A joint weighted power detector for Willie in two-hop covert communication system

This letter proposes a joint weighted power detector based on maximum a posteriori probability criterion for Willie aiming at two-hop covert communication scenario, which is a near optimal detector. Instead of only supervising one single phase, Willie combines the observations of two phases to make joint decision in the proposed scheme. The proposed scheme achieves lower probability of detection error than adding-power-directly-detector scheme and the existing single-phase-detector scheme due to sufficient utilization of the two-phase observations. Numerical results demonstrate the benefit of authors' proposed scheme.