Analysis and Performance Comparison of DVB-T and DTMB Systems for Terrestrial Digital TV

Orthogonal frequency-division multiplexing (OFDM) is the most popular transmission technology in digital terrestrial broadcasting (DTTB), adopted by many DTTB standards. In this paper, the bit error rate (BER) performance of two DTTB systems, namely cyclic prefix OFDM (CP-OFDM) based DVB-T and time domain synchronous OFDM (TDS-OFDM) based DTMB, is evaluated in different channel conditions. Spectrum utilization and power efficiency are also discussed to demonstrate the transmission overhead of both systems. Simulation results show that the performances of the two systems are much close. Given the same ratio of guard interval (GI), the DVB-T outperforms DTMB in terms of signal to noise ratio (SNR) in Gaussian and Ricean channels, while DTMB behaves better performance in Rayleigh channel in higher code rates and higher orders of constellation thanks to its efficient channel coding and interleaving scheme

Efficient MIMO-OFDM Schemes for Future Terrestrial Digital TV with Unequal Received Powers

International audienceThis article investigates the effect of equal and unequal received powers on the performances of different MIMO-OFDM schemes for terrestrial digital TV. More precisely, we focus on three types of non-orthogonal schemes: the BLAST scheme, the Linear Dispersion (LD) code and the Golden code, and we compare their performances to that of Alamouti scheme. Using two receiving antennas, we show that for moderate attenuation on the second antenna and high spectral efficiency, Golden code outperforms other schemes. However, Alamouti scheme presents the best performance for low spectral efficiency and equal received powers or when one antenna is dramatically damaged. When three antennas are used, we show that Golden code offers the highest robustness to power unbalance at the receiving sid

Efficient 3D Space Time Space Block Code for Future Terrestrial Digital TV

International audienceThis article introduces a 3D space-time-space block code for future terrestrial digital TV in single frequency networks. The proposed 3D code is based on a double layer structure designed for inter-cell and intra-cell space time coded transmissions. We show that this new structure is particularly efficient for SFN environments regardless of the location of the receiver. It is then suitable for fixed, portable and mobile receptions

2D Linear Precoded OFDM for future mobile Digital Video Broadcasting

International audienceIn this paper, we propose a novel channel estimation technique based on 2D spread pilots. The merits of this technique are its simplicity, its flexibility regarding the transmission scenarios, and the spectral efficiency gain obtained compared to the classical pilot based estimation schemes used in DVB standards. We derive the analytical expression of the mean square error of the estimator and show it is a function of the autocorrelation of the channel in both time and frequency domains. The performance evaluated over a realistic channel model shows the efficiency of this technique which turns out to be a promising channel estimation for the future mobile video broadcasting systems

A novel channel estimation based on spread pilots for terrestrial digital video broadcasting

International audienceIn this paper, we propose a novel channel estimation technique based on spread pilots for digital video broadcasting. This technique consists in adding a linear preceding function before the OFDM modulation and dedicating one of the preceding sequence to transmit the pilot symbols for the channel estimation. The merits of this technique are its simplicity, its flexibility, and the gains in terms of spectral efficiency and useful bit rate obtained compared to the classical pilot based estimation schemes used in DVB standards. The performance evaluated over realistic channel models, shows the efficiency of this technique which turns out to be a promising channel estimation technique for the future terrestrial video broadcasting systems

Stirring and mixing : 1999 Program of Summer Study in Geophysical Fluid Dynamics

The central theme of the 1999 GFD Program was the stirring, transport, reaction and mixing of passive and active tracers in turbulent, stratified, rotating fluids. The problem of mixing in fluids has applications in areas ranging from oceanography to engineering and astrophysics. In geophysical settings, mixing spans and unites a broad range of scales -- from micrometers to megameters. The mixing of passive tracers is of fundamental importance in environmental and industrial problems, such as pollution, and in determining the large-scale heat and salt balance of the worlds oceans. The transport of active tracers, on the other hand, such as vorticity, plays a key role in the turbulence that occurs in most geophysical and astrophysical fluids. William R. Young (Scripps Institution of Oceanography) gave a series of principal lectures, the notes of which as taken by the fellows, appear in this volume. Report of the projects of the student fellows makes up the second half of this volume.Funding was provided by the National Science Foundation under Grant No. OCE-9810647 and the Office of Naval Research under Grant No. NOO0l4-97-1-0934