Vertical handover method using mptcp with initial throughput improvement and mobile terminal using the method

The present invention relates to a vertical handover method in a mobile terminal transmitting data using a multi-path transmission control protocol (MPTCP). The vertical handover method in the mobile terminal comprises the steps of: (a) receiving, by the mobile terminal, signal strengths from a base station of the current network and a base station of a new network and measuring a difference between the signal strengths from the base stations of the new network and the current network; (b) transmitting a data packet to the base station of the new network as many as a preset number if the difference is greater than a first preset reference value, measuring and storing a congestion window, and then repeating the (a) step; (c) repeating the (a) step if the difference value is not greater than the first preset value; and (d) performing a handover to the new network if the difference value is greater than a second preset value, transmitting data using the stored congestion window, wherein the first reference value is smaller than the second reference value.