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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Performance Test of an Initial iNET-Like RF Network Using a Tethered Aerostat in Japan

Tanaka, Toshihisa, Aoyama, Daiki, Ito, Sei 10 1900 (has links)
ITC/USA 2015 Conference Proceedings / The Fifty-First Annual International Telemetering Conference and Technical Exhibition / October 26-29, 2015 / Bally's Hotel & Convention Center, Las Vegas, NV / Through the use of early iNET-prototype IP Transceiver technology, Kawasaki Heavy Industries, Ltd. (KHI) has been able to communicate with flight test vehicles during a recent research program. This technology provides a two-way high-capacity communication that has not been achieved with conventional telemetry and can be used not only for flight testing, but also for rescue work. KHI has been authorized to use S-band IP Transceivers since last year in Japan, and various communication tests have been performed. This paper describes Japan's first simulation of an iNET RF network which incorporated testing that performed data backfill, voice communication and video transmission. A data backfilling test was performed using retransmit of lock-off data (which is lost as the aircraft maneuvers) on command from the ground station. Moreover, a tethered aerostat is considered a very useful communication relay platform in the event of a large-scale disaster which results in the destruction of infrastructure. Also, the silence of an aerostat can be very important for search and rescue work.
2

THE PERFORMANCE TEST OF AN INITIAL iNET-LIKE RF NETWORK USING A HELICOPTER

Ito, Sei, Honda, Takeshi, Tanaka, Toshihisa, Aoyama, Daiki 11 1900 (has links)
Through the use of early iNET-prototype IP Transceiver technology, Kawasaki Heavy Industries, Ltd. (KHI) has been able to communicate with a flight test vehicle. This technology provides a two-way high-capacity communication that has not been achieved with conventional telemetry. KHI has been authorized to use S-band IP Transceivers since 2014 in Japan. Then various communication tests have been performed. Last year we presented the result of the performance test of initial iNET-like RF network using a tethered aerostat at ITC. As the next phase, we have a plan of the test using a helicopter. The test is going to be conducted in September. We will present the results at ITC. This paper describes plans of the test which includes improved data backfill techniques.
3

Initial iNET RF Networking Testing

Timme, M. Wayne, Newton, Todd A., Moodie, Myron L., Abbott, Ben A., Grace, Thomas B. 10 1900 (has links)
ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / One of the core philosophies of the integrated Network Enhanced Telemetry (iNET) project is to leverage standard networking technologies whenever possible to both reduce development cost and to allow standard networking applications to function properly. This also provides the best long-term scalability to new unforeseen applications much as the Internet has grown through its open standards. Unfortunately, the Radio Frequency (RF) channel characteristics do not fully lend themselves to the typical physical layer approaches utilized by Internet Protocol (IP) technologies. The iNET project is developing the Telemetry Network System (TmNS) RF Network to provide a flexible two-way IP telemetry capability. The Developmental Flight Test (DFT) phase is currently under way to perform initial flight testing of the RF Network. This paper provides an overview of the planned RF network testing and the expected results. Current results from flight testing will be presented at the conference.
4

Load balancing in hybrid LiFi and RF networks

Wang, Yunlu January 2018 (has links)
The increasing number of mobile devices challenges the current radio frequency (RF) networks. The conventional RF spectrum for wireless communications is saturating, motivating to develop other unexplored frequency bands. Light Fidelity (LiFi) which uses more than 300 THz of the visible light spectrum for high-speed wireless communications, is considered a promising complementary technology to its RF counterpart. LiFi enables daily lighting infrastructures, i.e. light emitting diode (LED) lamps to realise data transmission, and maintains the lighting functionality at the same time. Since LiFi mainly relies on line-of-sight (LoS) transmission, users in indoor environments may experience blockages which significantly affects users' quality of service (QoS). Therefore, hybrid LiFi and RF networks (HLRNs) where LiFi supports high data rate transmission and RF offers reliable connectivity, can provide a potential solution to future indoor wireless communications. In HLRNs, efficient load balancing (LB) schemes are critical in improving the traffic performance and network utilisation. In this thesis, the optimisation-based scheme (OBS) and the evolutionary game theory (EGT) based scheme (EGTBS) are proposed for load balancing in HLRNs. Specifically, in OBS, two algorithms, the joint optimisation algorithm (JOA) and the separate optimisation algorithm (SOA) are proposed. Analysis and simulation results show that JOA can achieve the optimal performance in terms of user data rate while requiring high computational complexity. SOA reduces the computational complexity but achieves low user data rates. EGTBS is able to achieve a better performance/complexity trade-off than OBS and other conventional load balancing schemes. In addition, the effects of handover, blockages, orientation of LiFi receivers, and user data rate requirement on the throughput of HLRNs are investigated. Moreover, the packet latency in HLRNs is also studied in this thesis. The notion of LiFi service ratio is introduced, defined as the proportion of users served by LiFi in HLRNs. The optimal LiFi service ratio to minimise system delay is mathematically derived and a low-complexity packet flow assignment scheme based on this optimum ratio is proposed. Simulation results show that the theoretical optimum of the LiFi service ratio is very close to the practical solution. Also, the proposed packet flow assignment scheme can reduce at most 90% of packet delay compared to the conventional load balancing schemes at reduced computational complexity.

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