Gaussian multiple access channels for radar and communications spectrum sharing

This paper develops the fundamental performance bounds for a radar operating in the presence of communication interference. To do so, we recast radar as a communication problem with the radar waveform acting as a convolutional encoder, which allows for the description of the achievable information-theoretic limits of the radar problem. While information theory has been applied to communications and radar, there has been little work on applying information theory to systems that explicitly combine sensing and communications. The new viewpoint presented in this paper, which does not require new mathematics, allows one to recast the problem of a radar operating in the presence of communication interference as a Gaussian multiple access channel problem. The derived bounds describe the fundamental limits on the amount of information the radar can obtain about the scattering environment in the presence of communications interference.