Laura Marie Feeney’s research while affiliated with Uppsala University and other places

Due to their popularity, large coverage areas, and diversity of radio technologies, Low Power Wide Area Networks (LPWAN) will experience high levels of cross-technology interference. In this work, we investigate the impact of LoRa interference on IEEE 802.15.4 (Wi-SUN) networks. Using hardware experiments , we characterize the interaction between these two very different radio technologies. In particular, we observe that the IEEE 802.15.4 Clear Channel Assessment (CCA) mechanism does not reliably detect interfering LoRa transmissions. We therefore propose an enhanced CCA mechanism based on a Multi-Layer Perceptron classifier and show that it significantly reduces the number of unsuccessful transmissions, while remaining compatible with the IEEE 802.15.4 standard.

We present some preliminary results on LoRaWAN and IEEE 802.15.4-SUN interference in urban environments. The results are based on a simple simulation that is parameterized using PHY layer measurements of controlled interference scenarios.

Testbeds have become a common method to test systems under real conditions. However, testbeds are often specialised and designed for a specific purpose. We have developed a generic software framework to help building and extending testbeds. This demo shows how our newly developed platform for experimenting with energy storage devices is integrated into our software framework. We will demonstrate how our platform works and how it is used in our testbed.

We present a hardware platform for performing experimental studies of energy storage devices for low power wireless networks. It is based on a low-cost custom card that can apply fine-grain synthetic loads ? both charge and discharge ? to a set of batteries or capacitors and measure their response in detail. Loads can be defined from a "live" trace of a running wireless device, from a recorded trace, or programmatically via a script. This approach makes it practical to run well controlled, large scale, long running experiments and to obtain high precision and accuracy. We describe two proof-of-concept experiments using rechargeable Li coin cells and capacitors to demonstrate the capabilities of our platform.

The large number and wide diversity of IoT networks operating in unlicensed spectrum will create a complex and challenging interference environment. To avoid a 'tragedy of the commons', networks may need to more explicitly coordinate their use of the shared channel.

We describe a testbed for studying battery discharge behavior and the lifetime of wireless devices under controlled temperature conditions and present preliminary measurement results.

The rapid growth of new radio technologies for Smart City/Building/Home applications means that models of cross-technology interference are needed to inform the development of higher layer protocols and applications. We systematically investigate interference interactions between LoRa and IEEE 802.15.4g networks. Our results show that LoRa can obtain high packet reception rates, even in presence of strong IEEE 802.15.4g interference. IEEE 802.15.4g is also shown to have some resilience to LoRa interference. Both effects are highly dependent on the LoRa radio's spreading factor and bandwidth configuration, as well as on the channelization. The results are shown to arise from the interaction between the two radios' modulation schemes. The data have implications for the design and analysis of protocols for both radio technologies.

Advances in low pwer wireless communication have resulted in new radio technologies that can achieve long distance communication in energy efficient ways. An emerging problem in this scenario is interference between networks that share the same medium. The fact that these networks have a long transmission range increases the possibility of interference even more. Thus the investigation of how different networks can share the medium independently in a optimal way becomes an essential requirement for the IoT vision. In this poster, we present the first step of this investigation, which is measuring how LoRa and IEEE 802.15.4g PHY layers interfere.