Improving LoRaWAN performance by randomizing network access for data and on-air activation

Abstract During the past years, the LoRaWAN technology took a prominent position among the wireless connectivity solutions for the Internet of Things (IoT) and has attracted substantial attention. The LoRaWAN technology has become popular for collecting the data from the sensors, which traditionally have periodic communication patterns. Meanwhile, recent studies have shown that the LoRaWAN procedures, such as the over-the-air activation, may also compromise the uniformity of data traffic distribution. Therefore, in this study, we investigate how the communication pattern of LoRaWAN devices during activation and data communication affects the overall network performance with respect to speed of activation and overall packet delivery probability. We show that the periodic communication patterns, widely employed by commercial LoRaWAN devices today, are less efficient than the patterns featuring random delays between the packets. Also, we find that introduction of a random delay between uplink data packets helps randomizing the channel access and enables network performance boost both for the application data transfer and during the activation. Finally, we show that implementation of the suggested communication patterns modification is feasible for the state-of-the-art LoRaWAN transceivers with no hardware modifications

Unifying multi-radio communication technologies to enable mMTC applications in B5G networks

Abstract Even though the wireless communication technologies have evolved significantly in the last decade, the performance requirements of versatile massive Machine-Type Communication (mMTC) use-cases grow at even faster pace. For this reason, the challenge of providing energy-efficient, reliable, secure, and variable devices with ubiquitous connectivity cannot be addressed by any single Radio Access Technology (RAT) available today. Therefore, the concept of multi-RAT devices in the context of next-generation communication technologies (5G and beyond 5G (B5G)) comes into play. In this paper, we investigate the utility of multi-RAT IoT connectivity in practice with respect to a Smart City scenario, in which the location of public transport vehicles e.g., trams and buses is tracked and reported by a device equipped with two Low-Power Wide-Area Network (LPWAN) technologies i.e., Narrowband IoT (3rd Generation Partnership Project (3GPP)) and LoRaWAN (non-3GPP). Both technologies got matured and have shown their momentum in the recent years, and are expected to play the key role also in the future. We first detail the constructed multi-RAT prototype and then report the initial results of its evaluation in a pilot deployment in the city of Brno, Czech Republic. The obtained results illustratively confirm the feasibility of joint usage of two diverse LPWAN RATs while their combination brings higher flexibility, reliability, and improve the overall Quality of Service (QoS) to wireless connectivity

Accuracy assessment and cross-validation of LPWAN propagation models in urban scenarios

Abstract With the proliferation of machine-to-machine (M2M) communication in the course of the last decade, the importance of low-power wide-area network (LPWAN) technologies intensifies. However, the abundance of accurate propagation models proposed for these systems by standardization bodies, vendors, and research community hampers the deployment planning. In this paper, we question the selection of accurate propagation models for Narrowband IoT (NB-IoT), LoRaWAN, and Sigfox LPWAN technologies, based on extensive measurement campaign in two mid-size European cities. Our results demonstrate that none of the state-of-the-art models can accurately describe the propagation of LPWAN radio signals in an urban environment. For this reason, we propose enhancements to the selected models based on our experimental measurements. Performing the fine-tuning of the propagation models for one of the cities, we select Ericsson Urban (NB-IoT, LoRaWAN) and 3GPP (Sigfox) models as the ones providing the closest match. Finally, we proceed to perform cross-validation of the propagation models using the data set for another city. The tuned models demonstrate an excellent match with the real data in the cross-validation phase. They outperform their competitors by at least 20–80% in terms of relative deviation from the measured signal levels presenting the accurate option for NB-IoT, LoRaWAN, and Sigfox deployments planning in mid-size cities

Communication performance of a real-life wide-area low-power network based on Sigfox technology

Abstract In this paper, we study real-world performance of Sigfox, which is one of the most mature Low-Power Wide-Area Network (LPWAN) technologies that operate in unlicensed frequency bands. During an extensive measurement campaign conducted over three months in the city of Brno, Czech Republic, we assessed the communication performance and the radio channel properties in 311 different test locations. We observed that despite the challenging natural landscape and urban environment of the test area, more than 94% of the packets sent were received successfully, with at least one packet delivered from 297 out of 311 tested locations. Our results also reported experiment-based radio channel and signal-to-noise characterization as well as provided insights into the efficiency of two crucial mechanisms used by Sigfox to improve the packet delivery — packet repetition and multi-gateway reception. Finally, we employed our experimental data to understand the efficiency of two non-fingerprint localization methods based on received signal strength indicator in a practical Sigfox network

On the performance of multi-gateway LoRaWAN deployments:an experimental study

Abstract A remarkable progress in the Low Power Wide Area Network (LPWAN) technologies over the recent years opens new opportunities for developing versatile massive Internet of Things (IoT) applications. In this paper, we focus on one of the most popular LPWAN technologies operating in the license-exempt frequency bands, named LoRaWAN. The key contribution of this study is our unique set of results obtained during an extensive measurement campaign conducted in the city of Brno, Czech Republic. During a three-months-period, the connectivity of a public Long Range Wide Area Network (LoRaWAN) with more than 20 gateways (GWs) was assessed at 231 test locations. This paper presents an analysis of the obtained results, aimed at capturing the effects related to the spatial diversity of the GW locations and the real-life multi-GW network operation with all its practical features. One of our findings is the fact that only for 47% tested locations the GW featuring the minimum geographical distance demonstrated the highest received signal strength and signal-to-noise ratio (SNR). Also, our results captured and characterized the variations in the received signal strength indicator (RSSI) and SNR as a function of the communication distance in an urban environment, and illustrated the distribution of the spreading factors (SFs) as a result of the adaptive data rate (ADR) algorithm operation in a real-life multi-GW deployment

LPWAN coverage assessment planning without explicit knowledge of base station locations

Abstract An assessment of radio network coverage, usually in the form of a measurement campaign, is essential for multi-base-station (multi-BS) network deployment and maintenance. It can be conducted by a network operator or its served consumers. However, the number of measurement points and their locations may not be known in advance for an efficient and accurate evaluation. The main goal of this study is to propose a new methodology for understanding the selection of measurement points during coverage and signal quality assessment. It is particularly tailored to multi-BS low-power wide-area network (LPWAN) deployments without explicit knowledge of BS locations. To this aim, we first conduct a large-scale measurement campaign for three popular LPWAN technologies, namely, NB-IoT, Sigfox, and LoRaWAN. Utilizing this baseline data, we develop a procedure for identifying the minimum set of measurement points for the coverage assessment with a given accuracy as well as study which interpolation algorithms produce the lowest approximation error. Our results demonstrate that a random choice of measurement points is on par with their deterministic selection. Out of the candidate interpolation algorithms, Kriging method offers attractive performance in terms of the absolute error for NB-IoT deployments. By contrast, for Sigfox and LoRaWAN infrastructures, less complex techniques, such as Natural-neighbor, Linear interpolation, or Inverse-Distance Weighting, can achieve comparable (and occasionally even better) accuracy levels

Tailoring NB-IoT for mass market applications:a mobile operator’s perspective

Abstract Today, about 6.5 billion “things” are connected to the public space. While this sounds like a lot, still less than 1% of all the things that are surrounding us and could be connected are actually utilizing this opportunity. Hence, the question is why all these devices are not equipped with wireless connectivity? In some cases, they are either too remote, too inaccessible, or there are simply too many of them to make it economically viable. To mitigate this gap, a promising solution emerges, which has the potential to become an enabler for true mass market IoT. In this paper, we discuss a professional point of view expressed by Vodafone Czech Republic a.s. As Vodafone has been one of the first in Europe to complete a commercial Narrowband IoT (NB-IoT) network roll-out, we build upon this long-term cooperation. First, we discuss the potential of NB-IoT for mass market applications. Then, we offer unique expert findings that reflect the operator’s considerations during implementation, testing, measuring, and evaluating this new 3GPP-ratified communications technology. Moreover, we outline our prototype design of the NB-IoT device and discuss the architecture challenges. Also, the configuration required on the side of a mobile operator is detailed to have NB-IoT communications ready to take off. Finally, we summarize the results obtained in our lab along with numerous field tests that we run during a long-term cooperation between the research partners

Multi-RAT LPWAN in Smart Cities:trial of LoRaWAN and NB-IoT integration

Abstract The landscape of the contemporary IoT radio access technologies (RATs) is excessively diverse, especially when it comes to such a complex environment as Smart City. On the one hand, this diversity offers operators sufficient flexibility to select the most appropriate RAT for their target application. On the other hand, it becomes a severe limiting factor leading to high level of uncertainty for the IoT device vendors, who need to decide, which technology to support in their hardware. In this paper, we consider the provisioning of the low-power wide area network (LPWAN) devices supporting multiple RATs. First, we briefly discuss the parameters of several potential radio technologies as well as analyze the pros and cons of combining them in a single device. Next, we prototype a real-life device capable of communicating via two perspective LPWAN technologies, namely, LoRaWAN and NB-IoT, and report on the initial results of its performance evaluation. These confirm the feasibility of instrumenting dual-mode devices as well as reveal several important aspects related to the development of multi-radio IoT equipment and its performance. In our view, due to their higher flexibility, reliability, and dependability, the devices such as the one developed can be beneficial for various Smart City applications, with smart energy grids and road traffic control being only two of many examples