Linear Interference Measurement Campaigns
Within this workpackage, a variety of interference scenarios will be recorded. By using both, a real-time spectrum analyzer and a signal recorder, the utilization of ISM frequency bands (e.g. 2.45 GHz, 5.8 GHz) will analyzed over frequency and time. The goal of this work is to gain statistical information on the duration and periodicity of the channel occupation.
The measurements will be repeated on different days (i.e. workday, weekend), different sites (e.g. university campus, rooftop, electronics store) and will be repeated after several months to provide better statistical models and to allow for an extrapolation of the occupation situation.
The results will be made publicly available and serve as the input for other workpackages dealing with complexity reduction and interference emulation.
Complexity Reduction in Interference Simulation/Emulation
To allow an efficient simulation as well as a simple hardware emulation of interference, it is desirable to reduce the complexity of the interference. For example, it might be possible to represent a WiFi-packet by band-limited noise for a certain period of time.
This work package implements simulations and also experiemental verifications of complexity reductions. This is done by comparing bit/packet error simulations of WiFi-interferers with those of band-limited noise. Furthermore, a hardware test-setup consisting of a Linux-PC with two WiFi cards (emulating station and access point) and a arbitrary RF signal source (emulating the WiFi-interferrer and the band-limited noise, resp.) will be implemented for detailled verification.
The results of the work will have direct influence onto the FPGA-based interference emulation hardware.
Interference Recording and Playback
The goal of the work is to provide tools for acquisition and analysis of signals and their processing and re-transmission to simulate various sources of interferences in real-live conditions. This will allow evaluating the impact of interferences on the operation of various devices. The use case technologies for this evaluation will be RFID, LoRa, and WiFi.
The task includes the design and development of algorithms and methods for real-time simulation of interference signals by a software-based radio (SDR) platform. It includes the development of prototypes of hardware interfaces for measurement as part of pilot case studies.
The advantage of the SDR is that, unlike a hardware implementation, different transmission standards and sources of interference can be implemented very flexibly. SDR is therefore ideal for implementing new standards at the conceptual stage, with relatively low prototype cost, which is also called an emulator. The problems of interference can therefore be assessed at a very early stage in the development of pilot studies.
Modeling of Nonlinear Interference
From the recorded interference scenarios, behavioral models of linear and nonlinear communication channels will be derived and the model parameters for these channel models calculated via optimization methods. A library for various channel scenarios will be developed and delivered to the interested community.
The simulations will be performed by the simulator LinzFrame, a C++ written mixed-level circuit and device simulator. Moreover, from the statistical information provided by the measurement campaigns, the parameters of the behavioral models will be benchmarked to provide confidence information to the users on the validity of the models. Powerful tools and algorithms rely on novel techniques such as Uncertainty Quantification (UQ).
For the complexity reduction of the models, it is intended to employ state of the art of model order reduction (MOR) algorithms. The models will be incorporated into the interference emulation hardware, providing for the end user a configurable real-time platform.