Meanwhile, when the in-use information is not received from the UE 100-Y, the UE 100-D notifies UE with which the UE 100-D communicates, of a change to the radio resource B. Then, the UE 100-D and the UE with which the UE 100-D communicates perform the D2D communication by using the radio resource B.

FIG. 8 is a diagram illustrating a specific example 1 of the interference avoidance operation pattern 2. In FIG. 8, a cell A is a cell belonging to a frequency band A included in the D2D radio resource, and a cell B is a cell belonging to a frequency band B included in the D2D radio resource.

As shown in FIG. 8(A), UE 100-1 and UE 100-2 constitute a D2D UE group, and UE 100-3 and UE 100-4 constitute another D2D UE group. These two D2D UE groups are adjacent to each other and use the same frequency band, resulting in the occurrence of interference between the D2D communications. Hereinafter, the case, in which the UE 100-4 detects interference from the UE 100-1, is considered.

As shown in FIG. 8(B), when interference is detected, the UE 100-4 changes a frequency band (a cell), in which D2D communication is performed, from the frequency band A (the cell A) to the frequency band B (the cell B). Then, the UE 100-D broadcasts change information, which indicates a change to the frequency band B (the cell B), in the frequency band B (the cell B).