This paper studies the joint multiplexing, Resource-Block and power allocation problem in underlay Device-to-Device (D2D) communications. The interfering signals are assumed fully asynchronous at the device receivers and at the Base Station. Inter-Channel Interference (ICI) then generates major impairment on the expected rate gain if Orthogonal Frequency Division Multiplex (OFDM) multi-carrier modulation is used, contrary to new multi-carrier modulations such as Filter Bank Multi-Carrier (FBMC) or Fast Fourier Transform (FFT)-FBMC. The proposed centralized algorithm provides a lower bound to the maximum sum rate over D2D pairs, taking into account ICI. It increases the sum data rate compared to a Frequency Division Multiple Access (FDMA) technique and compared to two other algorithms allowing multiplexing and applying power control.