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
This book is intended to help electric power and telephone company personnel and individuals interested in properly protecting critical tele communications circuits and equipment located in high voltage (HV) environments and to improve service reliability while maintaining safe working conditions. Critical telecommunications circuits are often located in HV environments such as electric utility power plants, substations, cell sites on power towers, and standalone telecommuni cations facilities such as 911 call centers and mountaintop telecom munications sites.
标签： Protection Voltage High
上传时间： 2020-05-27
上传用户：shancjb
Communication, a word that many associate with modern technology, actually has nothing to do with technology. At its core, communication involves nothing more than the spoken or written word, and symbolic languages like art and music. Technology has become synonymous with communication because technology has historically been the method by which communication to or by the general population takes place.
标签： Implementing 802.11
上传时间： 2020-05-27
上传用户：shancjb
The information technology (IT) revolution is surely coming in this century, just as did the agricultural and industrial revolutions that have already so enriched our lives. As the IT revolution progresses, it is expected that almost all social struc- tures and economic activities will be changed substantially
标签： Communication Intelligent Systems
上传时间： 2020-05-27
上传用户：shancjb
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
上传时间： 2020-05-27
上传用户：shancjb
To meet the future demand for huge traffic volume of wireless data service, the research on the fifth generation (5G) mobile communication systems has been undertaken in recent years. It is expected that the spectral and energy efficiencies in 5G mobile communication systems should be ten-fold higher than the ones in the fourth generation (4G) mobile communication systems. Therefore, it is important to further exploit the potential of spatial multiplexing of multiple antennas. In the last twenty years, multiple-input multiple-output (MIMO) antenna techniques have been considered as the key techniques to increase the capacity of wireless communication systems. When a large-scale antenna array (which is also called massive MIMO) is equipped in a base-station, or a large number of distributed antennas (which is also called large-scale distributed MIMO) are deployed, the spectral and energy efficiencies can be further improved by using spatial domain multiple access. This paper provides an overview of massive MIMO and large-scale distributed MIMO systems, including spectral efficiency analysis, channel state information (CSI) acquisition, wireless transmission technology, and resource allocation.
标签： Large-scale Antenna Systems
上传时间： 2020-05-27
上传用户：shancjb
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.
上传时间： 2020-05-27
上传用户：shancjb
During the 400 days and nights before we finalized this book on January 1, 2012, we saw the sunset decorated by the raindrop, and were accompanied by the flowers blooming to withering. All those past memories are engraved on our hearts and will last eternally, cementing the most profound friendship in the world.
标签： LTE-Advanced Technology Interface Air
上传时间： 2020-05-27
上传用户：shancjb
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
上传时间： 2020-05-27
上传用户：shancjb
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.
上传时间： 2020-05-28
上传用户：shancjb
