The Degrees-of-Freedom in Monostatic ISAC Channels: NLoS Exploitation vs. Reduction

The degrees of freedom (DoFs) attained in monostatic integrated sensing and communications (ISAC) are analyzed. Specifically, aims for extracting target-orientation information from the line sight (LoS) channel between transmitter target, since Non-LoS (NLoS) paths only contain clutter or interference. By contrast, wireless communications, typically, both LoS NLoS exploited achieving diversity multiplexing gains. Hence, we shed light on exploitation vs. reduction tradeoffs a ISAC scenario. In particular, optimize transmit power each signal path to maximize communication rate, while guaranteeing performance target. non-convex problem formulated is firstly solved closed form single-NLoS-link scenario, then harness popular successive convex approximation (SCA) method general multiple-NLoS-link Our simulation results characterize fundamental communication, demonstrating that available DoFs should be efficiently way distinctly different communication-only scenarios.