| 1. |
- Ahmad, Suhail, 1992, et al.
(författare)
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Predictive Resource Allocation Evaluation with Real Channel Measurements
- 2017
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Ingår i: IEEE International Conference on Communications. - 1550-3607.
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Konferensbidrag (refereegranskat)abstract
- Mobile services, especially video streaming, has seen a rapid usage increase in recent years. Base stations (BSs) need to employ smarter and efficient resource allocation strategies to maintain high quality of service (QoS) to users at all the times. Predictive resource allocation (PRA), is one such novel scheme, in which BSs seek to anticipate the user demands and offer service to users in advance. As a result, the QoS can be improved, network load can be distributed over time, while at the same time offering efficient utilization of BS power. In location-aware PRA, the BS exploits location information of the users to predict the channel expected variations and adapt the BS resources accordingly. We evaluate PRA strategies based on an empirical study of the radio channel variation from measured location-aided channel radio maps using a smart phone. We observed that gains offered by the PRA scheme are highly dependent on user mobility patterns.
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| 2. |
- Beckman, Claes, Professor, 1962-, et al.
(författare)
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High Reliability Air-to-Ground Communication System based on Aggregation of Terrestrial Networks
- 2023
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Ingår i: Proceedings - 2023 28th Asia Pacific Conference on Communications, APCC 2023. - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 75-80
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Konferensbidrag (refereegranskat)abstract
- Providing connectivity to helicopters and drones is a challenging issue both from a technical as well as financial perspective. One possible cost efficient solution to the problem is for the aircraft to connect directly to the already deployed terrestrial public networks and aggregate their combined capacity and coverage at the Internet Protocol (IP) level. In this study we equipped an Airbus helicopter H135 with external antennas from VITES GmbH, two Icomera 'X5/X6' multi-SIM routers, including Icomera's autonomous test and monitoring system 'Surveyor', and conducted multiple test flights over a rural area in southern Germany. The results showed that using Icomera's patented technology it is possible to connect a helicopter or a drone, flying at an altitude of 10.000 ft (3048 m), to multiple terrestrial public cellular networks. Thus, obtaining high capacity, large coverage and high reliability connections to the helicopter.
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| 3. |
- Garcia, Johan, 1970-, et al.
(författare)
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Measuring and Modeling Aggregate LTE Connection Reliability for Train Operations
- 2022
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Ingår i: 2022 IEEE International Workshop Technical Committee on Communications Quality and Reliability (CQR). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665410670 - 9781665410663 ; , s. 31-36
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Konferensbidrag (refereegranskat)abstract
- We examine the connection reliability of LTE cellular infrastructure for supporting train signaling systems. In particular, the impact of simultaneous use of multiple networks on reliability is considered, along with failure correlation effects. We present a tailored reliability model, and report on data collected from many train-mounted cellular routers. Connection reliability reaches 99.994% when aggregation is used, compared to 99.953% for the best single link. Both modeling and measurement results show greatly improved reliability when aggregating over multiple links, thus indicating that commercial cellular networks may be useful for providing connectivity to future train signaling systems.
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| 4. |
- Mikkelsen, Herman, et al.
(författare)
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Benchmarking Alternative Technologies for providing Voice Services onboard Trains
- 2020
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Ingår i: Proceedings of the IEEE Vehicular Technology Conference. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- Providing cellular voice onboard trains has proven to be a challenging task. The metallic chassis and the energysaving coating on the windows act as a radio shield. In combination with sparsely spaced cellular base stations on rural routes, the coverage onboard inter-city trains is under dimensioned. Since the late 1990s, analog 'amplify and forward' radio repeaters have been used extensively to provide coverage of cellular voice onboard trains. However, repeater systems have proven to be both expensive and technically problematic for both trains as well as mobile network operators. In this study, three alternative technologies for providing cellular voice onboard trains are investigated and benchmarked. The technologies under investigation are: circuit-switched voice on GSM and 3G; Voice over IP on LTE (VoLTE); Voice over the onboard Wi-Fi network (VoWiFi). To benchmark these systems against each other, measurements were conducted onboard Swedish X2000 trains, en-route between Stockholm and Gothenburg. In particular we measure: the Availability; the Retainability: Geographical Coverage and Voice quality. Our results show that VoWiFi over the onboard Wi-Fi network outperforms GSM, UMTS as well as VoLTE provided over the onboard repeaters, with equal voice quality as VoLTE but nearly 100% availability and nearly 100% retainability.
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