The application of linear precoding at the gateway side enables broadband multibeam satellite systems to use more aggressive frequency reuse patterns increasing the overall capacity of future High Throughput Satellites (HTS). However, although some previous works about precoding consider imperfect CSIT (Chanel State Information at the Transmitter) adding some CSI estimation errors, that is not the main cause of CSI degradation. In practice, receivers can only detect and estimate a few coefficients of the CSI vector being the other nullified, replaced by zeros. This introduces errors in the SINR calculation by the gateway that lead to the assignment of Modulation and Coding Schemes (MCS) over the decoding possibilities of the users, increasing the rate of erroneous frames. In this work, the errors in the SINR calculation caused by the nullification of the CSI are analyzing statistically and geographically using a radiation diagram of 245 beams over Europe. Furthermore, a solution based on a link adaptation algorithm with a per user adaptive margin is proposed, helping to achieve the QEF (Quasi-error Free) target of DVB-S2X systems.

Rain attenuation is among the major impairments for satellite systems operating in the K band and above. In this paper, we investigate the impact of spatially correlated rain attenuation on the performance of a multibeam satellite return link. For a comprehensive assessment, an analytical model for the antenna pattern that generates the beams is also proposed. We focus on the outage capacity of the link, and obtain analytical approximations at high and low SNR. The derived approximations provide insights on the effect of key system parameters – like the inter-user distance, the satellite beam radius, or the rain intensity– and simulation results show that it fits tightly to the Monte Carlo results. Additionally, the derived expressions can be easily particularized for the single-user case, providing some novel insights.

%B IEEE Transactions on Wireless Communications %P 1-1 %G eng %R 10.1109/TWC.2014.2329682 %0 Journal Article %J Communications Letters, IEEE %D 2013 %T MMSE Performance Analysis of Generalized Multibeam Satellite Channels %A Christopoulos, D. %A J. Arnau %A Chatzinotas, S. %A C. Mosquera %A Ottersten, B. %K dynacs %K linear minimum mean square error receivers %K multibeam satellites %K Multiuser detection %K return link %K satcom %B Communications Letters, IEEE %P 1-4 %G eng %R 10.1109/LCOMM.2013.052013.122658