Massive MIMO: survey and future research topics

Abstract

Massive multiple-input multiple-output technology has been considered a breakthrough in wireless communication systems. It consists of equipping a base station with a large number of antennas to serve many active users in the same time-frequency block. Among its underlying advantages is the possibility to focus transmitted signal energy into very short-range areas, which will provide huge improvements in terms of system capacity. However, while this new concept renders many interesting benefits, it brings up new challenges that have called the attention of both industry and academia: channel state information acquisition, channel feedback, instantaneous reciprocity, statistical reciprocity, architectures, and hardware impairments, just to mention a few. This paper presents an overview of the basic concepts of massive multiple-input multiple-output, with a focus on the challenges and opportunities, based on contemporary research.

Dynamic Spectrum Sharing in 5G Wireless Networks With Full-Duplex Technology: Recent Advances and Research Challenges

“…In the direction of energy-efficient 5G communications, authors in [53,54] provided a detailed survey of the existing works in the areas of energy-efficient techniques for 5G networks and analyzed various green trade-offs, namely, spectrum efficiency versus energy efficiency, delay versus power, deployment efficiency versus energy efficiency, and bandwidth versus power for the effective design of energy-efficient 5G networks [53]. In addition, several survey and overview papers exist in the area of 5G enabling technologies such as massive MIMO [7,[55][56][57], mmWave [7,8,58], Non Orthogonal Multiple Access (NOMA) [59,60], cellular and heterogeneous networks [61][62][63], Internet of Things (IoT) [66,68], Machine to Machine (M2M) communication [64][65][66] and Device to Device (D2D) communication [67].…”

Calculation Functions of SDN Controller for Wireless Backhaul Infrastructure

“…It includes the grouping of subscribers by the type, amount of traffic and by spatial location, and choose the most optimal topology for each group. Backhaul links might be subject to dynamic link outages, especially when operating at very high frequencies, where there are capacity requirements [16], [17]. A link can temporarily go from Non-Lineof-Sight to Outage, leading to changes in the BH topology and consequently, in the available capacity.…”

Enhanced redesigned spatial modulation: Design and performance evaluation under correlated fading channels

“…Increasing number of antennas provide extra degrees of freedom to combat the adverse effects of highly dynamic wireless channels. In addition, M‐MIMO systems also offer advantages like channel hardening effect, reliability, and spectral efficiency . However, multiple active antennas at the transmitter and receiver require equal number of multiple radio frequency (RF) chains, which in turn leads to increased computational complexity, equipment cost, and power consumption of the overall system.…”