352 research outputs found
Synchronization of a WDM Packet-Switched Slotted Ring
In this paper, we present two different strategies of
slot synchronization in wavelength-division-multiplexing (WDM)
packet-switched slotted-ring networks. Emphasis is given to the
architecture behind the WDM Optical Network Demonstrator
over Rings (WONDER) project, which is based on tunable
transmitters and fixed receivers. The WONDER experimental
prototype is currently being developed at the laboratories
of Politecnico di Torino. In the former strategy, a slotsynchronization
signal is transmitted by the master station on a
dedicated control wavelength; in the latter, slave nodes achieve
slot synchronization aligning on data packets that are received
from the master. The performance of both synchronization strategies,
particularly in terms of packet-collision probability, was
evaluated by simulation. The technique based on transmitting a
timing signal on a dedicated control wavelength achieves better
performance, although it is more expensive due to the need for an
additional wavelength. However, the technique based on aligning
data packets that are received from the master, despite attaining
lower timing stability, still deserves further study, particularly
if limiting the number of wavelengths and receivers is a major
requirement. Some experimental results, which were measured on
the WONDER prototype, are also shown. Measurement results,
together with theoretical findings, demonstrate the good synchronization
performance of the prototype
GLOBAL COMMUNICATIONS NEWSLETTER
Presents information and current topics of interest to the global communications industry
Block synchronization for quantum information
Locating the boundaries of consecutive blocks of quantum information is a
fundamental building block for advanced quantum computation and quantum
communication systems. We develop a coding theoretic method for properly
locating boundaries of quantum information without relying on external
synchronization when block synchronization is lost. The method also protects
qubits from decoherence in a manner similar to conventional quantum
error-correcting codes, seamlessly achieving synchronization recovery and error
correction. A family of quantum codes that are simultaneously synchronizable
and error-correcting is given through this approach.Comment: 7 pages, no figures, final accepted version for publication in
Physical Review
Synchronization of Micromechanical Oscillators Using Light
Synchronization, the emergence of spontaneous order in coupled systems, is of
fundamental importance in both physical and biological systems. We demonstrate
the synchronization of two dissimilar silicon nitride micromechanical
oscillators, that are spaced apart by a few hundred nanometers and are coupled
through optical radiation field. The tunability of the optical coupling between
the oscillators enables one to externally control the dynamics and switch
between coupled and individual oscillation states. These results pave a path
towards reconfigurable massive synchronized oscillator networks
Availability Evaluation of Service Function Chains Under Different Protection Schemes
Network Function Virtualization (NFV) calls for a new resource management approach where virtualized network functions (VNFs) replace traditional network hardware appliances. Thanks to NFV, operators are given a much greater flexibility, as these VNFs can be deployed as virtual nodes and chained together to form Service Function Chains (SFCs). An SFC represents a set of dedicated virtualized resources deployed to provide a certain service to the consumer. One of its most important performance requirements is availability. In this paper, the availability achieved by SFCs is evaluated analytically, by modelling several protection schemes and given different availability values for the network components. The cost of each protection scheme, based on its network resource consumption, is also taken into account. Extensive numerical results are reported, considering various SFC characteristics, such as availability requirements, number of NFV nodes and availability values of network components. The lowest-cost protection strategy, in terms of number of occupied network components, which meets availability requirement, is identified. Our analysis demonstrates that, in most cases, resource-greedy protection schemes, such as end-to-end protection, can be replaced by less aggressive schemes, even when availability requirements are in the order of five or six nines, depending on the number of elements in the service function chain
BER evaluation of post-meter PLC services in CENELEC-C band
Low voltage, in-home power-line communications (PLC) networks allow direct communication between smart meters (SM) and in-home devices (IHD). In order to minimize security issues, in many deployment scenarios transmission takes place only towards the IHD to display consumption data, with no backwards channel. As a result, channel estimation is difficult and it is necessary to use robust transmission techniques to mitigate the effect of the impulsive noise within the PLC channel. Performance of such system must be evaluated by taking into account realistic interference and channel models for a broad range of configurations. In this work we focus on performance in terms of bit error rate (BER) of a narrowband PLC (NB-PLC) operating in the CENELEC-C band (125–140 kHz) taking into account realistic noise models. Our system is based on binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) modulation
2nd IEEE International Mediterranean Conference on Communications and Networking (IEEE MeditCom 2022) 5-8 September 2022, Athens, Greece
International audienc
- …