Bandwidth Optimization for Satellite Digital Broadcasting

Abstract

The 2 nd -generation satellite digital video broadcasting (DVB-S2) system is at present under review with the aim of improving its spectral efficiency. In this paper, we have addressed the problem to optimize the user bandwidth taking into account a realistic satellite broadcasting channel. Two different receiver architectures have been evaluated in order to maximize the system spectral efficiency. Finally, some considerations on the OMUX dissipated power have been reported. Nomenclature α = Shaping pulse roll-off AWGN = Additive white Gaussian noise f T = Transponder bandwidth (or frequency spacing among adjacent channels) FTN = Faster-than-Nyquist ICI = Inter-channel interference IMUX = Input multiplexer ISI = Inter-symbol interference LMS = Least mean square MMSE = Minimum mean square error N u = Number of transmitting users OMUX = Output multiplexer SE = Spectral efficiency P sat = On-board saturation power R s = Symbol rate T s = Symbol interval TF = Time-frequency 1 Communication System Engineer, TEC-ETC, stefano.cioni@esa.int . 2 Microwave Engineer, TIA-TTP, christoph.ernst@esa.int . 3 Head of Communications and TT&C Section, TEC-ETC, alberto.ginesi@esa.int . 4 Associate Professor, SPADiCLab, giulio@unipr.it . Downloaded by CARLETON UNIVERSITY LIBRARY on July 30, 2015 | http://arc.aiaa.org |

DVB‐S2X physical layer performance results over realistic channel models

“…Again, it is confirmed that α = 20% has some advantages up to R s = 34 Mbaud, and this robustness is vanishing when the symbol rate is further increased. Following a similar analysis presented in [6] and motivated by this C/I analysis as a function of the symbol rate, the next set of results reports the comparison among different roll-off choices, when the transmission symbol rate is pushed to higher values. In particular, Figure 8 highlights the achievable spectral efficiency assuming the transmission symbol rate equal to 36 Mbaud.…”

“…This relatively high value of α eases the implementation of shaping filters and symbol-timing recovery algorithms, while the symbol rate has been chosen to ensure low interference into adjacent transponders and to guarantee a relatively low-power dissipation by the transponder filters [6]. In addition, typical legacy DVB-S2 receivers use symbol-by-symbol detection techniques followed by the decoding stage.…”

“…However, thanks to the advances in VLSI technology, today, lower roll-off values and more advanced detection algorithms can be easily implemented in the new DVB-S2X modems. In [6] and [7], the authors provided some guidelines to design more sophisticated receiver architectures to improve the system spectral efficiency along with better resilience against linear and nonlinear distortions. In particular, Cioni et al [6] recommend the adoption of a fractionally spaced equalizer [8] to better handle the increased distortions and interference arising when operating with high symbol rate values (e.g., greater than 31 Mbaud).…”

“…The selected methodology for the evaluation of the achievable enhancements has involved the optimization of the transmission symbol rate given the satellite system constraints related to the available signal bandwidth, W, and the roll-off factor, α, of the pulse-shaping filter [6,7]. Therefore, this paper presents the DVB-S2X performance in terms of spectral efficiency that can be obtained by fixing a reference satellite bandwidth, W ref , and then by optimizing the transmission data rate in combination with the roll-off factor.…”

“…In particular, Cioni et al [6] recommend the adoption of a fractionally spaced equalizer [8] to better handle the increased distortions and interference arising when operating with high symbol rate values (e.g., greater than 31 Mbaud). For clarity, today, legacy DVB-S2 receivers are not able to efficiently demodulate carrier symbol rate higher than 31 Mbaud (as reported in [6]); therefore, this work adopts the same receiver architecture discussed in Section 3, regardless of the transmitting waveform (DVB-S2 or DVB-S2X), in order to fairly compare pros and cons of the low roll-off values.…”