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      Cellular LTE-A Technologies for the Future Internet-of-Things: Physical Layer Features and Challenges

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          Internet of Things: A Survey on Enabling Technologies, Protocols, and Applications

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            Massive MIMO for Next Generation Wireless Systems

            , , (2014)
            Multi-user Multiple-Input Multiple-Output (MIMO) offers big advantages over conventional point-to-point MIMO: it works with cheap single-antenna terminals, a rich scattering environment is not required, and resource allocation is simplified because every active terminal utilizes all of the time-frequency bins. However, multi-user MIMO, as originally envisioned with roughly equal numbers of service-antennas and terminals and frequency division duplex operation, is not a scalable technology. Massive MIMO (also known as "Large-Scale Antenna Systems", "Very Large MIMO", "Hyper MIMO", "Full-Dimension MIMO" & "ARGOS") makes a clean break with current practice through the use of a large excess of service-antennas over active terminals and time division duplex operation. Extra antennas help by focusing energy into ever-smaller regions of space to bring huge improvements in throughput and radiated energy efficiency. Other benefits of massive MIMO include the extensive use of inexpensive low-power components, reduced latency, simplification of the media access control (MAC) layer, and robustness to intentional jamming. The anticipated throughput depend on the propagation environment providing asymptotically orthogonal channels to the terminals, but so far experiments have not disclosed any limitations in this regard. While massive MIMO renders many traditional research problems irrelevant, it uncovers entirely new problems that urgently need attention: the challenge of making many low-cost low-precision components that work effectively together, acquisition and synchronization for newly-joined terminals, the exploitation of extra degrees of freedom provided by the excess of service-antennas, reducing internal power consumption to achieve total energy efficiency reductions, and finding new deployment scenarios. This paper presents an overview of the massive MIMO concept and contemporary research.
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              An Overview of Massive MIMO: Benefits and Challenges

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                Author and article information

                Journal
                IEEE Communications Surveys & Tutorials
                IEEE Commun. Surv. Tutorials
                Institute of Electrical and Electronics Engineers (IEEE)
                1553-877X
                24 2017
                24 2017
                : 19
                : 4
                : 2544-2572
                Article
                10.1109/COMST.2017.2728013
                e3b1435a-adb1-492d-9a91-3e95ee57ab69
                © 2017
                History

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