High-throughput multicarrier satellite transmission using linearized traveling wave tube amplifiers

Sam Reisenfeld*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

Abstract

Traveling wave tube amplifiers (TWTAs), used in satellite transponders, are nonlinear devices. Often, multiple, frequency multiplexed, digitally modulated carriers are transmitted through a satellite transponder. Additionally, square-root raised cosine transmit and received filtering is frequently used to reduce bandwidth requirements, and a result is a large peak power to average power ratio for each carrier at the TWTA input. In this situation, when the TWTA is operated close to its saturation point, there is large bit error rate performance degradation due to the intermodulation products produced by the nonlinearity. Operation of the TWTA with large input and output backoffs provides more linear operation at the expense of TWTA output power. A linearizer, which may be implemented as an instantaneous nonlinearity inserted in front of the input to the TWTA, may be designed such that the cascade combination of the linearizer and the TWTA has a considerably more linear characteristic than the TWTA alone. The optimal TWTA operating point, which minimizes the performance losses both due to bit error rate degradation and TWTA output backoff, is obtained with less TWTA output backoff using the linearizer. In this paper, the performances for both the TWTA and the linearized TWTA are obtained by computer simulation, and the performance advantage of the linearized TWTA is determined for extremely bandwidth efficient, frequency multiplexed, square-root raised cosine pulse shaped QPSK modulated carriers. A modest power efficiency advantage of the linearizer is shown for this extremely bandwidth efficient, multicarrier case.

Original languageEnglish
Title of host publication33rd AIAA International Communications Satellite Systems Conference and Exhibition, ICSSC 2015
Place of PublicationQueensland, Australia
PublisherAmerican Institute of Aeronautics and Astronautics
Pages1-16
Number of pages16
ISBN (Print)9781624103759
DOIs
Publication statusPublished - 2015
Event33rd AIAA International Communications Satellite Systems Conference and Exhibition, ICSSC 2015 - Brisbane, Australia
Duration: 7 Sep 201510 Sep 2015

Publication series

Name33rd AIAA International Communications Satellite Systems Conference and Exhibition, ICSSC 2015

Other

Other33rd AIAA International Communications Satellite Systems Conference and Exhibition, ICSSC 2015
CountryAustralia
CityBrisbane
Period7/09/1510/09/15

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  • Cite this

    Reisenfeld, S. (2015). High-throughput multicarrier satellite transmission using linearized traveling wave tube amplifiers. In 33rd AIAA International Communications Satellite Systems Conference and Exhibition, ICSSC 2015 (pp. 1-16). (33rd AIAA International Communications Satellite Systems Conference and Exhibition, ICSSC 2015). Queensland, Australia: American Institute of Aeronautics and Astronautics. https://doi.org/10.2514/6.2015-4306