672 research outputs found
Receive Spatial Modulation for Massive MIMO Systems
In this paper, we consider the downlink of a massive
multiple-input-multiple-output (MIMO) single user transmission system operating
in the millimeter wave outdoor narrowband channel environment. We propose a
novel receive spatial modulation architecture aimed to reduce the power
consumption at the user terminal, while attaining a significant throughput. The
energy consumption reduction is obtained through the use of analog devices
(amplitude detector), which reduces the number of radio frequency chains and
analog-to-digital-converters (ADCs). The base station transmits spatial and
modulation symbols per channel use. We show that the optimal spatial symbol
detector is a threshold detector that can be implemented by using one bit ADC.
We derive closed form expressions for the detection threshold at different
signal-to-noise-ratio (SNR) regions showing that a simple threshold can be
obtained at high SNR and its performance approaches the exact threshold. We
derive expressions for the average bit error probability in the presence and
absence of the threshold estimation error showing that a small number of pilot
symbols is needed. A performance comparison is done between the proposed system
and fully digital MIMO showing that a suitable constellation selection can
reduce the performance gap
Massive MIMO is a Reality -- What is Next? Five Promising Research Directions for Antenna Arrays
Massive MIMO (multiple-input multiple-output) is no longer a "wild" or
"promising" concept for future cellular networks - in 2018 it became a reality.
Base stations (BSs) with 64 fully digital transceiver chains were commercially
deployed in several countries, the key ingredients of Massive MIMO have made it
into the 5G standard, the signal processing methods required to achieve
unprecedented spectral efficiency have been developed, and the limitation due
to pilot contamination has been resolved. Even the development of fully digital
Massive MIMO arrays for mmWave frequencies - once viewed prohibitively
complicated and costly - is well underway. In a few years, Massive MIMO with
fully digital transceivers will be a mainstream feature at both sub-6 GHz and
mmWave frequencies. In this paper, we explain how the first chapter of the
Massive MIMO research saga has come to an end, while the story has just begun.
The coming wide-scale deployment of BSs with massive antenna arrays opens the
door to a brand new world where spatial processing capabilities are
omnipresent. In addition to mobile broadband services, the antennas can be used
for other communication applications, such as low-power machine-type or
ultra-reliable communications, as well as non-communication applications such
as radar, sensing and positioning. We outline five new Massive MIMO related
research directions: Extremely large aperture arrays, Holographic Massive MIMO,
Six-dimensional positioning, Large-scale MIMO radar, and Intelligent Massive
MIMO.Comment: 20 pages, 9 figures, submitted to Digital Signal Processin
5G Uniform linear arrays with beamforming and spatial multiplexing at 28 GHz, 37 GHz, 64 GHz and 71 GHz for outdoor urban communication: A two-level approach
Multiple-input multiple-output (MIMO) spatial multiplexing and beamforming are regarded as key technology enablers for the fifth-generation (5G) millimeter wave (mmWave) mobile radio services. Spatial multiplexing requires sufficiently separated and incoherent antenna array elements, while in the case of beamforming, the antenna array elements need to be coherent and closely spaced. Extensive 28-, 60-, and 73-GHz ultra-wideband propagation measurements in cities of New York City and Austin have indicated formation of two or more spatial lobes for the angles-of-departure and angles-of-arrival even for line-of-sight (LOS) transmission, which is an advantageous feature of mmWave channels, indicating that the transmitting and receiving array antenna elements can be co-located, thus enabling a single architecture for both spatial multiplexing and beamforming. In this paper, a two-level beamforming architecture for uniform linear arrays is proposed that leverages the formation of these spatial lobes. The antenna array is composed of sub-arrays, and the impact of sub-array spacing on the spectral efficiency is investigated through simulations using a channel simulator named NYUSIM developed based on extensive measured data at mmWave frequencies. Simulation results indicate spectral efficiencies of 18.5–28.1 bits/s/Hz with a sub-array spacing of 16 wavelengths for an outdoor mmWave urban LOS channel. The spectral efficiencies obtained are for single-user (SU) MIMO transmission at the recently allocated 5G carrier frequencies in July 2016. The method and results in this paper are useful for designing antenna array architectures for 5G wireless systems
State-of-the-art assessment of 5G mmWave communications
Deliverable D2.1 del proyecto 5GWirelessMain objective of the European 5Gwireless project, which is part of the H2020 Marie Slodowska-
Curie ITN (Innovative Training Networks) program resides in the training and involvement of young
researchers in the elaboration of future mobile communication networks, focusing on innovative
wireless technologies, heterogeneous network architectures, new topologies (including ultra-dense
deployments), and appropriate tools. The present Document D2.1 is the first deliverable of Work-
Package 2 (WP2) that is specifically devoted to the modeling of the millimeter-wave (mmWave)
propagation channels, and development of appropriate mmWave beamforming and signal
processing techniques. Deliver D2.1 gives a state-of-the-art on the mmWave channel measurement,
characterization and modeling; existing antenna array technologies, channel estimation and
precoding algorithms; proposed deployment and networking techniques; some performance
studies; as well as a review on the evaluation and analysis toolsPostprint (published version
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