Cross-layer assisted TCP for seamless handoff in heterogeneous mobile wireless systems

We propose cross-layer assisted TCP enhancements to improve service quality of mobile users during handoff. Specifically, we investigate and resolve TCP issues that pertain to handovers between wireless networks with varying data rates. New adjustments to TCP´s round trip time, congestion window, and acknowledgment mechanism are proposed to ensure seamless handoff. The performances of the proposed cross-layer assisted handoff TCP (TCP-CLAH) are evaluated and compared to those of TCP NewReno (TCP-NR). Our results show that TCP-CLAH outperforms TCP-NR significantly in terms of jitter, round-trip time, and queue size, thereby reducing service disruptions and glitches of ongoing communications substantially during a handoff.