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Time filter

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Östermalm, Sweden

Lopez-Sanchez J.,Polytechnic University of Valencia | Zollner J.,TU Braunschweig | Atungsiri S.,Sony | Stare E.,Teracom AB | Gomez-Barquero D.,Polytechnic University of Valencia
IEEE Transactions on Broadcasting | Year: 2014

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. © 1963-12012 IEEE.


Makni M.,TU Braunschweig | Robert J.,TU Braunschweig | Stare E.,Teracom AB
2011 14th ITG Conference on Electronic Media Technology, CEMT 2011 - Conference Proceedings | Year: 2011

Time Frequency Slicing (TFS) is described in an informative annex of the DVB-T2 standard. It is able to bundle multiple (non-adjacent) standard RF channels into one big virtual channel that offers increased frequency diversity and robustness. Theoretically TFS requires a single receiver tuner only, because the tuner hops between the different channels. This naturally leads to certain dependencies within the framing structure of DVB-T2, which also influenced the development of the normal non-TFS operation of this standard. Therefore, this paper gives a brief introduction to TFS and its realization within DVB-T2, which has been heavily discussed during the DVB-T2 development. Furthermore, simulation results and theoretical analysis show the potential gains and limits of TFS. © 2011 Informatik Centrum.


Gimenez J.J.,Polytechnic University of Valencia | Stare E.,Teracom AB | Bergsmark S.,Teracom AB | Gomez-Barquero D.,Polytechnic University of Valencia
IEEE Transactions on Broadcasting | Year: 2014

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. © 1963-12012 IEEE.


Gimenez J.J.,Polytechnic University of Valencia | Stare E.,Teracom AB | Bergsmark S.,Teracom AB | Gomez-Barquero D.,Polytechnic University of Valencia
IEEE Transactions on Broadcasting | Year: 2015

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). © 1963-12012 IEEE.

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