188 research outputs found
Initial Access Frameworks for 3GPP NR at mmWave Frequencies
The use of millimeter wave (mmWave) frequencies for communication will be one
of the innovations of the next generation of cellular mobile networks (5G). It
will provide unprecedented data rates, but is highly susceptible to rapid
channel variations and suffers from severe isotropic pathloss. Highly
directional antennas at the transmitter and the receiver will be used to
compensate for these shortcomings and achieve sufficient link budget in wide
area networks. However, directionality demands precise alignment of the
transmitter and the receiver beams, an operation which has important
implications for control plane procedures, such as initial access, and may
increase the delay of the data transmission. This paper provides a comparison
of measurement frameworks for initial access in mmWave cellular networks in
terms of detection accuracy, reactiveness and overhead, using parameters
recently standardized by the 3GPP and a channel model based on real-world
measurements. We show that the best strategy depends on the specific
environment in which the nodes are deployed, and provide guidelines to
characterize the optimal choice as a function of the system parameters.Comment: 8 pages, 7 figures, 3 tables, accepted to the IEEE 17th Annual
Mediterranean Ad Hoc Networking Workshop (Med-Hoc-Net). arXiv admin note:
substantial text overlap with arXiv:1804.0190
A Tutorial on Beam Management for 3GPP NR at mmWave Frequencies
The millimeter wave (mmWave) frequencies offer the availability of huge
bandwidths to provide unprecedented data rates to next-generation cellular
mobile terminals. However, mmWave links are highly susceptible to rapid channel
variations and suffer from severe free-space pathloss and atmospheric
absorption. To address these challenges, the base stations and the mobile
terminals will use highly directional antennas to achieve sufficient link
budget in wide area networks. The consequence is the need for precise alignment
of the transmitter and the receiver beams, an operation which may increase the
latency of establishing a link, and has important implications for control
layer procedures, such as initial access, handover and beam tracking. This
tutorial provides an overview of recently proposed measurement techniques for
beam and mobility management in mmWave cellular networks, and gives insights
into the design of accurate, reactive and robust control schemes suitable for a
3GPP NR cellular network. We will illustrate that the best strategy depends on
the specific environment in which the nodes are deployed, and give guidelines
to inform the optimal choice as a function of the system parameters.Comment: 22 pages, 19 figures, 10 tables, published in IEEE Communications
Surveys and Tutorials. Please cite it as M. Giordani, M. Polese, A. Roy, D.
Castor and M. Zorzi, "A Tutorial on Beam Management for 3GPP NR at mmWave
Frequencies," in IEEE Communications Surveys & Tutorials, vol. 21, no. 1, pp.
173-196, First quarter 201
Standalone and Non-Standalone Beam Management for 3GPP NR at mmWaves
The next generation of cellular networks will exploit mmWave frequencies to
dramatically increase the network capacity. The communication at such high
frequencies, however, requires directionality to compensate the increase in
propagation loss. Users and base stations need to align their beams during both
initial access and data transmissions, to ensure the maximum gain is reached.
The accuracy of the beam selection, and the delay in updating the beam pair or
performing initial access, impact the end-to-end performance and the quality of
service. In this paper we will present the beam management procedures that 3GPP
has included in the NR specifications, focusing on the different operations
that can be performed in Standalone (SA) and in Non-Standalone (NSA)
deployments. We will also provide a performance comparison among different
schemes, along with design insights on the most important parameters related to
beam management frameworks.Comment: 7 pages, 5 figures, 1 table. Please cite it as M. Giordani, M.
Polese, A. Roy, D. Castor and M. Zorzi, "Standalone and Non-Standalone Beam
Management for 3GPP NR at mmWaves," in IEEE Communications Magazine, vol. 57,
no. 4, pp. 123-129, April 201
Initial access with neighbor assistance in 5G mmWave cellular networks
The advent of 5G communications has already started. In order to achieve the objectives of high speed and low latency, mmWave technologies will be adopted in the near future. In this thesis we present a new cell discovery algorithm that takes advantage of context information available through legacy networks in order to achieve a faster initial access. We compute analytically the relevant probabilities and then we implement a 3GPP-compliant and spatially consistent simulation environment.openEmbargo temporaneo per motivi di segretezza e/o di proprietĂ Â dei risultati e/o informazioni sensibil
AI/ML for Beam Management in 5G-Advanced
In beamformed wireless cellular systems such as 5G New Radio (NR) networks,
beam management (BM) is a crucial operation. In the second phase of 5G NR
standardization, known as 5G-Advanced, which is being vigorously promoted, the
key component is the use of artificial intelligence (AI) based on machine
learning (ML) techniques. AI/ML for BM is selected as a representative use
case. This article provides an overview of the AI/ML for BM in 5G-Advanced. The
legacy non-AI and prime AI-enabled BM frameworks are first introduced and
compared. Then, the main scope of AI/ML for BM is presented, including
improving accuracy, reducing overhead and latency. Finally, the key challenges
and open issues in the standardization of AI/ML for BM are discussed,
especially the design of new protocols for AI-enabled BM. This article provides
a guideline for the study of AI/ML-based BM standardization.Comment: 4 figure
Smart Pattern V2I Handover Based on Machine Learning Vehicle Classification
The mmwave frequencies will be widely used in future vehicular communications. At these frequencies, the radio channel becomes much more vulnerable to slight changes in the environment like motions of the device, reflections or blockage. In high mobility vehicular communications the rapidly changing vehicle environments and the large overheads due to frequent beam training are the critical disadvantages in developing these systems at mmwave frequencies. Hence, smart beam management procedures are desired to establish and maintain the radio channels. In this thesis, we propose that using the positions and respective velocities of the vehicles in the dynamic selection of the beam pair, and then adapting to the changing environments using machine learning algorithms, can improve both network performance and communication stability in high mobility vehicular communications
Cellular Wireless Networks in the Upper Mid-Band
The upper mid-band -- roughly from 7 to 24 GHz -- has attracted considerable
recent interest for new cellular services. This frequency range has vastly more
spectrum than the highly congested bands below 7 GHz while offering more
favorable propagation and coverage than the millimeter wave (mmWave)
frequencies. Realizing the full potential of these bands, however, will require
fundamental changes to the design of cellular systems. Most importantly,
spectrum will likely need to be shared with incumbents including communication
satellites, military RADAR, and radio astronomy. Also, due to the wide
bandwidth, directional nature of transmission, and intermittent occupancy of
incumbents, cellular systems will need to be agile to sense and intelligently
use large spatial and bandwidth degrees of freedom. This paper attempts to
provide an initial assessment of the feasibility and potential gains of
wideband cellular systems operating in the upper mid-band. The study includes:
(1) a system study to assess potential gains of multi-band systems in a
representative dense urban environment; (2) propagation calculations to assess
potential cross interference between satellites and terrestrial cellular
services; and (3) design and evaluation of a compact multi-band antenna array
structure. Leveraging these preliminary results, we identify potential future
research directions to realize next-generation systems in these frequencies.Comment: 11 page
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