Jordi Joan Gimenez

DVB Coverage Prediction Using Game Engine Based Ray-Tracing Techniques

This paper presents the results of an evaluation of a propagation model based on ray-tracing techniques using a game engine and Graphics Processing Unit (GPU) in outdoor scenarios, as a gap-filler for a Digital Video Broadcasting Handheld (DVB-H) service. This model involves complete identification of the parameters of wave propagation, multipath components between the transmitter and the receiver as attenuation, time delay of arrival (TDA), full polarimetric transmission matrix, direction of arrival DoA and the direction of departure DoD. In the paper, we present the results of the simulation and compare them with measurements, obtaining a satisfactory fit.

Rotated Constellations for Improved Time and Frequency Diversity in DVB-NGH

In this paper, we investigate the potential gains that can be obtained with rotated constellations in DVB-NGH, the next-generation mobile broadcasting standard. Rotated constellations exploit the concept of signal-space diversity (SSD) to increase the diversity order of bit-interleaved coded modulation (BICM) at the expense of higher demodulation complexity without the need of additional transmission power or bandwidth. Two-dimensional rotated constellations (2DRC) were originally included in DVB-T2 (terrestrial second generation) to improve the reception robustness in fading channels. DVB-NGH inherits the same 2DRC from DVB-T2 and includes four-dimensional rotated constellations (4DRC) for certain configurations. Moreover, the standard has adopted a new component interleaver optimized for the utilization of rotated constellations with long time interleaving (TI) and time-frequency slicing (TFS). In this context, the additional robustness of rotated constellations is very interesting to counter the presence of signal outages in the time and frequency domains. To investigate the potential gains of 2DRC and 4DRC, we employ an information-theoretic approach based on mutual information, as well as physical layer simulations in DVB-NGH systems. The results reveal that rotated constellations are important to increase the diversity gains of long TI and TFS, and also to reduce the zapping time perceived by the users.

Time Frequency Slicing for Future Digital Terrestrial Broadcasting Networks

Time Frequency Slicing (TFS) is a novel transmission technique for the future of terrestrial broadcasting. TFS breaks with the traditional transmission of TV services over single RF channels. With TFS, services are distributed across several channels by frequency hopping and time-slicing. The bundling of several RF channels into a TFS multiplex provides important advantages. A capacity gain is obtained due to a more efficient statistical multiplexing of video content since more services can be encoded in parallel. Improved frequency diversity also provides a coverage gain since signal imbalances between RF channels can be smoothed. Enhanced robustness against static and time varying interferences can also be achieved. TFS was described, although not implemented, for DVB-T2 and was fully adopted in DVB-NGH. At present, it is proposed for a future evolution of DVB-T2 and will also be considered in the ongoing ATSC 3.0 standard. This paper investigates the potential advantages of TFS by means of field measurements as well as simulations and discusses practical implementation aspects and requirements regarding transmission and reception. Results demonstrate the interesting advantages of TFS to improve both coverage and spectral efficiency, which addresses the future necessity of a more efficient DTT spectrum usage.

Combined Time and Space Diversity: Mobile Reception in DVB-T and DVB-T2 Systems

The simultaneous delivery of fixed and mobile services in digital terrestrial TV (DTT) networks is a very attractive concept, as it allows the reuse of content, spectrum, and infrastructure. However, the provision of mobile services in terrestrial networks is challenged by the more severe propagation conditions of the mobile scenario. In this context, significant gains can be achieved by exploiting the diversity over time, frequency, and space.

Advanced Network Planning for Time Frequency Slicing (TFS) Toward Enhanced Efficiency of the Next-Generation Terrestrial Broadcast Networks

The allocation of frequencies traditionally used by terrestrial broadcasting (digital dividend) to International Mobile Telecommunication is limiting the evolution of the digital terrestrial television (DTT) networks for enhanced service offering. Next-generation DTT standards are called to provide increased capacity within the reduced spectrum. Time Frequency Slicing (TFS) has been proposed as one of the key technologies for the future DTT networks. Beyond a coverage gain due to additional frequency diversity, and a virtual capacity gain due to a more efficient statistical multiplexing, TFS also provides an increased interference immunity which may allow for a tighter frequency reuse enabling more RF channels per transmitter station, within a given spectrum. Moreover, the implementation of advanced network planning (ANP) strategies together with next-generation DTT standards may result in additional spectral efficiency gains linked to network planning. This paper evaluates the potential spectral efficiency by TFS and ANP strategies in multiple frequency networks as well as in regional and large area single frequency networks. Different network configurations have been analyzed using single polarization, the systematic use of horizontal and vertical polarizations in different stations, or the use of multiple frequency reuse patterns for different frequencies of the TFS-Mux. Results indicate high potential network spectral efficiency gains compared to the existing network deployments with DVB-T2 (Digital Video Broadcasting Terrestrial 2nd Generation).

Using 3D game engines and GPU for ray launching based channel modeling in indoor

This paper investigates the use of a full 3D ray-launching system based on Game Engine and GPU for the prediction of channel parameters in indoor. We explore the behavior of the materials and the possible influence of objects external to the room where measurements were performed. We explore the modeling of indoor channel for Digital TV frequencies and analyze the behavior of material on such low frequencies and how the frequencies affect the constitutive parameters of materials in the scenario. Because of the environment used for experimentation, the number of rays is very high and the number of interactions is higher than usual. We show results of the ray tracing model compared with measurements of delay spread at 594MHz in a meeting room.

Wideband Broadcasting: A Power-Efficient Approach to 5G Broadcasting

Efficient and flexible use of spectrum will be inherent characteristics of 5G communication technologies with native support of wideband operation with frequency reuse 1 (i.e., all transmit sites use all available frequency resources). Although not in the very first 5G release of 3GPP, it is expected that broadcast/multicast technology components will later be added and fully integrated in the 5G system. The combination of both wideband and frequency reuse 1 may provide significant gains for broadcast transmissions in terms of energy efficiency, since it is more efficient to increase capacity by extending the bandwidth rather than increasing the transmit power over a given bandwidth. This breaks with the traditional concept of terrestrial broadcast frequency planning, and paves the way to new potential uses of UHF spectrum bands for 5G broadcasting. This article provides insight into the fundamental advantages in terms of capacity, coverage, as well as power saving of wideband broadcast operation. The role of network deployment, linked to frequency reuse in the UHF band, and its influence on the performance of a wideband broadcasting system are discussed. The technical requirements and features that would enable such a power-efficient solution are also addressed.

Indoor Propagation Using a Game Engine Ray-Based Model in Indoor Scenario at 5.4GHz

The results of a simulation of signal propagation strength in indoor environment using a game engine ray-based tool and use of an open source 3D modeling tool for scenario building are presented in this paper, showing the flexibility of the XML description language for this kind of scenario. We show simulation results and compare them with an extensive set of measurements for an indoor scenario with multiple materials in the 5.4GHz band, obtaining a good match between the ray-based tool and measurements of received power. We found also that constitutive parameters have an important effect on the simulation results and made some small adjustments to improve results.

Pilot optimization for mobile services in ATSC 3.0

The Advanced Television System Committee (ATSC) has released ATSC 3.0, the next-generation U.S. Digital Terrestrial Television (DTT) standard. ATSC 3.0 allows a higher flexibility compared to the previous state-of-the-art DTT standard, DVB-T2 (Digital Video Broadcasting - Terrestrial 2nd Generation). This higher flexibility allows broadcasters to adapt transmission configuration to network and reception requirements. Regarding pilot patterns (PP), whereas DVB-T2 provides 8 different PPs with a unique pilot boosting, ATSC 3.0 extends up to 16 different PPs, with 5 different boostings per each one. This paper is focused on the study of the PP and boosting combination that optimizes performance for time (Time Division Multiplexing, TDM) and power (Layered Division Multiplexing, LDM) multiplexing modes of ATSC 3.0 in mobility reception conditions. The selection of the optimum PP is particularly essential in LDM mode, because it must be shared between the two LDM layers.

Performance evaluation of Layer Division Multiplexing (LDM) combined with Time Frequency Slicing (TFS)

The Advanced Television System Committee (ATSC) is currently developing the next-generation U.S. Digital Terrestrial Television (DTT) standard, known as ATSC 3.0. Two disruptive technologies for the physical layer are being evaluated, Layer Division Multiplexing (LDM) and Time Frequency Slicing (TFS). LDM consist in the transmission of a signal composed of two independent signals (layers) which are superimposed together at different power levels. These two layer can be configured with the desired robustness and capacity. LDM enables the efficient provision of services addressed to mobile and fixed reception in a more efficient way than the classical Frequency Division Multiplexing (FDM) and Time Division Multiplexing (TDM) since full bandwidth and transmission time are used in both layers. However, practical operation is restricted due to several implementation constraints such as the use of common parameters and transmitter blocks for both layers (e.g. a common time interleaver). The use of TFS allows for an improved frequency diversity by the distribution of the service data across multiple Radio Frequency (RF) channels instead of using a single RF channel. The paper investigates the potential gains provided by the increased frequency diversity with TFS in conjunction with LDM.