A method performed by a network system is provided for canceling interference signals brought by introducing P2P communication in wireless communication systems, comprising: receiving a call request from a user equipment in a cell for communicating in UP-BASE STATION-DOWN mode; judging whether there is an appropriate link timeslot in the several available timeslots for the user equipment to avoid being interfered by P2P signals transmitted by the chosen user equipments allocated in the appropriate timeslot when the user equipment communicates in the appropriate timeslot, according to the relative position of the user equipment and the chosen user equipments in P2P communication in the cell; approving the call request from the user equipment and allocating the appropriate timeslot to the user equipment if the appropriate timeslot is available.