Towards Realistic Waveform-Level IoT Network Simulation via IQ Mixing

2026-04-07

AI Summary

Existing IoT network simulators predominantly rely on packet-level discrete-event models, which struggle to accurately capture waveform-level physical-layer effects—such as adjacent-channel leakage, intermodulation interference, and receiver non-idealities—in heterogeneous coexistence scenarios within sub-GHz ISM bands. This work proposes IQSim, a novel simulation paradigm that, for the first time, integrates real complex baseband IQ waveforms into network-level emulation, establishing an end-to-end pipeline from waveform generation and channel propagation through signal superposition to soft/hardware-based receiver demodulation. By transcending the limitations of conventional abstract collision models, IQSim enables high-fidelity modeling of critical nonlinearities and interference phenomena. An initial prototype demonstrates the feasibility of real-time simulation while preserving physical-layer fidelity, offering a new tool for IoT coexistence research.

Abstract

Most Internet of Things (IoT) network simulators are packet-level discrete-event systems in which physical-layer (PHY) behavior is approximated through analytical interference rules and precomputed error models. While this enables scalable experiments, it can miss key waveform-level effects such as adjacent-channel leakage, cross-modulation interference between coexisting signals, and receiver imperfections, which are critical in heterogeneous sub-GHz ISM-band coexistence scenarios. This paper discusses these limitations and introduces IQSim, a simulation paradigm based on in-phase/quadrature (IQ) stream mixing. Instead of predicting packet outcomes from abstract collision models, IQSim maintains a shared complex baseband IQStream into which simulated transmissions are inserted as IQ waveforms after propagation processing, and then demodulated by software-based receivers or hardware gateways. We outline the end-to-end workflow, including online or offline waveform generation, IQ-domain propagation, waveform superposition, and delivery to gateways. We also report preliminary prototype results supporting the feasibility of real-time execution.

Problem

• waveform-level simulation
• IoT network coexistence
• physical-layer effects
• ISM-band interference
• receiver imperfections

Innovation

• IQ mixing
• waveform-level simulation
• IoT network coexistence
• complex baseband
• physical-layer emulation