TCP throughput improvement over vertical handover between 3G LTE and WLAN

Abstract

We address TCP throughput degradation over vertical handover between 3G-LTE and WLAN. 3G-LTE link layer tries to recover packet loss and deliver recovered packets in-order. This may involve link layer holding packets before later arriving packets arrive, causing spurious timeout. A state-of-the-art scheme holds fast retransmit/recovery for one RTT waiting for packets arriving at TCP layer out of order. We show this wait is unnecessary and costs TCP throughput. Our scheme is also able to improve TCP throughput by loss differentiation with parameters adapted to new network on vertical handover, considering link layer characteristics of 3G LTE which supports in-order delivery. Simulation result shows improved TCP throughput under various scenarios with TCP Reno and TCP SACK. © 2011 Springer-Verlag.