4,291 research outputs found
A survey on OFDM-based elastic core optical networking
Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed
Cross-layer Resource Allocation Scheme for Multi-band High Rate UWB Systems
In this paper, we investigate the use of a cross-layer allocation mechanism
for the high-rate ultra-wideband (UWB) systems. The aim of this paper is
twofold. First, through the cross-layer approach that provides a new service
differentiation approach to the fully distributed UWB systems, we support
traffic with quality of service (QoS) guarantee in a multi-user context.
Second, we exploit the effective SINR method that represents the
characteristics of multiple sub-carrier SINRs in the multi-band WiMedia
solution proposed for UWB systems, in order to provide the channel state
information needed for the multi-user sub-band allocation. This new approach
improves the system performance and optimizes the spectrum utilization with a
low cost data exchange between the different users while guaranteeing the
required QoS. In addition, this new approach solves the problem of the
cohabitation of more than three users in the same WiMedia channel
Waveform Design for 5G and Beyond
5G is envisioned to improve major key performance indicators (KPIs), such as
peak data rate, spectral efficiency, power consumption, complexity, connection
density, latency, and mobility. This chapter aims to provide a complete picture
of the ongoing 5G waveform discussions and overviews the major candidates. It
provides a brief description of the waveform and reveals the 5G use cases and
waveform design requirements. The chapter presents the main features of cyclic
prefix-orthogonal frequency-division multiplexing (CP-OFDM) that is deployed in
4G LTE systems. CP-OFDM is the baseline of the 5G waveform discussions since
the performance of a new waveform is usually compared with it. The chapter
examines the essential characteristics of the major waveform candidates along
with the related advantages and disadvantages. It summarizes and compares the
key features of different waveforms.Comment: 22 pages, 21 figures, 2 tables; accepted version (The URL for the
final version:
https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119333142.ch2
Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites
Satellite Communication systems are a promising solution to extend and
complement terrestrial networks in unserved or under-served areas. This aspect
is reflected by recent commercial and standardisation endeavours. In
particular, 3GPP recently initiated a Study Item for New Radio-based, i.e., 5G,
Non-Terrestrial Networks aimed at deploying satellite systems either as a
stand-alone solution or as an integration to terrestrial networks in mobile
broadband and machine-type communication scenarios. However, typical satellite
channel impairments, as large path losses, delays, and Doppler shifts, pose
severe challenges to the realisation of a satellite-based NR network. In this
paper, based on the architecture options currently being discussed in the
standardisation fora, we discuss and assess the impact of the satellite channel
characteristics on the physical and Medium Access Control layers, both in terms
of transmitted waveforms and procedures for enhanced Mobile BroadBand (eMBB)
and NarrowBand-Internet of Things (NB-IoT) applications. The proposed analysis
shows that the main technical challenges are related to the PHY/MAC procedures,
in particular Random Access (RA), Timing Advance (TA), and Hybrid Automatic
Repeat reQuest (HARQ) and, depending on the considered service and
architecture, different solutions are proposed.Comment: Submitted to Transactions on Vehicular Technologies, April 201
Power Line Communication Technologies: Modeling and Simulation of PRIME Physical Layer
Power Line Communications is a relatively new
area of telecommunication. PLC employs full duplex methods
for transmitting data over power lines as medium of
transmission of electrical signals over a grid. PLC technologies
are used in advanced meter reading, home automation and
Public street lighting. Several PLC technologies classified
based on the operational frequency range, are explored in this
paper. PRIME is a new NBPLC system, which uses OFDM in
its physical layer, for power line communication in the last
mile. This work also focused on PRIME’s physical
specifications, which was modeled in MATLAB/SIMULINK.
In this paper, the performance of PRIME when its data is
modulated using DQPSK and 4-QAM in four (4) channel
models is shown.
- …