23 research outputs found
Simulation analysis of algorithms for interference management in 5G cellular networks using spatial spectrum sharing
In this thesis we completely overhaul past techniques to the new millimeter wave frequencies used in 5G and the aim is to study algorithm, protocols and architectures enablers to allow spatial spectrum sharing between different networks at these frequencies. With the use of specific modules of the network simulator ns-3, studies of simulations has been made in order to analyse performance of several sharing procedure with the goal of increase performance in a 5G mobile networkope
A Spectrum Sharing Solution for the Efficient Use of mmWave Bands in 5G Cellular Scenarios
Regulators all around the world have started identifying the portions of the
spectrum that will be used for the next generation of cellular networks. A band
in the mmWave spectrum will be exploited to increase the available capacity. In
response to the very high expected traffic demand, a sharing mechanism may make
it possible to use the spectrum more efficiently. In this work, moving within
the European and Italian regulatory conditions, we propose the use of Licensed
Spectrum Access (LSA) to coordinate sharing among cellular operators.
Additionally, we show some preliminary results on our research activities which
are focused on a dynamic spectrum sharing approach applied in simulated 5G
cellular scenarios.Comment: to be published in IEEE International Symposium on Dynamic Spectrum
Access Networks (IEEE DySPAN 2018), Seoul, Korea, Oct, 201
Hybrid Spectrum Sharing in mmWave Cellular Networks
While spectrum at millimeter wave (mmWave) frequencies is less scarce than at
traditional frequencies below 6 GHz, still it is not unlimited, in particular
if we consider the requirements from other services using the same band and the
need to license mmWave bands to multiple mobile operators. Therefore, an
efficient spectrum access scheme is critical to harvest the maximum benefit
from emerging mmWave technologies. In this paper, we introduce a new hybrid
spectrum access scheme for mmWave networks, where data is aggregated through
two mmWave carriers with different characteristics. In particular, we consider
the case of a hybrid spectrum scheme between a mmWave band with exclusive
access and a mmWave band where spectrum is pooled between multiple operators.
To the best of our knowledge, this is the first study proposing hybrid spectrum
access for mmWave networks and providing a quantitative assessment of its
benefits. Our results show that this approach provides major advantages with
respect to traditional fully licensed or fully unlicensed spectrum access
schemes, though further work is needed to achieve a more complete understanding
of both technical and non technical implications
Understanding Noise and Interference Regimes in 5G Millimeter-Wave Cellular Networks
With the severe spectrum shortage in conventional cellular bands,
millimeter-wave (mmWave) frequencies have been attracting growing attention for
next-generation micro- and picocellular wireless networks. A fundamental and
open question is whether mmWave cellular networks are likely to be noise- or
interference-limited. Identifying in which regime a network is operating is
critical for the design of MAC and physical-layer procedures and to provide
insights on how transmissions across cells should be coordinated to cope with
interference. This work uses the latest measurement-based statistical channel
models to accurately assess the Interference-to-Noise Ratio (INR) in a wide
range of deployment scenarios. In addition to cell density, we also study
antenna array size and antenna patterns, whose effects are critical in the
mmWave regime. The channel models also account for blockage, line-of-sight and
non-line-of-sight regimes as well as local scattering, that significantly
affect the level of spatial isolation
Multi-Sector and Multi-Panel Performance in 5G mmWave Cellular Networks
The next generation of cellular networks (5G) will exploit the mmWave
spectrum to increase the available capacity. Communication at such high
frequencies, however, suffers from high path loss and blockage, therefore
directional transmissions using antenna arrays and dense deployments are
needed. Thus, when evaluating the performance of mmWave mobile networks, it is
necessary to accurately model the complex channel, the directionality of the
transmission, but also the interplay that these elements can have with the
whole protocol stack, both in the radio access and in the higher layers. In
this paper, we improve the channel model abstraction of the mmWave module for
ns-3, by introducing the support of a more realistic antenna array model,
compliant with 3GPP NR requirements, and of multiple antenna arrays at the base
stations and mobile handsets. We then study the end-to-end performance of a
mmWave cellular network by varying the channel and antenna array
configurations, and show that increasing the number of antenna arrays and,
consequently, the number of sectors is beneficial for both throughput and
latency.Comment: to be published in 2018 IEEE Global Communications Conference:
Communication QoS, Reliability and Modeling (Globecom2018 CQRM), Abu Dhabi,
UAE, Dec 201
Performance Assessment of MIMO Precoding on Realistic mmWave Channels
In this paper, the performance of multi-user Multiple-Input Multiple-Output
(MIMO) systems is evaluated in terms of SINR and capacity. We focus on the case
of a downlink single-cell scenario where different precoders have been studied.
Among the considered precoders, we range from different Grid of Beams (GoB)
optimization approaches to linear precoders (e.g., matched filtering and zero
forcing). This performance evaluation includes imperfect channel estimation,
and is carried out over two realistic mmWave 5G propagation channels, which are
simulated following either the measurement campaign done by New York University
(NYU) or the 3GPP channel model. Our evaluation allows grasping knowledge on
the precoding performance in mmWave realistic scenarios. The results highlight
the good performance of GoB optimization approaches when a realistic channel
model with directionality is adopted.Comment: to be published in IEEE ICC Workshop on Millimeter-Wave
Communications for 5G and B5G, Shanghai, P.R. China, May, 201
Machine Learning-aided Design of Thinned Antenna Arrays for Optimized Network Level Performance
With the advent of millimeter wave (mmWave) communications, the combination
of a detailed 5G network simulator with an accurate antenna radiation model is
required to analyze the realistic performance of complex cellular scenarios.
However, due to the complexity of both electromagnetic and network models, the
design and optimization of antenna arrays is generally infeasible due to the
required computational resources and simulation time. In this paper, we propose
a Machine Learning framework that enables a simulation-based optimization of
the antenna design. We show how learning methods are able to emulate a complex
simulator with a modest dataset obtained from it, enabling a global numerical
optimization over a vast multi-dimensional parameter space in a reasonable
amount of time. Overall, our results show that the proposed methodology can be
successfully applied to the optimization of thinned antenna arrays.Comment: 5 pages, 7 figures. This paper has been presented at EuCAP 2020.
Copyright IEEE 2020. Please cite it as: M. Lecci, P. Testolina, M. Rebato, A.
Testolin, and M. Zorzi, "Machine Learning-aided Design of Thinned Antenna
Arrays for Optimized Network Level Performance," 14th European Conference on
Antennas and Propagation (EuCAP 2020), Copenhagen, Mar. 202
Study of Realistic Antenna Patterns in 5G mmWave Cellular Scenarios
Large antenna arrays and millimeter-wave (mmWave) frequencies have been
attracting growing attention as possible candidates to meet the high
requirements of future 5G mobile networks. In view of the large path loss
attenuation in these bands, beamforming techniques that create a beam in the
direction of the user equipment are essential to perform the transmission. For
this purpose, in this paper, we aim at characterizing realistic antenna
radiation patterns, motivated by the need to properly capture mmWave
propagation behaviors and understand the achievable performance in 5G cellular
scenarios. In particular, we highlight how the performance changes with the
radiation pattern used. Consequently, we conclude that it is crucial to use an
accurate and realistic radiation model for proper performance assessment and
system dimensioning.Comment: to be published in 2018 IEEE ICC Communications QoS, Reliability, and
Modeling Symposium (ICC18 CQRM), Kansas City, USA, May 201
Coverage and Connectivity Analysis of Millimeter Wave Vehicular Networks
The next generations of vehicles will require data transmission rates in the
order of terabytes per driving hour, to support advanced automotive services.
This unprecedented amount of data to be exchanged goes beyond the capabilities
of existing communication technologies for vehicular communication and calls
for new solutions. A possible answer to this growing demand for ultra-high
transmission speeds can be found in the millimeter-wave (mmWave) bands which,
however, are subject to high signal attenuation and challenging propagation
characteristics. In particular, mmWave links are typically directional, to
benefit from the resulting beamforming gain, and require precise alignment of
the transmitter and the receiver beams, an operation which may increase the
latency of the communication and lead to deafness due to beam misalignment. In
this paper, we propose a stochastic model for characterizing the beam coverage
and connectivity probability in mmWave automotive networks. The purpose is to
exemplify some of the complex and interesting tradeoffs that have to be
considered when designing solutions for vehicular scenarios based on mmWave
links. The results show that the performance of the automotive nodes in highly
mobile mmWave systems strictly depends on the specific environment in which the
vehicles are deployed, and must account for several automotive-specific
features such as the nodes speed, the beam alignment periodicity, the base
stations density and the antenna geometry.Comment: In press of Elsevier Ad Hoc Network