Wireless Profiled TCP Performance over Integrated Wireless LANs and Cellular Networks

An analytical framework for studying the performance of wireless profiled TCP (WP-TCP) flows over the integrated wireless LAN and cellular networks is proposed. The framework can be used to analyze the short-term performance during vertical handover and long-term performance of WP-TCP for a given set of network and protocol parameters. It captures the WP-TCP behavior under the influence of wireless channel errors, step change in network parameters and excessive packet losses due to vertical handovers. Extensive simulations are conducted to verify the accuracy of the analytical framework. The main findings in this study are: (1) when the network is subjected to hard handovers, increasing the maximum window size improves the efficiency in a high transmission error environment, but degrades the efficiency in a low transmission error environment; (2) increasing the congestion window reduces the chances of premature timeouts during soft upward vertical handover; and (3) depending on duplicate ACK threshold, increasing the congestion window can increase or reduce the chances of false fast retransmit during soft upward vertical handover.