Conference Paper

Multiuser detection in the presence of strong phase noise for DVB-RCS systems.

DOI: 10.1109/WCNC.2011.5779352 Conference: 2011 IEEE Wireless Communications and Networking Conference, WCNC 2011, Proceedings, Cancun, Mexico, 28-31 March, 2011
Source: DBLP
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    ABSTRACT: In satellite communications, the space segment is a large slice of the operating costs. Therefore every effort should be made to increase the spectral efficiency, thereby reducing the space segment costs. In order to optimize spectral efficiency, channel spacing (CS) should be reduced. Unfortunately, this introduces spectrally overlapping transmissions, thereby creating adjacent channel interference (ACI), which impairs the performance of satellite communication systems. To overcome this problem, intelligent interference mitigation schemes should be considered. This paper considers the problem of multi-channel synchronization of several spectrally overlapping transmissions in a satellite TDMA/frequency division multiple access burst system. The synchronization aims to estimate carrier frequency, carrier phase and symbol timing in the presence of ACI. The potential performance gain of multi-channel processing over conventional single channel processing is shown. Two types of low-complexity algorithms are proposed: ‘channelized’ expectation maximization and ‘channelized’ interference cancellation. Both of these algorithms attain this performance gain. Computer simulations show a 78% improvement in spectral efficiency for a wide range of carrier-imbalance values. This translates into a large potential saving in space segment costs compared to conventional CS. Copyright © 2006 John Wiley & Sons, Ltd.
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    ABSTRACT: Spectral efficiency is of great concern in the return channel of satellite based broadband systems. In (Beidas, 2002) the feasibility of increased efficiency by reducing channel spacing below the symbol rate was demonstrated using joint detection and decoding for a synchronized system. We extend this work by addressing the critical synchronization problem in the presence of adjacent channel interference (ACI) which limits performance as carrier spacing is reduced. A pilot sequence aided joint synchronization scheme for a multi-frequency time division multiple access (MF-TDMA) system is proposed. Based on a maximum likelihood (ML) criterion, the channel parameters, including frequency, time and phase are jointly estimated for the channel of interest and the adjacent channels. The impact of ACI on the synchronization and detection performance is investigated. It is shown that joint channel parameter estimation outperforms single carrier synchronization with reasonable additional computational complexity in the receiver. Based on the proposed synchronization scheme in conjunction with an appropriate joint detection mechanism, see (Beidas, 2002), carrier spacing can be reduced significantly compared to current systems providing a substantial increase in spectral efficiency.
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    International Journal of Satellite Communications and Networking 05/2004; 22(3):281 - 318. DOI:10.1002/sat.791
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