In this paper, we propose a FDL(Freeze DeadLine) algorithm to solve handover problems in heterogeneous wireless networks. Many previous studies concentrated on low level layer to solve handover. In this paper, however, we concentrate on high level handover problems such as network layer and transport layer. We analyze handover problems of transport layer in Heterogeneous wireless network, propose the FLD algorithm for better performance than others studies. The proposed method is analyzed by theoretical frames and we verify the propose method using the NS-2(Network Simulation-2).