sponsorship: This work is part of the project 2020-EXT-007, "MIRA-ESTE: Specific, innovative microgrids solutions (accounting for environmental, social, technological and economic aspects) for isolated rural areas of Ecuador" from the Research Group of Propagation, Electronic Control, and Networking (PROCONET) of Universidad de las Fuerzas Armadas ESPE and KU Leuven. This work has been developed with the support of VLIR-UOS and the Belgian Development Cooperation (DGD) under the project EC2020SIN322A101. (Universidad de las Fuerzas Armadas ESPE|2020-EXT-007, KU Leuven, VLIR-UOS, Belgian Development Cooperation (DGD)|EC2020SIN322A101)

Several studies have been conducted on Hybrid Power Generation Systems (HPGS) to reduce the existing gap in access to electricity, especially in isolated and difficult access areas. The appropriate use of HPGS allows to power a community, reduces environmental pollution, and improves the performance of a system that only uses Fossil Fuel Generators (FFG). However, despite the efforts made in several countries, there are still isolated areas that remain without electricity due to several factors, such as the high cost of generation, transmission, and energy distribution. For this reason, this work seeks to generate new viable solutions to improve access to electricity especially in isolated areas of Ecuador, although the tool can be applied to any community without constant electricity access. For this purpose, the modeling of an HPGS is proposed, such system is composed of an FFG, a photovoltaic generator, and a hybrid energy storage system (i.e., electrical and thermal). A control algorithm for the FFG is used to adapt the motor rotational speed by using a minimum fuel consumption to supply the load profile. The results are obtained from simulations with real data of three case studies. A reduction in fuel consumption, greenhouse gas emissions, and loss power from renewable energy is demonstrated.

A fuzzy logic-based energy management system is proposed to allow the power exchange (PE) between the storage systems of multiple interconnected residential microgrids. The adjacent microgrids are connected to the utility network and comprise a solar roof-top photovoltaic system and an Energy Storage System (ESS). The proposed strategy for PE considers the battery state-of-charge and the rate of power change of each microgrid. The strategy's objective is to use the excess energy in the ESS of one microgrid to charge the ESS of another one that has a power shortage. Therefore, it is possible to optimize the energy generated by the renewable energy system and reduce the peaks and fluctuations in the power profile that each microgrid exchanges with the mains. Simulations and comparison results under different scenarios with and without PE using up to five interconnected microgrids, demonstrates the effectiveness of the proposed PE management while preserving the batteries' life.

Theory of normal mode propagation in a line-of-sight street scenario is extended to include propagation into buildings through coupling to a diffuse indoor field. Signal strength predictions are in close agreement with measurements, producing 2 dB and ≤ 3.5 dB root-mean-square model-data difference, in line-of-sight and outdoor-indoor scenarios, respectively. The full 3-D field model predicts actual signal directions and antenna correlations as a function of range, important for evaluating performance of directional antennas and spatial diversity. Only minimal description of the environment is needed, i.e., street width and representative building wall properties, without any interior details.

Based on outdoor-indoor measurements we study the channel characteristics of wideband multiple-input-multiple-output (MIMO) wireless access with near-ground base-stations (BS). These provide broadband service to indoor nomadic users in suburban residential environments. We compare near-ground channel characteristics with those of a lamp-post BS for line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. Essentially path-loss models, spectral efficiencies for 2×2 and 4×4 MIMO systems, delay spreads and coherence bandwidth are evaluated. We found that in general lowering the BS array has a detrimental effect on path-loss and efficiencies. Up to 50% less efficiency was observed in the NLOS channel, and path-losses are moderately greater for both LOS and NLOS conditions. Our investigation also shows differences in the power delays profiles when varying the array height.

We present an empirically based model for the gain of an indoor antenna array. This corresponds to the re-parametrization of the Greenstein-Erceg model, as applied to 5 m-50 m narrowband outdoor-indoor links. Our model is applicable to a few adjacent tones in an OFDM femtocell system such as LTE. We find that as much as 14 out of 16 dB of antenna-gain are attainable even in rich indoor scattering conditions. At the same time, no larger fade margin is required when using the array vs. the omnidirectional antenna. To provide a reference for the observed results we consider a simple propagation model, which is analyzed theoretically and via simulation. This model is found to match our empirical results very well.

Americanae nace como un proyecto conjunto que surge dentro de la Red Europea de Información y Documentación sobre América Latina (REDIAL), y que ha afrontado la Biblioteca de la Agencia Española de Cooperación Internacional para el Desarrollo (AECID). Esta nueva biblioteca virtual hace más accesibles los libros digitales de tema americanista a los investigadores y usuarios interesados de cualquier parte del mundo.