Real-Time-Shift: Pseudo-Real-Time Event Scheduling for the Split-Protocol-Stack Radio-in-the-Loop Emulation

The incorporation of real radio hardware and physical emulated radio links into higher layer network and protocol simulation studies has been a largely untouched area of research so far. The Split-Protocol-Stack Radio-in-the-Loop emulation combines pure discrete-event protocol simulation with a hardware-based radio link emulation. Since the basic techniques involve contrary time concepts, event communication between the two domains requires a rethink of scheduling and synchronization. With the Real-Time-Shift conservative synchronization and time compensation scheme, the simulator is decoupled from real-time constraints and limitations by introducing predetermined pause times for event execution. In this paper, we present the core synchronization and event scheduling approach allowing for scalable pseudo-real-time simulations with radio hardware in the loop. This enables discrete-event simulations for wireless host systems and networks with link-level emulation accuracy, accompanied by an overall high modeling flexibility.