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.
上傳時間： 2020-05-27
上傳用戶：shancjb
Wireless is one of the most rapidly developing technologies in our time, with dazzling new products and services emerging on an almost daily basis. These developments present enormous challenges for communications engineers, as the demand for increased wireless capacity grows explosively. Indeed, the discipline of wireless communications presents many challenges to designers that arise as a result of the demanding nature of the physical medium and the complexities in the dynamics of the underlying network.
標簽： Communications Wireless MIMO
上傳時間： 2020-05-28
上傳用戶：shancjb
Many wireless communications channels consist of multiple signal paths from the transmitter to receiver. This multiplicity of paths leads to a phenomenon known as multipath fading. The multiple paths are caused by the presence of objects in the physical environment that, through the mechanisms of propagation, alter the path of radiated energy. These objects are referred to as scatterers. In the past, researchers often looked at ways to mitigate multipath scattering, such as in diversity systems. Multiple-input, multiple-output (MIMO) systems, on the other hand, use multipath diversity to their advantage; a MIMO system has the ability to translate increased spatial diversity into increased channel capacity.
標簽： Multiple-Output Multiple-Input Channel Models
上傳時間： 2020-05-31
上傳用戶：shancjb
The family of recent wireless standards included the optional employment of MIMO tyechniques. This was motivated by the observation according to the classic Shannon-Hartley law the achiev- able channel capacity increases logarithmically with the transmit power. By contrast, the MIMO capacity increases linearly with the number of transmit antennas, provided that the number of receive antennas is equal to the number of transmit antennas.
標簽： Simulation Modeling Network and
上傳時間： 2020-05-31
上傳用戶：shancjb
Emerging technologies such as WiFi and WiMAX are profoundly changing the landscape of wireless broadband. As we evolve into future generation wireless networks, a primary challenge is the support of high data rate, integrated multi- media type traffic over a unified platform. Due to its inherent advantages in high-speed communication, orthogonal frequency division multiplexing (OFDM) has become the modem of choice for a number of high profile wireless systems (e.g., DVB-T, WiFi, WiMAX, Ultra-wideband).
標簽： OFDM-Based Broadband Networks Wireless
上傳時間： 2020-05-31
上傳用戶：shancjb
This book provides the essential design techniques for radio systems that operate at frequencies of 3 MHz to 100 GHz and which will be employed in the telecommunication service. We may also call these wireless systems, wireless being synonymous with radio, Telecommunications is a vibrant indus- try, particularly on the ‘‘radio side of the house.’’ The major supporter of this upsurge in radio has been the IEEE and its 802 committees. We now devote ? . an entire chapter to wireless LANs WLANs detailed in IEEE 802.11. We also now have subsections on IEEE 802.15, 802.16, 802.20 and the wireless ? . ? metropolitan area network WMAN . WiFi, WiMax,, and UWB ultra wide- . band are described where these comparatively new radio specialties are demonstrating spectacular growth.
標簽： Telecommunication Design System Radio for
上傳時間： 2020-06-01
上傳用戶：shancjb
Mobile and wireless communication systems are a prominent communications technology of the twenty-first century with profound economic and social impacts in practically all parts of the world. The current state of wireless communication systems allows for a much wider scope of applications than what it used to be originally, that is, to be a mobile extension of the public switched telephone network.
標簽： Allocation Resource MIMO and
上傳時間： 2020-06-01
上傳用戶：shancjb
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.
標簽： Transceiver Design RF
上傳時間： 2020-06-01
上傳用戶：shancjb
Driven by the desire to boost the quality of service of wireless systems closer to that afforded by wireline systems, space-time processing for multiple-input multiple-output (MIMO) wireless communications research has drawn remarkable interest in recent years. Excit- ing theoretical advances, complemented by rapid transition of research results to industry products and services, have created a vibrant and growing area that is already established by all counts. This offers a good opportunity to reflect on key developments in the area during the past decade and also outline emerging trends.
標簽： Space-Time Processing
上傳時間： 2020-06-01
上傳用戶：shancjb
Wireless communications has become a field of enormous scientific and economic interest. Recent success stories include 2G and 3G cellular voice and data services (e.g., GSM and UMTS), wireless local area networks (WiFi/IEEE 802.11x), wireless broadband access (WiMAX/IEEE 802.16x), and digital broadcast systems (DVB, DAB, DRM). On the physical layer side, traditional designs typically assume that the radio channel remains constant for the duration of a data block. However, researchers and system designers are increasingly shifting their attention to channels that may vary within a block. In addition to time dispersion caused by multipath propagation, these rapidly time-varying channels feature frequency dispersion resulting from the Doppler effect. They are, thus, often referred to as being “doubly dispersive.”
標簽： Time-Varying Channels
上傳時間： 2020-06-01
上傳用戶：shancjb
