1. A method of reporting a buffer state by a user equipment (UE) connected to a first evolved node b (eNB) and a second eNB in a communication system, the method comprising:when new data is generated, triggering a buffer state report for the new data based on an amount of data stored in a buffer of the UE and at least one threshold value;
generating a random number and selecting at least one eNB of the first eNB and the second eNB that transmits the buffer state report based on a comparison result of the random number and a reference value and an amount of uplink data to be transmitted;
transmitting the buffer state report for the new data to the selected at least one eNB;
receiving a resource from at least one eNB of the first eNB and the second eNB in response to the buffer state report; and
transmitting the new data using the received resource.