1,470 research outputs found
Mobile Communication Networks and Digital Television Broadcasting Systems in the Same Frequency Bands â Advanced Co-Existence Scenarios
The increasing demand for wireless multimedia services provided by modern communication systems with stable services is a key feature of advanced markets. On the other hand, these systems can many times operate in a neighboring or in the same frequency bands. Therefore, numerous unwanted co-existence scenarios can occur. The aim of this paper is to summarize our results which were achieved during exploration and measurement of the co-existences between still used and upcoming mobile networks (from GSM to LTE) and digital terrestrial television broadcasting (DVB) systems. For all of these measurements and their evaluation universal measurement testbed has been proposed and used. Results presented in this paper are a significant part of our activities in work package WP5 in the ENIAC JU project âAgile RF Transceivers and Front-Ends for Future Smart Multi-Standard Communications Applications (ARTEMOS)â
Analysis and Simulation of the Signals Transmission in the DVB-H/SH Standards
Tato disertaÄnĂ prĂĄce se zabĂœvĂĄ analĂœzou, simulacĂ a mÄĆenĂm zpracovĂĄnĂ a pĆenosu signĂĄlĆŻ digitĂĄlnĂ televize pro pĆĂjem mobilnĂho TV vysĂlĂĄnĂ ve standardech DVB-H a DVB-SH. Tyto standardy vychĂĄzejĂ z pĆedpokladu, ĆŸe pĆĂjem signĂĄlu je charakterizovĂĄn modely pĆenosovĂœch kanĂĄlĆŻ s vĂcecestnĂœm ĆĄĂĆenĂm. Tyto, tzv. ĂșnikovĂ© kanĂĄly, jsou charakterizovĂĄny hlavnÄ zpoĆŸdÄnĂm a ziskem jednotlivĂœch cest. V zĂĄvislosti na dalĆĄĂch parametrech (rychlost pĆijĂmaÄe, DopplerovskĂ© spektrum), je moĆŸnĂ© rozdÄlit ĂșnikovĂ© kanĂĄly do tĆech hlavnĂch skupin: mobilnĂ, pĆenosnĂ© a fixnĂ. DĂĄ se pĆedpoklĂĄdat, ĆŸe v rĆŻznĂœch modelech kanĂĄlĆŻ bude pĆenĂĄĆĄenĂœ signĂĄl rĆŻznÄ ovlivnÄn. Proto je potĆebnĂ© najĂt optimĂĄlnĂ parametry systĂ©mĆŻ (DVB-H/SH) pro kvalitnĂ pĆĂjem vysĂlanĂœch sluĆŸeb mobilnĂ televize, coĆŸ je hlavnĂm cĂlem tĂ©to disertaÄnĂ prĂĄci. Pro tento ĂșÄel byly vytvoĆeny dvÄ vhodnĂ© aplikace (jedna pro DVB-H a jedna pro DVB-SH) s GUI v prostĆedĂ MATLAB, kterĂ© umoĆŸĆujĂ simulovat a analyzovat mĂru zkreslenĂ signĂĄlu v pĆĂpadÄ mobilnĂch, pĆenosnĂœch a fixnĂch scĂ©nĂĄĆĆŻ pĆenosu. NavĂc, tyto aplikace obsahujĂ i druhĂœ samostatnĂœ simulĂĄtor pro nastavenĂ a modifikaci parametrĆŻ jednotlivĂœch pĆenosovĂœch cest. DĂky tomu je moĆŸnĂ© zhodnotit vliv parametrĆŻ celĂ©ho systĂ©mu a kanĂĄlovĂœch modelĆŻ na dosaĆŸenou chybovost (BER a MER) a kvalitu pĆenosu. Ve vĆĄech pĆenosovĂœch scĂ©nĂĄĆĂch (v zĂĄvislosti na pomÄru C/N) byly zĂskanĂ©, vyhodnocenĂ© a diskutovanĂ© zkreslenĂ signĂĄlĆŻ. NavĂc, u standardu DVB-H, vĆĄechny zĂskanĂ© vĂœsledky ze simulacĂ byly ovÄĆeny mÄĆenĂm. RozdĂly mezi dosaĆŸenĂœmi vĂœsledky (simulace a mÄĆenĂ) byly rovnÄĆŸ podrobeny diskuzi. Tuto disertaÄnĂ prĂĄci je moĆŸnĂ© rozdÄlit do ÄtyĆ hlavnĂch ÄĂĄstĂ. PrvnĂ ÄĂĄst disertaÄnĂ prĂĄce se zabĂœvĂĄ reĆĄerĆĄĂ souÄasnĂ©ho vĂœvoje v oblasti digitĂĄlnĂho televiznĂho vysĂlĂĄnĂ na mobilnĂ terminĂĄly ve standardech DVB-H/SH. Na konci tĂ©to ÄĂĄsti jsou jasnÄ popsĂĄny cĂle tĂ©to disertaÄnĂ prĂĄce. DruhĂĄ ÄĂĄst prĂĄce je zamÄĆenĂĄ na struÄnĂœ popis blokovĂ©ho diagramu vysĂlaÄĆŻ v obou standardech DVB-H/SH. DĂĄle jsou struÄnÄ popsĂĄny modely pĆenosovĂœch kanĂĄlĆŻ, kterĂ© se pouĆŸĂvajĂ pro modelovĂĄnĂ pĆenosu signĂĄlu. StruÄnĂœ popis vytvoĆenĂœch aplikacĂ, i s vĂœvojovĂœm diagramem, kterĂ© jsou vhodnĂ© pro simulaci a analĂœzu pĆenosu v DVB-H/SH, jsou popsĂĄny v tĆetĂ ÄĂĄsti prĂĄce. ÄtvrtĂĄ a nejdelĆĄĂ ÄĂĄst tĂ©to disertaÄnĂ prĂĄce se zabĂœvĂĄ vyhodnocenĂm zĂskanĂœch vĂœsledkĆŻ ze simulacĂ a mÄĆenĂ.This dissertation thesis deals with the analysis, simulation and measurement of the signal processing and transmission in DVB-H and DVB-SH standards. These standards are based on the assumption that signal reception is characterized by the transmission channels with echoes. These, so called fading channels, are mainly characterized by the path delays and path losses. Depending on the other, additional features (speed of the receiver, Doppler spectrum, etc.), it can be possible divided these channels onto three main groups: mobile, portable and fixed. Of course, signal transmission in different transmission channel models are affected differently. Therefore, it is needed found the optimal system parameters in both, DVB-H and DVB-SH standards, for the quality reception of the broadcasted mobile TV services, which is the main goal of this thesis. For this purpose, two appropriate applications (one for DVB-H and one for DVB-SH) with GUI were created in MATLAB, which enable simulated and analyzed the signal distortions in mobile, portable and fixed transmission scenarios. Moreover, these applications also contain a second application with GUI for the easy set and modification of the parameters of the used channel models. Therefore, it is possible to evaluate the effect of parameters of whole system and channel models on the achieved error rate (BER and MER) and quality of the transmission. In all mentioned transmission scenarios, the signal distortions (depending on the Carrier-to-Noise ratio) were obtained, evaluated and discussed in this dissertation thesis. Furthermore, in case of DVB-H, all obtained results from the simulations, were verified by the measuring. Differences between the obtained results (simulation and measuring) are also discussed. This dissertation thesis can be divided into four main parts. The first part of this dissertation thesis, after the short introduction, deals with present state-of-the-art and literature survey in mobile broadcast DVB-H/SH standards. At the end of this part are clearly outlined the main aims of this dissertation thesis. Second part is focused on the brief description of the functional block diagram of transmitters in both, DVB-H/SH standards. Furthermore, there are briefly described the transmission fading channel models, which are commonly used for the modeling of the signal transmission. The brief description of program applications with flowcharts, appropriate for the simulation of the transmission in the DVB-H/SH standards, are presented and described in the third part of this thesis. Finally, the fourth and longest part of this thesis is focused on the evaluation and comparison of obtained results from the simulations and measurements.
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
Analysis of DVB-H network coverage with the application of transmit diversity
This paper investigates the effects of the Cyclic Delay Diversity (CDD) transmit diversity scheme on DVB-H networks. Transmit diversity improves reception and Quality of Service (QoS) in areas of poor coverage such as sparsely populated or obscured locations. The technique not only povides robust reception in mobile environments thus improving QoS, but it also reduces network costs in terms of the transmit power, number of
infrastructure elements, antenna height and the frequency reuse factor over indoor and outdoor environments. In this paper, the benefit and effectiveness of CDD transmit diversity is tackled
through simulation results for comparison in several scenarios of coverage in DVB-H networks. The channel model used in the simulations is based on COST207 and a basic radio planning
technique is used to illustrate the main principles developed in this paper. The work reported in this paper was supported by
the European Commission IST projectâPLUTO (Physical Layer DVB Transmission Optimization)
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A survey of handover algorithms in DVB-H
Digital Video Broadcasting for Handhelds (DVB-H) is a standard for
broadcasting IP Datacast (IPDC) services to mobile handheld terminals.
Based on the DVB-T standard, DVB-H adds new features such as time
slicing, MPE-FEC, in-depth interleavers, mandatory cell id identifier,
optional 4K-modulation mode and the use of 5 MHz bandwidth in addition
to the usually used 6, 7, or 8 MHz raster. IPDC over DVB-H is proposed
for ETSI to complement the DVB-H standard by combining IPDC and
DVB-H in an end-to-end system. Handover in such unidirectional broadcasting
networks is a novel issue. In the last few years since the birth of
DVB-H technology, great attention has been given to the performance
analysis of DVB-H mobile terminals. Handover is one of the main research
topics for DVB-H in mobile scenarios. Better reception quality and greater
power efficiency are considered to be the main targets of handover
research for DVB-H. New algorithms for different handover stages in
DVB-H have been the subject of recent research and are currently being
studied. Further novel algorithms need to be designed to improve the
mobile reception quality. This article provides a comprehensive survey of
the handover algorithms in DVB-H. A systematic evaluation and categorization
approach is proposed based on the problems the algorithms solve
and the handover stages being focused on. Criteria are proposed and analyzed
to facilitate designing better handover algorithms for DVB-H that
have been identified from the research conducted by the author
Diversity gain for DVB-H by using transmitter/receiver cyclic delay diversity
The objective of this paper is to investigate different diversity techniques for broadcast networks that will minimize the complexity and improve received SNR of broadcast systems.
Resultant digital broadcast networks would require fewer transmitter sites and thus be more cost-effective and have less environmental impact. The techniques can be applied to DVB-T,
DVB-H and DAB systems that use Orthogonal Frequency Division Multplexing (OFDM). These are key radio broadcast network technologies, which are expected to complement emerging technologies
such as WiMAX and future 4G networks for delivery
of broadband content. Transmitter and receiver diversity technologies can increase the frequency and time selectivity of the resulting channel transfer function at the receiver. Diversity exploits the statistical nature of fading due to multipath and reduces the likelihood of deep fading by providing a diversity of transmission signals. Multiple signals are transmitted in such
a way as to ensure that several signals reach the receiver each with uncorrelated fading. Transmit diversity is more practical than receive diversity due to the difficulty of locating two receive antennas far enough apart in a small mobile device. The schemes examined here comply with existing DVB standards and can be incorporated into existing systems without change. The diversity techniques introduced in this paper are applied to the DVB-H system. Bit error performance investigations were conducted by
simulation for different DVB-H and diversity parameters
Performance of an Echo Canceller and Channel Estimator for On-Channel Repeaters in DVB-T/H Networks
This paper investigates the design and performance of an FIR echo canceller for on-channel repeaters in DVB-T/H network within the framework of the PLUTO project. The possible
approaches for echo cancellation are briefly reviewed and the main guidelines for the design of such systems are presented. The main system parameters are discussed. The performance of an FIR echo canceller based on an open loop feedforward approach for channel estimation is tested for different radio channel conditions and for different number of taps of the FIR filter. It is shown that a minimum number of taps is recommended to achieve a certain mean rejection ratio or isolation depending on the type of channel. The expected degradation in performance due to the use of fixed point rather than floating point arithmetic in hardware implementation is presented for different number of bits. Channel estimation based on training sequences is investigated. The performance of Maximum Length Sequences and Constant Amplitude Zero Autocorrelation (CAZAC) Sequences is compared for different channels. Recommendations are given for training sequence type, length and
level for DVB-T/H on-channel repeater deployment
Design and Validation of a Software Defined Radio Testbed for DVB-T Transmission
This paper describes the design and validation of a Software Defined Radio (SDR) testbed, which can be used for Digital Television transmission using the Digital Video Broadcasting - Terrestrial (DVB-T) standard. In order to generate a DVB-T-compliant signal with low computational complexity, we design an SDR architecture that uses the C/C++ language and exploits multithreading and vectorized instructions. Then, we transmit the generated DVB-T signal in real time, using a common PC equipped with multicore central processing units (CPUs) and a commercially available SDR modem board. The proposed SDR architecture has been validated using fixed TV sets, and portable receivers. Our results show that the proposed SDR architecture for DVB-T transmission is a low-cost low-complexity solution that, in the worst case, only requires less than 22% of CPU load and less than 170 MB of memory usage, on a 3.0 GHz Core i7 processor. In addition, using the same SDR modem board, we design an off-line software receiver that also performs time synchronization and carrier frequency offset estimation and compensation
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