A communication apparatus in a wireless communication system including a first base station forming a first cell, and a second base station forming a second cell adjacent to the first cell, and a terminal that can wirelessly communicate with the first base station via the first cell and the second base station via the second cell, the communication apparatus forming part of the second base station and comprising: a communication status acquisition unit configured to acquire a communication status in the second base station ; and a control unit configured to eliminate cell identifier duplication between a cell identifier of the second cell and a cell identifier of a third cell that is adjacent the first cell based on a number of times that the second base station has received, from the terminal , a first message requesting for re-establishment of an RRC connection; wherein the control unit is configured to eliminate cell identifier duplication between a cell identifier of the second cell and a cell identifier of the third cell when a number of times that the second base station has received the first message from the terminal is equal to or more than a predetermined value, wherein the first message indicates handover failure of the terminal to the second cell and indicates that the first cell is the cell to which the terminal was connected before the handover failure; wherein when eliminating cell identifier duplication, said control unit is configured to autonomously re-select a cell identifier of the second cell; and wherein the control unit , at a time of reception of the first message from the terminal , is configured not to count the number of times of reception for the first message when the second base station transmitted, to the first base station , a second message requesting for handover of the terminal from the second cell to the first cell within a predetermined period of time before the reception of the first message. a communication status acquisition unit configured to acquire a communication status in the second base station ; and a control unit configured to eliminate cell identifier duplication between a cell identifier of the second cell and a cell identifier of a third cell that is adjacent the first cell based on a number of times that the second base station has received, from the terminal , a first message requesting for re-establishment of an RRC connection; wherein the control unit is configured to eliminate cell identifier duplication between a cell identifier of the second cell and a cell identifier of the third cell when a number of times that the second base station has received the first message from the terminal is equal to or more than a predetermined value, wherein the first message indicates handover failure of the terminal to the second cell and indicates that the first cell is the cell to which the terminal was connected before the handover failure; wherein when eliminating cell identifier duplication, said control unit is configured to autonomously re-select a cell identifier of the second cell; and wherein the control unit , at a time of reception of the first message from the terminal , is configured not to count the number of times of reception for the first message when the second base station transmitted, to the first base station , a second message requesting for handover of the terminal from the second cell to the first cell within a predetermined period of time before the reception of the first message. <EOS>