Improved RAN scheduling algorithms and the integration of edge functionality tackle low-latency requirements by reducing end-to-end communication delays. Despite these innovations, key architectural limitations remain, specifically the requirement to route user plane traffic through the core network's User Plane Functions (UPFs). This constraint is relevant in the case of traffic between two User Equipment devices (UEs) served by the same gNodeB (gNB), which is a common scenario in factory floor or campus network deployments where a large amount of the traffic would be between UEs in a small area. To address this limitation, an intra-gNB user plane shortcut mechanism is proposed. This shortcut mechanism involves a gNB directly routing user plane traffic between UEs connected to it, bypassing the UPF and some upper-layer user plane processing on the gNB. Considering the current 5G specifications, the proposed mechanism is investigated, and the necessary extensions are discussed. A proof of concept of this mechanism is also introduced and evaluated, built within the 5G RAN implementation of srsRAN. Our theoretical analysis demonstrates latency reduction, supported by prototype measurements conducted in a simulated environment, illustrating promising results for the shortcut concept in reducing end-to-end latency.

Fraunhofer FOKUS' Open6GCore is the first practical implementation of a 6G core network. It challenges the traditional view of network functions as rigidly connected components, by embracing a highly modular software-driven approach that offers significant adaptability and reduced complexity. The flexibility of Open6GCore allows dynamic adaptation to requirements, whether as a 5G core network, simplified microservices, microcore, or a distributed large-scale core network. By implementing 3GPP standards with modern IT methodologies, Open6GCore achieves scalability and resilience and simplifies the addition of experimental features. Thus, it is particularly well-suited for research environments, facilitating rapid prototyping and seamless integration of new functionalities. Initial functional validation demonstrates successful deployment, interoperability with 5G User Equipment and Radio Access Networks, and efficient core network operations. These results demonstrate Open6GCore's readiness as a platform for 5G and 6G testbeds, trials, and innovation. This paper highlights the architecture, development, validation, and integration techniques of Open6GCore, offering insight into its role as a foundational platform for next-generation networks.

To enable seamless 5G service continuity for mobile ground users traversing infrastructure-limited or obstructed regions, the integration of Non-Terrestrial Networks based on Low Earth Orbit satellite constellations is being actively pursued. However, the mobility dynamics of ground terminals frequently result in sudden Line-of-Sight loss, which undermines the feasibility of conventional handover preparation involving context transfer, synchronization, and identity continuity. Without pre-coordination, such transitions lead to uplink blindness, session interruption, and degraded performance. This paper addresses the handover problem under Non-Terrestrial Network-specific constraints by (i) defining a structured taxonomy of service continuity mechanisms suited for impaired Line-of-Sight conditions, (ii) introducing an analytical model that captures handover delay, authentication feasibility, and buffer dimensioning under varying visibility regimes, and (iii) quantitatively evaluating these mechanisms in a high-mobility highway scenario. The results underline that while context mirroring ensures superior continuity under full coordination, handover with reactive preparation emerges as the most practical and resilient fallback under constrained Non-Terrestrial-Networks conditions.

In the research project 5G-VICTORI we are looking into how fifth generation mobile network technology (5G) can help improve video streaming services for train passengers. We use the principle of a local 5G-based data link between trains and 5G base stations in railway stations to load media assets to a caching server in the train, from which passengers can stream media via the regular apps of video-on-demand (VoD) service operators. The paper gives an outlook on the challenges in delivering VoD services to trains via this type of cloud-edge platform. These include determination of relevant content for upload to the cache, enable good quality-of experience (QoE) live streaming and WiFi traffic shaping for fair allocation of network bandwidth to streaming clients.