In this paper we revisit hybrid analog-digital precoding systems with emphasis on their modelling and radio-frequency (RF) losses, to realistically evaluate their benefits in 5G system implementations. For this, we decompose the analog beamforming networks (ABFN) as a bank of commonly used RF components and formulate realistic model constraints based on their S-parameters. Specifically, we concentrate on fully-connected ABFN (FC-ABFN) and Butler networks for implementing the discrete Fourier transform (DFT) in the RF domain. The results presented in this paper reveal that the performance and energy efficiency of hybrid precoding systems are severely affected, once practical factors are considered in the overall design. In this context, we also show that Butler RF networks are capable of providing better performances than FC-ABFN for systems with a large number of RF chains.
标签： Analog-Digital Precoding Hybrid
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This research work aims at eliminating the off-chip RF SAW filters from fre- quency division duplexed (FDD) receivers. In the first approach, a monolithic passive RF filter was constructed using on-chip capacitors and bondwire inductors. The bond- wire characteristics were studied in details and the effect of mutual inductive coupling between the bondwires on the filter performance was analyzed. Based on that, a bond- wire configuration was proposed to improve the frequency response of the filter. The filter was implemented in 0.18 µm CMOS process for WCDMA applications.
标签： Interference Mitigation Techniques
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Our original effort in writing this book was to create a starting point for those in the business community who did not have a high level of technical expertise but needed to have some understanding of the technical functions of their information and communication technologies (ICT) in a corporate environment. As was true with the first edition of this book, if you are already an engineer, find some other form of pleasure reading—this text is not designed for you!
标签： Communications Introduction Technologies to
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The third generation (3G) mobile communication system is the next big thing in the world of mobile telecommunications. The first generation included analog mobile phones [e.g., Total Access Communications Systems (TACS), Nordic Mobile Telephone (NMT), and Advanced Mobile Phone Service (AMPS)], and the second generation (2G) included digital mobile phones [e.g., global system for mobile communications (GSM), personal digital cellular (PDC), and digital AMPS (D-AMPS)]. The 3G will bring digital multimedia handsets with high data transmission rates, capable of providing much more than basic voice calls.
标签： Communications Introduction Mobile 3G to
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Your Cisco Networking Academy Course Booklet is designed as a study resource you can easily read, high- light, and review on the go, wherever the Internet is not available or practical: ■ The text is extracted directly, word-for-word, from the online course so you can highlight important points and take notes in the “Your Chapter Notes” section. ■ Headings with the exact page correlations provide a quick reference to the online course for your class- room discussions and exam preparation. ■ An icon system directs you to the online curriculum to take full advantage of the images, labs, Packet Tracer activities, and dynamic Flash-based activities embedded within the Networking Academy online course interface.
标签： Switching Wireless LAN and
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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
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For nearly a hundred years telecommunications provided mainly voice services and very low speed data (telegraph and telex). With the advent of the Internet, several data services became mainstream in telecommunications; to the point that voice is becoming an accessory to IP-centric data networks. Today, high-speed data services are already part of our daily lives at work and at home (web surfing, e-mail, virtual private networks, VoIP, virtual meetings, chats...). The demand for high-speed data services will grow even more with the increasing number of people telecommuting.
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In the nineteenth century, scientists, mathematician, engineers and innovators started investigating electromagnetism. The theory that underpins wireless communications was formed by Maxwell. Early demonstrations took place by Hertz, Tesla and others. Marconi demonstrated the first wireless transmission. Since then, the range of applications has expanded at an immense rate, together with the underpinning technology. The rate of development has been incredible and today the level of technical and commercial maturity is very high. This success would not have been possible without understanding radio- wave propagation. This knowledge enables us to design successful systems and networks, together with waveforms, antennal and transceiver architectures. The radio channel is the cornerstone to the operation of any wireless system.
标签： LTE-Advanced Generation Next and
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Fordecades,microwavelineofsight(LOS)linkshavebeenoneofthebasictechnolo- gies used to build telephone networks. Until 1980, the fast rollout of high capacity transport networks and deployment of links in areas with challenging geographic characteristics could not be understood without this technology.
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This book presents millimeter wave communication system design and analysis at the level to produce an understanding of the interaction between a wireless system and its front end so that the overall performance can be predicted. Gigabit wireless commu- nications require a considerable amount of bandwidth, which can be supported by millimeter waves. Millimeter wave technology has come of age, and at the time of writing the standards of IEEE 802.15.3c, WiGig, Wireless HD TM , and the European Computer Manufacturers Association have recently been finalized.
标签： Communication Millimeter Systems Wave
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