, open issues, and future research opportunities. Secondly, we highlight the investigations on dynamic-adaptive AI solutions for dealing with the effect of concept drift. Thirdly, we identify typical dynamic scenarios in case studies and provide numerical results to illustrate the effectiveness of the discussed AI solutions.

Virtual Network Embedding (VNE) is an emerging area of Telecom Networks, in an era where the physical capacity of the substrate network is pushed to the limits in order to get the maximum achievable performance. Link mapping optimization is one of the two sub-problems which the VNE is subdivided into. The objective of the paper is to demonstrate the efficiency of a parallel approach with respect to the sequential one, in particular when there is a high level of heterogeneity among the Virtual Networks to be embedded, such as network slicing scenario. In this regard, this paper investigates the significance of a parallel approach in effectively implementing VNE. Specifically, we focus the attention to the link mapping, considering the node mapping is already known a priori. In contrast to the trend in the literature to use Genetic Algorithms (GAs) for a parallel computation, this paper proposes a novel and efficient parallel link mapping algorithm for enabling VNE in realistic system scenarios. Two important objectives are considered, load-balancing and energysaving, and the presented results demonstrate the superiority of the proposed parallel approach over the sequential one in terms of these objectives, at the expenses of the computing time. Furthermore, the scalability of the proposed algorithm is evaluated over a range of substrate network sizes.

No abstract