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
Mobilenetworkoperatorswillmeetmanychallengesinthecomingyears.Itisexpectedthatthe numberofpeopleconnected,wirelineandwireless,willreachfivebillionby2015.Atthesame time, people use more wireless services and they expect similar user experience to what they can now get from fixed networks. Because of that we will see a hundred-fold increase in network traffic in the near future. At the same time markets are saturating and the revenue per bit is dropping.
标签： Self-Organising Networks LTE
上传时间： 2020-05-27
上传用户：shancjb
Smartphones have become a key element in providing greater user access to the mobile Internet. Many complex applications which used to be limited to PCs, have been developed and operated on smartphones. These applications extend the functionalities of smartphones, making them more convenient for users to be connected. However, they also greatly increase the power consumption of smartphones, making users frustrated with long delays in Web browsing.
标签： Browsing Mobile Cloud Using Web the
上传时间： 2020-05-30
上传用户：shancjb
The family of recent wireless standards included the optional employment of Multiple-Input Multiple-Output(MIMO)techniques.This was motivatedby the observationaccordingto the classic Shannon–Hartley law that the achievable channel capacity increases logarithmically with the transmit power. In 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. With the further proviso that the total transmit power is increased in proportion to the number of transmit antennas, a linear capacity increase is achieved upon increasing the transmit power, which justifies the spectacular success of MIMO systems.
标签： Multi-Functional Systems MIMO
上传时间： 2020-05-30
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Ever since ancient times, people continuously have devised new techniques and technologies for communicating their ideas, needs, and desires to others. Thus, many forms of increasingly complex communication systems have appeared over the years. The basic motivations behind each new one were to improve the transmission fidelity so that fewer errors occur in the received message, to increase the transmission capacity of a communication link so that more infor- mation could be sent, or to increase the transmission distance between relay sta- tions so that messages can be sent farther without the need to restore the signal fidelity periodically along its path.
标签： Communications Essentials Optical
上传时间： 2020-05-31
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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
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This book focuses on the study and development of one of the most advanced topics in broadband wireless communications systems: power efficiency and power consumption in wireless communications systems, especially of mobile devices. Hence, the main focus of this book is on the most recent techniques for the conservation of power and increase in power efficiency.
标签： Communications Efficiency Broadband Power in
上传时间： 2020-05-31
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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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We are currently witnessing an increase in telecommunications norms and standards given the recent advances in this domain. The increasing number of normalized standards paves the way for an increase in the range of offers and services available for each consumer. Moreover, the majority of available radio frequencies have already been allocated.
标签： Allocation Resource Radio
上传时间： 2020-05-31
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Software defined radio (SDR) is an exciting new field for the wireless indus- try; it is gaining momentum and beginning to be included in commercial and defense products. The technology offers the potential to revolutionize the way radios are designed, manufactured, deployed, and used. SDR prom- ises to increase flexibility, extend hardware lifetime, lower costs, and reduce time to market
标签： Software Defined Radio for 3G
上传时间： 2020-05-31
上传用户：shancjb
