LTE Modem Research Articles

Continuous monitoring of the health status of cement-based structures: electrical impedance measurements and remote monitoring solutions

<p class="Abstract">The continuous monitoring of cement-based structures and infrastructures is fundamental to optimize their service life and reduce maintenance costs. In the framework of the EnDurCrete project (GA no. 760639), a remote monitoring system based on electrical impedance measurements was developed. Electrical impedance is measured according to the Wenner’s method, using 4-electrode arrays embedded in concrete during casting, selecting alternating current as excitation, to avoid the polarization of both electrode/material interface and of material itself. With this measurement, it is possible to promptly identify events related to contaminants ingress or damages (e.g. cracks formation). Conductive additions are included in some elements to enhance signal-to-noise ratio, as well as the self-sensing properties of concrete. Specifically, a distributed sensor network was implemented<span style="text-decoration: line-through;">,</span> consisting of measurement nodes installed in the elements to be monitored, then connected to a central hub (RS-232 protocol). Nodes are realized with an embedded unit for electrical impedance measurements (EVAL-AD5940BIOZ board with AD5940 chip, by Analog Device) and a digital thermometer (DS18B20 by Maxim Integrated), enclosed in cabinets filled with an IP68 gel against moist-related problems. Data are available on a Cloud through Wi-Fi network or LTE modem, hence can be accessed remotely via a use-friendly multi-platform interface.</p>

Locating eNodeBs through sectorization inference—Sector fitting evaluated on a railway use case

The ability to locate a radio transmitter can be useful in many contexts, and a range of localization methods have been proposed. In the context of cellular networks, the position of the base station is known to the operator and regulator, but often this knowledge is not publicly available. For the problem of base station localization, several approaches have been examined in the literature, and several public services exists which estimate the position of cellular infrastructure based on measurement data collected from cellular users. In this work we present sector fitting, a new approach for locating sectorized transmitters based only on observations of the positions and sector identifiers as reported by the cellular UEs. Sector fitting defines a sectorization model which is applied over a search grid to obtain a cost matrix, which is then merged over multiple frequencies to arrive at the best base station location estimate. An extensive evaluation of sector fitting is carried out, using a large data set of observations from train-mounted LTE modems. The results show that sector fitting outperforms the other applicable localization methods. Furthermore, an iterative grid search approach is examined and demonstrated to achieve the same localization accuracy as a full search while drastically reducing the computational cost. Finally, three downsampling methods are evaluated with the results showing that a trade-off can be made to further reduce computational cost, but with slightly worse localization accuracy in most cases.

Development of an IoT-Based Indoor Air Quality Monitoring Platform

In this paper, an IoT-based indoor air quality monitoring platform, consisting of an air quality-sensing device called “Smart-Air” and a web server, is demonstrated. This platform relies on an IoT and a cloud computing technology to monitor indoor air quality in anywhere and anytime. Smart-Air has been developed based on the IoT technology to efficiently monitor the air quality and transmit the data to a web server via LTE in real time. The device is composed of a microcontroller, pollutant detection sensors, and LTE modem. In the research, the device was designed to measure a concentration of aerosol, VOC, CO, CO2, and temperature-humidity to monitor the air quality. Then, the device was successfully tested for reliability by following the prescribed procedure from the Ministry of Environment, Korea. Also, cloud computing has been integrated into a web server for analyzing the data from the device to classify and visualize indoor air quality according to the standards from the Ministry. An application was developed to help in monitoring the air quality. Thus, approved personnel can monitor the air quality at any time and from anywhere, via either the web server or the application. The web server stores all data in the cloud to provide resources for further analysis of indoor air quality. In addition, the platform has been successfully implemented in Hanyang University of Korea to demonstrate its feasibility.

A cloud computing-based damage prevention system for marine structures during berthing

In this paper, a cloud computing-based damage prevention system for marine structures during berthing, consisting of a speed camera module and a cloud-computing based web server, is presented. The speed camera module consists of a laser distance sensor, a camera unit, and an LTE modem. These were installed on the marine structure to monitor the speed of ships during berthing. When the ship exceeds the berthing speed limit enacted by the Ministry of Oceans and Fisheries, an image of the ship and its speed data are transmitted to the web server via the LTE modem. This system was successfully tested at Maryang Harbor in Korea to confirm its feasibility. The web server activates an alert system when the image file is received, and the manager or other appropriate personnel can prevent or minimize damage from the berthing by responding immediately. All data were visualized and the berthing energy was calculated through the web server. Approved personnel can monitor the structure via the web server at any time and from anywhere. The system is effective in preventing and inspecting damages by berthing that can be used as an application of structural health monitoring for marine structures.

A Fine-grained Event-based Modem Power Model for Enabling In-depth Modem Energy Drain Analysis

Cellular modems enable ubiquitous Internet connectivities to modern smartphones, but in doing so they become a major contributor to the smartphone energy drain. Understanding modem energy drain requires a detailed power model. The prior art, an RRC-state based power model, was developed primarily to model the modem energy drain of application data transfer. As such, it serves well its original purpose, but is insufficient to study detailed modem behavior, eg. activities in the control plane. In [2], we propose a new methodology of modeling modem power draw behavior at the event-granularity, and develop to our knowledge the first fine-grained modem power model that captures the power draw of all LTE modem radio-on events in different RRC modes. Second, we quantitatively demonstrate the advantages of the new model over the state-based power model under a wide variety of context via controlled experiments. Finally, using our fine-grained modem power model, we perform the first detailed modem energy drain in-the-wild study involving 12 Nexus 6 phones under normal usage by 12 volunteers spanning a total of 348 days. Our study provides the first quantitative analysis of energy drain due to modem control activities in the wild and exposes their correlation with context such as location and user mobility. In this abstracts, we introduce the essence of the methodology and the highlighted results from the in-the-wild study.

A Fine-grained Event-based Modem Power Model for Enabling In-depth Modem Energy Drain Analysis

Cellular modems enable ubiquitous Internet connectivities to modern smartphones, but in doing so they become a major contributor to the smartphone energy drain. Understanding modem energy drain requires a detailed power model. The prior art, an RRC-state based power model, was developed primarily to model the modem energy drain of application data transfer. As such, it serves well its original purpose, but is insufficient to study detailed modem behavior, e.g., activities in the control plane. In this paper, we propose a new methodology of modeling modem power draw behavior at the event-granularity, and develop to our knowledge the first fine-grained modem power model that captures the power draw of all LTE modem radio-on events in different RRC modes. Second, we quantitatively demonstrate the advantages of the new model over the state-based power model under a wide variety of context via controlled experiments. Finally, using our fine-grained modem power model, we perform the first detailed modem energy drain in-the-wild study involving 12 Nexus 6 phones under normal usage by 12 volunteers spanning a total of 348 days. Our study provides the first quantitative analysis of energy drain due to modem control activities in the wild and exposes their correlation with context such as location and user mobility.

Abstract TP250: Defining Technical Quality Standards for Mobile Telestroke Assessment: A Substudy of the Improving Treatment with Rapid Evaluation of Acute Stroke via Mobile Telemedicine (iTREAT) Mobile Telestroke Platform

Introduction: In-ambulance use of remote videoconferencing for prehospital stroke assessment (mobile telestroke) is an emerging innovation in acute stroke care. As a new technology, there is a dearth of technical standards to ensure transmission quality and guide deployment in various EMS settings. Hypothesis: Subjective video quality ratings during in-vehicle mobile telestroke assessment correlate to objective video data transmission metrics. Methods: We performed videoconferencing via a low-cost, utilitarian mobile telestroke platform: tablet endpoint, high-speed 4G LTE modem, external antennae, HIPAA-secure videoconferencing application, and portable bracket mounting. We held test calls along typical ambulance routes recording transmission quality by a stationary and a mobile rater. We used a standardized 6-point scale of video quality: rating ≥ 4 deemed acceptable for mobile telestroke assessment. We recorded jitter, the variance in transmission data reception order, as simultaneously reported by the videoconferencing application. Results: We completed five test runs yielding 64 data ratings. Average jitter for ratings 1 through 6 was 434.9ms (SD = 407), 106.1ms (SD = 110), 41.4ms (SD = 29), 35.3ms (SD = 15), 29.5ms (SD = 6), and 29.0ms (SD = 2) respectively. Analyzing the raw data yielded an R2 of 0.41. As seen in Chart 1, video quality decreased as average jitter increased, but jitter values as low as 30ms were still seen across video transmission of all qualities. Conclusion: These preliminary data suggest modest correlation of transmission variance with subjective quality ratings using a low-cost mobile telestroke platform along rural-based ambulance routes. However, average transmission variance correlated highly (R2 = 0.93) suggesting more data ratings may improve the correlation. Testing of our mobile telestroke platform to assess performance and clinical efficacy as well as incorporate live acute stroke encounters is ongoing.

Abstract 90: NIH Stroke Scale Assessment via iPad-based Mobile Telestroke During Ambulance Transport is Feasible - Pilot data from the Improving Treatment with Rapid Evaluation of Acute Stroke via Mobile Telemedecine (iTREAT) Study

Introduction: The AHA-ASA Target:Stroke Program calls for innovative approaches to prehospital stroke care. We previously showed that mobile videoconferencing during ambulance transport is technically feasible in a rural EMS setting using an iPad-based telemedicine system. We now hypothesize that this mobile telestroke system is clinically feasible as measured by agreement of the NIH Stroke Scale (NIHSS) between face-to-face (FTF) and remote ambulance-based assessments (iTREAT). Methods: The iTREAT system comprises an Apple iPad® with retina display, high-speed 4G LTE modem, Cisco Jabber secure video conferencing application, mounting apparatus, and magnetic external antenna. We developed 4 unique stroke and 2 unique stroke-mimic scenarios to simulate prehospital stroke alerts. We recruited 3 standardized patients each assigned two scenarios, and randomly assigned each scenario to one of 6 major ambulance routes triaging to UVA Medical Center. To eliminate bias, we alternated the order of FTF and iTREAT evaluations. Statistical measures were inter- and intra-rater correlation coefficient for the NIHSS and audio/visual(AV) quality ratings on a 6-point scale (>4 indicating “good” or “excellent” connectivity). Results: For the 12 iTREAT and 10 FTF evaluations (two FTF missing data), intra-rater correlation of NIHSS scores was consistently >0.91 (mean=0.96). Inter-rater correlation for FTF evaluations was >0.89 (mean 0.96), and inter-rater correlation for iTREAT evaluations was >0.84 (mean=0.94). AV quality ratings during all iTREAT evaluations were deemed “good” or “excellent” (audio mean=5.3, median=5.5; video mean=4.67, median=4.5). Both NIHSS correlation and AV quality rating increased over the study period. Conclusion: In this pilot feasibility study, NIHSS scores obtained via ambulance using our iPad-based mobile telestroke system correlated well with in person assessments. These results support further research to determine feasibility and efficacy of this low-cost mobile telestroke system in prehospital stroke care.

Methods for mitigating inter-carrier interference caused by power amplifier transient in LTE modem

Methods for mitigating inter-carrier interference caused by power amplifier transient in LTE modem

WCDMA-LTE 기반의 Smart HACCP 시스템 구축을 위한 단말기 개발에 관한 연구

본 논문에서는 초 중 고등학교의 급식과 관련하여 학생들의 식중독 사고를 예방하기 위해 급식소의 냉 온장고 및 각종 주방 기기의 온도와 습도를 모니터링하여 WCDMA-LTE 망을 이용하는 스마트 HACCP 시스템을 제안한다. 단말기로부터 수집된 데이터는 특정서버로 전송되며 더욱 안전한 식품을 제공하기위해 식중독지수와 비교된 후, 단말기가 설치된 장소의 식중독지수를 LCD화면에 표시하도록 한다. 이러한 시스템을 구현하는데 있어 주요 요소가 WCDMA-LTE 망 기반의 온습도 측정 및 모니터링 시스템 전용 단말기이다. 따라서 본 논문에서는 다른 단말기와 상호 통신이 가능하도록 424 MHz 및 블루투스 4.0 무선모뎀을 포함한 LTE 단말기를 설계하고 구현하였다. 향후 본 시스템은 비닐하우스의 온도감시 시스템 또는 원격 환경감시 시스템으로의 적용이 가능하다. To protect the students from food poisoning, in this paper, it is proposed that the Smart HACCP system which based with WCDMA-LTE to monitoring the temperature and humidity of a freezer, a heating cabinet and kitchen instruments at the elementary, junior and high school. After gathering the data, It is compared with a standard food poisoning index to provide more safe food reserves from the server. Then the server send a index to the terminal which is installed in a kitchen at any school to show the current environment. It is need an WCDMA-LTE terminal to realize smart HACCP system that is proposed from this paper. So, the proposed WCDMA-LTE terminal is designed with using a LTE modem included a 424 MHz wireless modem and a bluetooth 4.0 modem to communicate with other terminals. It can be use the monitoring system of a plastic greenhouse or remotely environment control system.

Abstract 103: Mobile Telestroke During Ambulance Transport is Feasible in a Rural EMS setting - pilot data from the Improving Treatment with Rapid Evaluation of Acute stroke via mobile Telemedicine (iTREAT) study

Introduction: The American Heart Association-American Stroke Association (AHA-ASA) Target:Stroke iniative calls for innovative approaches to prehospital stroke care. We hypothesize that mobile telestroke from a hospital-based neurologist to an ambulance-based provider, using tablet devices and commercially available broadband, will facilitate earlier stroke diagnosis and more accurate prenotification to reduce stroke onset-to-treatment times. Methods: We assessed the technical feasibility of mobile teleconferencing along the six common rural emergency medical service (EMS) routes into the University of Virginia Medical Center, allowing a minimum travel time of 15 minutes and continuous connectivity of 5 minutes. Our mobile telestroke platform included Apple iPad with retina display, high-speed 4G LTE modem, Cisco Jabber secure video conferencing application, and magnetic-mount external antennae. Continuous mobile connectivity was facilitated through the commercial Verizon Wireless network. Continuous transmission audiovisual (AV) quality along each route was rated by independent raters from both hospital and vehicle using a standardized six-point scale (≥4 indicating technical feasibility). Results: Of 31 test runs, two had extraneous technical issues and one failed to meet the minimum duration for continuous connectivity. The mean transmission video quality rating was 4.51 (4.54 vehicle; 4.48 hospital) and overall audio quality 5.00 (5.13 vehicle; 4.87 hospital). Both raters deemed AV quality as "good" or "excellent" (rating ≥4) for 78.5% of test runs. Five out of six EMS routes consistently demonstrated feasible connectivity, with 87.5% of runs achieving "good" or "excellent" bidirectional AV quality for these five routes. Conclusion: Our pilot data suggest technical feasibility for mobile teleconferencing between transporting ambulance and hospital-based provider using low-cost, off-the-shelf technology and commercial networks. These results support our hypothesis that mobile telestroke in a rural EMS setting can be implemented. Further troubleshooting along routes with limited connectivity, and prospective testing of the impact on stroke diagnosis and time-to-treatment is planned.

Video Over LTE: Exploring Efficiency in Distribution

Interest in LTE Broadcast technology is increasing rapidly. With consumer desire for Anywhere at an all-time high, more and more leading mobile operators are trialling the LTE Broadcast technology within their networks to start identifying different use-cases and scenarios globally to explore its business potential. Broadcasting is efficient usually if more than one user is receiving from one transmitter. Roof top reception enables a wide reach from High-Power High Tower (HPHT) transmitters, so that broadcasting is efficient for popular TV programs, particularly if transmitters operate in Single Frequency Network (SFN) mode. LTE, including LTE Broadcast, is currently designed to operate on Low Power Low Tower (LPLT) networks. This paper discusses the spectral efficiency and flexibility of LTE Broadcast, which is only efficient when several devices receive the same content stream. Unicast is much more efficient for less popular, so called long-tail content. At times when there is only low interest in a certain part of the network, the infrastructure can stop the broadcast and use the resources for unicast content delivery and use the spare resources for mobile broadband (MBB). Furthermore, the implications of differences in replacement cycles of fixed TV receivers and mobile devices are discussed. A signal adapted to the high radio signal quality of roof-top antennas should be used for the legacy technologies supporting fixed receivers, whereas a signal adapted to the low radio signal quality typical for mobile reception is required. Thus, it is essential to use the most efficient technologies soon after ratification of the standards. Finally, we outline a potential use of existing roof-top antenna installations for LTE modems that can be used for TV distribution and beyond.

System Architecture for 3GPP-LTE Modem using a Programmable Baseband Processor

The evolution of third generation mobile communications toward high-speed packet access and long-term evolution is ongoing and will substantially increase the throughput with higher spectral efficiency. This paper presents the system architecture of an LTE modem based on a programmable baseband processor. The architecture includes a baseband processor that handles processing time and frequency synchronization, IFFT/FFT (up to 2048-p), channel estimation and subcarrier de-mapping. The throughput and latency requirements of a Category four User Equipment (CAT4 UE) is met by adding a MIMO symbol detector and a parallel Turbo decoder supporting H-ARQ, which brings both low silicon cost and enough flexibility to support other wireless standards. The complexity demonstrated by the modem shows the practicality and advantage of using programmable baseband processors for a single-chip LTE solution.