With the rapid growth in the number of wireless applications, services and devices, using a single wireless technology such as a second generation (2G) and third gener- ation (3G) wireless system would not be efficient to deliver high speed data rate and quality-of-service (QoS) support to mobile users in a seamless way. The next genera- tion wireless systems (also sometimes referred to as Fourth generation (4G) systems) are being devised with the vision of heterogeneity in which a mobile user/device will be able to connect to multiple wireless networks (e.g., WLAN, cellular, WMAN) simultaneously.
标签： Heterogeneous Wireless Networks Access
上传时间： 2020-05-27
上传用户：shancjb
Radio frequency (RF) power amplifiers are used in everyday life for many applica- tions including cellular phones, magnetic resonance imaging, semiconductor wafer processing for chip manufacturing, etc. Therefore, the design and performance of RF amplifiers carry great importance for the proper functionality of these devices. Furthermore, several industrial and military applications require low-profile yet high-powered and efficient power amplifiers.
标签： Introduction Amplifier Design Power to RF
上传时间： 2020-05-27
上传用户：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.
标签： Propagation Light Media Gain in
上传时间： 2020-05-27
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With the rapid growth of the wireless mobile applications, wireless voice has begun to challenge wireline voice, whereas the desire to access e-mail, surf the Web or download music (e.g., MP3) wirelessly is increasing for wireless data. While second generation (2G) cellular wireless systems, such as cdmaOne1, GSM2 and TDMA3, introduced digital technology to wireless cellular systems to deal with the increasing demand for wireless applications, there is still the need for more spectrally efficient technologies for two reasons. First, wireless voice capacity is expected to continue to grow. Second, the introduction of high-speed wireless data will require more bandwidth.
标签： Wireless Systems Mobile Beyond and 3G
上传时间： 2020-05-30
上传用户：shancjb
In the past few decades, a technological revolution has occurred that has changed the way we live in dramatic ways. This technological revolution is the result of the emergence and evolution of a wide variety of new wireless networking tech- nologies. Now people using these technologies are able to access the network and control many applications at will with their handheld devices anywhere, anytime. Although these technologies have made a long lasting impact in the revolution, it has also opened up various challenging issues which are yet to be resolved to make them more efficient and cost-effective.
标签： Next-Generation Technologies Wireless
上传时间： 2020-05-30
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The ever-increasing demand for private and sensitive data transmission over wireless net- works has made security a crucial concern in the current and future large-scale, dynamic, and heterogeneous wireless communication systems. To address this challenge, computer scientists and engineers have tried hard to continuously come up with improved crypto- graphic algorithms. But typically we do not need to wait too long to find an efficient way to crack these algorithms. With the rapid progress of computational devices, the current cryptographic methods are already becoming more unreliable. In recent years, wireless re- searchers have sought a new security paradigm termed physical layer security. Unlike the traditional cryptographic approach which ignores the effect of the wireless medium, physi- cal layer security exploits the important characteristics of wireless channel, such as fading, interference, and noise, for improving the communication security against eavesdropping attacks. This new security paradigm is expected to complement and significantly increase the overall communication security of future wireless networks.
标签： Communications Physical Security Wireless Layer in
上传时间： 2020-05-31
上传用户：shancjb
Mobile operators must continuously pursue cost‐ effective and efficient solutions to meet the high data demand requirements of their subscribers. Limited spectrum allocations and non‐contiguous spectrum blocks continue to pose challenges for mobile operators supporting large data uploads and downloads across their networks. With the increase in video and social media content, the challenges have increased exponentially.
标签： qorvo-carrier-aggregation-fundame ntals
上传时间： 2020-05-31
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The multiple-input multiple-output (MIMO) technique provides higher bit rates and better reliability in wireless systems. The efficient design of RF transceivers has a vital impact on the implementation of this technique. This first book is com- pletely devoted to RF transceiver design for MIMO communications. The book covers the most recent research in practical design and applications and can be an important resource for graduate students, wireless designers, and practical engineers.
标签： Transceiver Design RF
上传时间： 2020-05-31
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The radio spectrum is one of the most precious resources which must be managed to ensure efficient access for the wireless communication services which use it. The allocation and management of spectrum are administered by the regulatory authorities. Traditionally, spectrum allocation is carried out exclusively of its use in large geographic areas and assigning frequency bands to specific users or service providers is proved to be inefficient. Recently, substantial knowledge about dynamic spectrum access scheme has been accumulated to enable efficient spectrum sharing.
标签： Management Spectrum Access and
上传时间： 2020-05-31
上传用户：shancjb
Heterogeneous Network (HetNet): A network that consists of a mix of macro cells and low-power nodes, e.g. Pico, Femto, Relay Node (RN) and Remote Radio Head (RRH)
标签： efficient Spectrum Energy and
上传时间： 2020-05-31
上传用户：shancjb
