PAPR-optimized OFDM Design for Opportunistic Communications and Sensing

We consider the problem of peak-to-average power ratio (PAPR) reduction in orthogonal frequency division mul-tiplexing (OFDM) systems via optimized sparsification of tone reservation (TR) aimed at freeing resources for the opportunistic operation of co-existing communication and sensing systems. In particular, we propose a novel TR-optimization method in which the minimum number of effectively used peak-reserved tones (PRTs) required to satisfy a prescribed PAPR level in a primary system is found, leaving the remaining resources free to be opportunistically allocated by a secondary system and other functionalities, such as joint communication and sensing (JCAS), index modulation (IM) and cognitive radio (CR). The proposed method relies on an £0 norm regularization approach to penalize the number of PRTs, leading to a problem convexized via fractional programming (FP), whose solution is shown to ensure that the prescribed PAPR is achieved with high probability with a smaller number of PRTs than state of the art (SotA) methods. The contribution can be seen as a mechanism to enable the opportunistic coexistence of systems with adjacent functionalities in presence of existing OFD M - based systems.