Prediction of performance of the DVB-SH system relying on mutual information

DVB-SH (Digital Video Broadcasting-Satellite Handled) is a broadcasting standard dedicated to hybrid broadcasting systems combining a satellite and a terrestrial part. On the satellite part, dedicated interleaving and time slicing mechanisms are proposed to mitigate the effects of Land Mobile Satellite (LMS) channel, based on a convolutional interleaver. Depending on the parameters of this interleaver, this mechanism enables to split in time a codeword on duration from 100 ms to about 30s. This mechanism signi?cantly improves the error recovery performance of the code but in literature, exact evaluation at system level of this improvement is missing. The objective of this paper is to propose a prediction method compatible with fast simulations, to quantitatively evaluate the system performance in terms of Packet Error Rate (PER). The main dif?culty is to evaluate the decoding probability of a codeword submitted to several levels of attenuation. The method we propose consists in using as metric the Mutual Information (MI) between coded bit at the emitter side and the received symbol. It is shown that, by averaging the MI over the codeword and by using the decoding performance function g such that PER=g(MI)determined on the Gaussian channel, we can signi?cantly improve the precision of the prediction compared to the two other methods based on SNR and Bit Error Rate (BER). We evaluated these methods on three arti?cial channels where each codeword is transmitted with three or four different levels of attenuations. The prediction error of the SNR-based (resp. the input BER-based) method varies from 0.5 to 1.7 dB (resp. from 0.7 to 1.2 dB) instead of the MI-based method achieves a precision in the order of 0.1 dB in the three cases. We then evaluate this method on real LMS channels with various DVB-SH interleavers and show that the instantaneous PER can also be predicted with high accuracy

Generic Approach for Hierarchical Modulation Performance Analysis: Application to DVB-SH

Broadcasting systems have to deal with channel diversity in order to offer the best rate to the users. Hierarchical modulation is a practical solution to provide several rates in function of the channel quality. Unfortunately the performance evaluation of such modulations requires time consuming simulations. We propose in this paper a novel approach based on the channel capacity to avoid these simulations. The method allows to study the performance in terms of spectrum efficiency of hierarchical and also classical modulations combined with error correcting codes. Our method will be applied to the DVB-SH standard which considers hierarchical modulation as an optional feature.Comment: To appear in WTS 2011 proceeding

Evaluation of cross-layer reliability mechanisms for satellite digital multimedia broadcast

This paper presents a study of some reliability mechanisms which may be put at work in the context of Satellite Digital Multimedia Broadcasting (SDMB) to mobile devices such as handheld phones. These mechanisms include error correcting codes, interleaving at the physical layer, erasure codes at intermediate layers and error concealment on the video decoder. The evaluation is made on a realistic satellite channel and takes into account practical constraints such as the maximum zapping time and the user mobility at several speeds. The evaluation is done by simulating different scenarii with complete protocol stacks. The simulations indicate that, under the assumptions taken here, the scenario using highly compressed video protected by erasure codes at intermediate layers seems to be the best solution on this kind of channel

Trade-off between spectrum efficiency and link unavailability for hierarchical modulation in DVB-S2 systems

Broadcasting systems have to deal with channel variability in order to offer the best spectrum efficiency to the receivers. However, the transmission parameters that optimize the spectrum efficiency generally leads to a large link unavailability. In this paper, we study the performance of hierarchical and nonhierarchical modulations in terms of spectrum efficiency and link unavailability for DVB-S2 systems. Our first contribution is the design of the hierarchical 16-APSK for the DVB-S2 standard. Then we introduce the link unavailability to compare the performance of hierarchical and non-hierarchical modulations in terms of spectrum efficiency and link unavailability. The results show that hierarchical modulation is a good alternative to nonhierarchical modulation for the DVB-S2 standard

Making hierarchical modulation more flexible

In a broadcast system using the hierarchical modulation, the system delivers several streams with different waveforms and required Signal-to-Noise Ratio (SNR), typically SD- TV and HD-TV. At the application layer, each stream is delivered with a particular rate. The physical layer must be defined in order to optimize the protection of each stream with respect to the double constraints of both the data rates and the SNR thresholds. We show in this paper that a standard like DVB-SH is not always well adapted to meet these system constraints in operational typical cases. After exposing the current limitations of a classical hierarchical modulation approach, we present two possible adaptations to address these operational requirements and offer more flexibility in hierarchical modulation design

The BLLAST field experiment: Boundary-Layer late afternoon and sunset turbulence

Due to the major role of the sun in heating the earth's surface, the atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The afternoon transition, the period of the day that connects the daytime dry convective boundary layer to the night-time stable boundary layer, still has a number of unanswered scientific questions. This phase of the diurnal cycle is challenging from both modelling and observational perspectives: it is transitory, most of the forcings are small or null and the turbulence regime changes from fully convective, close to homogeneous and isotropic, toward a more heterogeneous and intermittent state. These issues motivated the BLLAST (Boundary-Layer Late Afternoon and Sunset Turbulence) field campaign that was conducted from 14 June to 8 July 2011 in southern France, in an area of complex and heterogeneous terrain. A wide range of instrumented platforms including full-size aircraft, remotely piloted aircraft systems, remote-sensing instruments, radiosoundings, tethered balloons, surface flux stations and various meteorological towers were deployed over different surface types. The boundary layer, from the earth's surface to the free troposphere, was probed during the entire day, with a focus and intense observation periods that were conducted from midday until sunset. The BLLAST field campaign also provided an opportunity to test innovative measurement systems, such as new miniaturized sensors, and a new technique for frequent radiosoundings of the low troposphere. Twelve fair weather days displaying various meteorological conditions were extensively documented during the field experiment. The boundary-layer growth varied from one day to another depending on many contributions including stability, advection, subsidence, the state of the previous day's residual layer, as well as local, meso- or synoptic scale conditions. Ground-based measurements combined with tethered-balloon and airborne observations captured the turbulence decay from the surface throughout the whole boundary layer and documented the evolution of the turbulence characteristic length scales during the transition period. Closely integrated with the field experiment, numerical studies are now underway with a complete hierarchy of models to support the data interpretation and improve the model representations.publishedVersio

Procédé de réception et récepteur pour transmission numérique série codée sur un canal non stationnaire

L'invention concerne un procédé de réception de données sur un canal série bruité à atténuation non stationnaire dans lequel au moins une valeur représentative d'un taux d'erreurs ER du flux reçu de bits est élaborée sans réalisation du décodage. Une valeur d'information mutuelle I est élaborée (34) selon une fonction prédéterminée de la qualité de transmission Q , et une moyenne d'information mutuelle est élaborée (35) sur chaque mot codé reçu, puis au moins une valeur du taux d'erreurs ER du flux reçu de bits est élaborée (38) à partir de chaque valeur de la moyenne d'information mutuelle par utilisation d'une fonction standard prédéterminée sur un canal à bruit blanc gaussien additif

Procédé et dispositif d'évaluation d'une transmission numérique série codée sur un canal non stationnaire

L'invention concerne un procédé d'évaluation des performances d'une transmission numérique série codée et modulée sur un canal série bruité à atténuation non stationnaire dans lequel au moins une valeur représentative d'un taux d'erreurs ER du flux reçu de bits est élaborée sans réalisation du décodage. Une valeur d'information mutuelle I est élaborée (34) selon une fonction prédéterminée de la qualité de transmission Q , et une moyenne d'information mutuelle est élaborée (35) sur chaque mot codé reçu, puis au moins une valeur du taux d'erreurs ER du flux reçu de bits est élaborée (38) à partir de chaque valeur de la moyenne d'information mutuelle par utilisation d'une fonction standard prédéterminée sur un canal à bruit blanc gaussien additif. Elle s'étend à un dispositif, un produit logiciel, et un support d'enregistrement pour la mise en œuvre de ce procédé

Trade-off between spectrum efficiency and link unavailability for hierarchical modulation in DVB-S2 systems

International audienceBroadcasting systems have to deal with channel variability in order to offer the best spectrum efficiency to the receivers. However, the transmission parameters that optimize the spectrum efficiency generally leads to a large link unavailability. In this paper, we study the performance of hierarchical and nonhierarchical modulations in terms of spectrum efficiency and link unavailability for DVB-S2 systems. Our first contribution is the design of the hierarchical 16-APSK for the DVB-S2 standard. Then we introduce the link unavailability to compare the performance of hierarchical and non-hierarchical modulations in terms of spectrum efficiency and link unavailability. The results show that hierarchical modulation is a good alternative to nonhierarchical modulation for the DVB-S2 standard