Architecture Proposal for 6G Systems Integrating Sensing and Communication

Integrating sensing functionality into 6G communication networks requires some changes to existing components as well as new entities processing the radar sensing signals received by the communication antennas. This whitepaper provides a comprehensive overview of the 6G design proposal for ISaC (Integrated Sensing and Communication). The whitepaper has been created by the architecture group of the KOMSENS-6G project with the intend to serve as a basis for further discussions and alignment across innovative 6G projects.

💡 Research Summary

This whitepaper, authored by the architecture group of the KOMSENS-6G project, presents a comprehensive logical system architecture proposal for integrating sensing capabilities into future 6G communication networks, termed Integrated Sensing and Communication (ISaC). The proposal builds upon the established 3GPP 5G system architecture, advocating for a pragmatic evolution through enhancements to existing components and the introduction of new, dedicated ISaC entities.

The core architectural concept involves modifications on two fronts: the Radio Access Network (RAN) and the Core Network. In the RAN, base stations (gNBs) are enhanced with new signal processing functions (e.g., “L1-high Sensing”) to handle radar-like reflected signals received by communication antennas. In the Core, a new logical function called the Sensing Management Function (SeMF) is introduced. The SeMF acts as a central orchestrator, managing sensing tasks, collecting and fusing sensing data from multiple gNBs, and interfacing with the Charging Function (CHF).

To expose the sensing service to applications, a new ISaC-API is proposed, extending the Network Exposure Function (NEF). For communication between the SeMF and the gNBs, a new Sensing Protocol (SeP) is defined, carrying both sensing control commands and sensing data. The whitepaper discusses three primary options for transporting SeP: a new dedicated point-to-point interface (currently standardized for 5G Advanced), a split using existing control-plane (via AMF) and a new data-plane interface, or a full transition to a Service-Based Interface (SBI) model between RAN and Core, each with distinct trade-offs in complexity, flexibility, and required changes.

The document details various sensing operational modes: monostatic (co-located TX/RX), quasi-monostatic (separate TX/RX at same site), and bi-static/multi-static (TX and RX at different sites). In multi-static sensing, the SeMF’s “Sensing Fusion” function combines data from multiple receivers to generate more accurate results, such as object position via trilateration.

A significant portion is dedicated to the RAN-internal architecture and the critical challenge of resource allocation. A new “Sensing Control” function within the gNB interacts with the SeMF. The scheduler must dynamically allocate limited radio resources between communication and sensing demands. Three strategies are outlined: using dedicated sensing signals, reusing existing communication signals (opportunistically), or a hybrid approach. The complexities of reference signal sharing for bistatic sensing—either over-the-air or via backhaul—are also explored.

In summary, this whitepaper provides a detailed and systematic blueprint for realizing ISaC in 6G. It moves beyond high-level concept by specifying logical functions, interfaces, protocols, and operational procedures, thereby serving as a foundational document for upcoming standardization and research efforts aimed at merging sensing and communication in next-generation networks.