HERMES Radio: Energy and Spectral Efficient Transmitter Architectures for Small Satellites

Visweswaran Karunanithi, Delft University of Technology
Chris Verhoeven, Delft University of Technology
Alexander Yarovay, Delft University of Technology
Cicero Silveira Vaucher, Delft University of Technology

Abstract

As the complexity of nanosatellite missions have increased over time, the data generated on-board nanosatellites have increased multiple folds. As a result, there is a need to downlink large amounts of data. Multiple nanosatellite missions have started using spectral efficient modulation schemes recommended in DVB.S2 and DVB.S2X to make the best use of available spectrum. One of the main challenges in adopting higher order modulation schemes is to power efficiently upconvert and amplify the baseband signals. All the lost efficiency in converting the DC power to the RF output is converted to heat and the relatively small thermal mass of nanosatellites poses thermal management challenges.

As a first step to addressing the challenge of improving the power efficiency of the communication module, optimization techniques to improve the Peak to Average Power Ratio (PAPR) of the modulation schemes (16/32-APSK) are discussed in this paper. It can be seen that the PAPR of 16-APSK reduces by ~2 dB by incorporating filtering techniques discussed in this paper. Further, a well-known efficiency and linearity enhancement technique; Out-phasing/LINC (Linear Amplification using Non-linear Components) is discussed. As a variant of LINC architecture, a novel approach is proposed using dual circularly polarized antenna to combine the constant envelope signals of an outphasing/LINC architecture. Simulations results are used to demonstrate how the higher efficiencies can be achieved using the proposed architecture.

 
Aug 12th, 10:00 AM

HERMES Radio: Energy and Spectral Efficient Transmitter Architectures for Small Satellites

Utah State University, Logan, UT

As the complexity of nanosatellite missions have increased over time, the data generated on-board nanosatellites have increased multiple folds. As a result, there is a need to downlink large amounts of data. Multiple nanosatellite missions have started using spectral efficient modulation schemes recommended in DVB.S2 and DVB.S2X to make the best use of available spectrum. One of the main challenges in adopting higher order modulation schemes is to power efficiently upconvert and amplify the baseband signals. All the lost efficiency in converting the DC power to the RF output is converted to heat and the relatively small thermal mass of nanosatellites poses thermal management challenges.

As a first step to addressing the challenge of improving the power efficiency of the communication module, optimization techniques to improve the Peak to Average Power Ratio (PAPR) of the modulation schemes (16/32-APSK) are discussed in this paper. It can be seen that the PAPR of 16-APSK reduces by ~2 dB by incorporating filtering techniques discussed in this paper. Further, a well-known efficiency and linearity enhancement technique; Out-phasing/LINC (Linear Amplification using Non-linear Components) is discussed. As a variant of LINC architecture, a novel approach is proposed using dual circularly polarized antenna to combine the constant envelope signals of an outphasing/LINC architecture. Simulations results are used to demonstrate how the higher efficiencies can be achieved using the proposed architecture.