The paper gives an overview of phase based ranging techniques, focusing on the phase difference of arrival method measured in frequency domain (FD-PDoA). After a theoretical overview of distance estimation and localization, it introduces an experimental RFID front-end prototype used for FD-PDoA measurements. Proposed modular design is very flexible and allows easy replacement of any block, as well as direct access to all required low-level signals. The main part of the article is devoted to range estimation experiments in an anechoic chamber, using the developed front-end and signal processing in a PC with MATLAB. Several measurement problems are addressed, such as demodulator phase imbalance correction, wrapped phase recovery, etc. Ranging is performed with common passive EPC Gen2 RFID tags.

In the past decade, Long-Range Wire-Area Network (LoRaWAN) has emerged as one of the most widely adopted Low Power Wide Area Network (LPWAN) standards. Significant efforts have been devoted to optimizing the operation of this network. However, research in this domain heavily relies on simulations and demands high-quality real-world traffic data. To address this need, we monitored and analyzed LoRaWAN traffic in four European cities, making the obtained data and post-processing scripts publicly available. For monitoring purposes, we developed an open-source sniffer capable of capturing all LoRaWAN communication within the EU868 band. Our analysis discovered significant issues in current LoRaWAN deployments, including violations of fundamental security principles, such as the use of default and exposed encryption keys, potential breaches of spectrum regulations including duty cycle violations, SyncWord issues, and misaligned Class-B beacons. This misalignment can render Class-B unusable, as the beacons cannot be validated. Furthermore, we enhanced Wireshark’s LoRaWAN protocol dissector to accurately decode recorded traffic. Additionally, we proposed the passive reception of Class-B beacons as an alternative timebase source for devices operating within LoRaWAN coverage under the assumption that the issue of misaligned beacons can be addressed or mitigated in the future. The identified issues and the published dataset can serve as valuable resources for researchers simulating real-world traffic and for the LoRaWAN Alliance to enhance the standard to facilitate more reliable Class-B communication.

The last decade has transformed wireless access technologies and crystallized a new direction for the internet of things (IoT). The modern low-power wide-area network (LPWAN) technologies have been introduced to deliver connectivity for billions of devices while keeping the costs and consumption low, and the range of communication high. While the 5G (fifth generation mobile network) LPWAN-like radio technologies, namely NB-IoT (narrowband internet of things) and LTE-M (long-term evolution machine type communication) are emerging, the long-range wide-area network (LoRaWAN) remains extremely popular. One unique feature of this technology, which distinguishes it from the competitors, is the possibility of supporting both public and private network deployments. In this paper we focus on this aspect and deliver original results comparing the performance of the private and public LoRAWAN deployment options; these results should help understand the LoRaWAN technology and give a clear overview of the advantages and disadvantages of the private versus public approaches. Notably, we carry the comparison along the three dimensions: the communication performance, the security, and the cost analysis. The presented results illustratively demonstrate the differences of the two deployment approaches, and thus can support selection of the most efficient deployment option for a target application.

This paper describes a software defined radio system for measurements of minimum activation power and backscatter power of UHF RFID tags. We propose a platform for performance testing of tags, which is based on a general purpose universal software radio peripheral (USRP) and optimized for operation in the frequency band from 700 MHz to 1100 MHz at the output power of 2 W ERP. The presented HW and SW stack extends the standard library of USRP with RFID specific functions, an interface to LabVIEW, and by a top level LabVIEW code for automated testing.