A survey of digital television broadcast transmission techniques

This paper is a survey of the transmission techniques used in digital television (TV) standards worldwide. With the increase in the demand for High-Definition (HD) TV, video-on-demand and mobile TV services, there was a real need for more bandwidth-efficient, flawless and crisp video quality, which motivated the migration from analogue to digital broadcasting. In this paper we present a brief history of the development of TV and then we survey the transmission technology used in different digital terrestrial, satellite, cable and mobile TV standards in different parts of the world. First, we present the Digital Video Broadcasting standards developed in Europe for terrestrial (DVB-T/T2), for satellite (DVB-S/S2), for cable (DVB-C) and for hand-held transmission (DVB-H). We then describe the Advanced Television System Committee standards developed in the USA both for terrestrial (ATSC) and for hand-held transmission (ATSC-M/H). We continue by describing the Integrated Services Digital Broadcasting standards developed in Japan for Terrestrial (ISDB-T) and Satellite (ISDB-S) transmission and then present the International System for Digital Television (ISDTV), which was developed in Brazil by adopteding the ISDB-T physical layer architecture. Following the ISDTV, we describe the Digital Terrestrial television Multimedia Broadcast (DTMB) standard developed in China. Finally, as a design example, we highlight the physical layer implementation of the DVB-T2 standar

Improved Reception Schemes for Digital Video Broadcasting Based on Hierarchical Modulation

In this paper, we first provide an overview of Hierarchical Modulation (HM) along with the opportunities offered by this modulation in the context of the recent Digital Video Broadcasting standard for Satellite to Handheld devices (DVB-SH).With HM, the binary data is partitioned into a “high-priority” (HP) and a “low-priority” (LP) bit stream that are separately and independently encoded before being mapped on non-uniformly spaced constellation points. We will show that the robustness of the HP stream is obtained at the expense of performance degradation of the less protected LP stream with respect to a non-hierarchical modulation. To overcome this inherent drawback of HM, we propose two different reception schemes for improving the bit error rate performance of the less protected LP stream, while keeping the HP decoding performance unchanged. The important point is that in one of the proposed reception schemes, the performance improvement is achieved together with the reduction of the receiver’s complexity

Iterative decoding and channel estimation of MIMO-OFDM transmissions with hierarchical constellations and implicit pilots

In this paper we consider the use of M-QAM hierarchical constellations (Quadrature Amplitude Modulation) combined with implicit pilots for the transmission of multicast and broadcast services in a MIMO-OFDM (Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing) system. This method of pilot transmission allows coherent detection at the receiver while avoiding the spectral degradation associated with the usual pilot multiplexing techniques but results in mutual interference between pilots and data. Due to the demanding channel estimation requirements and the high sensitivity to interference resulting from the usage of several antennas and hierarchical constellations, an enhanced receiver based on the turbo concept is developed which is capable of dealing with the inherent interference between pilots and data.info:eu-repo/semantics/acceptedVersio

Hierarchical MIMO modulation in digital TV transmission

It is possible to use hierarchical modulation in broadcast systems so that there are two different levels of service with different coverage patterns. There is a basic reception quality, which should be available to almost all users in the system, and there is a higher reception quality which should be available for most users in the system. The higher quality is realized by combining the basic signal with an incremental signal. For this, the basic part of the signal should be more robustly encoded than the incremental part. The fundamental tradeoff in hierarchical modulation is between the coverage of the basic signal and the coverage of the incremental signal. Independently of the method used to multiplex the basic and incremental signals, the presence of the incremental signal takes resources from the basic signal or causes interference. Thus the larger the coverage of the incremental signal is, the smaller the coverage of the basic signal becomes. Most digital broadcast standards (DVB-T, DVB-H, LTE MBMS) are based on orthogonal frequency division multiplexing (OFDM) and single-frequency network (SFN) operation. In this thesis, hierarchical modulation for single-antenna transmission is studied from technical point of view, based on a SFN environment, where time division multiplexing (TDM), superposition, hierarchical quadrature amplitude modulation (QAM) and hierarchical multiple-input and multiple-output (MIMO) scheme are illustrated. The alternatives for hierarchical multi-antenna modulation are investigated. The fundamental tradeoff of different hierarchical broadcasting methods are evaluated in MATLAB. This thesis mainly focuses on the progress of hierarchical broadcasting methods and possible improvements that could be made. The aim of this thesis is to improve current digital broadcasting methods by introducing multiple antennas to both transmitter and receiver

Error performance analysis of n-ary Alamouti scheme with signal space diversity.

Masters Degree. University of KwaZulu-Natal, Durban.In this dissertation, a high-rate Alamouti scheme with Signal Space Diversity is developed to improve both the spectral efficiency and overall error performance in wireless communication links. This scheme uses high modulation techniques (M-ary quadrature amplitude modulation (M-QAM) and N-ary phase shift keying modulation (N-PSK)). Hence, this dissertation presents the mathematical models, design methodology and theoretical analysis of this high-rate Alamouti scheme with Signal Space Diversity.To improve spectral efficiency in multiple-input multiple-output (MIMO) wireless communications an N-ary Alamouti M-ary quadrature amplitude modulation (M-QAM) scheme is proposed in this thesis. The proposed N-ary Alamouti M-QAM Scheme uses N-ary phase shift keying modulation (NPSK) and M-QAM. The proposed scheme is investigated in Rayleigh fading channels with additive white Gaussian noise (AWGN). Based on union bound a theoretical average bit error probability (ABEP) of the system is formulated. The simulation results validate the theoretical ABEP. Both theoretical results and simulation results show that the proposed scheme improves spectral efficiency by 0.5 bit/sec/Hz in 2 × 4 16-PSK Alamouti 16-QAM system compared to the conventional Alamouti scheme (16-QAM). To further improve the error performance of the proposed N-ary Alamouti M-QAM Scheme an × N-ary Alamouti coded M-QAM scheme with signal space diversity (SSD) is also proposed in this thesis. In this thesis, based on the nearest neighbour (NN) approach a theoretical closed-form expression of the ABEP is further derived in Rayleigh fading channels. Simulation results also validate the theoretical ABEP for N-ary Alamouti M-QAM scheme with SSD. Both theoretical and simulation results further show that the 2 × 4 4-PSK Alamouti 256-QAM scheme with SSD can achieve 0.8 dB gain compared to the 2 × 4 4-PSK Alamouti 256-QAM scheme without SSD

Multiuser MIMO-OFDM for Next-Generation Wireless Systems

This overview portrays the 40-year evolution of orthogonal frequency division multiplexing (OFDM) research. The amelioration of powerful multicarrier OFDM arrangements with multiple-input multiple-output (MIMO) systems has numerous benefits, which are detailed in this treatise. We continue by highlighting the limitations of conventional detection and channel estimation techniques designed for multiuser MIMO OFDM systems in the so-called rank-deficient scenarios, where the number of users supported or the number of transmit antennas employed exceeds the number of receiver antennas. This is often encountered in practice, unless we limit the number of users granted access in the base station’s or radio port’s coverage area. Following a historical perspective on the associated design problems and their state-of-the-art solutions, the second half of this treatise details a range of classic multiuser detectors (MUDs) designed for MIMO-OFDM systems and characterizes their achievable performance. A further section aims for identifying novel cutting-edge genetic algorithm (GA)-aided detector solutions, which have found numerous applications in wireless communications in recent years. In an effort to stimulate the cross pollination of ideas across the machine learning, optimization, signal processing, and wireless communications research communities, we will review the broadly applicable principles of various GA-assisted optimization techniques, which were recently proposed also for employment inmultiuser MIMO OFDM. In order to stimulate new research, we demonstrate that the family of GA-aided MUDs is capable of achieving a near-optimum performance at the cost of a significantly lower computational complexity than that imposed by their optimum maximum-likelihood (ML) MUD aided counterparts. The paper is concluded by outlining a range of future research options that may find their way into next-generation wireless systems

Quantifying Potential Energy Efficiency Gain in Green Cellular Wireless Networks

Conventional cellular wireless networks were designed with the purpose of providing high throughput for the user and high capacity for the service provider, without any provisions of energy efficiency. As a result, these networks have an enormous Carbon footprint. In this paper, we describe the sources of the inefficiencies in such networks. First we present results of the studies on how much Carbon footprint such networks generate. We also discuss how much more mobile traffic is expected to increase so that this Carbon footprint will even increase tremendously more. We then discuss specific sources of inefficiency and potential sources of improvement at the physical layer as well as at higher layers of the communication protocol hierarchy. In particular, considering that most of the energy inefficiency in cellular wireless networks is at the base stations, we discuss multi-tier networks and point to the potential of exploiting mobility patterns in order to use base station energy judiciously. We then investigate potential methods to reduce this inefficiency and quantify their individual contributions. By a consideration of the combination of all potential gains, we conclude that an improvement in energy consumption in cellular wireless networks by two orders of magnitude, or even more, is possible.Comment: arXiv admin note: text overlap with arXiv:1210.843

Efficient channel estimation for OFDM systems with hierarchical constellations

In this paper we consider the use of M-QAM hierarchical constellations (Quadrature Amplitude Modulation) combined with implicit pilots for the transmission of multicast and broadcast services in OFDM (Orthogonal Frequency Division Multiplexing) systems. This method of pilot transmission allows coherent detection at the receiver while avoiding the spectral degradation associated with the usual pilot multiplexing techniques but results in mutual interference between pilots and data. Due to the demanding channel estimation requirements and the high sensitivity to interference resulting from the usage of QAM hierarchical constellations, an enhanced receiver based on the turbo concept is developed which is capable of dealing with the inherent interference between pilots and data.info:eu-repo/semantics/acceptedVersio

Design of a simulation platform to test next generation of terrestrial DVB

Digital Terrestrial Television Broadcasting (DTTB) is a member of our daily life routine, and nonetheless, according to new users’ necessities in the fields of communications and leisure, new challenges are coming up. Moreover, the current Standard is not able to satisfy all the potential requirements. For that reason, first of all, a review of the current Standard has been performed within this work. Then, it has been identified the needing of developing a new version of the standard, ready to support enhanced services, as for example broadcasting transmissions to moving terminals or High Definition Television (HDTV) transmissions, among others. The main objective of this project is the design and development of a physical layer simulator of the whole DVB-T standard, including both the complete transmission and reception procedures. The simulator has been developed in Matlab. A detailed description of the simulator both from a functional and an architectural point of view is included. The simulator is the base for testing any possible modifications that may be included into the DVB-T2 future standard. In fact, several proposed enhancements have already been carried out and their performance has been evaluated. Specifically, the use of higher order modulation schemes, and the corresponding modifications in all the system blocks, have been included and evaluated. Furthermore, the simulator will allow testing other enhancements as the use of more efficient encoders and interleavers, MIMO technologies, and so on. A complete set of numerical results showing the performance of the different parts of the system, are presented in order to validate the correctness of the implementation and to evaluate both the current standard performance and the proposed enhancements. This work has been performed within the context of a project called FURIA, which is a strategic research project funded by the Spanish Ministry of Industry, Tourism and Commerce. A brief description of this project and its consortium has been also included herein, together with an introduction to the current situation of the DTTB in Spain (called TDT in Spanish)

Technical Solutions for Local Service Insertion in DVB-NGH Single Frequency Networks

Current digital terrestrial television networks make use of either single frequency networks (SFN) or multifrequency networks (MFN). These network topologies are not ideally suited for delivery of both global and local services in an efficient way. MFNs enable the efficient transmission of local services but need a significant amount of frequency spectrum. The basic principle of SFNs is that all transmitters radiate the same signal synchronized in time and frequency, therefore are especially suitable for global services due to mutual support of the signal by multiple transmitters. Without violating the SFN principle, local services meant to address sub-regions of an SFN must therefore be transmitted throughout the whole network, causing inefficient distribution of local services. This paper describes the complementary techniques adopted by the next generation mobile broadcasting standard digital video broadcasting - next generation handheld for providing global and local contents in SFN topologies: hierarchical modulation (H-LSI) and orthogonal local services insertion (O-LSI) techniques. H-LSI uses hierarchical modulation to transmit local services on top of the global services in areas close to the transmitters, by transmitting the local services in the low priority stream and the global services in the high priority stream. The O-LSI scheme specifies groups of OFDM subcarriers in specific OFDM symbols for the exclusive use of particular transmitters to transmit local services. For both techniques, the transmission of local content through the whole SFN network can be scheduled in a way that different local areas do not interfere with each other. In addition to the description of both H-LSI and O-LSI schemes, the applicability of these approaches in terms of network topologies, implementation issues, and performance evaluation are analyzed.López Sánchez, J.; Zöllner, J.; Atungsiri, S.; Stare, E.; Gómez Barquero, D. (2014). Technical Solutions for Local Service Insertion in DVB-NGH Single Frequency Networks. IEEE Transactions on Broadcasting. 60(2):293-301. doi:10.1109/TBC.2014.2322502S29330160