Purpose
The lack of a standard framework for pervasive mobile network renders this project timely. It aims to develop a truly pervasive and mobile all IP (v6) network infrastructure across heterogeneous wireless and ad hoc networks with the novel use of public transport system as backbone infrastructure. It also addresses QoS and mobility management for mobile ad-hoc sub-networks attached to fixed IP network and develops novel adaptive applications using location-awareness. Collaboration with University of Ulm, which participates in EU project Daidalos will allow Singapore to contribute this project outputs to the development of a standardization of framework for pervasive networks in mobile communication.
Motivation
Introduction
Two major trends in technology could be observed over the last decade: pervasive communication and the Internet. The era of pervasive communication is slowly but surely becoming an integral part of our daily life. In almost every family there is a mobile phone. The Internet has also become an integral part of our daily life. It is thus essential for us to bridge the two technologies. The need for communication is more evident now than ever, real estate agent use wireless technology to help them access data. Access to the Internet is a must if one is to stay on par with competitors. It is no longer a luxury but a necessity.
Singapore has always prided itself of having an efficient and modern IT and transport infrastructure. It can boast of being one of the most IT savvy community in the world. It has been one of the first to introduce the Electronic Road Pricing System - ERP. It has also provided its people with one of the most extensive broadband access in the world and has high Internet users among its population. Singaporeans are mobile and more than half of its population uses the public transport system. It is therefore essential to provide universal access to the Internet and provide ubiquitous multimedia services on the public transport system. While 802.11 type systems are a good choice when you are stationary, operating a wireless device while in a public transport system requires sophisticated network architecture.
Our operating scenario is as follows: (Refer to figure) There is full coverage by 3G networks but the cell diameter will be large, which leads to expensive costs for using the link. In town, there is coverage by Wireless LAN. MRT stations, bus stations, toll and petrol stations have also Wireless LAN connectivity. The buses and MRT trains related to the scenario have at least Universal Mobile Telecommunication system (UMTS), and Wireless LAN connectivity, while the cars might have only Wireless LAN but might be enhanced by UMTS. The buses and MRT trains form a mobile backbone while the cars on the motorway are attached to the mobile backbone in an ad-hoc-network style. The bus closest to the car can build the router to enter via the MRT station, toll-station or the petrol station into the Internet. Users within the bus or MRT train are connected to the wireless router in the bus or MRT train in an ad hoc mode. In this, the ad-hoc network is acting as a cheap network infrastructure. Cheap unidirectional services such as Voice over IP can be maintained with a certain degree of quality.
In this research project we propose a framework that supports inter-vehicular communication as well as provides Internet access for wireless users traveling in public transport systems like buses or MRT. The buses form a mobile network, a set of nodes composed by one or more IP-subnets. The mobile network consists of Mobile Routers (MR) forming an ad hoc network inside the buses, which will be connected to the Internet using one or more wireless routers (WR) located inside the buses or MRT trains. Mobility Gateways are connected with the infrastructure network and serve as contact point for the WRs. Such mobile networks are important for new applications in the wireless domain. It enables mobile routers like future cameras, PDAs, and other wireless devices inside the buses to be reachable over the Internet, which gives service providers new opportunities and operators more possibilities for revenue. The proposed research project mainly consists of the following parts:
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Mobility architecture, where we design a wireless network architecture suitable for the proposed scenario, that supports the mobility of the (sub-) network, ad hoc extensions in the buses and QoS.
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Mobility management, where we design mechanisms to support both horizontal (intra-technology) and vertical (inter-technology) handover
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Routing functionality, where we design a routing scheme that operates in the very flexible environment, where ad hoc networks may form inside the buses, which are connected to the infrastructure based wireless network of the operator. Here it is important to update the fixed network about the mobility of the mobile network.
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QoS management, where we design a QoS architecture that supports such environments and interworks with mobility management so that users experience high quality VoIP calls
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Intelligent services and applications, where we build prototypes of applications that are relevant in the proposed context, like inter-vehicle communication, location based information retrieval, etc. As it is important to hide the mobility from the applications, we will look at a service platform that integrates QoS and mobililty management so that it enables a rapid deployment of new services
Novelty
The novelty of the approach is the building of an open network architecture based on a common network protocol (IPv6) which supports heterogeneous access networks, including multi-hop wireless network, that uses a public transport system as a kind of wireless backbone. The use of mobile ad hoc networks coupled with cellular systems provides for a pervasive QoS-enhanced access to the users. Our approach will be to support the mobility in a new and integrated manner, both at the level of pervasive and adaptive applications, and at the network services level. We will achieve this by extending mobility concepts. We will integrate a range of network technologies in an efficient and scaleable manner. Network technologies considered by this project include mobile, wireless, ad-hoc and infrastructure mode networks. This set of technologies is selected because it strives for completeness, and at the same time for openness to future technologies. Specifically, technologies such as Bluetooth, WLAN, W-CDMA, TD-CDMA will be addressed. Further, we will provide the necessary mobility management, routing and discovery, QoS, and Resource Management functionalities for Beyond 3G network configurations specifically including multi-technology, multi-access and multi-homing scenarios. Finally, we will enable the user to interact with devices in their environment and to have personalised access to feature rich services and applications, including those based on pervasive computing and intelligent context-awareness. For a successful project, we will be strongly aligned to relevant standardisation bodies (IETF NSIS, MMUSIC, MANET, NEMO, SEAMOBY) and national research initiatives, but also able to contribute to their development when appropriate.
In the following we provide a short overview on the innovations that this research project brings forth:
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Transparent automated selection of appropriate transport and delivery technology.
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Quality of Service architecture integrating different access technologies. This will evolve from results achieved by previous research projects (Moby Dick, Tequila) and on current standardization bodies' evolution paths (DiffServ, QoS Brokers, Aggregation).
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Mobility-related techniques such as optimisation of access network and interface discovery, efficient handover techniques managed by the network, and network selection based on different parameters will be developed.
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Routing protocol that exploits the special environment of the project including multihop ad hoc networks.
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An IP protocol stack, taking wireless implications into consideration.
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A common signalling framework covering QoS and mobility, based on the IETF (NSIS and SIP workgroups).
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New and powerful applications that interact with a wide range of devices in the environment and provide the basis for intelligent context awareness.
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Context-aware access to feature rich services and applications including those that make communication and collaboration between people more effective and pleasurable.
State of the Art
Mobility mechanisms are well defined for the case of a mobile node, which changes its point of attachment to the global network. Solutions exist at the network and application layer and can handle Macro and Micro mobility situations. The scenarios of mobile networks (like our proposal), which change frequently their point(s) of attachment, are foreseen as very valuable scenarios for the near future and are just starting to be investigated in IETF Network Mobility (NEMO) working group. Mobile networks may contain personal area networks (various portable IP devices interconnected). Managing the mobility of an entire network, viewed as a single unit, which changes its point of attachment to the Internet and thus its reachability in the topology is not a simple task. The mobile network is moving as a unit, and includes one or more mobile and wireless routers, which connect it to the global Internet. For these nodes behind the mobile router the network movement needs to be completely transparent. IETF NEMO WG has come up with requirements for mobile router support, threat analysis and security requirements, and protocol specification (tunnel establishment, etc.). The current mobility mechanisms do not support well the mobile network scenarios and some new schemes have been proposed in IETF NEMO WG. However, these schemes do not address route optimization issues or forming a mobile backbone by using public infrastructure.
The characteristics of an ad hoc network differ substantially from those of the fixed Internet. Addressing in the Internet is hierarchical and an Internet host does not have to keep track of routes to every Internet host. Routing information can be aggregated. In mobile networks, Mobile IPv6, Hierarchical MobileIPv6 has been designed to allow packets destined for a mobile node to be routed to the right place where the mobile node is attached currently. In ad hoc networks, these features are not required. Many ad hoc routing protocols e.g. AODV, DSR use on-demand approach. Connecting an ad hoc network to the Internet brings up several issues. For example, nodes within an ad hoc network do not know whether a destination is located within the ad hoc network. The route discovery mechanism of an ad hoc routing protocol first has to search for the destination within the ad hoc network. Another problem is the sending node needs to have an IP address that is routable from the rest of the Internet.
There is some existing work on connecting nodes within an ad hoc network to the internet. Research in integrating ad-hoc network access with the Mobile IP infrastructure has provided some insight into the problems placed by this integration. Most of the papers assume each ad hoc node will register with a foreign agent. However, these papers assume that the ad hoc network is flat, which does not fit our scenario. Moreover, they do not consider QoS based routing. QoS negotiation in infrastructure-based networks can be in-band (Diffserv) or out-of band (IntServ with RSVP signaling) or a combination of both and are usually not combined with routing messages. However, in ad hoc networks, one possibility of providing paths that meet certain QoS is to include QoS parameters in the route request packets. When considering an integrated ad hoc and infrastructure network, research needs to be done to integrate these two different approaches. Existing research does not address the possibility of having an ad hoc node that possibly has access to 3G/4G network and hence can be a moving router for other nodes to reach the internet.
Publications
2007
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M. Amir, B.S. Lee, T.M. Lim, "Enhanced Ad Hoc Qs: MAC-Independent Adaptive Traffic Differentiation in IEEE 802.11-based Ad Hoc Networks", in Proc. IEEE Consumer Communications and Networking Conference, Jan 11-13, Harrah's Las Vegas, Nevada, 2007.
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T.T. Luong, B.C. Seet, and B.S. Lee, "Local Maximum Avoidance with Correlated Street Blocking for Map-based Geographic Routing in VANETs", IEEE International Symposium on Wireless Pervasive Computing, Puerto Rico, USA, Feb 2007.
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T.M. Lim, J.W. Tantra, B.S. Lee, C.K Yeo, "Terminal-assisted Network Mobility Management", in Proc. IEEE Wireless Communications and Networking Conference, Mar. 11-15, Hong Kong, 2007. (An IEEE Communications Society Flagship Conference)
2006
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B.S. Lee, T.M. Lim, C.K. Yeo, L.Q. Vinh, "Enabling IP Mobility without using permanent IP address", US Provisional Patent, Application No. 60/762,115, January 2006.
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T.M. Lim, Y. Xia, B.S. Lee, C.K. Yeo, "IPv6 Mobile Router for Multihop Ad hoc Network: Proof-of-concept", in Proc. International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks, Workshop on Networking in Public Transport, Aug. 7-9, Waterloo, Ontario, Canada, 2006.
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R.A. Santosa, B.S. Lee, C.K. Yeo, T.M. Lim, "Distributed Neighbor Discovery in Ad Hoc Networks Using Directional Antennas", in Proc. IEEE International Conference on Computer and Information Technology, Sep 20-22, Seoul, Korea, 2006.
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B.S. Lee, M.N. Son, T.M. Lim, C.K. Yeo, B.C. Seet, "Processing Delay as a New Metric for On-Demand Mobile Ad hoc Network Routing Path Selection", in Proc. IEEE International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM), Sep 22-24, Wuhan, PRC, 2006. (An IEEE Communications Society Flagship Conference)
2005
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C.H. Foh, G. Liu, B.S Lee, B.C. Seet, K.J. Wong and C.P. Fu, "Network Connectivity of One-Dimensional MANETs with Random Waypoint Movement", IEEE Communications Letters, vol.9, no. 1, Jan 2005, pp.31-33.
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B.C. Seet, C.T. Lau, W.J. Hsu and B.S. Lee, "A Mobile System of Super-Peers Using a Fleet of City Buses", IEEE PerCom Workshop on Mobile Peer-to-Peer Computing, Kauai Island, Hawaii, Mar 2005.
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T.M. Lim, B.C. Seet, B.S. Lee, C.K. Yeo, A. Kassler, "Pervasive Communication for Commuters in Public Buses", IEEE International Conference on Pervasive Computing and Communications Workshops, Mar. 8-12, Kauai Islands, Hawaii, 2005, pp.75-79.
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T.M. Lim, B.S. Lee, C.K. Yeo, A. Kassler, B.C. Seet, "IPv6 Network Mobility on Ad Hoc Network for Public Transportation Systems", TERENA Networking Conference, Jun. 6-9, Poznan, Poland, 2005.
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T.M. Lim, B.S. Lee, C.K. Yeo, M. Amir, "Ad hoc Qs: MAC-independent Traffic Differentiation in IEEE 802.11-based Ad hoc WLAN", in Proc. IEEE International Conference on Networks, Nov. 16-18, Kuala Lumpur, Malaysia, 2005.
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T.M. Lim, B.S. Lee, C.K. Yeo, "IPv6 Network Mobility for Flat Ad hoc Routing Protocol:, in Proc. IEEE International Conference on Global Telecommunications (Globecom), Nov. 28-2, St. Louis, USA, 2005.
2004
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B.S.Lee, B.C.Seet, G.P.Liu, C.H.Foh, K.J.Wong, " A Routing Strategy for Metropolis Vehicular Communications ", in Proceedings of The International Conference on Information Networking (ICOIN'04), (Korea), vol. 2, pp 533-542, Feburary 2004
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Lijuan Zhu, B.S.Lee, Boon Chong Seet, K.J.Wong, Genping Liu, S.Y.Huang, K.K.Lee, " Performance of New Broadcast Forwarding Criteria in MANET ", in Proceedings of The International Conference on Information Networking (ICOIN'04), (Korea), vol. 1, pp. 33-42 , Feburary 2004
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B.C Seet, G.P Liu, B.S Lee, C.H Foh, K.J Wong, K.K Lee, " A-STAR: A Mobile Ad Hoc Routing Strategy for Metropolis Vehicular Communications ", in Proceedings of The 3rd International IFIP-TC6 Networking Conference (Athens, Greece), vol. 3042/2004, pp. 989-999, May 9-14, 2004
2003
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K.J.Wong, B.S.Lee, B.C.Seet, G.P.Liu, L.J.Zhu, " BUSNet: Model and Usage of Regular Traffic Patterns in Mobile Ad Hoc Networks for Inter-vehicular Communications ", in Proceedings of The International Conference on Information and Communication Technologies (ICT'03), (Thailand), pp. 102-108, April 2003
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B.S.Lee, K.J.Wong, B.C.Seet, L.J.Zhu, G.P.Liu, " Performance of Mobile Ad Hoc Network in Constrained Mobility Pattern ", in Proceedings of The International Conference on Wireless Networks (ICWN'03), (U.S.A), pp. 92-97, June 2003
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G.P.Liu, K.J.Wong, B.S.Lee, B.C.Seet, C.H.Foh, L.J.Zhu, " PATCH: A Novel Local Recovery Mechanism for Mobile Ad-hoc Networks ", in Proceedings of The IEEE Vehicular Technology Conference (VTC'03 Fall), (U.S.A), October 2003
Funding
- Agency for Science and Technology Research (A*STAR) of Singapore
Project number: 0421010012 - M47020012
Funding Amount: SGD690,690
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