Journal ArticleDOI
Noncooperative Cellular Wireless with Unlimited Numbers of Base Station Antennas
TLDR
A cellular base station serves a multiplicity of single-antenna terminals over the same time-frequency interval and a complete multi-cellular analysis yields a number of mathematically exact conclusions and points to a desirable direction towards which cellular wireless could evolve.Abstract:
A cellular base station serves a multiplicity of single-antenna terminals over the same time-frequency interval. Time-division duplex operation combined with reverse-link pilots enables the base station to estimate the reciprocal forward- and reverse-link channels. The conjugate-transpose of the channel estimates are used as a linear precoder and combiner respectively on the forward and reverse links. Propagation, unknown to both terminals and base station, comprises fast fading, log-normal shadow fading, and geometric attenuation. In the limit of an infinite number of antennas a complete multi-cellular analysis, which accounts for inter-cellular interference and the overhead and errors associated with channel-state information, yields a number of mathematically exact conclusions and points to a desirable direction towards which cellular wireless could evolve. In particular the effects of uncorrelated noise and fast fading vanish, throughput and the number of terminals are independent of the size of the cells, spectral efficiency is independent of bandwidth, and the required transmitted energy per bit vanishes. The only remaining impairment is inter-cellular interference caused by re-use of the pilot sequences in other cells (pilot contamination) which does not vanish with unlimited number of antennas.read more
Citations
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Journal ArticleDOI
What Will 5G Be
Jeffrey G. Andrews,Stefano Buzzi,Wan Choi,Stephen V. Hanly,Angel Lozano,Anthony C. K. Soong,Jianzhong Charlie Zhang +6 more
TL;DR: This paper discusses all of these topics, identifying key challenges for future research and preliminary 5G standardization activities, while providing a comprehensive overview of the current literature, and in particular of the papers appearing in this special issue.
Journal ArticleDOI
Massive MIMO for next generation wireless systems
TL;DR: 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.
Journal ArticleDOI
Scaling Up MIMO: Opportunities and Challenges with Very Large Arrays
Fredrik Rusek,Daniel Persson,Buon Kiong Lau,Erik G. Larsson,Thomas L. Marzetta,Fredrik Tufvesson +5 more
TL;DR: The gains in multiuser systems are even more impressive, because such systems offer the possibility to transmit simultaneously to several users and the flexibility to select what users to schedule for reception at any given point in time.
Journal ArticleDOI
Five disruptive technology directions for 5G
TL;DR: In this article, the authors describe five technologies that could lead to both architectural and component disruptive design changes: device-centric architectures, millimeter wave, massive MIMO, smarter devices, and native support for machine-to-machine communications.
Journal ArticleDOI
Energy and Spectral Efficiency of Very Large Multiuser MIMO Systems
TL;DR: In this paper, the tradeoff between the energy efficiency and spectral efficiency of a single-antenna system is quantified for a channel model that includes small-scale fading but not large scale fading, and it is shown that the use of moderately large antenna arrays can improve the spectral and energy efficiency with orders of magnitude compared to a single antenna system.
References
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Journal ArticleDOI
Network Duality for Multiuser MIMO Beamforming Networks and Applications
TL;DR: This work applies the network duality to the joint MIMO beamforming and power control problem with individual SINR constraints, and proposes a high-performance iterative algorithm which, compared with past centralized approaches, has improved convergence behavior.
Journal ArticleDOI
Adapting a downlink array from uplink measurements
TL;DR: It is demonstrated that obtaining a good estimate of the uplink covariance matrix is not essential for the successful operation of the adaptive scheme, and even when the mobile is at rest and the uplinking information comprises only a single snapshot from the receiver array, an adaptive scheme can improve the SNR.
Journal ArticleDOI
Antenna Packing in Low-Power Systems: Communication Limits and Array Design
TL;DR: Using spectral efficiency as a target metric for array optimization, it is shown that any array configuration, transmit or receive, can be characterized via a parameter that is interpreted as ldquoeffective degrees of freedom, which describes the best possible performance for any transceiver array which confines its elements inside a given space.
Proceedings ArticleDOI
Evolution of Base Stations in Cellular Networks: Denser Deployment versus Coordination
TL;DR: This work adopts the criterion to maximize the minimum spectral efficiency of served users with a certain user outage constraint, and considers another approach by dividing the system into microcells through denser base station deployment.
Proceedings Article
On Limits of Antenna Packing in Low Power Systems
TL;DR: The notion of antenna-space capacity measures the maximum growth of spectral efficiency that antenna configuration can achieve, given arbitrary number of antennas, and has a practical utility as a benchmark for design of actual antenna configurations.