In cellular networks, it is estimated that 2 3 of calls and over 90% of data services occur indoors. However, some surveys show that many households and businesses experience a poor indoor coverage problem. It has been identified that poor coverage is the main reason for churn, which is very costly for operators in saturated markets. How to provide good indoor coverage cost effectively is thus a demanding challenge for operators.
標簽： Technologies Femtocells Deployment and
上傳時間： 2020-05-27
上傳用戶：shancjb
Free Space Optical Communication (FSOC) is an effective alternative technology to meet the Next Generation Network (NGN) demands as well as highly secured (mili- tary) communications. FSOC includes various advantages like last mile access, easy installation, free of Electro Magnetic Interference (EMI)/Electro Magnetic Compatibil- ity (EMC) and license free access etc. In FSOC, the optical beam propagation in the turbulentatmosphereisseverelyaffectedbyvariousfactorssuspendedinthechannel, geographicallocationoftheinstallationsite,terraintypeandmeteorologicalchanges. Therefore a rigorous experimental study over a longer period becomes significant to analyze the quality and reliability of the FSOC channel and the maximum data rate that the system can operate since data transmission is completely season dependent.
標簽： Communication Optical System Space Free
上傳時間： 2020-05-27
上傳用戶：shancjb
Providing QoS while optimizing the LTE network in a cost efficient manner is very challenging. Thus, radio scheduling is one of the most important functions in mobile broadband networks. The design of a mobile network radio scheduler holds several objectives that need to be satisfied, for example: the scheduler needs to maximize the radio performance by efficiently distributing the limited radio re- sources, since the operator’s revenue depends on it.
標簽： Communications Future Mobile LTE
上傳時間： 2020-05-27
上傳用戶：shancjb
An optical fiber amplifier is a key component for enabling efficient transmission of wavelength-divisionmultiplexed(WDM)signalsoverlongdistances.Eventhough many alternative technologies were available, erbium-doped fiber amplifiers won theraceduringtheearly1990sandbecameastandardcomponentforlong-haulopti- caltelecommunicationssystems.However,owingtotherecentsuccessinproducing low-cost, high-power, semiconductor lasers operating near 1450 nm, the Raman amplifiertechnologyhasalsogainedprominenceinthedeploymentofmodernlight- wavesystems.Moreover,becauseofthepushforintegratedoptoelectroniccircuits, semiconductor optical amplifiers, rare-earth-doped planar waveguide amplifiers, and silicon optical amplifiers are also gaining much interest these days.
標簽： Propagation Light Media Gain in
上傳時間： 2020-05-27
上傳用戶：shancjb
This books presents the research work of COST 273 Towards Mobile Broadband Multimedia Networks, hence, it reports on the work performed and on the results achieved within the project by its participants. The material presented here corresponds to the results obtained in four years of collaborative work by more than 350 researchers from 137 institutions (universities, operators, manufacturers, regulators, independent laboratories and others – a full list is provided in Appendix B) belonging to 29 countries (mainly European, but also from Asia and North America) in the area of mobileradio. Theobjectiveofpublishingtheseresultsasabookisessentiallytomakethemavailable to an audience wider than the project. In fact, it just follows a ‘tradition’ of previous COST Actions in this area of telecommunications, i.e. COST 207, 231 and 259.
標簽： Multimedia Techniques Broadband Networks Mobile
上傳時間： 2020-05-30
上傳用戶：shancjb
This paper covers the keynote address delivered by the Chairman of the COST Action 285 at the Symposium. It outlines the studies undertaken by the members of the Action with the objective of enhancing existing modeling and simulation tools and to develop new ones for research in emerging multiservice telecommunication networks. The paper shows how the scope of COST Action 285 has been enriched by the contributions made at the Symposium.
標簽： Simulation Modeling Tools and
上傳時間： 2020-05-31
上傳用戶：shancjb
The telecommunications industry has seen a rapid boost within the last decade. New realities and visions of functionalities in various telecommunications networks have brought forward the concept of next-generation networks (NGNs). The competitions among operators for support- ing various services, lowering of the cost of having mobile and cellular phones and smartphones, increasing demand for general mobility, explosion of digital traffic, and advent of convergence network technologies added more dynamism in the idea of NGNs. In fact, facilitating con- vergence of networks and convergence of various types of services is a significant objective of NGNs.
標簽： Next-Generation Converged Networks
上傳時間： 2020-05-31
上傳用戶：shancjb
Orthogonal frequency division multiplexing (OFDM) has been shown to be an effective technique to combat multipath fading in wireless channels. It has been and is going to be used in various wireless communication systems. This book gives a comprehensive introduction on the theory and practice of OFDM for wireless communications.
標簽： Multiplexing Orthogonal Frequency Division
上傳時間： 2020-05-31
上傳用戶：shancjb
The single-carrier frequency division multiple access (SC-FDMA) system is a well-known system that has recently become a preferred choice for mobile uplink channels. This is attributed to its advantages such as the low peak-to-average power ratio (PAPR) and the use of frequency domain equalizers. Low PAPR allows the system to relax the specifications of linearity in the power amplifier of the mobile terminal, which reduces cost and power consumption.
標簽： Communications SC-FDMA Mobile for
上傳時間： 2020-06-01
上傳用戶：shancjb
The use of light to send messages is not new. Fires were used for signaling in biblical times, smoke signals have been used for thousands of years and flashing lights have been used to communicate between warships at sea since the days of Lord Nelson. The idea of using glass fibre to carry an optical communications signal originated with Alexander Graham Bell. However this idea had to wait some 80 years for better glasses and low-cost electronics for it to become useful in practical situations.
標簽： Communications Understanding Optical
上傳時間： 2020-06-01
上傳用戶：shancjb
