This paper provides a review of the second generation of terrestrial digital video broadcasting standard (DVB-T2). DVB-T2 is the evolution of DVB-T and, together with DVB-S2 and DVB-C2, inaugurated a new transition from the first-generation digital broadcasting systems, similar to the transition from analog-to-digital systems. In this paper, the most relevant features of DVB-T2 are explained in detail, along with their benefits and trade-offs. This paper also presents a comprehensive review of the laboratory and field trial results available so far. Especial emphasis is placed in the results of the measurements carried out to test the mobile reception and the novel technologies as multiple input single output and time frequency slicing.

In the last years multiple Internet of Things (IoT) solutions have been developed to detect, track, count and identify human activity from people that do not carry any device nor participate actively in the detection process. When WiFi radio receivers are employed as sensors for device-free human activity recognition, channel quality measurements are preprocessed in order to extract predictive features towards performing the desired activity recognition via machine learning (ML) models. Despite the variety of predictors in the literature, there is no universally outperforming set of features for all scenarios and applications. However, certain feature combinations could achieve a better average detection performance compared to the use of a thorough feature portfolio. Such predictors are often obtained by feature engineering and selection techniques applied before the learning process. This manuscript elaborates on the feature engineering and selection methodology for counting device-free people by solely resorting to the fluctuation and variation of WiFi signals exchanged by IoT devices. We comprehensively review the feature engineering and ML models employed in the literature from a critical perspective, identifying trends, research niches and open challenges. Furthermore, we present and provide the community with a new open database with WiFi measurements in several indoor environments (i.e. rooms, corridors and stairs) where up to 5 people can be detected. This dataset is used to exhaustively assess the performance of different ML models with and without feature selection, from which insightful conclusions are drawn regarding the predictive potential of different predictors across scenarios of diverse characteristics.

This paper provides minimum C/N values for correct reception of DVB-T2 signals under fixed reception conditions. The C/N values are obtained after analyzing the results of field and laboratory trials. The field measurements were taken in a middle-sized city, along 33 locations, with MFN and SFN configurations. Both the system configuration options (constellation and code rate, FFT size, pilot pattern, and rotated constellations) and the propagation channel are taken into account to quantify their influence on the reception requirements. DVB-T was also measured and both systems are compared. The final objective is to provide the broadcasters with some guides based on measurements to optimize the DVB-T2 networks by choosing the parameters that best fit their needs.

This paper presents the results of laboratory tests carried out to study the performance of DVB-T2 in presence of multipath in fixed reception with rooftop antenna. The typical multipath cause in this scenario is a Single Frequency Network (SFN) reception. A range of relative levels and delays between the main path and one echo are tested to obtain the C/N requirements for each case. DVB-T2 supports a large number of options that can be chosen to optimize the system. Some of those options (Pilot Patterns, Guard Interval Fraction, Rotated Constellations, FFT sizes) are tested to evaluate their performance. The results are compared with the simulation results available in the implementation guidelines for the extreme cases of Gaussian channel (no echo) and 0 dB echo channel (main path and echo at same level).

This paper presents the field trials carried out in Bilbao (Spain) for testing and analyzing the performance of the DVB-T2 indoor (fixed and pedestrian) reception. Test services with different DVB-T2 and T2-Lite configuration modes have been broadcasted and indoor measurements have been carried out. As a result, signal to noise ratio threshold values for DVB-T2 indoor reception have been obtained. These values update those provided by previous studies and are also valid for planning tools to be used by broadcasters in the development of DVB-T2 networks.