Wireless communications in the twenty-first century: a perspective

Shafi, Mansoor; Hashimoto, Akira; Umehira, Masahiro; Ogose, Shigeaki; Murase, T.

doi:10.1109/5.640770

Cited by 45 publications

(11 citation statements)

References 45 publications

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“…Equation (1) illustrates that at K-and Ka-band frequencies, large bandwidth systems will have to transmit at higher power levels than current cellular and PCS systems in order to compensate for the higher noise levels inherent in large bandwidth systems.…”

Section: General System Considerationsmentioning

confidence: 99%

Tunable Dielectric Materials and Devices for Broadband Wireless Communications

Mueller

Miranda

Dayton³

2000

Handbook of Thin Film Devices

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Wireless and satellite communications are a rapidly growing industries which are slated for explosive growth into emerging countries as well as countries with advanced economies.The dominant trend in wireless communication systems is towards broadband applications such as multimedia file transfer, video transmission and Internet access. These applications require much higher data transmission rates than those currently used for voice transmission applications. To achieve these higher data rates, substantially larger bandwidths and higher carrier frequencies are required. A key roadblock to implementing these systems at K-band (18-26.5 GHz) and is the need to develop hardware which meets the requirements for high data rate transmission in a cost effective manner. In this chapter, we report on the status of tunable dielectric thin films for devices, such as resonators, filters, phased array antennas, and tunable oscillators, which utilize nonlinear tuning in the control elements. Paraelectric materials such as Barium StrontiumTitanate ((Ba, Sr)TiO 3) have dielectric constants which can be tuned by varying the magnitude of the electric field across the material. Therefore, these materials can be used to control the frequency and/or phase response of various devices such as electronically steerable phased array antennas, oscillators, and filters. Currently, tunable dielectric devices are being developed for applications which require high tunability, low loss, and good RF power-handling capabilities at microwave and millimeter-wave frequencies. These properties are strongly impacted by film microstructure and device design, and considerable developmental work is still required. However, in the last several years enormous progress has occurred in this field, validating the

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Section: General System Considerationsmentioning

confidence: 99%

Tunable Dielectric Materials and Devices for Broadband Wireless Communications

Mueller

Miranda

Dayton³

2000

Handbook of Thin Film Devices

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“…T HE future telecommunications networks (such as the third-generation wireless networks) aim to provide integrated services such as voice, data, and multimedia via inexpensive low-powered mobile computing devices over wireless infrastructures [21]. As the demand for multimedia services over the air has been steadily increasing over the last few years, wireless multimedia networks have been a very active research area.…”

Section: Introductionmentioning

confidence: 99%

Call admission control schemes and performance analysis in wireless mobile networks

Fang

Zhang²

2002

IEEE Trans. Veh. Technol.

335

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Abstract-Call admission control (CAC) plays a significant role in providing the desired quality of service in wireless networks. Many CAC schemes have been proposed. Analytical results for some performance metrics such as call blocking probabilities are obtained under some specific assumptions. It is observed, however, that due to the mobility, some assumptions may not be valid, which is the case when the average values of channel holding times for new calls and handoff calls are not equal. In this paper, we reexamine some of the analytical results for call blocking probabilities for some call admission control schemes under more general assumptions and provide some easier-to-compute approximate formulas.

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“…During the last few years, wireless devices have become more and more widely adopted, due to the users' needs for mobility and information anywhere and at any time [6] [8]. New and very powerful wireless handheld equipments are now available at reasonable costs, and times are mature to develop new services that can be easily accessed by the final user.…”

Section: Introductionmentioning

confidence: 99%

VOD services for mobile wireless devices

Bruneo

Villari

Zaia

et al.

Proceedings of the Eighth IEEE Symposium on Computers and Communications. ISCC 2003

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Wireless devices are becoming very popular and powerful enough to be commonly adopted to access distributed services. More and more sophisticated applications are being developed and a very promising market is quickly being established where mobile users may access multimedia data while roaming from a cell to another, anytime and everywhere. Such scenario requires a strong infrastructure in order to adequately manage all the different issues related with high level service provisioning. QoS represents one of the most crucial issues as it involves many different aspects and directly impacts the user satisfaction. In order to achieve this target, we propose an architecture which allows mobile devices to access advanced services available in the wired part of the network. This architecture, based on mobile agents technology, assumes the presence of a VOD Virtual Server. The strategy adopted is to hide all the basic mechanisms inside a middleware layer that provides the necessary interfaces to allow a simple interaction between the user on the one side and the network and the distributed services on the other. The overall architecture, that is currently being implemented and tested, has been used as an experimental environment to provide mobile users with a new service to access MPEG-4 flows.

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Wireless communications in the twenty-first century: a perspective

Cited by 45 publications

References 45 publications

Tunable Dielectric Materials and Devices for Broadband Wireless Communications

Tunable Dielectric Materials and Devices for Broadband Wireless Communications

Call admission control schemes and performance analysis in wireless mobile networks

VOD services for mobile wireless devices

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