Enhanced TCP Congestion Control for Vertical Handover with the RTT inflation and the measured-RTT of the new network

The recent trend is that the mobile internet service has been offered in the integration of various wireless networks. In such heterogeneous networks, vertical handover is more common and important handover technologies. But during vertical handover, standard TCP has experienced many problems such as multiple packet losses, the packet reordering, the under-utilization due to the drastic change of the Bandwidth Delay Product (BDP) and the network transmission delay (Round Trip Time :RTT). In this paper, we propose “Enhanced TCP congestion control scheme with RTT inflation and the measured-RTT of the new network” for the seamless soft vertical handover and evaluate this by OPNET simulation. We assume the proposed scheme uses the cross-layer design in a TCP receiver and a TCP time-stamp option. OPNET simulation results show that our proposed scheme improves better TCP performance than other handover congestion control schemes such as Freeze-TCP or SSTCP during the vertical handover.