The capability of radio waves to provide almost instantaneous distant communications without interconnecting wires was a major factor in the explosive growth of communica- tions during the 20th century. With the dawn of the 21st century, the future for communi- cations systems seems limitless. The invention of the vacuum tube made radio a practical and affordable communications medium.
標(biāo)簽： Communications Receivers
上傳時(shí)間： 2020-05-26
上傳用戶：shancjb
Over the past few decades, wireless communications and networking have witnessed an unprecedented growth, and have become pervasive much sooner than anyone could have predicted. For example, cellular wireless networks are expected to become the dominant and ubiquitous telecommunication means in the next few decades. The widespread success of cellular and WLAN systems prompts the development of advanced wireless systems to provide access to information services beyond voice such as telecommuting, video conferencing, interactive media, real-time internet gaming, and so on, anytime and anywhere.
標(biāo)簽： Compressive Networks Wireless Sensing for
上傳時(shí)間： 2020-05-27
上傳用戶：shancjb
The rapid growth in mobile communications has led to an increasing demand for wide- band high data rate communications services. In recent years, Distributed Antenna Systems (DAS) has emerged as a promising candidate for future (beyond 3G or 4G) mobile communications, as illustrated by projects such as FRAMES and FuTURE. The architecture of DAS inherits and develops the concepts of pico- or micro-cell systems, where multiple distributed antennas or access points (AP) are connected to and con- trolled by a central unit.
標(biāo)簽： Distributed Antenna Systems
上傳時(shí)間： 2020-05-27
上傳用戶：shancjb
During the past two decades there has been a substantial growth in research in wireless communications. The number of journals published from various parts of the world catering to the research community has grown exponentially. Despite such a growth, the engineering community still needs more information so as to thoroughly comprehend wireless channel characteristics. What specifically must be understood are the effects of channel degradation brought on by statistical fluctua- tions in the channel.
標(biāo)簽： Shadowing Wireless Systems Fading and in
上傳時(shí)間： 2020-05-27
上傳用戶：shancjb
Currently, the information and communications technology (ICT) industry sector accounts for about 2–6% of the energy consumption worldwide, and a significant por- tion of this is contributed by the wireless and mobile communications industry. With the proliferation of wireless data applications, wireless technology continues to increase worldwide at an unprecedented growth rate. This has resulted in an increased number of installed base stations and higher demand on power grids and device power usage, causing an increased carbon footprint worldwide.
標(biāo)簽： Communication Networks Green Radio
上傳時(shí)間： 2020-05-27
上傳用戶：shancjb
The wireless market has experienced a phenomenal growth since the first second- generation (2G) digital cellular networks, based on global system for mobile communications (GSM) technology, were introduced in the early 1990s. Since then, GSM has become the dominant global 2G radio access standard. Almost 80% of today’s new subscriptions take place in one of the more than 460 cellular networks that use GSM technology. This growth has taken place simultaneously with the large experienced expansion of access to the Internet and its related multimedia services.
標(biāo)簽： Performance Evolution GPRS EDGE GSM and
上傳時(shí)間： 2020-05-27
上傳用戶：shancjb
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.
標(biāo)簽： Heterogeneous Wireless Networks Access
上傳時(shí)間： 2020-05-27
上傳用戶：shancjb
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.
標(biāo)簽： Wireless Systems Mobile Beyond and 3G
上傳時(shí)間： 2020-05-30
上傳用戶：shancjb
The last decade proved to be hugely successful for the mobile communications industry, characterised by continued and rapid growth in demand, spurred on by new technological advances and innovative marketing techniques. Of course, when we refer to mobile commu- nications, we tend to implicitly refer to cellular systems, such as GSM. The plight of the mobile-satellite industry over the last decade, although eventful, has, at times, been more akin to an out of control roller coaster ride.
標(biāo)簽： Communication Satellite Networks Mobile
上傳時(shí)間： 2020-05-30
上傳用戶：shancjb
The growth of mobile technologies is remarkable. At a recent Mobile World Congress Conference, Eric Schmidt, CEO of Google predicted that within three years, smart phones will surpass Personal Com- puter sales. The number of mobile phones used worldwide has exceeded 4.6 billion with continued growth expected in the future. In fact, in the United States alone, the numbers of mobile phone users comprise over 80% of the population.
標(biāo)簽： Opportunities Consumption Technology Mobile
上傳時(shí)間： 2020-05-30
上傳用戶：shancjb
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