Methods and apparatus for using a plurality of cells by an evolved NodeB (eNB) in a communication system are provided. A first eNB, which manages a first cell and is providing a communication service to a User Equipment (UE) located in the first cell, determines to provide the communication service to the UE together with a second cell of a second eNB, which neighbors the UE. A cell addition request message, making a request for aggregation of the first cell and the second cell, is transmitted to the second eNB to provide the communication service. When a cell addition response message, accepting the request for aggregation of the first cell and the second cell, is received from the second eNB, a cell activation request message, making a request for activation of the second cell, is transmitted to the second eNB.