Whistleblower Joint Communications and Sensing Using Retrodirectional Array Processing

In joint communications and sensing (JCS), both functions are integrated in the same wireless transceiver. A conflict between communications and sensing in JCS is how to handle the newly emerging radar targets: if the sensing is too frequent, communications will suffer from the loss of transmission opportunities; if the sensing frequency is set too low, in order to enhance the communication throughput, the delay of target detection will be substantial. In this paper, a whistleblower mechanism is proposed based on the retrodirectional array processing (RAP), in which the radio frequency (RF) frontend can automatically transmit signals along the opposite direction of the incident (reflected) signals. Therefore, when a new radar target emerges, the communication signal will be reflected from the target and then regenerated by the whistleblower mechanism, pointing to the target, thus forming a resonance between the JCS transceiver and target. The detailed design of the RAP based whistleblower JCS is discussed. Numerical simulations are provided to demonstrate the validity of the proposed JCS mechanism.

I. Introduction

Communications and sensing are two major technologies for information collection and processing in various cyber physical systems (CPSs) such as autonomous driving, vehicular networks and unmanned aerial systems (UASs). In traditional systems, communications and sensing use independent devices with independent operations. However, such a separated design consumes substantial bandwidth, since both communication and sensing need to be allocated sufficient bandwidth separately. This results in a potential bandwidth congestion when there are many nodes in the CPS, each requesting significant resource of bandwidth.