  In recent years, with the explosive growth of data traffic, communication
base stations (BSs) need to serve more and more users. Offloading traffic from
BSs has become an efficient way to reduce the burden on BSs. Device-to-Device
(D2D) communications have emerged to improve spectrum utilization by reusing
the frequency spectrum of the cellular frequency band. In the general
environment, Heterogeneous Cellular Networks (HCNs) including millimeter wave
(mm-wave) have appeared. Since the D2D link allows to share of spectrum
resources with the cellular user, it will bring potential interference to the
cellular user. Fortunately, an emerging technology called Reconfigurable
Intelligent Surface (RIS) can mitigate the severe interference caused by D2D
links by shaping the incident beam and improving the multipath phase shift. In
this paper, we study the resource allocation scheme to maximize the system sum
rate, in the RISassisted single-cell heterogeneous D2D communication scenario.
To solve the Block Coordinate Descent (BCD) problem, the problem of maximizing
the sum rate is decomposed into three sub-problems. The resource allocation
sub-problem is solved by a coalitional game method based on the game theory.
The power allocation problem of the coalition converts the concave function
into a convex optimization by mathematical transformation. The problem is
solved by the gradient descent method. The local search method is adopted to
find the optimum for the phase conversion problem. Then iterate until the
difference of sum rate is less than the threshold. The simulation results show
that the designed algorithm is superior to other benchmark schemes in the
literature.
