On the Use of Multiple Satellites to Improve the Spectral Efficiency of Broadcast Transmissions

TL;DR

This paper explores using multiple co-located satellites transmitting on overlapping frequencies to enhance spectral efficiency, analyzing theoretical models and comparing different transmission strategies including overlapped signals and space-time coding.

Contribution

It introduces a theoretical framework for multi-satellite broadcast systems using network information theory and evaluates strategies like overlapped signals versus traditional methods.

Findings

Overlapped signals outperform frequency division in balanced power scenarios.

Multiuser detection is essential for overlapped signal strategies.

Space-time coding offers alternative trade-offs in spectral efficiency.

Abstract

We consider the use of multiple co-located satellites to improve the spectral efficiency of broadcast transmissions. In particular, we assume that two satellites transmit on overlapping geographical coverage areas, with overlapping frequencies. We first describe the theoretical framework based on network information theory and, in particular, on the theory for multiple access channels. The application to different scenarios will be then considered, including the bandlimited additive white Gaussian noise channel with average power constraint and different models for the nonlinear satellite channel. The comparison with the adoption of frequency division multiplexing and with the Alamouti space-time block coding is also provided. The main conclusion is that a strategy based on overlapped signals is the most convenient in the case of no power unbalance, although it requires the adoption of a multiuser detection strategy at the receiver.