Massive MIMO, also known as very-large MIMO or large-scale antenna systems, is a new technique that potentially can offer large network capacities in multi-user scenarios. With massive system, we consider the case where base station equipped with number of elements simultaneously serves multiple single-antenna users same time-frequency resource. So far, investigations are mostly based on theoretical channels independent and identically distributed (i.i.d.) complex Gaussian coefficients,...

Wireless communication using very-large multiple-input multiple-output (MIMO) antennas is a new research field, where base stations are equipped with very large number of as compared to previously considered systems. In theory, the increases, propagation properties that were random before start become deterministic. Theoretical investigations independent identically distributed (i.i.d.) complex Gaussian (Rayleigh fading) channels and unlimited have been done, but in practice we need know...

Massive MIMO can greatly increase both spectral and transmit-energy efficiency. This is achieved by allowing the number of antennas RF chains to grow very large. However, challenges include high system complexity hardware energy consumption. Here we investigate possibilities reduce required chains, performing antenna selection. While this approach not a effective strategy for theoretical independent Rayleigh fading channels, substantial reduction in be real massive without significant...

Very-large multiple-input multiple-output (MIMO), also called massive MIMO, is a new technique that potentially can offer large network capacities in multi-user scenarios, where the base stations are equipped with number of antennas simultaneously serving multiple single-antenna users on same frequency. We investigate channel behavior for realistic outdoor station scenario using arrays. Specifically we compare dirty-paper coding (DPC) and zero-forcing (ZF) sum-rates when physically linear...

Spatial multiplexing using Massive MIMO has been shown to have very promising properties, including large gains in spectral efficiency and several orders of magnitude lower transmit power, as compared today's access schemes. The properties massive studied mostly for theoretical channels with independent identically distributed (i.i.d.) complex Gaussian coefficients. To efficiently evaluate more realistic scenarios, we need channel models that capture important characteristics. We pursue this...

Massive MIMO is considered a key technology for the future wireless communication systems. The promising properties in terms of higher spectral and transmit-energy efficiency are brought by large number antennas at base station(BS). As increases, aperture BS antenna array may become much larger, as compared to today's arrays. In this case, mobile stations (MSs) significant scatterers can locate inside Rayleigh distance arrays, spherical wavefronts rather than planar experienced over paper,...

Fully-synchronous measurements of a massive multi-user multiple-input multiple-output (MU-MIMO) radio propagation channel are presented. We evaluate the ability MIMO system to spatially separate users located close each other in line-of-sight (LOS) conditions. The consists base-station (BS) antenna array equipped with 64 dual-polarized elements (128 ports) arranged cylindrical configuration, and eight single-antenna users. confined five-meter diameter circle move randomly at pedestrian...

Massive MIMO has been shown to greatly improve spectral and transmit-energy efficiency. When implementing a massive system, one challenge is high hardware complexity. A solution reduce the number of radio frequency (RF) transceiver chains by performing antenna selection. However, full RF switch that connects antennas can be highly complex incurs significant loss in output signal quality, especially when are large. We therefore propose simpler - binary switching architecture, which suboptimal...

We investigate the ability of Massive multiple-input multiple-output (MIMO) systems to spatially separate up eighteen users located close one another in line-of-sight (LOS) propagation conditions, both indoor and outdoor environments. For that, we use fully-synchronous measured channels at 2.6 GHz single-antenna moving within a small area concurrently communicating with base station (BS) equipped compact 128-port array. To quantify degree spatial user separability, three scalar metrics,...

Massive MIMO has been shown to greatly improve spectral and transmit-energy efficiency. When implementing a massive system, one challenge is high hardware complexity. A solution reduce the number of radio frequency (RF) transceiver chains by performing antenna selection. However, full RF switch that connects antennas can be highly complex incurs significant loss in output signal quality, especially when are large. We therefore propose simpler - binary switching architecture, which suboptimal...

In conventional MIMO, propagation conditions are often considered wide-sense stationary over the entire antenna array. massive MIMO systems, where arrays can span large physical dimensions, situation is quite different. For instance, significant variations in signal strength, due to shadowing, be experienced across a These effects vary with environment which array placed, and influence achievable sum-rates. We characterize these for several measured scenarios 2.6 GHz frequency range...

We investigate antenna correlation of an M-antenna massive multiple-input multiple-output (MIMO) setup with the purpose obtaining a low-rank representation instantaneous MIMO channel. Low-rank bases using short-term and long-term statistics are defined, their performance is evaluated data sets obtained from channel measurements in both indoor outdoor environments at 2.6 GHz. Our results indicate that can capture larger amount energy compared to ones, but they have limited timespan, one...

We consider optimal precoder design for multiuser multiple-input multiple-output broadcasting channels in single-carrier systems. Instead of linear detection, we assume that the advanced nonlinear channel shortening detectors are utilized at receivers. Such a scenario is challenging as uplink-downlink duality inapplicable. The target our to maximize sum achievable information rate (sum-AIR), with AIR each user being explicitly derived. analyze such general, and provide an efficient per-user...

Massive multiple-input multiple-output (MIMO) has been widely deployed in practice due to its capability of improving spectral efficiency. In mobility scenarios where users move at relatively high velocities (e.g., 40 km/h), however, massive MIMO faces a severe problem called "channel aging". This leads performance degradation as outdated and inaccurate channel state information (CSI) is used beamforming. the paper, we study time-variant characteristics real propagation environments, propose...

As a key technology for 5G and beyond mobile communications, massive MIMO has been implemented, tested will be widely deployed soon. Rectangular antenna arrays, associated with 32 to 64 transceivers, are the most commonly-considered configurations base stations. When testing such MIMOsystems in practical environments, we often obtain lower-than-expected system performance. That is say, performance gain does not keep up increases hardware complexity cost, making cost-inefficient practice. We...