  Device-to-device (D2D) communication has become one important part of the 5G
cellular networks particularly due to the booming of proximity-based
applications, e.g. D2D relays. However, the D2D relays may create strong
interference to nearby users. Thus interference management in a cellular
network with D2D relays is critical. In this paper, we study the optimal time
reuse patterns in a cellular network with cooperative D2D relays and derive the
corresponding optimized relaying strategies. Due to the binary association
constraints and the fact that the total number of feasible time reuse patterns
increase exponentially with the number of servers, we have a large scale
integer programming problem which is formidable to solve. However, we show that
we just need to activate a few time reuse patterns in the order of the number
of users. Accordingly, a low-complexity algorithm is proposed to find the set
of active time reuse patterns and solve this problem in an approximated way.
Numerical simulations demonstrate that our scheme can efficiently allocate the
time resources and determine the relaying strategies. Furthermore, the proposed
scheme offers significant gains relative to the existing ones.
