Seamless media streaming over mobile IP-enabled wireless LAN

In the mobile IP-enabled wireless LAN (WLAN), packet transfer is interrupted due to the handoff of mobile node (MN), which results in burst packet losses. This transient behavior hurts time-critical streaming media applications. In case of one-way streaming media applications, it is well known that pre-buffering at the receiver side is effective in overcoming network fluctuations. However, determining the required margin of buffering is difficult in the Mobile IP network, since it depends on the efficiency of adopted link-/IP-layer handoff options. In this paper, we introduce a scheme that helps estimate the required pre-buffering level more accurately by considering both handoff duration and transient packet losses. For experiment, we implement a packet buffering and forwarding mechanism (a.k.a. smooth handoff) to reduce the packet losses during the link/IP-layer handoffs. Also, pre-buffering adjustment is performed based on the handoff latency experimentally measured and analytically obtained by the handoff transient time analysis. The experiment and simulation results shows that the proposed scheme can provide an appropriate guideline on the buffer parameters and thus can facilitate the seamless streaming over the Mobile IP networks.