  In this paper, a Device-to-Device communication on unlicensed bands (D2D-U)
enabled network is studied. To improve the spectrum efficiency (SE) on the
unlicensed bands and fit its distributed structure while ensuring the fairness
among D2D-U links and the harmonious coexistence with WiFi networks, a
distributed joint power and spectrum scheme is proposed. In particular, a
parameter, named as price, is defined, which is updated at each D2D-U pair by a
online trained Neural network (NN) according to the channel state and traffic
load. In addition, the parameters used in the NN are updated by two ways,
unsupervised self-iteration and federated learning, to guarantee the fairness
and harmonious coexistence. Then, a non-convex optimization problem with
respect to the spectrum and power is formulated and solved on each D2D-U link
to maximize its own data rate. Numerical simulation results are demonstrated to
verify the effectiveness of the proposed scheme.
