. Dans-le-cas-du-codage-convolutif, nous avons d'abord introduit les différents algorithmes, sans et avec recombinaison, avec décodage Viterbi ou MAP. Nous avons ensuite par simulation évalué les performances des différents algorithmes en terme de BER et mis en évidence l'influence de la configuration de puissance sur leur comportement. Nous avons enfin montré que dans le cas sans recombinaison la ré-estimation de canal permet d

. Dans-le-cas-du-turbocodage, nous nous sommes intéressés à l'éventuelle présence d'un plancher d'erreur sur les résultats en terme de PER. Sur les résultats obtenus, il ne semble pas y avoir de plancher évident jusqu'à des PER de 10 -4

. Dans-le-chapitre-suivant, nous nous intéressons à l'extension des algorithmes considérés au cas du canal asynchrone, puis du canal asynchrone avec écarts de fréquence

J. Millerioux, M. Boucheret, C. Bazile, and A. , Ducasse, « Iterative joint detection with channel estimation for multibeam satellite systems, AIAA International Communications Satellite Systems Conference (ICSSC), 2005.

J. Millerioux, M. Boucheret, C. Bazile, and A. , Ducasse, « Iterative multiuser detection and channel estimation for multibeam satellite communication systems, th IEEE International Workshop on Signal Processing Advances for Wireless Communications (SPAWC), 2006.

J. Millerioux, M. Boucheret, C. Bazile, and A. , Ducasse, « Iterative multiuser detection performance evaluation on a satellite multibeam coverage, 14 th European Signal Processing Conference (EUSIPCO), 2006.

J. Millerioux, M. Boucheret, C. Bazile, and A. , Ducasse, « Iterative multiuser detection in multibeam satellite communication systems: channel estimation issues, th International Workshop on Signal Processing for Space Communications (SPSC), 2006.

J. Millerioux, M. Boucheret, C. Bazile, and A. , Ducasse, « Iterative frequency and channel estimation coupled with multiuser detection in multibeam satellite communications, 49 th IEEE Global Telecommunications Conference (GLOBECOM), 2006.

. Dvb-rcs, Digital Video Broadcasting (DVB): Interaction channel for satellite distribution systems, ETSI EN 301 790, pp.1-2, 2000.

. Dvb-rcs, Digital Video Broadcasting (DVB): Interaction channel for satellite distribution systems, Guidelines for the use of, 2001.

&. Gayrard, ]. J. Blanc, F. Gayrard, and . Blanc, Ka-band Satellite System for Public Protection and Disaster Relief Operations, 22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 (ICSSC), 2004.
DOI : 10.2514/6.2004-3222

. Kreuer, A prototype adaptive fade countermeasure system for TDMA operation at Ka band, 5th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Wireless Networks, Catching the Mobile Future., 1994.
DOI : 10.1109/WNCMF.1994.529444

. Lutz, Satellite systems for personal and broadband communications, 2000.
DOI : 10.1007/978-3-642-59727-5

. Pech, Fabre, « A Ka-band OBP satellite system simulation platform involving Fade Mitigation Techniques with channel attenuation timeseries and static radar images of rain cell evolution, Proceedings of AIAA International Communication Satellite Systems Conference, 2003.

A. Alrustamani, Turbo greedy multiuser detection, Turbo Greedy Mutliuser Detection, pp.1638-1645, 2001.
DOI : 10.1109/49.942524

. Bahl, Optimal decoding of linear codes for minimizing symbol error rate (Corresp.), IEEE Transactions on Information Theory, vol.20, issue.2, pp.284-287, 1974.
DOI : 10.1109/TIT.1974.1055186

. Beidas, Iterative interference cancellation for high spectral efficiency satellite communications, Iterative interference cancellation for High Spectral Efficiency Satellite Communications, pp.31-36, 2002.
DOI : 10.1109/26.975741

&. Bohlin and . Lundberg, Lundberg, « A blind and robust space-time receiver for a turbo coded system, Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers, pp.532-536, 2000.

&. Boutros, ]. J. Caire, G. Boutros, and . Caire, Iterative multiuser joint decoding: unified framework and asymptotic analysis, IEEE Transactions on Information Theory, vol.48, issue.7, pp.1772-1793, 2002.
DOI : 10.1109/TIT.2002.1013125

. Brannstrom, Iterative detectors for trellis-code multiple-access, IEEE Transactions on Communications, vol.50, issue.9, pp.1478-1481, 2002.
DOI : 10.1109/TCOMM.2002.802563
URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.10.7242

&. Buehrer, ]. R. Nicoloso, S. P. Buehrer, and . Nicoloso, Comments on "Partial parallel interference cancellation for CDMA", IEEE Transactions on Communications, vol.47, issue.5, pp.658-661, 1999.
DOI : 10.1109/26.768754

. Bugallo, A maximum likelihood approach to blind multiuser interference cancellation, IEEE Transactions on Signal Processing, vol.49, issue.6, pp.1228-1239, 2001.
DOI : 10.1109/78.923305

. Caire, A multiuser approach to narrowband cellular communications, Multiuser Approach to Narrowband Cellular Communications, pp.1503-1517, 1997.
DOI : 10.1109/18.623148

]. N. Courville, « Détection multi-utilisateurs pour le système Argos, 2000.

&. Damnjanovic, ]. A. Vojcic, and B. R. Damnjanovic, Iterative multiuser detection/decoding for turbo coded CDMA systems, IEEE Communications Letters, vol.5, issue.3, pp.104-106, 2001.
DOI : 10.1109/4234.913154

&. Gershman, ]. A. Shahbazpanahi, S. Gershman, and . Shahbazpanahi, Robust blind multiuser detection for synchronous CDMA systems, 2003 IEEE International Conference on Acoustics, Speech, and Signal Processing, 2003. Proceedings. (ICASSP '03)., pp.53-56, 2003.
DOI : 10.1109/ICASSP.2003.1202539

]. L. Godara, Application of antenna arrays to mobile communications. II. Beam-forming and direction-of-arrival considerations, Proceedings of the IEEE, pp.1195-1245, 1997.
DOI : 10.1109/5.622504

. Hagenauer, Iterative decoding of binary block and convolutional codes, IEEE Transactions on Information Theory, vol.42, issue.2, pp.429-445, 1996.
DOI : 10.1109/18.485714

]. C. Helstrom, Elements of signal detection and estimation, 1995.

. Honig, Blind adaptive multiuser detection, Blind Adaptative Multiuser Detection, pp.944-960, 1995.
DOI : 10.1109/18.391241

&. Honig, ]. M. Ratasuk, R. Honig, . Ratasuk, and . Large, Large-system performance of iterative multiuser decision-feedback detection, IEEE Transactions on Communications, vol.51, issue.8, pp.1368-1377, 2003.
DOI : 10.1109/TCOMM.2003.815041

]. S. Kay, Modern spectral estimation: theory and application, 1987.

. Kobayashi, Successive interference cancellation with SISO decoding and EM channel estimation, IEEE Journal on Selected Areas in Communications, vol.19, issue.8, pp.1450-1460, 2001.
DOI : 10.1109/49.942508

&. Li, ]. K. Wang, X. Li, and . Wang, « EXIT chart analysis of turbo multiuser detection, IEEE Transactions on Wireless Communications, vol.4, pp.300-311, 2005.

&. Lupas, ]. R. Verdu, &. S. Lupas, and . Verdu, Near-far resistance of multiuser detectors in asynchronous channels, IEEE Transactions on Communications, vol.38, issue.4, pp.496-508, 1990.
DOI : 10.1109/26.52661

&. Madhow, ]. U. Honig, and M. L. Madhow, MMSE interference suppression for direct-sequence spread-spectrum CDMA, IEEE Transactions on Communications, vol.42, issue.12, pp.3178-3188, 1994.
DOI : 10.1109/26.339839

&. Miguez, ]. J. Castedo, L. Miguez, and . Castedo, A linearly constrained constant modulus approach to blind adaptive multiuser interference suppression, IEEE Communications Letters, vol.2, issue.8, pp.217-219, 1998.
DOI : 10.1109/4234.709436

&. Moher, ]. M. Guinand, P. Moher, and . Guinand, An iterative algorithm for asynchronous coded multiuser detection, IEEE Communications Letters, vol.2, issue.8, pp.229-231, 1998.
DOI : 10.1109/4234.709440

. Nasiri-kenari, An efficient soft-in-soft-out multiuser detector for synchronous CDMA with error-control coding, IEEE Transactions on Vehicular Technology, vol.47, issue.3, pp.947-953, 1998.
DOI : 10.1109/25.704848

. Ranheim, Siege, « An iterative receiver algorithm for spacetime encoded signals, Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers, pp.516-520, 2000.

]. M. Reed, C. B. Schlegel, P. D. Alexander, and J. A. , Iterative multiuser detection for CDMA with FEC: near-single-user performance, IEEE Transactions on Communications, vol.46, issue.12, pp.1693-1699, 1998.
DOI : 10.1109/26.737408

&. Reynolds, ]. D. Wang, X. Reynolds, and . Wang, Turbo multiuser detection with unknown interferers, IEEE Transactions on Communications, vol.50, issue.4, pp.616-622, 2002.
DOI : 10.1109/26.996076
URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.319.397

. Robertson, A comparison of optimal and sub-optimal MAP decoding algorithms operating in the log domain, Proceedings IEEE International Conference on Communications ICC '95, pp.1009-1013, 1995.
DOI : 10.1109/ICC.1995.524253

. Romero-garcia, A frequency error resistant blind CDMA detector, A frequency Error Resistant Blind CDMA Detector, pp.1070-1076, 2000.
DOI : 10.1109/26.855511

&. Shalvi, ]. O. Weinstein, E. Shalvi, and . Weinstein, New criteria for blind deconvolution of nonminimum phase systems (channels), IEEE Transactions on Information Theory, vol.36, issue.2, pp.312-321, 1990.
DOI : 10.1109/18.52478

&. Shen, ]. J. Burr, A. G. Shen, and . Burr, « Iterative multi-user-antenna detector for MIMO CDMA employing space-time turbo codes, Proceedings of the Global Telecommunications Conference, pp.419-423, 2002.

&. Singh, R. Milstein-], L. B. Singh, . Milstein, D. Interference-suppression-for et al., Interference suppression for DS/CDMA, IEEE Transactions on Communications, vol.47, issue.3, pp.446-453, 1989.
DOI : 10.1109/26.752825

. Swindleshurst, Analysis of a decision directed beamformer, Analysis of a Decision Directed Beamformer, pp.2920-2927, 1995.
DOI : 10.1109/78.476435

. Tarable, Analysis and design of interleavers for CDMA systems, IEEE Communications Letters, vol.5, issue.10, pp.420-422, 2001.
DOI : 10.1109/4234.957381

. Tarable, Analysis and Design of Interleavers for Iterative Multiuser Receivers in Coded CDMA Systems, IEEE Transactions on Information Theory, vol.51, issue.5, pp.1650-1666, 2005.
DOI : 10.1109/TIT.2005.846848

&. Terry, ]. J. Williams, D. B. Terry, and . Williams, Convergence analysis of finite alphabet beamformers for digital cochannel signals, IEEE Transactions on Communications, vol.51, issue.6, pp.929-939, 2003.
DOI : 10.1109/TCOMM.2003.811407

&. Tracenko, ]. A. Vaidyanathan, and P. P. Tracenko, Vaidyanathan, « Generalized Kurtosis and applications in blind equalization of MIMO channels, Conference on Signals, Systems and Computers proceedings, pp.742-746, 2001.

&. Valenti, ]. M. Woerner, B. D. Valenti, and . Woerner, Distributed multiuser detection for the TDMA cellular uplink, Distributed multiuser detection for the TDMA cellular uplink, pp.1803-1804, 1999.
DOI : 10.1049/el:19991255

&. Valenti, ]. M. Woerner, D. Valenti, and . Woerner, Iterative multiuser detection, macrodiversity combining, and decoding for the TDMA cellular uplink, IEEE Journal on Selected Areas in Communications, vol.19, issue.8, pp.1570-1583, 2001.
DOI : 10.1109/49.942518

&. Varanasi, ]. M. Aazhang, and B. Varanasi, Multistage detection in asynchronous code-division multiple-access communications, IEEE Transactions on Communications, vol.38, issue.4, pp.509-519, 1990.
DOI : 10.1109/26.52662

]. S. Verdu, Multiuser detection, 1998.

&. Wang, ]. X. Poor, and H. Wang, Blind multiuser detection: a subspace approach, IEEE Transactions on Information Theory, vol.44, issue.2, pp.677-690, 1998.
DOI : 10.1109/18.661512

&. Wang, ]. X. Poor, V. Wang, . Poor, and . Iterative, Iterative (turbo) soft interference cancellation and decoding for coded CDMA, IEEE Transactions on Communications, vol.47, issue.7, pp.1046-1061, 1999.
DOI : 10.1109/26.774855

. Wang, Antoniou, « A Constant-Modulus Algorithm for Blind Multiuser Detection in DS-CDMA Systems with Antenna Array, Proceedings of the IEEE Pacific Rim Conference on Communications, Computers and Signal Processing, pp.234-237, 2001.

&. Wang, ]. X. Phan, V. D. Wang, and . Phan, « Turbo multiuser detection for nonlinearly modulated CDMA in unknown channels, Proceedings of the IEEE Sixth International Symposium on Spread Spectrum Techniques and Applications, pp.598-602, 2000.

&. Weber and . Meurer, Meurer, « Iterative Multiuser Detection for TD-CDMA Exploiting Data Estimate Refinement Techniques, Vehicular Technology Conference Proceedings, pp.1642-1646, 2002.
DOI : 10.1109/vetecf.2002.1040494

. Woodward, Minimum mean-squared error multiuser decision-feedback detectors for DS-CDMA, IEEE Transactions on Communications, vol.50, issue.12, pp.2104-2112, 2002.
DOI : 10.1109/TCOMM.2002.806550

&. Wu, ]. K. Wang, C. L. Wu, and . Wang, « An iterative multiuser receiver using partial parallel interference cancellation for turbo-coded DS-CDMA systems, Proceedings of the Global Telecommunications Conference, pp.25-29, 2001.

. Xie, A family of suboptimum detectors for coherent multiuser communications, IEEE Journal on Selected Areas in Communications, vol.8, issue.4, pp.2943-2959, 1990.
DOI : 10.1109/49.54464

. Xu, Blind Multiuser Detection: FromMOE to Subspace Methods, Blind Multiuser Detection: From MOE to Subspace Methods, pp.510-524, 2004.
DOI : 10.1109/TSP.2003.821111

&. Xu, ]. Z. Liu, P. Xu, and . Liu, Blind Multiuser Detection by Kurtosis Maximization/Minimization, IEEE Signal Processing Letters, vol.11, issue.1, pp.1-4, 2004.
DOI : 10.1109/LSP.2003.819342

&. Zha, ]. W. Blostein, S. D. Zha, and . Blostein, « Soft-Decision Multistage Multiuser Interference Cancellation, IEEE Transactions on Vehicular Technology, vol.52, pp.380-389, 2003.

&. Zhang, ]. X. Wei, W. Zhang, and . Wei, Blind adaptive multiuser detection based on Kalman filtering, IEEE Transactions on Signal Processing, vol.50, issue.1, pp.87-95, 2002.
DOI : 10.1109/78.972485

A. Adriaensen, Van Doninck, « MF-TDMA burst demodulator design with pilot symbol assisted frequency estimation, Proceedings of the International Workshop on Signal Processing for Space Communications, 2003.

. Taisant, Performance of low SNR DVB-RCS modem using test frequency algorithm, Proceedings of the International Conference on Acoustics, Speech and Signal processing, 2006.

]. M. Boucheret, « Récepteur numérique pour système à modulations codées en treillis : algorithmes et architecture, 1997.

. Caire, « Perspectives of adopting interference mitigation techniques in the context of broadband multimedia satellite systems, Proceedings of the AIAA International Communications Satellite Systems Conference, 2005.

[. Andrea, The modified Cramer-Rao bound and its application to synchronization problems, IEEE Transactions on Communications, vol.42, issue.2/3/4, pp.1391-1399, 1994.
DOI : 10.1109/TCOMM.1994.580247

]. M. Fitz, Planar filtered techniques for burst mode carrier synchronization, IEEE Global Telecommunications Conference GLOBECOM '91: Countdown to the New Millennium. Conference Record, pp.365-369, 1991.
DOI : 10.1109/GLOCOM.1991.188412

. Giugno, Turbo-Something': Carrier Synchronization, European Signal Processing Conference, 2002.

&. Luise, ]. M. Regiannini, R. Luise, and . Reggiannini, Carrier frequency recovery in all-digital modems for burst-mode transmissions, IEEE Transactions on Communications, vol.43, issue.2/3/4, pp.1169-1178, 1995.
DOI : 10.1109/26.380149

. Lutz, Satellite systems for personal and broadband communications, 2000.
DOI : 10.1007/978-3-642-59727-5

&. Oerder, ]. M. Meyer, H. Oerder, and . Meyr, Digital filter and square timing recovery, Digital filter and square timing recovery, pp.605-612, 1988.
DOI : 10.1109/26.1476

. Raheli, Per-Survivor Processing: a general approach to MLSE in uncertain environments, IEEE Transactions on Communications, vol.43, issue.2/3/4, pp.354-364, 1995.
DOI : 10.1109/26.380054

&. Viterbi, ]. A. Viterbi, A. M. Viterbi, and . Viterbi, « Nonlinear Estimation of PSK-Modulated Carrier Phase with Applications to Burst Digital Transmission, IEEE Transactions on Information Theory, pp.543-551, 1983.

. Hagenauer, Les résultats sont moins bons qu'en prenant les informations extrinsèques au sens symbole d'information [Saouter En effet, les entrelaceurs DVB- RCS permutent les symboles d'information. Lors du décodage itératif, les informations extrinsèques de deux bits d'un même symbole d'information sont corrélées, et les informations a priori correspondantes à l'itération suivante sont donc aussi corrélées, ce qui implique une perte d'indépendance des informations a priori, et donc de moins bonnes performances du décodage itératif. Les performances peuvent cependant être légèrement améliorées en pondérant les rapports de vraisemblance logarithmiques des informations a priori par une constante inférieure à 1 augmentant avec l'itération, 1996.

. En-effet and . Dans-cette-zone, est le processus itératif qui est déterminant : puisqu'on prend des informations extrinsèques au sens bit avec un entrelaceur sur les symboles d'information dans le cas de l'entrelaceur DVB-RCS, on a une perte de performance au niveau du décodage itératif. Ce n'est plus vrai pour les PER plus bas (inférieurs à 10 -3 ) : dans cette zone

A. Bahl, Optimal decoding of linear codes for minimizing symbol error rate (Corresp.), IEEE Transactions on Information Theory, vol.20, issue.2, pp.284-287, 1974.
DOI : 10.1109/TIT.1974.1055186

[. Andrea, The modified Cramer-Rao bound and its application to synchronization problems, IEEE Transactions on Communications, vol.42, issue.2/3/4, pp.1391-1399, 1994.
DOI : 10.1109/TCOMM.1994.580247

. Dvb-rcs, Digital Video Broadcasting (DVB): Interaction channel for satellite distribution systems, ETSI EN 301 790, pp.1-2, 2000.

. Dvb-rcs, Digital Video Broadcasting (DVB): Interaction channel for satellite distribution systems, Guidelines for the use of, 2001.

]. F. Gustafsson, Adaptive filtering and change detection, 2000.
DOI : 10.1002/0470841613

. Hagenauer, Iterative decoding of binary block and convolutional codes, IEEE Transactions on Information Theory, vol.42, issue.2, pp.429-445, 1996.
DOI : 10.1109/18.485714

]. T. Moon, The expectation-maximization algorithm, IEEE Signal Processing Magazine, vol.13, issue.6, pp.47-60, 1996.
DOI : 10.1109/79.543975

&. Pauluzzi, ]. D. Beaulieu, N. C. Pauluzzi, and . Beaulieu, A comparison of SNR estimation techniques for the AWGN channel, IEEE Transactions on Communications, vol.48, issue.10, pp.1681-1691, 2000.
DOI : 10.1109/26.871393

A. , A. De-l-'estimateur, . De, . En, and . Data-aided, La figure suivante propose les résultats d'analyse de l'estimateur de canal (paragraphe 5.4.1) en mode Data-Aided avec réduction de la longueur des fenêtres d'estimation (les erreurs sont mesurées sur les coefficients des signaux interférents, les bornes de Cramer-Rao sont indiquées en pointillé)