Javier Morgade

DVB-T2: The Second Generation of Terrestrial Digital Video Broadcasting System

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.

On the feasibility of unlicensed communications in the TV white space: Field measurements in the UHF band

In practical unlicensed communications in TV band, radio devices have to identify, at first, the transmission opportunities, that is, the portion of the spectrum licensed for broadcasting services unoccupied in a certain region at certain time, that is, the so-called TV white space. In this paper the outcome of field measurements in the UHF TV band (470–860 MHz) conducted in EU is presented. To obtain empirical values for the parameters upon which unlicensed radio devices are able to distinguish in a real scenario between empty and occupied TV channels, signal power measurements have been performed in Italy, Spain, and Romania on rural, suburban, and urban sites, at different heights over the ground by using different analysis bandwidths. The aim of this work is to provide a set of practical parameters upon which harmless unlicensed communication in the UHF TV white space is feasible. The results have been analyzed with respect to the hidden node margin problem, spectrum sensing bandwidth, and occupancy threshold.

Co-Channel and Adjacent Channel Interference and Protection Issues for DVB-T2 and IEEE 802.22 WRAN Operation

This paper presents a study on the coexistence issue of digital terrestrial TV broadcasting and cognitive broadband access operation in the TV white spaces (TVWS). Extended measurements were performed to evaluate the protection of the existing Second generation of digital video broadcasting terrestrial standard (DVB-T2) services in the presence of IEEE 802.22 WRAN co-channel and adjacent channel interference. The absence of picture failure over 30 consecutive seconds on decoded DVB-T2 streams has been monitored to obtain the maximum tolerable level of IEEE 802.22 WRAN interference, which ensures the protection of the primary broadcast system. This paper considers practical DVB-T2 system configuration options by varying parameters of the standard, such as constellation and code rate, FFT size, pilot pattern and guard interval, and rotated constellations and compares them in terms of robustness with respect to the interference generated by IEEE 802.22 WRAN operation. The goal is to provide cognitive broadband operators in the TVWS with guidelines to optimize their network by choosing the parameters that best fit their needs in case of coexistence with DVB-T2 broadcasting services.

Optimization of the Coverage Area for DVB-T Single Frequency Networks Using a Particle Swarm Based Method

Single frequency networks (SFN) are usually considered to deploy OFDM modulation based digital broadcast systems, exploiting the multipath tolerance of the OFDM receivers, which are capable of combining signals coming from several transmitters with different propagation delays. In this work, a planning tool is proposed to improve the coverage area in SFN networks, optimizing transmission parameters such as the transmitters delay or power, using 3D digital terrain maps along with a propagation prediction tool to estimate the power received at each location inside the coverage area. A heuristic particle swarm optimization algorithm is used (PSO) to optimize transmission parameters. The approach proposed makes it possible to consider several configurations regarding both transmitters and receivers. Preliminary test results are shown for a SFN with eighteen transmitters and omnidirectional radiators at both sides that demonstrate the usefulness of the approach. Furthermore, results considering receivers with directive antennas as well as transmitters with sectored antennas are also included and discussed.

SFN-SISO and SFN-MISO Gain Performance Analysis for DVB-T2 Network Planning

In DVB-T2, the single frequency network (SFN) mode is an attractive planning alternative to the well-known multiple frequency network (MFN) mode. SFN networks provide augmented spectrum efficiency as well as a quality of service improvement due to a more homogeneous distribution of the received signal strength over the coverage area. Nevertheless, some areas will also show degradation in practice. In order to improve the performance of the SFN operation, the second generation broadcast system DVB-T2 standard incorporates multiple input single output (MISO) antenna diversity mechanisms. Based on empirical analyses and system level simulations, this paper analyzes the key factors affecting the SFN operation. This paper analyzes SFN effects as well as the corresponding MISO gain margins for commercial and custom software defined radio (SDR) receiver implementations. The results show that the MISO gain is restricted only to the overlapping areas of an SFN where a small power imbalance between MISO groups, is present being the achievable MISO gain higher with high modulation code rates. The results also address that degradation arises in the non-overlapping regions of an SFN. This paper provides also updated C/N thresholds for DVB-T2 network planning.

Coverage optimization and power reduction in SFN using simulated annealing

An approach that predicts the propagation, models the terrestrial receivers and optimizes the performance of single frequency networks (SFN) for digital video broadcasting in terms of the final coverage achieved over any geographical region, enhancing the most populated areas, is proposed in this paper. The effective coverage improvement and thus, the self-interference reduction in the SFN is accomplished by optimizing the internal static delays, sector antenna gain, and both azimuth and elevation orientation for every transmitter within the network using the heuristic simulated annealing (SA) algorithm. Decimation and elevation filtering techniques have been considered and applied to reduce the computational cost of the SA-based approach, including results that demonstrate the improvements achieved. Further representative results for two SFN in different scenarios considering the effect on the final coverage of optimizing any of the transmitter parameters previously outlined or a combination of some of them are reported and discussed in order to show both, the performance of the method and how increasing gradually the complexity of the model for the transmitters leads to more realistic and accurate results.

3DTV Roll-Out Scenarios: A DVB-T2 Approach

This paper presents an analysis of the characteristics of the DVB-T2 standard to deliver 3DTV contents (3DTV). The work has been based on the current state-of-the-art developments in technologies that enable 3DTV delivery, from production to displays, with special emphasis on formats and coding efficiencies. Based on bitrate and format requirements the capacity of DVB-T2 is investigated, proposing two roll-out scenarios and discussing the associated DVB-T2 configuration parameters. The target receivers are both fixed and portable, and different backward compatibility problems and solutions are highlighted. The result of this work is an estimation of the number and type of services (both 2D and 3D) that this standard will be able to deliver in the mid term future as 2D HD and 3D services become commercially available.

Hidden node margin and man-made noise measurements in the UHF broadcasting bands

This paper presents an extended study of the spectrum occupancy in the UHF frequency band (470-870MHz) in Spain and in Italy. The objective of the study is to establish by signal power measuring if cognitive devices are able to detect and distinguish in a Hidden Node scenario between empty and occupied TV channels. The study has been performed, for each of these two countries, at three different sites and at different heights over the ground for assessing the hidden node margin. The measurements in Spain were carried out in urban, suburban and rural environments close to the city of Bilbao while the measurements in Italy were carried out in Sardinia, in different urban areas of the city of Cagliari, surrounding suburban spots and a rural location 50 km west. The measurement methodology was the same in both scenarios. The results from the spectrum measurements performed in the various scenarios have been analyzed and conclusions have been drawn.

Coverage optimization for DVB-T/H single frequency networks using a PSO algorithm

In this work, the usefulness and limitations of a planning tool that combines a propagation prediction method and a modern heuristic technique when applied to improve the coverage area in single frequency networks (SFN) is presented. The propagation prediction method uses 3D digital terrain maps along with a propagation model to estimate the contribution of any transmitter of the SFN at each location within the region in which the SFN is intended to be deployed, given in terms of parameters such as the received power and propagation delay. Furthermore, a particle swarm optimization (PSO) algorithm is used to optimize the transmission parameters of any of the transmitters within the SFN, including transmitters delay or gain for their sector antennas, in order to exploit the multipath tolerance in OFDM receivers. Preliminary results comparing the performance of different PSO schemes considering as the canonical problem a SFN consisting of eighteen transmitters, in which transmitters and receivers have been simplified, are reported and discussed. Moreover, results considering sector and directive antennas at the transmitter and receiver sides, respectively, are also included.

DRM 20 kHz Simulcast Field Trials in the Medium Wave Band in Mexico D.F.

This paper presents the results obtained from the first extensive field trials of medium wave DRM (digital radio mondiale) simulcast, which were carried out in Mexico D.F.. The transmitted signal was composed of a 10 kHz bandwidth AM part at 1060 kHz and an adjacent 10 kHz bandwidth DRM part at 1070 kHz broadcasting the same audio contents and with a theoretically calculated back-off ratio of 16 dB at transmission. The results in this paper will be accompanied by a thorough description of the transmission network set up and also with the measurement system and measurement techniques. The data processing techniques are also included to give a meaningful interpretation of the final results. The conclusions of this work have focused on threshold values for AM and DRM correct reception, simulcast time variability, mutual analogue - digital SNR degradation and reception impairment analysis. The overall result of this work is a high reliability of the AM and DRM services in the difficult Medium Wave reception environments of Mexico D.F.