IEEE Wireless Communications - April 2017 - page 92

IEEE Wireless Communications • April 2017
90
1536-1284/17/$25.00 © 2017 IEEE
Franco Mazzenga is with the
University of Rome Tor
Vergata, and with the
Radiolabs consortium.
Romeo Giuliano is with
Guglielmo Marconi
University.
Alessandro Neri is with the
University of ROMA TRE, and
with the Radiolabs
consortium
Francesco Rispoli is with
Ansaldo STS.
A
bstract
The European train control system employs
GSM-R for communications between trains and
the command/control centers. GSM-R technol-
ogy is quite old and will be replaced in the near
future by other technologies offering less expen-
sive solutions, especially for regional and local
lines. This article investigates a new telecommu-
nication solution based on multi radio bearers
using cellular and satellite public networks as
an alternative to the deployment of a dedicated
infrastructure. A test campaign on a 300 km of
rail line (about 10,000 km of tests) has been car-
ried out to evaluate the performance of cellular
and satellite networks in a railway environment.
Test trial results presented and discussed in this
article have been used to assess the perfor-
mance of a multipath TCP protocol to effectively
support multi-bearer communications. A discus-
sion of the economic benefits and the potential
industrial implications of the proposed solution
concludes the article.
I
ntroduction
Telecommunication systems are fundamental for
railway applications to connect passengers as
well as to improve safety, security, and efficien-
cy in the train management process. In [1, 2], it
is envisioned that future railway communication
systems will integrate a variety of systems, each
of them oriented to specific services. Services
to passengers will be provided by several radio
systems according to market demands and to
advanced content-based applications. In contrast,
the communication platform for railway manage-
ment will be based on a unified infrastructure
supporting (real-time) collaborative services, to
improve operational effectiveness and facilitate
information exchange. The management of rail-
way operations will require highly reliable and
stable telecommunication platforms, supporting
new operational modes enabling the increase of
railway traffic capacity while ensuring high securi-
ty and safety levels [3]. The European Rail Agency
(ERA) has undertaken studies to evaluate options
for the evolution/replacement of GSM-R, which
is suffering from technology obsolescence, elec-
tromagnetic compatibility with 4G (LTE) networks
and limited capacity [4]. Capacity improvement
is important [5] to support future broadband
advanced control services such as train monitor-
ing based on real-time video captured from the
train’s cabin.
In the definition of a viable solution, two major
challenges arise: to comply with the interoperabil-
ity requirement and, from the train operator side,
to protect their investment in GSM-R. Already,
a migration path to a fully IP-based system has
started, and 4G and the incoming 5G could facil-
itate the evolution toward a full service-based
system for every rail application [6]. Concerning
cost reduction, a first significant breakthrough
in economic sustainability is represented by the
replacement of proprietary, dedicated networks
with commercial public land mobile networks
(PLMNs) and satellite. The use of public telecom-
munication infrastructure(s) makes it possible to
rapidly extend the existing automated train con-
trol procedures (such as the European Rail Traffic
Management System/European Train Control Sys-
tem (ERTMS/ETCS), and communications based
train control [7]) for improving rail traffic capacity
for local/regional lines where the deployment of
a dedicated radio infrastructure is expensive in
terms of both CAPEX and OPEX. Furthermore,
public networks can be considered as low cost
and effective enablers for the rapid deployment
of the modern railway information systems such
as that proposed and investigated in the InteGRail
project, [8].
This innovative scenario would imply a step-
change in the liability process with the introduc-
tion of guaranteed QoS in the provisioning of
mobile connectivity services by telecommuni-
cation operators. Considering that in the short/
medium term radio bearers provided by public
networks will offer best-effort services only, in the
framework of the ESA 3InSat project [9] we have
evaluated the possibility of achieving acceptable
QoS through public networks as well as the eco-
nomical feasibility of this approach.
In this article we evaluate the performance
of train control systems adopting PLMNs for sig-
naling. The considered system jointly uses all the
available best-effort bearers, which are intelligently
managed by an on-board multipath router device,
i.e., the multiple access router (MAR). The MAR
F
ranco
M
azzenga
, R
omeo
G
iuliano
, A
lessandro
N
eri
,
and
F
rancesco
R
ispoli
I
ntegrated
P
ublic
M
obile
R
adio
N
etworks
/S
atellite
for
F
uture
R
ailway
C
ommunications
A
ccepted
from
O
pen
C
all
Digital Object Identifier:
10.1109/MWC.2016.1500266WC
1...,82,83,84,85,86,87,88,89,90,91 93,94,95,96,97,98,99,100,101,102,...132
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