IEEE Communications Magazine - June 2017 - page 66

IEEE Communications Magazine • June 2017
64
0163-6804/17/$25.00 © 2017 IEEE
A
bstract
Different from conventional mobile networks
designed to optimize the transmission efficiency
of one particular service (e.g., streaming voice/
video) primarily, the industry and academia are
reaching an agreement that 5G mobile networks
are projected to sustain manifold wireless require-
ments, including higher mobility, higher data
rates, and lower latency. For this purpose, 3GPP
has launched the standardization activity for the
first phase 5G system in Release 15 named New
Radio (NR). To fully understand this crucial tech-
nology, this article offers a comprehensive over-
view of the state-of-the-art development of NR,
including deployment scenarios, numerologies,
frame structure, new waveform, multiple access,
initial/random access procedure, and enhanced
carrier aggregation (CA) for resource requests
and data transmissions. The provided insights thus
facilitate knowledge of design and practice for
further features of NR.
I
ntroduction
Cellular mobile networks have been deployed
for several decades. In the past, these networks
were developed to optimize a particular service
primarily (e.g., voice/video streams), while other
services were supported additionally (e.g., Inter-
net browsing and Internet of Things deployment).
Nevertheless, in the upcoming decades, manifold
applications (to name a few, unmanned vehicles/
robots, intelligent transportation systems, smart
grid/buildings/cities, virtual/augmented/senso-
ry reality, mobile social services, and ubiquitous
remote control) are urgently desired. To empow-
er these emerging applications with miscellaneous
traffic characteristics, an engineering paradigm
shift is needed in the development of fifth genera-
tion (5G) mobile networks.
Instead of solely enhancing data rates to
optimize transmissions of a handful of traffic
patterns, the International Telecommunication
Union Radiocommunications Standardization Sec-
tor (ITU-R) has announced multifold design goals
of 5G mobile networks known as International
Mobile Telecommunications 2020 (IMT-2020) [1,
2], which include 20 Gb/s peak data rate, 100
Mb/s user experienced data rate, 10 Mb/s/m
2
area traffic capacity, 106 devices/km
2
connection
density, 1 ms latency, mobility up to 500 km/h,
backward compatibility to LTE/LTE-Advanced
(LTE-A), and forward compatibility to potential
future evolution. To meet these design goals,
the Third Generation Partnership Project (3GPP)
started a normative work plan in 2016. To deploy
the first phase (Phase I) system in 2018 and the
“ready” system in 2020, the standardization activi-
ty of
5G New Radio
(
NR
) has been launched, and
the first 5G specifications are framed in Release
15 with the following scope.
Standalone and Non-Standalone NR Opera-
tions:
Standalone operation implies that full con-
trol plane and data plane functions are provided
in NR, while non-standalone operation indicates
that the control plane functions of LTE and LTE-A
are utilized as an anchor for NR.
Spectrum Below and Above 6 GHz:
Subject
to existing fixed spectrum allocation policies, it is
a challenge to obtain available spectrum with a
sufficiently wide bandwidth from frequency range
below 6 GHz. Consequently, spectrum above 6
GHz turns out to be critical. On the other hand,
accessing the radio resources below 6 GHz is still
necessary to fulfill diverse deployment scenarios
required by operators.
Enhanced Mobile Broadband (eMBB),
Ultra-Reliable and Low Latency Communications
(URLCC) and Massive Machine-Type Commu-
nications (mMTC):
Offering urgent data deliv-
ery with ultra low latency and massive packet
transmissions are of crucial importance for NR.
In Release 15, three maJor use cases are empha-
sized. eMBB supports high capacity and high
mobility (up to 500 km/h) radio access (with 4 ms
user plane latency). URLCC provides urgent and
reliable data exchange (with 0.5 ms user plane
latency). NR also supports infrequent, massive,
and small packet transmissions for mMTC (with
10 s latency).
To integrate these features, agile radio
resource management is essential to achieve opti-
mized network performance. Before developing
advanced resource management, deployment
scenarios, numerologies, frame structure, new
waveform, multiple access, initial/random access,
and enhanced carrier aggregation (CA) should be
ready as THE inevitable foundation. In this arti-
cle, insightful knowledge to the state-of-the-art
standardization of NR is consequently provided.
The performance in terms of random access (RA)
latency of enhanced CA is also demonstrated,
as a performance benchmark to facilitate future
engineering practice.
5G New Radio: Waveform, Frame Structure,
Multiple Access, and Initial Access
Shao-Yu Lien, Shin-Lin Shieh, Yenming Huang, Borching Su, Yung-Lin Hsu, and Hung-Yu Wei
A
gile
R
adio
R
esource
M
anagement
T
echniques
for
5G N
ew
R
adio
The authors offer a com-
prehensive overview of
the state-of-the-art devel-
opment of NR, including
deployment scenarios,
numerologies, frame
structure, new waveform,
multiple access, initial/
random access procedure
and enhanced carrier
aggregation (CA) for
resource request and data
transmissions. The provid-
ed insights thus facilitate
knowledge to design and
practice further features
of NR.
Shao-Yu Lien is with National Formosa University; Shin-Lin Shieh is with National Taipei University;
Yenming Huang, Borching Su, Yung-Lin Hsu, and Hung-Yu Wei are with National Taiwan University.
Digital Object Identifier:
10.1109/MCOM.2017.1601107
1...,56,57,58,59,60,61,62,63,64,65 67,68,69,70,71,72,73,74,75,76,...228
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