1,720,961 research outputs found
Exploring Joint Voltage and Impedance Modulation in Wired Networks
No full textConventionally, transmission of information in wired networks, as power line communication ones, is realized by modulating the voltage source at the transmitter side assuming a constant source impedance. If the impedance at the source is changed, this will induce a change of the line impedance at the receiver node. If such a change is measurable at the receiver node, then one may think to implement joint modulation of the voltage and impedance at the source, therefore transforming the wired network into two parallel communication channels. This paper investigates the principles behind this idea by deriving the input/output voltage/impedance relations, and possible transmitter/receiver architectures. A first architecture comprises only impedance modulation at the transmitter side with an impedance meter at the receiver side. Another architecture comprises joint voltage and impedance modulation with two possible receivers: a) a received voltage meter together with an impedance meter, or b) a voltage meter with a switched impedance receiver frontend. Numerical results are reported in terms of symbol error rate. They show that the approach has potentiality and opens the door to further investigations
On Defining and Retrieving an Invariant Channel Model in Wired Communication Systems
No full textThe wired channel model, including the power line communication (PLC) one, is often derived using the voltage gain, i.e., the ratio between its output and input voltages. Although this modelling approach offers information, it is often incomplete and can be dependent on the front-ends and connections used to measure such a channel. To overcome this limitation, this paper discusses how an invariant channel model can be defined and retrieved, i.e., a model that completely and intrinsically describes the transmission medium and that is not affected by the boundary conditions, e.g., the hardware blocks that are necessary to carry out measurements such as the couplers and cables used in PLC. In this paper, we firstly describe the theory that stands behind the problem, and then we validate it with numerical results in a real wired communication scenario
Broadband PLC Field Trial on a Compact Electric Vehicle
No full textPower line communication (PLC) is a valuable solution to limit the amount of wiring, reduce the weight and thus increase the performance of electric vehicles. Basically, PLC removes the need of a dedicated wiring infrastructure for the data exchange by signaling over the power delivery cables. This work shows the potentialities of such technology reporting the performance of commercially available PLC devices designed for in-home networks and adapted for the in-vehicle scenario. Further, it provides an insight on the channel and noise characteristics and proves the robustness of PLC, a technology that is able to cope with high attenuation, large periodic noise and disruptive impulses. Finally, an application example where a rear camera is connected via PLC to a display placed on the dashboard of the vehicle is describe
Characteristics of the PLC channel: Reciprocity, symmetry and port decoupling for impedance matching
No full textThis paper analyzes the reciprocity, symmetry and port decoupling effect in real home PLC networks. The reciprocity has an impact on the fact that the input and output ports of a PLC link are decoupled, and the study on the symmetry can explain the reason for the decoupling effect. The analysis of experimental data in the band 2-100 MHz shows that the PLC channel is reciprocal and that the input-output ports are largely decoupled. In turn, the port decoupling property implies that impedance matching at the transmitter and receiver ports can be implemented independently one from the other. That is, the choice of the receiver impedance does not have effect on the choice of the transmitter impedance and vice versa, in home broad band PLC systems
Learning the Impedance Entanglement for Wireline Data Communication
No full textIn wireline communication networks, a line impedance entanglement exists since changes of the line impedance at one network port cause a change of the line impedance at the other port. This physical phenomenon can be constructively exploited to realize a form of digital modulation that is referred to as impedance modulation (IM). IM is an alternative method to more conventional voltage modulation (VM). In this paper, the impedance entanglement is studied and learned through a supervised machine learning (ML) approach which enables the implementation of a ML based receiver. Numerical results are obtained in a data set of measured power line communication channels, which is among the most challenging environments for such a modulation approach. The resulting system can have practical implementation, for instance in a smart building automation network where monitoring-control of sensors and devices enables the efficient energy management. Comparisons with the optimal maximum-likelihood (MaxL) receiver that perfectly knows the impedance entanglement transfer function are made. It is found that the ML based receiver performs close to the optimal genie receiver
Indoor Path Loss Statistical Characterization and Modeling for the Broad VHF-UHF Band
No full textIn this letter, an investigation of the very high frequency-ultrahigh frequency (VHF-UHF) wireless broadband indoor channel is carried out. In particular, a wireless channel measurement campaign in an indoor environment has been made, in order to characterize the path loss in a broad set of frequencies. The wireless channel is sounded by using a set of discone wideband antennas and a vector network analyzer set to sweep the transmitted signal in the considered band. The measurement results lead to the derivation of a well specified indoor path loss exponent statistical model that takes into account the frequency dependence as well as the distance between the antennas. Three different statistical model refinements are presented, and each of them shows an enhanced ability to predict the path loss
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
