Hands-On Experience with UWB : Angle of Arrival Accuracy Evaluation in Channel 9

This paper evaluates IEEE 802.15.4z standard- compliant NXP SR040 and SR150 chips in Angle of Arrival (AoA) capabilities in Channel 9 (7.737—8.237 GHz) of the Ultra-WideBand (UWB) spectrum. Due to the shorter wavelength, higher frequencies may encounter certain limitations when it comes to harsh environments, as more reflections and multipath propagation can occur. Furthermore, they also can be affected by their enclosure used to protect the electronics in such an environment, which needs to be taken into account during product design. This work presents the results of the evaluation measurement scenario relatable to real-life use cases and concludes potentially valuable insight important for consideration when creating a new UWB product. Besides a basic overview of the theoretical estimation of AoA by Time Difference of Arrival (TDoA) and Phase Difference of Arrival (PDoA), and the evaluation of the corresponding results, the main contribution is the repeatable topology considered for the conducted measurements. The presented results allow vendors to compare their solutions with the various radio chips or antenna configurations.acceptedVersionPeer reviewe

Performance Assessment of Reinforcement Learning Policies for Battery Lifetime Extension in Mobile Multi-RAT LPWAN Scenarios

Considering the dynamically changing nature of the radio propagation environment, the envisioned battery lifetime of the end device (ED) for massive machine-type communication (mMTC) stands for a critical challenge. As the selected radio technology bounds the battery lifetime, the possibility of choosing among several low-power wide-area (LPWAN) technologies integrated at a single ED may dramatically improve its lifetime. In this paper, we propose a novel approach of battery lifetime extension utilizing reinforcement learning (RL) policies. Notably, the system assesses the radio environment conditions and assigns the appropriate rewards to minimize the overall power consumption and increase reliability. To this aim, we carry out extensive propagation and power measurements campaigns at the city-scale level and then utilize these results for composing real-life use-cases for static and mobile deployments. Our numerical results show that RL-based techniques allow for a noticeable increase in EDs’ battery lifetime when operating in multi-RAT mode. Furthermore, out of all considered schemes, the performance of the weighted average policy shows the most consistent results for both considered deployments. Specifically, all RL policies can achieve 90 % of their maximum gain during the initialization phase for the stationary EDs while utilizing less than 50 messages. Considering the mobile deployment, the improvements in battery lifetime could reach 200 %.acceptedVersionPeer reviewe

Optimizing NB-IoT Communication Patterns for Permanently Connected mMTC Devices

The new types of industry-driven applications that need to be supported by low-power wide-area networks (LP-WANs), such as remote control or metering of devices within the massive machine-type infrastructures (e.g., Smart Grids), require a permanent connection to the remote server. In addition, there is also a shift in the communication paradigm, as the user equipment (UE) nodes are queried in regular and frequent intervals. Notably, the presence of this type of traffic may drastically deteriorate the performance of LPWAN technologies initially developed to support conventional use-cases characterized by non-synchronized transmissions. Though none of the LPWAN technologies is inherently designed to handle such demanding communication patterns, the narrowband Internet of things (NB-IoT) still stands for the best candidate as it operates within the license frequency spectrum. To optimize the delay performance of both types of traffic coexisting at the NB-IoT air interface, we propose an approach based on spreading the message transmission time instants of regular and stochastic traffic. We show an optimal value of the spreading interval minimizing the message transmission delay of regular traffic and propose a mathematical model to estimate its value. By parameterizing the model using a detailed measurements campaign of NB-IoT, we show that the optimal value of spreading interval and associated mean message delay is a linear function of the number of UEs. We report these values for a wide range of UEs in the coverage area of the NB-IoT base station and show that conventional stochastic traffic does not influence regular traffic performance.acceptedVersionPeer reviewe

Performance Analysis of Different LoRaWAN Frequency Bands for mMTC Scenarios

The possibility of utilizing different frequencies for the LoRaWAN is a key component which, together with the other parameters, i.e., (i) bandwidth, (ii) spreading factor, (iii) coding rate, and (iv) transmission power, defines the communication performance. In this paper, we present the substantive im- provements for both the end devices and the radio access network (gateways) to enhance the data rates and decrease the communication latency. The implementation changes were made for the publicly available LoRaWAN module “signetlabdei” for Network Simulator 3. Utilizing the frequency 2.4GHz, the transmission time in the LoRaWAN network has improved by 80 % decreasing from 75 ms to 14 ms. The frequency 2.4 GHz for the EU region also showed the best performance due to the extended bandwidth (transmission success above 90%) in the case of the mMTC scenario with thousands of devices deployed. Together with the updated LoRaWAN module, the reported results are expected to serve as a building block for mMTC- oriented simulation scenarios.acceptedVersionPeer reviewe

Narrowband Internet Of Things: Prototype Design And Hands-On Experiences

With the IoT (Internet of Things) and upcoming next-generation communication systems, demand for low-power devices keeps growing on the worldwide scale. This paper presents a design of a universal device prototype for LPWAN (Low-PowerWide Area Network) technology called NB-IoT (Narrow Band Internet of Things), the latest member of the 3GPP family standardized in Release 13. Prototype board and its components are introduced alongside with the application that controls all the elements and the communication. In the end, initial measurements of power consumption, transmission reliability and delay are shown and evaluated

A perspective on wireless M-bus for smart electricity grids

The Internet of Things (IoT) enables long-range outdoor networks, such as smart grid and municipal lighting, as well as short-range indoor systems for smart homes, residential security, and energy management. Wireless connectivity and standardized communication protocols become an essential technology baseline for these diverse IoT applications. The focus of this work is wireless connectivity for smart metering systems. One of the recent protocols in this field is Wireless M-BUS, which is being widely utilized for remote metering applications across Europe. Therefore, in this paper, we detail a novel multi-platform framework designed to serve as a data generator for the protocol in question. The developed software allows to construct Wireless M-Bus telegrams with a high level of detail according to the EN 13757-4 specification and then schedule them for periodic transmission. The evaluation of the data generator is done in real scenario by using previously developed prototype equipped with IQRF TR72DA communication module acting as a smart meter with implemented software framework. As a result, the evaluation of communication distance between the developed Wireless MBus prototype and commercial gateway was tested in case of indoor scenario at Brno University of Technology, Faculty of Electrical Engineering and Communication.acceptedVersionPeer reviewe

On the performance of narrow-band internet of things (NB-IoT) for delay-tolerant services

Narrowband IoT (NB-IoT) stands for a radio access technology standardized by the 3GPP organization in Release 13 to enable a large set of use-cases for massive Machine-type Communications (mMTCs). Compared to legacy human-oriented 4G (LTE) communication systems, NB-IoT has game-changing features in terms of extended coverage, enhanced power saving modes, and a reduced set of available functionality. At the end of the day, these features allow for connectivity of devices in challenging positions, enabling long battery life and reducing device complexity. This article addresses the development of the universal testing device for delay-tolerant services allowing for in-depth verification of NB-IoT communication parameters. The presented outputs build upon our long-term cooperation with the Vodafone Czech Republic a.s. company.acceptedVersionPeer reviewe

Time-Dependent Propagation Analysis and Modeling of LPWAN Technologies

Contemporary low-power wide area network (LPWAN) technologies have been introduced as connectivity enablers with low complexity, extended communication range, and excellent signal penetration. On the other hand, they suffer from a substantial delay and low packet-delivery guarantees. As a result, numerous novel applications entering the Internet of things (IoT) market suffer from insufficient performance. To mitigate this issue, further optimization and adaptation of the LPWAN technologies to the needs of these new applications requires an indepth understanding of the propagation environment dynamics. Motivated by that, in this paper, we thoroughly investigate timedependent statistical characteristics of the reference signal receive power (RSRP) dynamics of Narrowband IoT (NB-IoT) technology. We demonstrate that even for a stationary user equipment, RSRP is subject to drastic variations that are characterized by exponentially decaying autocorrelation function. We then demonstrate that first- A nd second-order statistical properties of the RSRP dynamics can be closely captured using a doublystochastic Markov model that retains the tractability of the conventional Markov models. The reported model is expected to serve as a building block for analytical and simulation-based system-level studies and optimization of LPWAN technologies.acceptedVersionPeer reviewe

Pitfalls of LPWA Power Consumption: Hands-On Design of Current Probe

The unique opportunities introduced by the emerging Industrial Internet of Things (IIoT) applications have accelerated the momentum of the massive Machine-Type Communications (mMTC) worldwide. As the number of already deployed Low-Power Wide-Area (LPWA) applications growth exponentially over the last decade, new open challenges started to be discussed across the industry sector. The most critical parameter of the LWPA devices in question is energy efficiency and the overall power consumption of designed end-devices. Therefore, the need for precise measurement of power consumption has attracted engineers’ attention as the unique communication parameters of the LPWA devices form the current consumption measurements challenging task. To facilitate accurate current measurements ranging between hundreds of nA and hundreds of µA, we propose a unique design of the current probe prototype. We then demonstrate the obtained results concerning the accuracy, measurement range switching, and sufficient sampling speed. All the measurements from the designed prototype are further compared with the industry-grade DC power analyzer Agilent N6705B.acceptedVersionPeer reviewe