| 1. |
- Dinc, Ergin, et al.
(författare)
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Seamless Gate-to-Gate Connectivity Concept : Onboard LTE, Wi-Fi and LAA
- 2017
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Ingår i: 2017 IEEE 86th Vehicular Technology Conference (VTC-FALL). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509059355
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Konferensbidrag (refereegranskat)abstract
- Aircraft is one of the last venues with no highspeed connectivity, which makes it an important research issue to address for both industry and academia. This paper introduces seamless gate-to-gate connectivity concept so that passengers can stay connected in all phases of the flight. The backhaul capacity is provided via direct air-to-ground communications links. Passengers can utilize both LTE andWi-Fi access technologies on-board. In order to avoid interference with licensed ground LTE network, in-cabin LTE users will be served in the unlicensed spectrum via license assisted access (LAA) functionality when the aircraft is close to the ground. In this paper, we determine the altitude threshold for switching to LAA in order to provide seamless LTE connectivity. According to our analysis the myth about the 3 km threshold for the interference with the terrestrial network is not anymore valid. In addition, throughput and user data rates for LTE and Wi-Fi networks are investigated in different flight phases. We have found out that in-cabin LTE network can serve 80-240 users between 5-15 Mbps data rates, and Wi-Fi network can provide peak data rates of 14 Mbps in the worst-case scenario.
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| 2. |
- Garcia, Johan, 1970-, et al.
(författare)
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Train Velocity and Data Throughput : A Large Scale LTE Cellular Measurements Study
- 2017
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Ingår i: Proceedings of the 2017 IEEE 86th Vehicular Technology Conference (VTC Fall). - New York : IEEE. - 9781509059355 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- Train-mounted aggregation routers that provide WiFi access to train passengers and bundle external communication over multiple cellular modems/links is an efficient way of providing communication services on trains. However, the characteristics of such systems have received limited attention in the literature. In this paper we address this gap by examining the communication characteristics of such systems based on a large data set gathered over six months from an operational Swedish railway system. We focus our examination on the relationship between per link throughput and train velocity. Using Levenberg- Marquardt non-linear regression a noticeable critical point is observed for an RS-SINR of around 12 dB. At this point the impact of increased train velocity on per link throughput changes from being negative to becoming positive. Using a machine learning approach we also explore the relative importance of several observed metrics in relation to per link throughput.
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| 3. |
- Johanson, Matthias, et al.
(författare)
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Joint subjective and objective data capture and analytics for automotive applications
- 2017
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Ingår i: IEEE Vehicular Technology Conference. - 1550-2252. - 9781509059355
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Konferensbidrag (refereegranskat)abstract
- In this paper we describe a novel technological framework for capture and analysis of both objective measurement data and subjective user experience data for automotive applications. We also investigate how the framework can be extended to address privacy issues by enforcing a rigorous privacy model called differential privacy. The system under development integrates a telematics system with a smartphone app service architecture and a data-driven analytics framework. The hypothesis is that the framework will improve the opportunities of conducting large scale user trials of automotive functions and services, while improving the quality of collected data. To achieve this, a number of challenges are addressed in the paper, including how to design the subjective data capture mechanisms to be both simple to use yet powerful, how to correlate subjective data with objective measurement data, and how to protect the privacy of users.
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| 4. |
- Rusek, Fredrik, et al.
(författare)
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Bandwidth Minimization under Probabilistic Constraints and Statistical CSI for NOMA
- 2018
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Ingår i: 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017. - 9781509059362 - 9781509059355
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Konferensbidrag (refereegranskat)abstract
- Non-Orthogonal Multiple Access (NOMA) is studied under statistical Channel State Information (CSI) and probabilistic constraints. Unlike the conventional power domain only NOMA, the definition of NOMA here considers both the power and the frequency domains simultaneously, where a flat power spectrum is assumed for each UE. This increases the capacity region when compared to the conventional definition. The problem of minimizing the number of consumed resource elements (REs) while satisfying the outage constraints is solved. An RE here is a frequency slot of unit bandwidth resolution, so the considered problem translates to a saving in bandwidth. The solution techniques involve a Gaussian Approximation of NOMA user rates and an offline empirical approach based on tail distributions. Numerical results show that the former is a good approximation while the latter provides exact results. In any case, these methods outperform the orthogonal multiple access techniques.
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