The integration of terrestrial and non-terrestrial networks is a key enabler for seamless global connectivity in 6G systems. Existing simulation tools typically address only one domain, lacking unified architectures for capturing transient protocol-level behavior during satellite mobility events. This paper introduces BrightLight, a hybrid emulation–simulation testbed for space–terrestrial integrated networks (STINs) that combines Linux network namespaces, NS-3 mmWave channel modeling, and an Open5GS core to execute real protocol stacks under configurable satellite mobility and gateway impairments. To demonstrate the platform's ability to capture fine-grained handover dynamics, we evaluate backhaul-aware handover over a Starlink-based constellation topology, comparing conventional satellite switching against inter-satellite link (ISL) assisted rerouting under ground-segment congestion. BrightLight successfully captures transient throughput evolution, TCP buffer drainage effects, and RTT dynamics throughout the handover process, revealing that routing via ISLs to uncongested ground stations substantially reduces latency and eliminates throughput degradation. These results validate BrightLight as an effective platform for studying protocol-level handover behavior in 6G STIN architectures.
Murat Parlakisik, Ertan Ozturk· International Mediterranean...· 0 citations
Evaluating end-to-end network performance in Low Earth Orbit (LEO) satellite mega-constellations requires systemlevel testbeds capable of capturing extreme satellite mobility, rapidly evolving topologies, and realistic protocol behavior at scale. Existing approaches rely on analytical models or eventdriven simulations that abstract away protocol-level interactions and time-varying orbital dynamics. This paper demonstrates the capability of our developing hybrid emulation-simulation testbed for end-to-end system-level evaluation of LEO megaconstellations, using ground station placement as a representative case study. The testbed instantiates each satellite as an isolated network namespace with a real protocol stack, computes all propagation delays from instantaneous satellite distances and the speed of light, and evaluates performance across a full orbital period rather than a single static snapshot. Using the testbed, we evaluate four placement strategies across Starlink Gen1, OneWeb, and Amazon Kuiper architectures. The results reveal previously unreported system-level insights, including latency saturation beyond approximately 100 ground stations, a reduction in orbital sensitivity from 10-15 ms to less than 1 ms, and fundamental performance differences between ISL-enabled and non-ISL architectures.
Murat Parlakisik, Ertan Ozturk· International Mediterranean...· 0 citations
The integration of terrestrial and Non-Terrestrial Networks (NTNs) is a cornerstone of the sixth-Generation (6G) vision, yet orchestrating artificial intelligence (AI) workloads across these heterogeneous domains remains an open challenge. This paper introduces an AI-driven orchestration architecture for integrated satellite-terrestrial 6G networks that extends four components of our previously proposed AI-native design, namely the 3rd Generation Partnership Project (3GPP) enhanced Network Data Analytics Function (NWDAF), Service Hosting Environment (SHE), Network Knowledge Exposure Function (NKEF), and AI agent framework, with NTN-specific capabilities. Drawing on a systematic analysis of the 20 ubiquitous connectivity use cases and the five AI-NTN convergence use cases from the 3GPP Technical Report (TR) 22.870 document, we conceptualize these architectural extensions: (i) an NTN-enhancement to NWDAF for ingesting satellite telemetry and ephemeris data to be used in predictive handover and coverage analytics, (ii) a space-edge computing tier within SHE that enables onboard satellite AI inference with a latency-aware model placement framework, (iii) a cross-domain AI agent for intent-driven orchestration across terrestrial and satellite operator boundaries, and (iv) an NKEF feature exposing constellation topology and coverage predictions to third-party applications. In order to demonstrate the effectiveness of this orchestration architecture, we present a handover management framework addressing four transition types (satellite-to-satellite, satellite-to-terrestrial hand-out, terrestrial-to-satellite hand-in, and inter-orbit) with backhaul-aware path selection leveraging inter-satellite links. Next, a comparative evaluation of eight NTN testbed platforms identifies current validation capabilities and gaps with respect to the discussed end-to-end system. [...]
Murat Parlakisik, Ertan Ozturk, Nazli Guney· ITU Journal on Future and Ev...· 1 citation