2,174 research outputs found
A Link Quality Model for Generalised Frequency Division Multiplexing
5G systems aim to achieve extremely high data rates, low end-to-end latency
and ultra-low power consumption. Recently, there has been considerable interest
in the design of 5G physical layer waveforms. One important candidate is
Generalised Frequency Division Multiplexing (GFDM). In order to evaluate its
performance and features, system-level studies should be undertaken in a range
of scenarios. These studies, however, require highly complex computations if
they are performed using bit-level simulators. In this paper, the Mutual
Information (MI) based link quality model (PHY abstraction), which has been
regularly used to implement system-level studies for Orthogonal Frequency
Division Multiplexing (OFDM), is applied to GFDM. The performance of the GFDM
waveform using this model and the bit-level simulation performance is measured
using different channel types. Moreover, a system-level study for a GFDM based
LTE-A system in a realistic scenario, using both a bit-level simulator and this
abstraction model, has been studied and compared. The results reveal the
accuracy of this model using realistic channel data. Based on these results,
the PHY abstraction technique can be applied to evaluate the performance of
GFDM based systems in an effective manner with low complexity. The maximum
difference in the Packet Error Rate (PER) and throughput results in the
abstraction case compared to bit-level simulation does not exceed 4% whilst
offering a simulation time saving reduction of around 62,000 times.Comment: 5 pages, 8 figures, accepted in VTC- spring 201
Cross-Layer Resource Allocation for MB-OFDM UWB Systems
ISBN 978-953-3076461-0International audienc
Towards Massive Machine Type Communications in Ultra-Dense Cellular IoT Networks: Current Issues and Machine Learning-Assisted Solutions
The ever-increasing number of resource-constrained Machine-Type Communication
(MTC) devices is leading to the critical challenge of fulfilling diverse
communication requirements in dynamic and ultra-dense wireless environments.
Among different application scenarios that the upcoming 5G and beyond cellular
networks are expected to support, such as eMBB, mMTC and URLLC, mMTC brings the
unique technical challenge of supporting a huge number of MTC devices, which is
the main focus of this paper. The related challenges include QoS provisioning,
handling highly dynamic and sporadic MTC traffic, huge signalling overhead and
Radio Access Network (RAN) congestion. In this regard, this paper aims to
identify and analyze the involved technical issues, to review recent advances,
to highlight potential solutions and to propose new research directions. First,
starting with an overview of mMTC features and QoS provisioning issues, we
present the key enablers for mMTC in cellular networks. Along with the
highlights on the inefficiency of the legacy Random Access (RA) procedure in
the mMTC scenario, we then present the key features and channel access
mechanisms in the emerging cellular IoT standards, namely, LTE-M and NB-IoT.
Subsequently, we present a framework for the performance analysis of
transmission scheduling with the QoS support along with the issues involved in
short data packet transmission. Next, we provide a detailed overview of the
existing and emerging solutions towards addressing RAN congestion problem, and
then identify potential advantages, challenges and use cases for the
applications of emerging Machine Learning (ML) techniques in ultra-dense
cellular networks. Out of several ML techniques, we focus on the application of
low-complexity Q-learning approach in the mMTC scenarios. Finally, we discuss
some open research challenges and promising future research directions.Comment: 37 pages, 8 figures, 7 tables, submitted for a possible future
publication in IEEE Communications Surveys and Tutorial
A Review of UWB MAC Protocols
In this paper, we review several ultra-wideband
(UWB) medium access control (MAC) protocols that have been
proposed to date. This review then considers the possibility of
developing an optimal MAC layer for high data rate UWB
transmission systems that transmit very little power especially
in application to mobile devices. MAC in UWB wireless
networks is necessary to coordinate channel access among
competing devices. Unique UWB characteristics offer great
challenges and opportunities in effective UWB MAC design.
We first present the background of UWB and the concept of MAC protocols for UWB. Secondly, we summarize four UWB MAC protocols that have been proposed by other researchers
and finally, a conclusion with a view to the planned future
work. The main contribution of this paper is that it presents a summarised version of several MAC protocols applicable to UWB systems. This will hopefully initiate further research and developments in UWB MAC protocol design
Radio Frequency Interference Impact Assessment on Global Navigation Satellite Systems
The Institute for the Protection and Security of the Citizen of the EC Joint Research Centre (IPSC-JRC) has been mandated to perform a study on the Radio Frequency (RF) threat against telecommunications and ICT control systems. This study is divided into two parts. The rst part concerns the assessment of high energy radio frequency (HERF) threats, where the focus is on the generation of electromagnetic pulses (EMP), the development of corresponding devices and the possible impact on ICT and power distribution systems. The second part of the study concerns radio frequency interference (RFI) with regard to global navigation satellite systems (GNSS). This document contributes to the second part and contains a detailed literature study disclosing the weaknesses of GNSS systems. Whereas the HERF analysis only concerns intentional interference issues, this study on GNSS also takes into account unintentional interference, enlarging the spectrum of plausible interference scenarios.JRC.DG.G.6-Security technology assessmen
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