Journal ArticleDOI
Making smart use of excess antennas: Massive MIMO, small cells, and TDD
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TLDR
It is suggested that time division duplexing (TDD) could be a key enabler for a new heterogeneous network architecture with the potential to provide ubiquitous coverage and unprecedented spectral area efficiencies.Abstract:
In this paper, we present a vision beyond the conventional Long Term Evolution Fourth Generation (LTE-4G) evolution path and suggest that time division duplexing (TDD) could be a key enabler for a new heterogeneous network architecture with the potential to provide ubiquitous coverage and unprecedented spectral area efficiencies. This architecture is based on a cochannel deployment of macro base stations (BSs) with very large antenna arrays and a secondary tier of small cells (SCs) with a few antennas each. Both tiers employ a TDD protocol in a synchronized fashion. The resulting channel reciprocity enables not only the estimation of large-dimensional channels at the BSs, but also an implicit coordination between both tiers without the need to exchange user data or channel state information (CSI) over the backhaul. In particular, during the uplink (UL), the BSs and SCs can locally estimate the dominant interference sub-space. This knowledge can be leveraged for downlink (DL) precoding to reduce intra- and inter-tier interference. In other words, the BSs and SCs “sacrifice” some of their degrees of freedom for interference rejection. Our simulation results demonstrate that the proposed architecture and precoding scheme can achieve a very attractive rate region compared to several baseline scenarios. For example, with 100 antennas at each BS and four antennas at each SC, we observe an aggregate area throughput of 7.63 Gb/s/km2 (DL) and 8.93 Gb/s/km2 (UL) on a 20 MHz band shared by about 100 mobile devices.read more
Citations
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Massive MIMO Networks: Spectral, Energy, and Hardware Efficiency
TL;DR: This monograph summarizes many years of research insights in a clear and self-contained way and providest the reader with the necessary knowledge and mathematical toolsto carry out independent research in this area.
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Fifty Years of MIMO Detection: The Road to Large-Scale MIMOs
Shaoshi Yang,Lajos Hanzo +1 more
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Massive MIMO: An Introduction
TL;DR: Massive MIMO is a brand new technology that has yet to be reduced to practice, but its principles of operation are well understood, and surprisingly simple to elucidate.
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Optimal Resource Allocation in Coordinated Multi-Cell Systems
TL;DR: The use of multiple antennas at base stations is a key component in the design of cellular communication systems that can meet high-capacity demands in the downlink.
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Massive MIMO with Non-Ideal Arbitrary Arrays: Hardware Scaling Laws and Circuit-Aware Design
TL;DR: In this article, the authors derived closed-form expressions for the user rates and a scaling law that shows how fast the hardware imperfections can increase with $N$ while maintaining high rates.
References
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Proceedings ArticleDOI
Compensation of interference non-reciprocity in adaptive TDD MIMO-OFDM systems
Antti Tolli,Marian Codreanu +1 more
TL;DR: In a time-division-duplex (TDD) system, the channel state information can be easily obtained at the transmitter side due to channel reciprocity and it can be used to dramatically increase the spectral efficiency of a MIMO system, but the interference structure between transmission directions does not necessarily correlate at all.
Patent
Band switching for coherent beam forming in full-duplex wireless communication
Peter Bosch,Sape J. Mullender +1 more
TL;DR: In this paper, the authors proposed to use at least two frequency bands, where during a first time period a first one of the frequency bands is used for signal transmission (e.g., downlink) while a second one of frequency bands was used for the signal reception.
Posted Content
On the Coexistence of Macrocell Spatial Multiplexing and Cognitive Femtocells
Ansuman Adhikary,Giuseppe Caire +1 more
TL;DR: The impact of multiuser MIMO spatial multiplexing in the macrocell under the proposed scheme is investigated, and it is found that large gains are achievable by letting the macro cell schedule groups of co-located users, such that the number of femtocells affected by the interference temperature power constraint is small.
Proceedings ArticleDOI
On the coexistence of macrocell spatial multiplexing and cognitive femtocells
Ansuman Adhikary,Giuseppe Caire +1 more
TL;DR: In this article, a two-tier macrocell/femtocell system where the macrocell base station is equipped with multiple antennas and makes use of multiuser MIMO (spatial multiplexing), and the femtocells are "cognitive" is considered.
Patent
Band switching for coherent beam forming in full-duplex wireless communication
사페 제이 뮬렌더,피터 보치 +1 more
TL;DR: In this article, the authors proposed to use a plurality of antennas (i.e., antenna arrays) throughout the communication and synchronization beamforming (coherent beam foarming) and antenna diversity (antenna the overall communication efficiency is improved if the system is implemented using a diversity), the latency time is significantly reduced.