Sensing-assisted Physical Layer Security

Integrated Sensing and Communication (ISAC) is intuitively expected to enhance energy and spectrum efficiencies, while it is further promoted to get a deeper integration where the two functionalities are co-designed for mutual benefits. Concerning the communication data security risks resulting from the unification of these two operations, we address the sensing-aided physical layer security (PLS) for ISAC systems in this paper. In our design, the ISAC base station (BS) sends information to communication users and detects targets simultaneously, where targets are reckoned as potential eavesdroppers (Eves). The BS firstly emits an omnidirectional waveform to search for potential Eves’ angles adopting the combined Capon and approximate maximum likelihood (CAML) technique. We then formulate a weighted optimization problem for both the secrecy maximization and the Cramér-Rao bound (CRB) minimization, with the wide main beam design covering all possible directions of Eves. With the estimation accuracy improving iteratively, the secrecy rate benefits from the sensing functionality, that is, accordingly gets higher. Finally, the simulation results validate the effectiveness of the proposed method.