MOBILE AND WIRELESS COMMUNICATION NETWORKS IFIP - The International Federation for Information Processing IFIP was founded in 1960 under the auspices of UNESCO, following the First World Computer Congress held in Paris the previous year. An umbrella organization for societies working in information processing, IFIP's aim is two-fold: to support information processing within its member countries and to encourage technology transfer to developing nations. As its mission statement clearly states, IFIP's mission is to be the leading, truly international, apolitical organization which encourages and assists in the development, exploitation and application of information technology for the benefit of all people. IFIP is a non-profitmaking organization, run almost solely by 2500 volunteers. It operates through a number of technical committees, which organize events and publications. IFIP's events range from an international congress to local seminars, but the most important are: • The IFIP World Computer Congress, held every second year; • Open conferences; • Working conferences. The flagship event is the IFIP World Computer Congress, at which both invited and contributed papers are presented. Contributed papers are rigorously refereed and the rejection rate is high. As with the Congress, participation in the open conferences is open to all and papers may be invited or submitted. Again, submitted papers are stringently refereed. The working conferences are structured differently. They are usually run by a working group and attendance is small and by invitation only. Their purpose is to create an atmosphere conducive to innovation and development. Refereeing is less rigorous and papers are subjected to extensive group discussion. Publications arising from IFIP events vary. The papers presented at the IFIP World Computer Congress and at open conferences are published as conference proceedings, while the results of the working conferences are often published as collections of selected and edited papers. Any national society whose primary activity is in information may apply to become a full member of IFIP, although full membership is restricted to one society per country. Full members are entitled to vote at the annual General Assembly, National societies preferring a less committed involvement may apply for associate or corresponding membership. Associate members enjoy the same benefits as full members, but without voting rights. Corresponding members are not represented in IFIP bodies. Affiliated membership is open to non-national societies, and individual and honorary membership schemes are also offered. MOBILE AND WIRELESS COMMUNICATION NETWORKS IFIP 19th World Computer Congress, TC-6, 8th IFIP/IEEE Conference on Mobile and Wireless Communications Networks, August 20-25, 2006, Santiago, Chile Edited by Guy Pujolle University Pierre and Marie Curie (Paris 6), France Springer Library of Congress Control Number: 2006927821 Mobile and Wireless Communication Networks Edited by G. Pujolle p. cm. (IFIP International Federation for Information Processing, a Springer Series in Computer Science) ISSN: 1571-5736/ 1861-2288 (Internet) ISBN: 10:0-387-34634-1 ISBN: 13: 9780-387-34634-2 elSBN: 10:0-387-34736-4 Printed on acid-free paper Copyright © 2006 by International Federation for Information Processing. All rights reserved. This work may not be translated or copied in whole or in part without the written permission of the publisher (Springer Science+Business Media, LLC, 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use in connection with any form of information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed is forbidden. The use in this publication of trade names, trademarks, service marks and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. Printed in the United States of America. 9 8 7 6 5 4 3 21 springer.com MWCN'06 A Survey on Wireless Ad Hoc Networks 1 Marcelo G. Rubinstein, Igor M. Moraes, Miguel Elias M. Campista, Luis Henrique M. K. Costa, Otto Carlos M. B. Duarte HIT: A Human-Inspired Trust Model 35 Pedro B. Velloso, Rafael P. Laufer, Otto C. M. B. Duarte, Guy Pujolle Privacy and Location-Aware Service Discovery for Mobile and Ubiquitous Systems 47 Leonardo Galicia Jimenez, J. Antonio Garcia-Macias An Adaptive Approach to Service Discovery in Ad Hoc Networks _6i Carlos Henrique Pereira Augusto, Jose Ferreira de Rezende Performances of geographical routing protocols combined with a position estimation process in wireless heterogenous networks 77 Erwan Ermel, Anne Fladenmuller, Guy Pujolle Event-Driven Field Estimation for Wireless Sensor Networks 89 Daniel de O. Cunha, Otto Carlos M. B. Duarte, Guy Pujolle Exploiting Web Technologies to Build Autonomic Wireless Sensor Networks 99 Fldvia C Delicato, Luci Pirmez, Paulo F. Pires, Jose Ferreira de Rezende Energy Efficiency Maximization for Wireless Sensor Networks 115 Inwhee Joe A Simple and Fair Proposal to Improve the Performance of the IEEE 802.11e Enhanced Coordination Function 123 Marta Barria, Pablo Sanchez, Luciano Ahumada A Comparative Analysis of Adaptive Middleware Architectures Based on Computational Reflection and Aspect Oriented Programming to Support Mobile Computing Applications 133 Celso Maciel da Costa, Marcelo da Silva Strzykalski, Guy Bernard ISPCell: An Interactive Image-Based Streaming Protocol for Wireless Cellular Networks 149 Azzedine Boukerche, Richard Werner Nelem Pazzi, Tingxue Huang The Generic Context Sharing Protocol GCSP 161 Rony Chahine, Claude Rigault ASMA: Towards Adaptive Secured Multipath in MANETs 175 Vincent Toubiana, Honda Labiod Wireless Ad Hoc Networks on Underserved Communities:An Efficient Solution for Interactive Digital TV 187 Miguel Elias M. Campista, Igor M. Moraes, Pedro Miguel Esposito, Aurelio Amodei Jr., Daniel de O. Cunha, Luis Henrique M. K. Costa, Otto Carlos M. B. Duarte Understanding the Role of Mobile Ad hoc Networks in Non- traditional Contexts 199 Roberto G. Aldunate, Gregg E. Larson, Miguel Nussbaum, Sergio F. Ochoa, Oriel A. Herr era A Time-based Admission Control Mechanism for IEEE 802.11 Ad Hoc Networks 217 Carlos Rodrigo Cerveira, Luis Henrique M. K. Costa Evaluation and Improvement of Multicast Service in 802.11b 229 Christian Bravo, Agustin Gonzalez A Survey on Wireless Ad Hoc Networks Marcelo G. Rubinstein^ Igor M. Moraes^, Miguel Elias M. Campista^, Luis Henrique M. K. Costa^, and Otto Carlos M. B. Duarte^* 1 PEL/DETEL/FEN - Universidade do Estado do Rio de Janeiro R. Sao Fco. Xavier, 524 - 20550-013 - Rio de Janeiro - RJ - Brazil ^ GTA/COPPE/Poli - Universidade Federal do Rio de Janeiro P.O. Box 68504 - 21945-970 - Rio de Janeiro - RJ - Brazil Abstract. A wireless ad hoc network is a collection of wireless nodes that can dynamically self-organize into an arbitrary and temporary topology to form a network without necessarily using any pre-existing infrastructure. These characteristics make ad hoc networks well suited for military activities, emergency operations, and disaster recoveries. Nevertheless, as electronic devices are getting smaller, cheaper, and more powerful, the mobile market is rapidly growing and, as a con sequence, the need of seamlessly internetworking people and devices becomes mandatory. New wireless technologies enable easy deployment of commercial applications for ad hoc networks. The design of an ad hoc network has to take into account several interesting and difficult problems due to noisy, limited-range, and insecure wireless transmis sions added to mobility and energy constraints. This paper presents an overview of issues related to medium access control (MAC), routing, and transport in wireless ad hoc networks and techniques proposed to improve the performance of protocols. Research activities and problems requiring further work are also presented. Finally, the paper presents a project concerning an ad hoc network to easily deploy Internet services on low-income habitations fostering digital inclusion. 1 Introduction Wireless networks are being increasingly used in the communication among devices of the most varied types and sizes. Personal computers, handhelds, tele phones, appliances, industrial machines, sensors, and others are being used in several environments, such as residences, buildings, cities, forests, and battle fields. Different wireless network standards and technologies have appeared in the last years to enable easy deployment of applications. The deployment of wireless networks where there is no infrastructure or the local infrastructure is not reliable can be difficult. Ad hoc networks have been proposed in order to solve such problems. A wireless ad hoc network is a collection of wireless nodes that can dynamically self-organize into an arbi trary and temporary topology to form a network without necessarily using any Supported by CNPq, CAPES, FAPERJ, UOL, FUJB, FINEP, and FUNTTEL. Please use the following format when citing this chapter: Rubinstein, M.G., Moraes, I.M., Campista, M.E.M., Costa, L.H.M.K., Duarte, O.C.M.B., 2006, in IFIP International Federation for Information Processing, Volume 211, ed. PujoUe, G., Mobile and Wireless Communication Networks, (Boston: Springer), pp. 1—33. 2 Rubinstein et al. pre-existing infrastructure. In ad hoc networks, each node may communicate directly to each other. Nodes that are not directly connected communicate by forwarding their traffic through intermediate nodes. Every ad hoc node acts as a router. The main advantages of ad hoc networks are flexibility, low cost, and robust ness. Ad hoc networks can be easily set up, even in desert places and can endure to natural catastrophes and war. These characteristics make ad hoc networks well suited for military activities, emergency operations, disaster recovery, large scale community networks, and small networks for interaction between meeting attendees or students in a lecture room. The design of a wireless ad hoc network has to take into account several in teresting and difficult problems. Traditional wireless communication problems related to the physical medium, such as low transmission rate, high bit error rates, noise, limited range, and significant variation in physical medium condi tions, must be overcomed. In the MAC sublayer, the difficulty of collision detec tion and the hidden and the exposed terminal problems demand new medium access algorithms. Moreover, as wireless ad hoc nodes may move arbitrarily and the status of the communication links between the nodes may vary, routing protocols proposed for wired networks are not suited for operation in wireless ad hoc networks. Several routing protocols have been proposed to cope with the various challenges of ad hoc networks. At the transport layer, TCP-like trans port protocols also present several problems when used on wireless networks. High bit-error rates and frequent route failures reduce TCP performance, de manding modifications to TCP or the design of new transport protocols. Other issues are also important when designing a wireless ad hoc network. The uncontained shared medium creates difficult challenges for securing the wireless network. On the other hand, the use of mobile devices equipped with radio interfaces turns energy conservation an important issue. Additionally, peculiarities of the wireless technology used, such as multiple channels and directional antennas, may improve the performance of the network but have to be carefulley taken into account in redesigning some of the protocol layers. This paper presents an overview of issues related to MAC, routing, and transport in wireless ad hoc networks and techniques proposed to improve the performance of protocols. Research activities and problems requiring further work are also presented. Finally, the paper presents a project concerning an ad hoc network to easily deploy Internet services on low-income habitations fostering digital inclusion. This paper is organized as follows. Section 2 presents different MAC proto cols designed for wireless ad hoc networks. Section 3 describes Bluetooth and IEEE 802.11, the most widespread technologies for wireless ad hoc networks. Section 4 compares the main routing protocols for ad hoc networks. In Section 5, we present protocol proposals to solve the TCP performance issues related to wireless networks. Section 6 presents the issues related to directional antennas and security and gives an overview of a project that investigates a community ad hoc network for underserved populations. A Survey on Wireless Ad Hoc Networks 3 2 Medium Access Control Protocols The design of a suitable Medium Access Control (MAC) protocol is an im portant issue for an ad hoc network. The protocol must deal with channel constraints, attenuation, and noise, whereas provide an efficient medium access considering requirements, such as quality of service (QoS), low energy consump tion, fairness, and scalability. MAC protocols for wireless networks can be classified as contention-free or contention-based, depending on the medium access strategy [1]. The contention- free schemes pre-define assignments to allow stations to transmit without con tending for the medium, e.g., TDMA, CDMA, FDMA, polling, and token-based. Contention-free mechanisms are normally employed to provide bounded end- to-end delay and minimum bandwidth, privileging delay sensitive applications such as audio and video streams. Bluetooth personal area networks employ a master-slave MAC mechanism. On the other hand, contention-based schemes are more appropriate for sporadic data transfer on mobile networks due to the random and temporary nature of the topologies. Wi-Fi local area networks in their ad hoc mode employ contention-based MAC protocols. ALOHA and Slotted-ALOHA are the pioneers contention-based schemes for medium access. In ALOHA, a station accesses the medium as soon as it has a frame to send. If two or more stations send data at the same time collisions oc cur. To decrease the collision probability, in the Slotted-ALOHA access scheme, a station must wait for the beginning of a pre-defined interval of time to start its transmission. Slotted-ALOHA doubled the efficiency of ALOHA, however, it introduced the necessity of synchronization. CSMA (Carrier Sense Multiple Access) is another access scheme that added carrier sensing before transmitting a frame to minimize the number of collisions. In CSMA, a station that has data to send becomes aware of current transmissions sensing the medium. If a carrier is sensed, the medium is considered busy and the station postpones its medium access. Nevertheless, if the medium is idle, the station transmits its data frame immediately. CSMA can be non-persistent or p-persistent depending on the scheme deployed to attempt a transmission after sensing the medium busy. The non-persistent CSMA sets a random period of time to perform another medium access. In the p-persistent CSMA the station transmits with a probability p as soon as the medium gets idle. The most famous access scheme for wired net works is a variation of CSMA persistent that detects collisions. This scheme is employed by Ethernet and is called Carrier Sense Multiple Access with Collision Detection. Unfortunately, in free space collision detection is not possible. Thus, a successful reception is not guaranteed because stations may not sense a col lision at the receiver. The phenomenon known as the hidden terminal problem is depicted in Figure 1. In this figure, each station centers a dotted circle that represents its own transmission range. In the example of Figure 1, the station A is transmitting to B. As station C cannot sense the ongoing transmission, it may also transmit to B, resulting in a collision at B.