Information Raining for Mobile Hotspots
Recently we witness proliferation of hotspots in places such as coffee shops,
shopping malls, airports, hotels, convention centers, and so on. An apparent
question is whether it is possible to extend hotspot technology to mobile users.
In this paper, we present challenges on achieving such a goal and propose an
open architecture for mobile hotspots.
Cellular systems and wireless local area networks (WLANs) are the two major
wireless technologies. The next generation wireless networks should consolidate
cellular systems and WLANs. If such an integration is achieved, users can move
between cellular systems and WLANs without service interruption. Figure 1
illustrates the bandwidth versus mobility for cellular and WLAN technologies.As
seen these two technologies have different bandwidth-mobility requirements and
the integration may not be straightforward.
There are a few challenges in designing an architecture that can
support mobile hotspots. The first problem is the high velocity of vehicles. The
current cellular systems have not been designed to support the speeds beyond 250
km/h. The second challenge arises from the fact that a large number of users
travel together. Therefore, a large bandwidth should be delivered to the
vehicle. Current technologies can only support high bandwidth for stationary or
nomadic users. Mobile users cannot enjoy the same bandwidth as the nomadic
users.
In this project, we design a system architecture that supports high bandwidth
for mobile users travelling at very high speed. Examples of such users are the
passengers of maglev (magnetic levitation) trains travelling at 450 km/h.
We propose an architecture that allows the passengers of such trains to connect
to the Internet while travelling on their route. A similar architecture can be
used to support high bandwidth wireless connectivity to subway trains in urban
areas and in mining industry.
Further Reading:
[1] S. Valaee, “Information Raining for Mobile Hotspots in 4G Wireless Networks”, (invited paper) in the proceedings of 22nd Biennial Symposium in Communications, June 2004. [pdf]
[2] D. Ho and S. Valaee, “Information Raining for Link-Layer Design of Mobile Hotspots”, in IEEE Trans. on Mobile Computing, 2005. [pdf]
[3] D. Ho and S. Valaee, “Mobile Hot Spot in Railway Systems”, in the proceedings of 22nd Biennial Symposium in Communications, June 2004. [pdf]
[4] D. Ho, "Link-layer Design and Throughput Optimization to Mobile Hotspot in Railway Systems", MASc Thesis, University of Toronto, 2004. [pdf]