1,023 research outputs found
Improved User Tracking in 5G Millimeter Wave Mobile Networks via Refinement Operations
The millimeter wave (mmWave) frequencies offer the availability of huge
bandwidths to provide unprecedented data rates to next-generation cellular
mobile terminals. However, directional mmWave links are highly susceptible to
rapid channel variations and suffer from severe isotropic pathloss. To face
these impairments, this paper addresses the issue of tracking the channel
quality of a moving user, an essential procedure for rate prediction, efficient
handover and periodic monitoring and adaptation of the user's transmission
configuration. The performance of an innovative tracking scheme, in which
periodic refinements of the optimal steering direction are alternated to
sparser refresh events, are analyzed in terms of both achievable data rate and
energy consumption, and compared to those of a state-of-the-art approach. We
aim at understanding in which circumstances the proposed scheme is a valid
option to provide a robust and efficient mobility management solution. We show
that our procedure is particularly well suited to highly variant and unstable
mmWave environments.Comment: Accepted for publication to the 16th IEEE Annual Mediterranean Ad Hoc
Networking Workshop (MED-HOC-NET), Jun. 201
An Efficient Uplink Multi-Connectivity Scheme for 5G mmWave Control Plane Applications
The millimeter wave (mmWave) frequencies offer the potential of orders of
magnitude increases in capacity for next-generation cellular systems. However,
links in mmWave networks are susceptible to blockage and may suffer from rapid
variations in quality. Connectivity to multiple cells - at mmWave and/or
traditional frequencies - is considered essential for robust communication. One
of the challenges in supporting multi-connectivity in mmWaves is the
requirement for the network to track the direction of each link in addition to
its power and timing. To address this challenge, we implement a novel uplink
measurement system that, with the joint help of a local coordinator operating
in the legacy band, guarantees continuous monitoring of the channel propagation
conditions and allows for the design of efficient control plane applications,
including handover, beam tracking and initial access. We show that an
uplink-based multi-connectivity approach enables less consuming, better
performing, faster and more stable cell selection and scheduling decisions with
respect to a traditional downlink-based standalone scheme. Moreover, we argue
that the presented framework guarantees (i) efficient tracking of the user in
the presence of the channel dynamics expected at mmWaves, and (ii) fast
reaction to situations in which the primary propagation path is blocked or not
available.Comment: Submitted for publication in IEEE Transactions on Wireless
Communications (TWC
Throughput and Robustness Guaranteed Beam Tracking for mmWave Wireless Networks
With the increasing demand of ultra-high-speed wireless communications and
the existing low frequency band (e.g., sub-6GHz) becomes more and more crowded,
millimeter-wave (mmWave) with large spectra available is considered as the most
promising frequency band for future wireless communications. Since the mmWave
suffers a serious path-loss, beamforming techniques shall be adopted to
concentrate the transmit power and receive region on a narrow beam for
achieving long distance communications. However, the mobility of users will
bring frequent beam handoff, which will decrease the quality of experience
(QoE). Therefore, efficient beam tracking mechanism should be carefully
researched. However, the existing beam tracking mechanisms concentrate on
system throughput maximization without considering beam handoff and link
robustness. This paper proposes a throughput and robustness guaranteed beam
tracking mechanism for mobile mmWave communication systems which takes account
of both system throughput and handoff probability. Simulation results show that
the proposed throughput and robustness guaranteed beam tracking mechanism can
provide better performance than the other beam tracking mechanisms.Comment: Accepted by IEEE/CIC ICCC 201
60 GHz MAC Standardization: Progress and Way Forward
Communication at mmWave frequencies has been the focus in the recent years.
In this paper, we discuss standardization efforts in 60 GHz short range
communication and the progress therein. We compare the available standards in
terms of network architecture, medium access control mechanisms, physical layer
techniques and several other features. Comparative analysis indicates that IEEE
802.11ad is likely to lead the short-range indoor communication at 60 GHz. We
bring to the fore resolved and unresolved issues pertaining to robust WLAN
connectivity at 60 GHz. Further, we discuss the role of mmWave bands in 5G
communication scenarios and highlight the further efforts required in terms of
research and standardization
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
CogCell: Cognitive Interplay between 60GHz Picocells and 2.4/5GHz Hotspots in the 5G Era
Rapid proliferation of wireless communication devices and the emergence of a
variety of new applications have triggered investigations into next-generation
mobile broadband systems, i.e., 5G. Legacy 2G--4G systems covering large areas
were envisioned to serve both indoor and outdoor environments. However, in the
5G-era, 80\% of overall traffic is expected to be generated in indoors. Hence,
the current approach of macro-cell mobile network, where there is no
differentiation between indoors and outdoors, needs to be reconsidered. We
envision 60\,GHz mmWave picocell architecture to support high-speed indoor and
hotspot communications. We envisage the 5G indoor network as a combination of-,
and interplay between, 2.4/5\,GHz having robust coverage and 60\,GHz links
offering high datarate. This requires an intelligent coordination and
cooperation. We propose 60\,GHz picocellular network architecture, called
CogCell, leveraging the ubiquitous WiFi. We propose to use 60\,GHz for the data
plane and 2.4/5GHz for the control plane. The hybrid network architecture
considers an opportunistic fall-back to 2.4/5\,GHz in case of poor connectivity
in the 60\,GHz domain. Further, to avoid the frequent re-beamforming in 60\,GHz
directional links due to mobility, we propose a cognitive module -- a
sensor-assisted intelligent beam switching procedure -- which reduces the
communication overhead. We believe that the CogCell concept will help future
indoor communications and possibly outdoor hotspots, where mobile stations and
access points collaborate with each other to improve the user experience.Comment: 14 PAGES in IEEE Communications Magazine, Special issue on Emerging
Applications, Services and Engineering for Cognitive Cellular Systems
(EASE4CCS), July 201
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