Overview

The goal of mobile internet connectivity is for IP-based applications to continue working as a mobile host moves. The mobile host should be unconstrained in its choice of attachment points to whichever IP network it chooses to use. There are various approaches to internet mobility, each with their own definition of 'continue working' and 'unconstrained'. We can broadly classify these into link, IP, and application layer solutions.

Link layer solutions (such as IEEE 802.11 wireless LANs - WiFi, or cellular data services - 3G, 4G) allow the IP topology to appear static even as the hosts (and possibly routers) move geographically relative to each other. However, link layer solutions typically require you to stay within the geographical range of that specific link layer (for example, a few hundred feet for 802.11 solutions, or within a carrier's coverage area for cellular modem solutions).

IP layer solutions (the IETF's "mobile IPv4" and "mobile IPv6" being most obvious examples) support mobility across a range of link layers (for example, allowing you to migrate from an 802.11 LAN to a Bluetooth to cellular wireless) while maintaining a host's "identity" at the IP level. Applications running on such a host see no change to their IP connectivity.

Application level solutions require an application to be aware that the underlying host's IP address may change multiple times while the application is in use. The application includes its own mechanisms for discovering IP address or connectivity changes, and for re-establishing connectivity with their peers once IP level connectivity resumes.

Activities

To date, the research in MAGIC has two branches:

• Theoretical work into the link layer solutions focusing on the IEEE 802.11 medium access control (MAC) protocol families. The aim is to understand the performance of contention based MAC protocols and their influence on upper layers in terms of quality of service (QoS). To this end, we aim to understand the capacity limit, mobility impact and to improve the efficiency of disseminating information and delivering real-time interactive services over wireless data networks.
• Experiments that will qualitatively and quantitatively explore the viability of wireless solutions for various applications in WiFi, WiMax and Vehicular Ad-Hoc Networks (VANETs).

Research Output

Journal Papers and Book Chapters

Md. Imrul Hassan, Hai L. Vu, Taka Sakurai and Lachlan L. H. Andrew,
Effect of Retransmissions on the Performance of the IEEE 802.11 MAC Protocol for DSRC,
to appear in IEEE Trans. Vehicular Technology, 2011.

Md. Imrul Hassan, Hai L. Vu and Taka Sakurai,
Performance Analysis of the IEEE 802.11 MAC Protocol for DSRC Safety Applications,
to appear in IEEE Trans. Vehicular Technology, 2011.

Medium Access Protocols for Cooperative Collision Avoidance in Vehicular Ad-Hoc Networks
M. I. Hassan, H. L. Vu and T. Sakurai,
Book chapter in Advances in Vehicular Ad-Hoc Networks: Developments and Challenges, IGI Global, 2010, pp. 1-24.

Accurate delay distribution for IEEE 802.11 DCF
Hai L. Vu and Taka Sakurai,
in IEEE Communications Letters, vol. 10, no. 4, April 2006, pp. 317-319.

MAC Access Delay of IEEE 802.11 DCF
Taka Sakurai and Hai L. Vu,
in IEEE Transaction on Wireless Communications, vol. 6, no. 5, May 2007, pp. 1702-1710.

An Access Delay Model for IEEE 802.11e EDCA
Dongxia Xu, Taka Sakurai and Hai L. Vu,
in IEEE Transaction on Mobile Computing, vol. 8, Feb. 2009, pp. 261-275.

VoIP Capacity - Analysis, Improvements and Limits in IEEE 802.11 Wireless LAN
K. O. Stoeckigt and H. L. Vu,
in IEEE Transaction Vehicular Technology, vol. 59, no. 9, Nov. 2010, pp. 4553-4563.

Performance Analysis of Best-Effort Service in Saturated IEEE 802.16 Networks
H. L. Vu and S. Chan and L. L. H. Andrew,
in IEEE Transaction Vehicular Technology, vol. 59, no. 1, Jan. 2010, pp. 460-472.

Conference Papers

Real Time Route Guidance with Correlated Link Cost
Wei Dong, Hai L. Vu, and Quoc Bao Vo,
Proc. of 14th International IEEE Conference on Intelligent Transportation Systems (ITSC), Washington, DC, USA, 2011.

Performance Analysis of the IEEE 802.11 MAC Protocol for DSRC with and without Retransmissions
Md. I. Hassan, H. L. Vu and T. Sakurai,
Proc. of IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM), June, 2010.

Effect of Retransmissions on the Performance of the IEEE 802.11 MAC Protocol for DSRC
Md. I. Hassan, H. L. Vu, T. Sakurai, L. L. Andrew and M. Zukerman,
Proc. of IEEE Vehicular Networking Conference (VNC), Dec, 2010.

Conservative Soft Handoff for Heterogeneous Wireless Networks
A. Nazari, P. Branch, J. But and H. L. Vu,
Proc. of IEEE Wireless Communications and Networking Conference (WCNC), 2010.

• See also the list of technical reports and related publications.

Funding

Some projects in MAGIC are supported by the following Grant(s):

• 2010-2012 "Mechanism design for next generation random access wireless protocols", ARC DP1095103, $150k, Chief Investigators: L. Andrew and H. Vu

Project Members

CAIA members A/Prof. Hai L. Vu (Project leader) Prof. Grenville Armitage (CAIA Director) A/Prof. Lachlan L. Andrew (ARC Future Fellow) Dr Philip Branch Imrul Hassan (PhD student) Kewin Stoeckigt (PhD student) Suong Nguyen (PhD student) Abolfazl Nazari (PhD student)

Collaborators Dr Quoc Bao Vo (SUCCESS, FICT) Dr Yoni Nazarathy (FEIS) Wei Dong (PhD student)

Alumni Dr Ihsan Qazi (Post-Doc Research Fellow) Andres Rojas Le Anh Tuan Paul VanDen Bergen