Communication on the Move with Satellite Digital Beamforming
Technical Report,09 Mar 2017,14 Nov 2018
Wichita State University Wichita United States
Pagination or Media Count:
In a satellite communication system, channel coefficients from multiple-input-multiple-output MIMO antennas are correlated strongly because of a long propagation distance and a narrow angle spread. This is referred to as a keyhole KH channel, which results in a rank deficiency in the MIMO channel, and reduction of the number of simultaneously supportable multiple-access users. In addition, a high-power amplifier HPA in a satellite transponder distorts the transmitted signal due to its nonlinearity and memory. The aim of this report is to study a satellite beam-forming BF method and to investigate its signal-to-interference-plus-noise ratio SINR degradation due to the KH and HPA nonlinearity effects. A closed form of an optimum BF vector is not available due to the HPA nonlinearity and memory, and a BF vector with simple complexity is desirable in practice. Therefore, this report proposes for a satellite transponder to use column vectors from a discrete Fourier transform matrix as precoding BF vectors for multiple ground terminals to meet their SINR demands. Each receiver can apply maximal ratio combining post processing for further processing gain, and should feedback his SINR observation to the transponder.
- Radio Communications