| Popis: |
It is widely known that satellite communications require highly-efficient transmission structures. This is even more important in the forward link, since the available power at the transponders is limited. For that purpose, having a highly-efficient amplification scheme is critical. However, since the spectral-efficient transmission techniques (e.g. single-carrier modulations with large constellations or multicarrier modulations) present a large peak-to-average power ratio (PAPR), high amplification efficiency is very difficult to obtain. In fact, a linear amplification of such techniques requires high back-offs, which significantly degrades the amplification efficiency. In this work, a novel amplification scheme based on the use of multiple parallel highly-efficient power amplifiers (PAs) is presented, which is suitable for satellite communications. This amplification scheme is based on the decomposition of a high-PAPR signal into a set of constant-envelope components that are individually amplifying and efficiently combined. As it is demonstrated with a set of performance results of a QDA prototype operating with multicarrier signals, the proposed amplification scheme presents a large amplification efficiency, while preserving the linearity of the transmitted signals.1 |
