COST EFFICIENT PROVISIONING OF MASS MOBILE MULTIMEDIA SERVICES IN HYBRID CELLULAR AND BROADCASTING SYSTEMS

Uno de los retos a los que se enfrenta la industria de las comunicaciones móviles e inalámbricas es proporcionar servicios multimedia masivos a bajo coste, haciéndolos asequibles para los usuarios y rentables a los operadores. El servicio más representativo es el de TV móvil, el cual se espera que sea una aplicación clave en las futuras redes móviles. Actualmente las redes celulares no pueden soportar un consumo a gran escala de este tipo de servicios, y las nuevas redes de radiodifusión móvil son muy costosas de desplegar debido a la gran inversión en infraestructura de red necesaria para proporcionar niveles aceptables de cobertura. Esta tesis doctoral aborda el problema de la provisión eficiente de servicios multimedia masivos a dispositivos móviles y portables utilizando la infraestructura de radiodifusión y celular existente. La tesis contempla las tecnologías comerciales de última generación para la radiodifusión móvil (DVB-H) y para las redes celulares (redes 3G+ con HSDPA y MBMS), aunque se centra principalmente en DVB-H. El principal paradigma propuesto para proporcionar servicios multimedia masivos a bajo coste es evitar el despliegue de una red DVB-H con alta capacidad y cobertura desde el inicio. En su lugar se propone realizar un despliegue progresivo de la infraestructura DVB-H siguiendo la demanda de los usuarios. Bajo este contexto, la red celular es fundamental para evitar sobre-dimensionar la red DVB-H en capacidad y también en áreas con una baja densidad de usuarios hasta que el despliegue de un transmisor o un repetidor DVB-H sea necesario. Como principal solución tecnológica la tesis propone realizar una codificación multi-burst en DVB-H utilizando códigos Raptor. El objetivo es explotar la diversidad temporal del canal móvil para aumentar la robustez de la señal y, por tanto, el nivel de cobertura, a costa de incrementar la latencia de la red.Gómez Barquero, D. (2009). COST EFFICIENT PROVISIONING OF MASS MOBILE MULTIMEDIA SERVICES IN HYBRID CELLULAR AND BROADCASTING SYSTEMS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6881Palanci

Bit-Interleaved Coded Modulation (BICM) for ATSC 3.0

"(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.")In this paper, we summarize and expound upon the choices made for the bit-interleaved coded modulation (BICM) part of the next-generation terrestrial broadcast standard known as ATSC 3.0. The structure of the ATSC 3.0 BICM consists of a forward error correcting code, bit interleaver, and constellation mapper. In order to achieve high efficiency over a wide range of reception conditions and carrier-to-noise (C/N) ratio values, several notable new elements have been standardized. First, 24 original low-density parity check (LDPC) codes have been designed, with coding rates from 2/15 (0.13) up to 13/15 (0.87) for two code sizes: 16 200 bits and 64 800 bits. Two different LDPC structures have been adopted; one structure more suited to medium and high coding rates and another structure suited to very low coding rates. Second, in addition to quaternary phase shift keying, non-uniform constellations (NUCs) have been chosen for constellation sizes from 16QAM to 4096QAM to bridge the gap to the Shannon theoretical limit. Two different types of NUCs have been proposed: 1-D NUCs for 1024- and 4096-point constellations, and 2-D-NUCs for 16-, 64-, and 256-point constellations. 2-D-NUCs achieve a better performance than 1-D-NUCs but with a higher complexity since they cannot be separated into two independent I/Q components. NUCs have been optimized for each coding rate for the 64 800 bits LPDCs. The same constellations are used for 16 200 bits LDPCs, although they have been limited up to 256QAM. Finally, a bit interleaver, optimized for each NUC/coding rate combination, has been designed to maximize the performance. The result is a BICM that provides the largest operating range (more than 30 dB, with the most robust mode operating below -5 dB C/N) and the highest spectral efficiency compared to any digital terrestrial broadcast system today, outperforming the current state-of-the-art DVB-T2 standard BICM by as much as 1 dB in some cases. ATSC 3.0 will also provide a considerable increase in the maximum transmission capacity when using the high-order NUCs such as 1024QAM and 4096QAM, which will represent a major milestone for terrestrial broadcasting since the highest order constellation currently available is uniform 256QAM. This paper describes the coding, modulation, and bit interleaving modules of the BICM block of ATSC 3.0 and compares its performance with other DTT standards such as ATSC A/53 and DVB-T2.Michael, L.; Gómez Barquero, D. (2016). Bit-Interleaved Coded Modulation (BICM) for ATSC 3.0. IEEE Transactions on Broadcasting. 62(1):181-188. doi:10.1109/TBC.2015.2505414S18118862

Low-Complexity Demapping Algorithm for Two-Dimensional Non-Uniform Constellations

"(c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.")Non-uniform constellations (NUCs) have been recently introduced in digital broadcasting systems to close the remaining gap to the unconstrained Shannon theoretical limit. Compared to uniform quadrature amplitude modulation (QAM) constellations, NUCs provide a signal-to-noise ratio (SNR) gain (i.e., a reduction in the required SNR), especially for high-order constellations. One-dimensional NUCs (1D-NUC) have a squared shape with non-uniform distance between the constellation symbols. Since the I and Q components remain as two independent signals, a 1D-demapper as for uniform QAM constellations is feasible. Two-dimensional NUCs (2D-NUC) provide a better performance than 1D-NUCs, since they are designed by relaxing the square shape constraint, with arbitrary shape along the complex plane. However, the main drawback of 2D-NUCs is the higher complexity at the receiver, since a 2D-demapper is needed. In this paper, we propose a demapping algorithm that reduces from 69% to 93% the number of required distances when using 2D-NUCs. The algorithm discards or replicates those constellation symbols that provide scarce information, with a performance degradation lower to 0.1 dB compared to the optimal maximum likelihood demapper.Fuentes Muela, M.; Vargas, D.; Gómez Barquero, D. (2016). Low-Complexity Demapping Algorithm for Two-Dimensional Non-Uniform Constellations. IEEE Transactions on Broadcasting. 62(2):375-383. doi:10.1109/TBC.2015.2492477S37538362

Transmit Diversity Code Filter Sets (TDCFSs), an MISO Antenna Frequency Predistortion Scheme for ATSC 3.0

"(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.")Transmit diversity code filter sets (TDCFSs) are a method of predistorting the common waveforms from multiple transmitters in the same frequency channel, as in a single frequency network, in order to minimize the possibility of cross-interference among the transmitted signals over the entire reception area. This processing is achieved using all-pass linear filters, allowing the resulting combination of predistortion and multipath to be properly compensated as part of the equalization process in the receiver. The filter design utilizes an iterative computational approach, which minimizes cross-correlation peak side lobe under the constraints of number of transmitters and delay spread, allowing customization for specific network configurations. This paper provides an overview of the TDCFS multiple-input single output antenna scheme adopted in ATSC 3.0, together with experimental analysis of capacity and specific worst-case conditions that illustrate the benefits of using the TDCFS approach.Lopresto, S.; Citta, R.; Vargas, D.; Gómez Barquero, D. (2016). Transmit Diversity Code Filter Sets (TDCFSs), an MISO Antenna Frequency Predistortion Scheme for ATSC 3.0. IEEE Transactions on Broadcasting. 62(1):271-280. doi:10.1109/TBC.2015.2505400S27128062

Fading Margin Reduction due to Inter-Burst Upper Layer FEC in Terrestrial Mobile Broadcast Systems

In this paper, we investigate the reduction of the shadowing fading margin that can be achieved with interburst upper layer forward error correction (UL-FEC) in terrestrial mobile broadcast systems with time slicing (i.e., discontinuous transmission). A theoretical framework is derived, for both streaming and file delivery services, as a function of the number of bursts jointly encoded, the UL-FEC code rate, the shadowing standard deviation, and the ratio between the moved distance by the user during the cycle time between bursts and the shadowing correlation distance. Results are validated with Digital Video BroadcastingHandheld (DVB-H) and DVB-Satellite to Handhelds (DVB-SH) laboratory measurements. © 2010 IEEE.This work was supported in part by the Spanish Ministry of Industry, Tourism, and Commerce under the Celtic project Enabling Next-Generation Networks for Broadcast Services ENGINES (TSI-020400-2010-108). The review of this paper was coordinated by Prof. M. D. Yacoub.Gómez Barquero, D.; Gozálvez Serrano, D.; Gómez Molina, PF.; Cardona Marcet, N. (2011). Fading Margin Reduction due to Inter-Burst Upper Layer FEC in Terrestrial Mobile Broadcast Systems. IEEE Transactions on Vehicular Technology. 60(7):3110-3117. https://doi.org/10.1109/TVT.2011.2162535S3110311760

A Novel Physical Layer Split FEC Scheme for Long Time Interleaving with Fast Zapping Support

This paper describes a novel forward error correction (FEC) and time interleaving scheme, known as BB-iFEC (Base Band inter-burst FEC), aimed to provide long time interleaving with fast zapping support. BB-iFEC is a split FEC scheme with an outer FEC and an outer time interleaver concatenated to the inner FEC and inner time interleaver. It is based on the link layer FEC scheme of the hybrid satellite-terrestrial mobile broadcasting standard DVB-SH (Satellite to Handhelds), known as MPE-iFEC (Multi Protocol Encapsulation inter-burst FEC), but moved down to the physical layer. This allows full transparency towards upper layers, as well as reduced signaling overhead and packet fragmentation. However, the major novelty is that it allows re-using the soft information at the output of the inner FEC decoder (i.e., the log-likelihood ratios, LLRs). Compared to hard decoding, this improves the performance at the expense of higher memory requirements at the receivers. Nevertheless, BB-iFEC allows to efficiently perform either soft or hard decoding, being thus a scalable solution. Another important advantage is that it can be introduced in future evolutions of existing systems, because it allows allows co-existence of terminals with and without long time interleaving support. The paper describes the main features of BB-iFEC and its implementation at the transmitter and receiver side. The paper also presents illustrative results for future evolutions of the digital terrestrial TV standard DVB-T2 (Second Generation Terrestrial), such as the next generation mobile broadcasting technology DVB-NGH (Next Generation Handheld).Gómez Barquero, D.; Gómez Molina, PF.; Gozálvez Serrano, D.; Sayadi, B.; Roullet, L. (2012). A Novel Physical Layer Split FEC Scheme for Long Time Interleaving with Fast Zapping Support. IEEE Transactions on Broadcasting. 58(2):269-276. doi:10.1109/TBC.2012.2185574S26927658

DVB-NGH: the Next Generation of Digital Broadcast Services to Handheld Devices

This paper reviews the main technical solutions adopted by the next-generation mobile broadcasting standard DVB-NGH, the handheld evolution of the second-generation digital terrestrial TV standard DVB-T2. The main new technical elements introduced with respect to DVB-T2 are: layered video coding with multiple physical layer pipes, time-frequency slicing, full support of an IP transport layer with a dedicated protocol stack, header compression mechanisms for both IP and MPEG-2 TS packets, new low-density parity check coding rates for the data path (down to 1/5), nonuniform constellations for 64 Quadrature Amplitude Modulation (QAM) and 256QAM, 4-D rotated constellations for Quadrature Phase Shift Keying (QPSK), improved time interleaving in terms of zapping time, end-to-end latency and memory consumption, improved physical layer signaling in terms of robustness, capacity and overhead, a novel distributed multiple input single output transmit diversity scheme for single-frequency networks (SFNs), and efficient provisioning of local content in SFNs. All these technological solutions, together with the high performance of DVB-T2, make DVB-NGH a real next-generation mobile multimedia broadcasting technology. In fact, DVB-NGH can be regarded the first third-generation broadcasting system because it allows for the possibility of using multiple input multiple output antenna schemes to overcome the Shannon limit of single antenna wireless communications. Furthermore, DVB-NGH also allows the deployment of an optional satellite component forming a hybrid terrestrial-satellite network topology to improve the coverage in rural areas where the installation of terrestrial networks could be uneconomical.Gómez Barquero, D.; Douillard, C.; Moss, P.; Mignone, V. (2014). DVB-NGH: the Next Generation of Digital Broadcast Services to Handheld Devices. IEEE Transactions on Broadcasting. 60(2):246-257. doi:10.1109/TBC.2014.2313073S24625760

Layer-Aware Forward Error Correction for Mobile Broadcast of Layered Media

The bitstream structure of layered media formats such as scalable video coding (SVC) or multiview video coding (MVC) opens up new opportunities for their distribution in Mobile TV services. Features like graceful degradation or the support of the 3-D experience in a backwards-compatible way are enabled. The reason is that parts of the media stream are more important than others with each part itself providing a useful media representation. Typically, the decoding of some parts of the bitstream is only possible, if the corresponding more important parts are correctly received. Hence, unequal error protection (UEP) can be applied protecting important parts of the bitstream more strongly than others. Mobile broadcast systems typically apply forward error correction (FEC) on upper layers to cope with transmission errors, which the physical layer FEC cannot correct. Today's FEC solutions are optimized to transmit single layer video. The exploitation of the dependencies in layered media codecs for UEP using FEC is the subject of this paper. The presented scheme, which is called layer-aware FEC (LA-FEC), incorporates the dependencies of the layered video codec into the FEC code construction. A combinatorial analysis is derived to show the potential theoretical gain in terms of FEC decoding probability and video quality. Furthermore, the implementation of LA-FEC as an extension of the Raptor FEC and the related signaling are described. The performance of layer-aware Raptor code with SVC is shown by experimental results in a DVB-H environment showing significant improvements achieved by LA-FEC. © 2011 IEEE.Hellge, C.; Gómez Barquero, D.; Schierl, T.; Wiegand, T. (2011). Layer-Aware Forward Error Correction for Mobile Broadcast of Layered Media. IEEE Transactions on Multimedia. 13(3):551-562. doi:10.1109/TMM.2011.2129499S55156213

Time Diversity in Mobile DVB-T2 Systems

DVB-T2 implements a very flexible time interleaving that allows multiple tradeoffs in terms of time diversity, latency and power saving. In this paper, we study in detail these tradeoffs in the context of mobile reception. Together with time diversity, we also investigate the impact of reduced time de-interleaving memory and Alamouti-based MISO in the mobile reception of DVB-T2 services. In addition, we propose the utilization of upper layer FEC protection in order to overcome the limitations of the DVB-T2 physical layer for the provision of long time interleaving, and enable fast zapping. The performance is evaluated by means of simulations in mobile channels that include the presence of fast fading and shadowing in the received signal. © 2010 IEEE.Manuscript received October 13, 2010; revised April 22, 2011; accepted May 11, 2011. Date of publication July 25, 2011; date of current version August 24, 2011. This work was supported in part by the Spanish Ministry of Industry, Tourism, and Commerce under the Celtic project Enabling Next-Generation Networks for Broadcast Services ENGINES (TSI-020400-2010-108). The work of D. Gozalvez was supported by the FPU Grant AP2008-03293 of the Spanish Ministry of Education.Gozálvez Serrano, D.; Gómez Barquero, D.; Vargas, D.; Cardona Marcet, N. (2011). Time Diversity in Mobile DVB-T2 Systems. IEEE Transactions on Broadcasting. 57(3):617-628. doi:10.1109/TBC.2011.2161189S61762857