Physical Layer Security Using Joint Directional Modulation and Encoding for Distributed Receivers Serving Chaotic Antenna Arrays

Chaotic antenna arrays (CAAs) are phased antenna arrays with randomized antenna elements exhibiting unique and spatially dependent phase errors. CAAs are promising for generating strong RF fingerprints that can be used for device authentication. For the RF fingerprint to remain secure, it is crucial that the phase errors remain unknown to the user of the CAA. This on the other hand inhibits conventional beam steering that relies on a known antenna array structure. Additionally, the user with the CAA cannot employ known physical layer security methods that are based on phased antenna arrays. To alleviate this issue, we propose a novel security method in networks with distributed receivers. The approach combines i) distortion caused by changes in the array pattern with ii) encoding based on the phase difference at distributed locations, which makes the method resistant against eavesdropping. Mitigating the distortion and decoding the signal becomes only possible if the eavesdropper can obtain all signals received at all legitimate receivers.