# Adaptive Interference Removal for Un-coordinated Radar/Communication Co-existence

## TL;DR

This paper introduces two novel algorithms for interference removal in uncoordinated radar/communication coexistence scenarios, leveraging sparsity and convex optimization to estimate active radar waveforms and improve data demodulation.

## Contribution

It proposes sparsity-based joint interference estimation algorithms using compressed sensing and atomic norm constraints for uncoordinated radar/communication coexistence.

## Key findings

- Algorithms effectively estimate active radar waveforms.
- Enhanced atomic norm method improves efficiency.
- Simulations demonstrate robust performance under various conditions.

## Abstract

Most existing approaches to co-existing communication/radar systems assume that the radar and communication systems are coordinated, i.e., they share information, such as relative position, transmitted waveforms and channel state. In this paper, we consider an un-coordinated scenario where a communication receiver is to operate in the presence of a number of radars, of which only a sub-set may be active, which poses the problem of estimating the active waveforms and the relevant parameters thereof, so as to cancel them prior to demodulation. Two algorithms are proposed for such a joint waveform estimation/data demodulation problem, both exploiting sparsity of a proper representation of the interference and of the vector containing the errors of the data block, so as to implement an iterative joint interference removal/data demodulation process. The former algorithm is based on classical on-grid compressed sensing (CS), while the latter forces an atomic norm (AN) constraint: in both cases the radar parameters and the communication demodulation errors can be estimated by solving a convex problem. We also propose a way to improve the efficiency of the AN-based algorithm. The performance of these algorithms are demonstrated through extensive simulations, taking into account a variety of conditions concerning both the interferers and the respective channel states.