Juan José Sánchez-Martínez

Analysis of the Indoor Broadband Power-Line Noise Scenario

Indoor broadband power-line noise is composed of three main terms: impulsive components, narrowband interferences, and background noise. Most impulsive components have a cyclostationary behavior. However, while some of them consist of impulses of considerable amplitude, width, and repetition rates of 50/100 Hz (in Europe), others have lower amplitude and shorter width but repetition rates of up to hundreds of kilohertz. Classical studies compute statistics of the impulse characteristics without taking into account these significant differences. This paper presents a detailed analysis of these noise terms with a clear distinction between their constituent terms. A classification of the narrowband interferences according to their power spectral density and their statistical behavior is also given. Finally, the instantaneous power spectral density of the background noise and its probability distribution are investigated. Some of the results presented in this paper are available for download from the web site http://www.plc.uma.es/index_eng.htm.

Characterization and Evaluation of In-Vehicle Power Line Channels

This paper presents a statistical characterization of in-vehicle power lines, based on channel measurements carried out in a automobile. In particular, the impact of the engine speed on the characteristics of the channels is analyzed. Performance of an Orthogonal Frequency-Division Multiplexing (OFDM) system is assessed using the channel measurements.

ARTIFICIAL TRANSMISSION LINE WITH LEFT/RIGHT-HANDED BEHAVIOR BASED ON WIRE BONDED INTERDIGITAL CAPACITORS

Abstract—A novel artificial transmission line with right/left-handed behavior is presented in this paper. The unit cell of the new artificial line consists of one series and one shunt wire bonded interdigital capacitors. When wire bonded interdigital capacitors are used, the artificial line has a wider frequency band of operation. A combined analytical-graphical design method of the proposed artificial transmission line is also presented. The method has been assessed with the help of an electromagnetic solver based on the method of moments, and experimental work.

Performance analysis of OFDM modulation on indoor PLC channels in the frequency band up to 210 MHz

This paper analyses the performance of Orthogonal Frequency-Division Multiplexing (OFDM) systems on indoor power line. The studied frequency band extends up to 210MHz, as specified in the upcoming International Telecommunication Union (ITU) G.hn standard for wired home networks. Four frequency bands have been considered, from 1MHz up to 30MHz, from 30MHz up to 86MHz, from 1MHz up to 86MHz and from 110MHz up to 210MHz. Conventional OFDM modulation with rectangular pulses and OFDM with pulse-shaping at the transmitter and non-rectangular window at the receiver are assessed. Bit-rates attained with both schemes are evaluated as a function of the number of carriers and the cyclic prefix length. Presented results can be used to select the most appropriate system parameters for each frequency band.

Time-Varying Channel Emulator for Indoor Power Line Communications

In this paper, an FPGA-based channel emulator for indoor power line communications (PLC) is described. It has been designed for a band up to 30 MHz and is able to emulate time-varying channels and to generate a great variety of disturbances.

Performance analysis of OFDM modulation on indoor broadband PLC channels

Indoor broadband power-line communications is a suitable technology for home networking applications. In this context, orthogonal frequency-division multiplexing (OFDM) is the most widespread modulation technique. It has recently been adopted by the ITU-T Recommendation G.9960 and is also used by most of the commercial systems, whose number of carriers has gone from about 100 to a few thousands in less than a decade. However, indoor power-line channels are frequency-selective and exhibit periodic time variations. Hence, increasing the number of carriers does not always improves the performance, since it reduces the distortion because of the frequency selectivity, but increases the one caused by the channel time variation. In addition, the long impulse response of power-line channels obliges to use an insufficient cyclic prefix. Increasing its value reduces the distortion, but also the symbol rate. Therefore, there are optimum values for both modulation parameters. This article evaluates the performance of an OFDM system as a function of the number of carriers and the cyclic prefix length, determining their most appropriate values for the indoor power-line scenario. This task must be accomplished by means of time-consuming simulations employing a linear time-varying filtering, since no consensus on a tractable statistical channel model has been reached yet. However, this study presents a simpler procedure in which the distortion because of the frequency selectivity is computed using a time-invariant channel response, and an analytical expression is derived for the one caused by the channel time variation.

Synthesis and Design of High-Selectivity Wideband Quasi-Elliptic Bandpass Filters Using Multiconductor Transmission Lines

A comprehensive study of high-selectivity filters that employ series multiconductor transmission lines (MTLs) and a shunt MTL is presented. It is shown that this topology is suitable for implementing three- and five-pole bandpass filters having a quasi-elliptic frequency response. An exact synthesis procedure with analytical design equations for achieving equal-ripple passband response as a function of the operating bandwidth is described. To validate the theory, several bandpass filters are designed, fabricated, and measured. The excellent agreement between the measurements and the predicted results validates the proposed procedure as a reliable and quick technique for designing wideband quasi-elliptic bandpass filters.

Analytical Design of Wire-Bonded Multiconductor Transmission-Line-Based Ultra-Wideband Differential Bandpass Filters

A systematic design process of ultra-wideband differential bandpass filters based on wire-bonded multiconductor transmission lines is presented. The topology is thoroughly analyzed by means of analytical design equations that provide some insights into the physical behavior of the proposed structure. Single- and double-section configurations are introduced and exact closed-form design equations are derived to design differential filters with either a Butterworth or Chebyhsev frequency response. To validate the design procedure, two differential filters are designed and fabricated with an equal-ripple fractional bandwidth (FBW) of 100% and 60% (3-dB FBW of 145% and 97%), respectively. The measured differential-mode responses show a good in-band flatness with insertion losses lower than 1 dB and with high common-mode rejection levels greater than 20 dB. Experimental results demonstrate a good agreement with theory and prove that the proposed design methodology is useful for accurate and fast ultra-wideband differential filter synthesis.

Comments on “Wideband Coupled-Line Microstrip Filters With High-Impedance Short-Circuited Stubs”

In the above paper, authors analyze the realization of coupled-line filters by means of the II equivalent circuit of a short-circuited coupler. Therefore, a a wide-band bandpass filter composed of several quarter-wavelength coupled-line sections connected in cascade is designed and values for the II equivalent network are calculated. Then, an alternative to implement a high-impedance short-circuited stub (Fig. 1(a)) using a pair of coupled lines with three short circuits (Fig. 1(b)) is proposed. Nevertheless, the equation [1, (2)] used to calculate the equivalent characteristic impedance Z of the proposed alternative seems to be incorrect.

Analysis of Wire-Bonded Multiconductor Transmission-Line-Based Stubs

Wire-bonded multiconductor transmission lines (MTLs) can be used as shunt stubs as a way of overcoming the limitations regarding impedance levels and frequency response of single transmission-line (TL) stubs. The wire-bonded MTL is a particular case that provides greater bandwidth by eliminating high-frequency undesired resonances. In this paper, a general analysis of the behavior of this structure is presented. The performance of all eight possible configurations and an arbitrary number of strips is assessed and some physical insight into their frequency behavior is provided. Six of them allow the implementation of shunt stubs with impedance levels that are complicated or unapproachable with a single stub, while the other two provide additional degrees of freedom that are of interest for the design of filtering structures.