Power Allocation Strategy for Joint Communications and Sensing in NOMA-assisted Low-Latency Networks

Joint communication and sensing (JCAS) is envisioned as the enabler to many advanced applications in future 6G networks. This paper investigates a power allocation strategy for JCAS networks with multiple transmitters and receivers. To take advantage of spatial diversity, the dual-functional radio signal is constructed via superimposed NOMA. Moreover, to fulfill the stringent latency requirement, transmissions are carried out with finite blocklength (FBL) codes. We formulate the optimization problem aimed at maximizing the minimal transmission rate among NOMA users while guaranteeing the target estimation requirement, which is represented by the Cramer-Rao lower bound (CRLB). An efficient approach is proposed to obtain the optimal solutions based on the characterization of communication and sensing metrics. Via simulation, the analytical finding are validated and insights into the trade-off between communication and radar sensing in JCAS networks are provided.