0000000000098252
AUTHOR
Fabio Campoccia
WCMA:tecniche di accesso e codifica canale
An architecture Wi-fi and GPRS for efficient management of distribution electrical networks
In this paper, a telecommunication infrastructure for faults management is proposed. The complete automation of the electrical energy distribution requires the implementation of suitable data transmission systems able to easily interface with microprocessor based systems and to handle large amount of data. In particular, reliability and speed of the data transmission system are required in the fault diagnosis and post-fault management procedures, in order to guarantee high quality standards. The proposed diagnostic system indeed works by means of a set of intercommunicating MV/LV dasiaintelligent substationspsila. In this paper, after a brief description of the fault diagnostic system, an o…
A fast heuristic for solving the D1EC coloring problem
In this paper we propose an efficient heuristic for solving the Distance-1 Edge Coloring problem (D1EC) for the on-the-fly assignment of orthogonal wireless channels in wireless as soon as a topology change occurs. The coloring algorithm exploits the simulated annealing paradigm, i.e., a generalization of Monte Carlo methods for solving combinatorial problems. We show that the simulated annealing-based coloring converges fast to a sub optimal coloring scheme even for the case of dynamic channel allocation. However, a stateful implementation of the D1EC scheme is needed in order to speed-up the network coloring upon topology changes. In fact, a stateful D1EC reduces the algorithm’s convergen…
Studio di tecnologie radio per reti wifi con applicazioni a sistemi di diagnostica implementati su architetture chain e a grafo.
A heuristic for fast convergence in interference-free channel assignment using D1EC coloring
This work proposes an efficient method for solving the Distance-1 Edge Coloring problem (D1EC) for the assignment of orthogonal channels in wireless networks with changing topology. The coloring algorithm is performed by means of the simulated annealing method, a generalization of Monte Carlo methods for solving combinatorial problems. We show that the simulated annealing-based coloring converges fast to a suboptimal coloring scheme. Furthermore, a stateful implementation of the D1EC scheme is proposed, in which network coloring is executed upon topology changes. The stateful D1EC is also based on simulated annealing and reduces the algorithm’s convergence time by one order of magnitude in …
An Integrated System for Efficient Management of Distribution Networks: The System's Architecture and the Telecommunication Infrastructure
Modern distribution systems must keep up with high power quality standards due to the new regulations of the European Community and of the different national legislations. Efficient faults management is one of the basic tasks utilities must accomplish and this objective can be attained if and only if automation is present and efficient diagnostic procedures have been implemented in the centralized or distributed units all over the network. In this paper, the architecture of an integrated system for management of modern distribution systems is presented. The system includes routines for normal on-line optimal operation of distribution systems and for outage management, the latter including f…
Improving IEEE 802.11 Performance in Chain Topologies through Distributed Polling and Network Coding
Wireless multi-hop networks often rely on the use of IEEE 802.11 technology. Despite of the robustness of the IEEE 802.11 Distributed Coordination Function (DCF) for working in various network scenarios, it has been proven that critical inefficiencies can arise in the case of multi-hop packet forwarding. In this paper, we propose a MAC scheme, based on the virtualization of the Point Coordination Function, optimized for working on chain topologies with bidirectional traffic flows. Our scheme is based on a token-like access mechanism coupled with network coding. The basic idea is the use of multiple Point Coordinators (PCs) along the node chain, which are elected by passing special token fra…
Analysis of the limitations of WiFi communications managed by the IEEE 802.11 protocol in data transmission in automated power distribution systems
This paper presents a study on the performances of the IEEE 802.11 protocol used in a Medium Voltage networks management system, carried out using a model for the simulation of WiFi chains architectures. The results of the simulations give some practical indications for the use of the IEEE 802.11 protocol also in presence of transmissions characterized by rigid time intervals, for which this protocol is usually not suitable. Finally the whole communications system is presented.
Improving performance evaluation in a IEEE 802.11 chain topologies through a deterministic setting of backoff values
The chain networks based on the IEEE 802.11 protocol are implied in several applications. Their advantage is the robustness of protocol, but they suffer of performance decreasing due to the so-called hidden node problem. In literature some changes to the protocol have been proposed, but generally they are complex and request important modifications to the protocol structure. In this work, on the contrary, it is proposed an easily feasible 802.11 protocol change. In order to avoid collision, it is shared the channel in transmissions perfectly separated in time. Analysis and simulations, executed in chain networks composed by 4 nodes, will show how the proposed modification increases the perf…
An Improved IEEE 802.11 Protocol for Reliable Data Transmission in Power Distribution Fault Diagnosis
A high level of power quality in distribution networks is obtained by means of a diagnostic software, that on-line assesses the status of the network, by elaborating the measured data. An efficient telecommunication system is thus necessary. Upon occurrence of a fault the reliability of the distribution system depends on the security of the timely protective and restorative actions on the network. In this paper, after a brief examination of the diagnostic method, the telecommunication system is examined. For this purpose, the WiFi telecommunication system has been considered the most suitable due to its economy, although it is not adequately reliable for how it is managed by the IEEE 802.11…