Smart Grids are becoming a reality all over the world. Nowadays, the research efforts for the introduction and deployment of these grids are mainly focused on the development of the field of Smart Metering. This emerging application requires the use of technologies to access the significant number of points of supply (PoS) existing in the grid, covering the Low Voltage (LV) segment with the lowest possible costs. Power Line Communications (PLC) have been extensively used in electricity grids for a variety of purposes and, of late, have been the focus of renewed interest. PLC are really well suited for quick and inexpensive pervasive deployments. However, no LV grid is the same in any electricity company (utility), and the particularities of each grid evolution, architecture, circumstances and materials, makes it a challenge to deploy Smart Metering networks with PLC technologies, with the Smart Grid as an ultimate goal. This paper covers the evolution of Smart Metering networks, together with the evolution of PLC technologies until both worlds have converged to project PLC-enabled Smart Metering networks towards Smart Grid. This paper develops guidelines over a set of strategic aspects of PLC Smart Metering network deployment based on the knowledge gathered on real field; and introduces the future challenges of these networks in their evolution towards the Smart Grid.

The Lee method, which was recommended by the International Telecommunications Union (ITU) and the European Conference of Postal and Telecommunications Administrations (CEPT) to obtain the local mean values of the received signal along a route, was developed for a Rayleigh distribution in the ultrahigh-frequency (UHF) band. This paper describes the generalization of this method to any propagation channel and frequency band and describes the methodology to obtain the parameters involved. The Generalized Lee Method is based on field data samples, which allows estimating the mean values without the requirement of a priori knowing the distribution function that better fits the propagation channel. The accuracy in obtaining the averaging interval is also improved. The Generalized Lee Method is solved for ground-wave propagation at the medium-wave (MW) band, taking data from field trials of a Digital Radio Mondiale (DRM) transmission. The results show that the values considerably differ from those obtained for a Rayleigh channel and prove that the method allows the adequate differentiation of long-term and short-term signals. The Generalized Lee Method completes the results obtained by Lee and Parsons and makes better characterization of the spatial variability possible.

Radiofrequency fields are usually measured in order to be compared with electromagnetic exposure limits defined by international standardization organizations with the aim of preserving the human health. However, in the case of WiFi technology, accurate measurement of the radiation coming from user terminals and access points is a great challenge due to the nature of these emissions, which are noncontinuous signals transmitted in the form of pulses of short duration. Most of the methodologies defined up to now for determining WiFi exposure levels use or take as reference exposimeters, broadband probes, and spectrum analyzers without taking into account that WiFi signals are not continuously transmitted. This leads to an overestimation of the radiation level that cannot be considered negligible when data of the actual exposure are needed. To avoid this, other procedures apply empirical weighting factors that account for the actual duration of burst transmissions. However, this implies the implementation of additional measurements for calculating the weighting factors, and thus, increases the complexity of the work. According to this, it was still necessary to define the frequency domain measurement setup that is optimal for obtaining realistic WiFi signal values, without requiring the performance of additional recordings. Thus, the definition of an appropriate methodology to achieve this goal was established as the main objective of this paper. The set of tasks carried out to identify such a configuration, as well as the limitations obtained for other measurement settings, are deeply explained in this paper.

The Digital Radio Mondiale (DRM) digital radio standard is the only one recommended by the ITU to be used in Short Wave bands. These bands present unique characteristics for the broadcasting, very big coverage areas and long-range transmission. But they suffer of complicated propagation channel with big time variations that make difficult the regular broadcasting operation. In order to evaluate the DRM performance, field trials were made in Brazil by the Brazilian Government. The objective was to evaluate DRM technology for long-range transmission in Short Wave frequencies. In this paper, the results of these field trials are explained. Two frequencies were used during a period of three weeks at different hours of the day. The transmission was made from French Guyana and the reception was tested in Brasilia.

This paper presents a study of indoor digital radio reception in the Medium Wave band. The results are based on a large database of measurements in indoor locations in cities in northern Spain in frequencies from 600 to 1600 kHz. The paper proposes a prediction model for indoor field strength. The results are combined with indoor noise levels to study the statistics of available C/N (Carrier to Noise) ratios. The model is intended to help broadcasters planning digital broadcasting networks in Medium Wave for indoor reception. Signal time and space variability have also been studied and reference values are provided in the paper. The paper includes curves to calculate indoor losses in respect to ground wave propagation values provided by ITU-R P.368.