Anytime, Anyplace, Anyhow Multimedia Wireless Access:
The Vision of Mobile Ad Hoc Networking

 Prof. George N. Aggelou, Institute of Technology, Athens, Greece, Director, G-Alpha Telecomms, Athens, Greece


 Tutorial Overview:

The past decade has shown a phenomenal growth in wireless communications.  Cellular systems have been standardized and Personal Communication Services (PCS) and the 3rd generation radio technology are being used providing wide-band services to mobile users.

 Additionally, wireless networking is being used more and more in both fixed and mobile usage scenarios, whereas high quality multimedia (voice, video and data) services over high-speed wireless local area networks (LANs) are becoming a reality. Wireless LANs (e.g. HiperLAN2, IEEE 802.11), being interconnected to a fixed network, are offering up to 54Mbps both to residential and business environments with high quality of service (QoS). The demand of these multimedia applications has been largely witnessed so far in fixed networks but as life style is rapidly changing, internet-like applications are more and more attractive to mobile users as well. 

 In parallel with (and separately from) the single hop model for today’s cellular/wireless communications, another type of model based on radio to radio multihopping, has been evolving to serve a growing number of applications which rely on a fast deployable, multihop, wireless infrastructure. A multihop mobile radio network, also called mobile ad hoc network (MANET) is a self-organizing and rapidly deployable network in which neither a wired backbone nor a centralized control exists. The network nodes communicate with one another over scarce wireless channels in a multi-hop fashion. The ad hoc network is adaptable to the highly dynamic topology resulted from the mobility of network nodes and the changing propagation conditions.

MANETs are a new paradigm of wireless wearable devices enabling instantaneous person-to-person, person-to-machine or machine-to-person communications immediately and easily. Possible commercial applications include business associates sharing information during a meeting, students using laptop computers to participate in an interactive lecture, and emergency disaster relief personnel coordinating efforts in natural disasters. In these applications, where a fixed backbone is not available, a readily deployable wireless network is needed. Mobile ad hoc networks are also a good alternative in rural areas or third world countries where basic communication infrastructure is not well established. Another interesting application of mobile ad hoc networks is ubiquitous computing. Intelligent devices are connected with one another via wireless links and are self-organized in such a way that a newly joined node can request service from local servers without any human intervention.

 When designing mobile ad hoc networks, several interesting and difficult problems arise due to shared nature of the wireless medium, limited transmission power (range) of wireless devices, node mobility, and battery limitations. The limited transmission range of wireless network interfaces coupled with the highly dynamic routing infrastructure, due to mobility, create a lot of concerns when addressing issues such as dynamic routing, efficient channel access and quality-of-service (QoS) support.

 This tutorial will describe first the idea of ad hoc networking and scenarios where this technology will make an impact. How the environment of an ad hoc network is very different from the wired environment, and the effect this has on the design and operation of routing protocols for ad hoc networks will be extensively explained. A description of a number of different issues related to medium access control (MAC), routing, and QoS in mobile ad hoc networks, including the prominent protocols under consideration for standardization by the IETF, will follow up.

 Finally, integration issues with wide area mobility models, such as Mobile-IP, and Cellular systems, such as the GSM, will also be presented. Open problems and challenges for ad hoc networks will conclude the presentation.


 Tutorial Outline:

1.       Introduction to Wireless Networks

a.        GSM/GPRS wireless communications systems

b.       Baseline UMTS infrastructure

c.        Evolution of All-IP wireless networks


2.       Mobile AD HOC Networking

a.        Issues &Applications

b.       Research Challenges: from MAC to Transport Layer


3.       Dynamic Routing in Mobile AD HOC Networks

a.        Routing problems in MANETs

b.       Standardization efforts and the role of the IETF MANET WG

c.        Overview of IETF MANET Routing Protocols & Analysis of the RDMAR protocol (IETF candidate by G. N. Aggélou)


4.       Wireless Medium Access Control/Channel Access Protocols

a.        Problems at Wireless Access Layer

b.       Overview of IEEE 802.11 & ETSI HIPERLAN type 2 protocols

c.        Analysis of MBCA/BRCA Channel Assignment (Filed for Patent by G. N. Aggélou)


5.       Quality-of-Service (QoS) in Wireless/Mobile Networks

a.        Issues & problems

b.       QoS Signalling protocols

c.        Framework for QoS Wireless Access


6.       Integration with Wide-Area Mobility Models

a.        Issues, Challenges & System Requirements

b.       Analysis of an integrated GSM-MANET model (Proposed model to Nokia 3G Lab/UK by G. N. Aggélou)


7.       Conclusions & Discussion

Intended Audience:

This presentation is designed to provide an overview of research issues related to mobile ad hoc networking. The presentation should benefit researchers as well as postgraduate students from academia, who are interested in areas related to wireless communications and mobile networking.

Speaker's Biography:

George N. Aggelou ( is a full-time Professor in the Institute of Technology, Athens, Greece and director of G-Alpha Telecomms, Athens, Greece. He holds a Ph.D. in Mobile Multimedia Ad Hoc Networks, a B.Eng. in Communications Networks and a B.Sc. in Electronics.

In the past years George has joined various international companies, including IBM, Thomas J. Watson Research Center, NY as a research assistant, D.M. Data, NJ as a senior software engineer, CISCO Systems, London, UK as a UMTS Consultant Engineer and INTRACOM S.A, Athens, Greece as a senior UMTS research engineer. In 1999, he also co-founded Mobile E-Commerce Technologies, in London, UK.

George is the editor of a number of conference and journal publications, IETF drafts and one patent. He is the author of the book “Mobile Ad Hoc Networking: Design and Integration” by Mcgraw-Hill, February 2003, and co-author of the book “Handbook of Wireless Ad Hoc Networks” by CRC Press, September 2002. He has served as a technical program committee member in a number of international conferences and as a panelist at ATAMS' 2001. He is a member of the editorial board of the IEEE Transactions on Wireless Communications (TWireless). George was the recipient of the 2000 RACAL Prize for Research Excellence, honored by Dr. Chris Ash, RACAL Research Director.