Paper Submission
Call for Papers
Techn. Papers
Cluster Day

[full papers will be linked after the workshop with permission of the authors]

Workshop Presentations

Tuesday 24 May 2005

Abstracts & Papers


Tuesday, 10:30 – 12:30, B.5: Session I-a [Sensor Networks]


ID:                   48

Title:                 On the Probability Distribution of the Minimal Number of Hops Between any Pair of Nodes in a Bounded Wireless Ad-Hoc Network Subject to Fading

Authors:            Sayandev Mukherjee, Dan Avidor

Affiliation:         Wireless Research Laboratory, Lucent Technologies – Bell Laboratories, New Jersey, USA

Email:               {sayan,avidor}

Abstract:           We investigate an ad hoc network where node locations are distributed according to a homogeneous Poisson process with intensity ln. We assume that all the nodes are equipped with an identical wireless transceiver capable of operating satisfactorily up to a certain maximal link loss. Our link model depends on the length of the link and on random lognormal fading. Each node functions as a source and destination of data packets, and may also serve as a repeater to transport packets over multi-hop routes as determined by the network router. We focus on the probability distribution of the minimum number of hops between a source and a destination node known to be at distance D from the source. When the distribution of source-to-destination distances is known, the distribution of the minimal number of hops between any arbitrary pair of nodes can also be found. Many variations of this same problem have been studied in the literature. However, as far as we know, no exact closed form analytic results for fading environments have been presented before.


ID:                   21

Title:                 On the Probability Bound for Uncovered Areas in Sensor Networks

Authors:            Wei Yen

Affiliation:         Department of Computer Science and Engineering, Tatung University


Abstract:           In a sensor network, a large number of sensors are deployed in the sensing field.  Although there are guidelines describing the recommended number of sensors, not many analyses have been done to capture the characteristics of the uncovered areas.  Given the system parameters, this paper provides a probability bound that estimates the likeliness of the uncovered areas.  We find that the probability bound is equal to the probability that no sensor is found in a corresponding circle.  This bound has a concise form and provides quantitative measurement to deployment efficiency.  In addition, it impacts other related research topics such as finding minimum full coverage sets for lengthening sensor expectancy.  Numerical results are included to show how the bound changes along with various system parameters.


ID:                   30

Title:                 A Hierarchical Model for a Sensor Network

Authors:            John Orriss, S.K. Barton, Roberto Verdone

Affiliation:         University of Manchester


Abstract:           This paper introduces a new model for a sensor network in which sensors report information to supervisors through cluster heads which are themselves selected at random from the sensors. Assuming an inverse power law for attenuation, various shadowing or fading models, and uniform random spatial distributions of sensors and supervisors, the probability distribution of the number of sensors reporting to a supervisor is obtained. The result is extended to the case of a hierarchy of supervisors, which may or may not themselves be sensors, each reporting to the next level up the hierarchy.


ID:                    90

Title:                 Self-organizing sensor networks with information propagation based on mutual coupling of dynamic systems [invited]

Authors:            Sergio Barbarossa

Affiliation:         Sergio Barbarossa, University of Rome "La Sapienza", INFOCOM Department


Abstract:           Sensor networks are typically used as a distributed system, composed of a set of cheap, lightweight components, for detection of events of interest or estimation of physical parameters. The most typical approach consists in asking the sensors to collect data and to send them to a sensor fusion center which takes the final decision. In this paper, we propose a totally different approach. Each network node is composed of a sensor, that measures the parameter of interest, and of a dynamic system (oscillator), initialized by the sensor measurement. The oscillators of nearby nodes are mutually coupled. We show that, through proper local coupling strategies, we may design networks, with no fusion center, where each dynamic system, on each node, converges to the globally optimal maximum likelihood estimator that could have been achieved only by an ideal fusion center having access to all system parameters and observations perfectly.


ID:                   83

Title:                 Power and Energy Consumption for Multi-Hop Protocols: A Sensor Network Point of View [invited]

Authors:            Katja Schwieger and Gerhard Fettweis

Affiliation:         Vodafone Chair Mobile Communications Systems, Dresden University of Technology, Mommsenstr. 18, D-01062 Dresden, Germany

Email:               {schwieg, fettweis}

Abstract:           Information theoretic approaches often investigate power consumption of mobile nodes in wireless multi-hop networks. In high data rate systems high spectral efficiencies are required to transmit data at a given bandwidth. On the other hand, bandwidth efficiency is not very important in low data rate networks, namely sensor networks. Here, the design criterium number one is energy efficiency, as the nodes are battery operated. Using known results from information theory, we investigate power consumption in multi-hop networks with simple protocols. Moreover we bridge the gap between power consumption and energy consumption and propose a model for the relation between those. Applying real-world radio chips the analysis combines theoretical and practical approaches. We show what transmission distance has to be exceeded to make multi-hop more energy efficient than direct transmission.


Tuesday, 13:30 – 15:30, B.5:  Session II-a [Network Capacity, Coding & Detection]


ID:                   81

Title:                 Network Coding for Wireless Applications: A Brief Tutorial [invited]

Authors (alph.):  Supratim Deb (3), Michelle Effros (4), Tracey Ho (3), David Karger (5), Ralf Koetter (2), Desmond Lun (1), Muriel Medard (1), Niranjan Ratnakar (2)           

Affiliation:         (1): Laboratory for Information and Decision Systems, Massachusetts Institute of Technology; (2): Coordinated Science Laboratory, University of Illinois Urbana-Champaign; (3) Lucent Bell Laboratories; (4) Data Compression Laboratory, California Institute of Technology; (5) Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology

Email:               medard@MIT.EDU

Abstract:           The advent of network coding promises to change many aspects of networking. Network coding moves away from the classical approach of networking, which treats networks as akin to physical transportation systems. We overview some of the main features of network coding that are most relevant to wireless networks. In particular, we discuss the fact that random distributed network coding is asymptotically optimal for wireless networks with and without packet erasures. These results are extremely general and allow packet loss correlation, such as may occur  in fading wireless channels. The coded network lends itself, for multicast connections, to a cost optimization which not only outperforms traditional routing tree-based approaches, but also lends itself to a distributed implementation and to a dynamic implementation when changing conditions, such as mobility, arise. We illustrate the performance of such optimization methods for energy efficiency in wireless networks and propose some new directions for research in the area.


ID:                   87

Title:                 On the relation between Source and Channel Coding and Sensor Network Deployment [invited]

Authors:            Iordanis Koutsopoulos1, Stavros Toumpis2 and Leandros Tassiulas1

Affiliation:         1Department of Computer Engineering and Communications, University of Thessaly, Greece, and Center for Research and Technology Hellas (CERTH), 2Telecommunications Research Center Vienna (ftw.)

Email:               {jordan,leandros},

Abstract:           In this paper, we identify analogies between the themes of source and channel coding and some problems that arise in the context of wireless sensor networks. Our aim is to establish a framework within which well-known methods from the former two areas are used in tackling problems associated to sensor networks. First, we address an important tradeoff between required precision and transmission rate in a class of sensor networks by using rate-distortion theory. We then address the problem of optimal placement of super-sensors in an area covered by sensors with the objective to minimize a generic cost factor that captures several special cases, and we show the analogy to a vector quantization problem. Based on the analogy of the resulting system with a discrete source emitting symbols, we show that a traffic load balancing problem in the sensor network can be reduced to an entropy maximization problem. Finally, we consider a hierarchical sensor coverage problem that involves deploying a set of sensors with sophisticated sensing capabilities over a grid of ordinary sensors. We cast the problem in the framework of channel coding by defining appropriate analogies under the common denominator of redundancy.


ID:                   80

Title:                 On coded cooperative schemes: codes, choice of partners and routes [invited]

Authors:            Liwen Yu, Jerry C.H. Lin, Andrej Stefanov

Affiliation:         Polytechnic University, Brooklyn, NY


Abstract:           In this paper, we consider the applicability of cooperative information transmission to wireless local area networks (WLANs). As the next generation WLANs will utilise OFDM, we consider the analysis and design of cooperative codes in the context of OFDM systems. We then consider the information transfer through WLANs from an energy consumption perspective. For networks operating over a slowly Rayleigh fading channel, we consider the optimum choice of partners for cooperation and develop minimum energy cooperative routing protocols.


ID:                   70

Title:                 A Cross-Layer Approach to Decentralized Detection in Sensor Networks with Noisy Communication Links and Multiple Observations

Authors:            Gianluigi Ferrari and Roberto Pagliari

Affiliation:         Universita di Parma, Dipartimento di Ingegneria dell’Informazione, Parco Area delle Scienze 181A, I-43100 Parma, Italy

Email:     ,

Abstract:           This paper presents a general approach to distributed detection in sensor networks in scenarios with noisy communication links between the sensors and the fusion center (or access point, AP). The sensors are independent and observe a common phenomenon. While in most of the literature the performance metrics usually considered are missed detection and false alarm probabilities, in this paper we follow a Bayesian approach for the evaluation of the probability of decision error at the AP. We first derive an optimized fusion rule at the AP in a scenario with ideal communication links. We then consider the presence of noisy links and model them as binary symmetric channels (BSCs). In this case, we show that if the noise intensity is above a critical level (i.e., the cross-over probability of the BSC is above a critical value), the probability of decision error at the AP reduces when the AP selectively discards the information transmitted by the sensors with noisy links. We will also show that use of multiple observations at the sensors can be traded for increased robustness against channel impairments in the communication links.


ID:                   53

Title:                 Decentralized Detection In Binary Dense Sensor Networks: To Transmit Or Not To Transmit

Authors:            Marcelino Lazaro, Antonio Artes-Rodrıguez, and Matilde Sanchez-Fernandez

Affiliation:         Departmento de Teorıa de la Senal y Comunicaciones, Universidad Carlos III de Madrid, Avda. Universidad 30, 28911, Leganes (Madrid) SPAIN

Email:               {mlazaro,antonio,mati}

Abstract:           We consider the problem of binary decentralized detection in large-scale, randomly deployed, dense wireless sensor networks. We compare the performance of a Neyman-Pearson global detector under two different transmission strategies. The first one is based on a censoring scheme in which only the sensors with positive detections try to transmit; the second being the corresponding uncensored one. The aim of the paper is to determine in which situations each strategy needs less energy to achieve a given probability of error.


Tuesday, 16:00 – 18:00, G.79: Session III-a [MAC – Part I]


ID:                   35

Title:                 Performance Evaluation of a Stability-Oriented Clustering Protocol for Ad Hoc Networks using different Mobility Models

Authors:            Vincenzo Cacace, Danilo Blasi, Luca Casone

Affiliation:         STMicroelectronics, Lecce Lab (Italy)

Email:               {vincenzo.cacace, danilo.blasi, luca.casone}

Abstract:           In wireless, infrastructure-less, self-organizing and multihop networks - generally termed ‘Ad Hoc’ – several clustering protocols have been designed to establish a virtual infrastructure in an otherwise flat network, thus enhancing communications reliability and network management efficiency. However, the usefulness of such hierarchical organizations strongly depends on how often they need to be refreshed because of hosts’ movements: for that reason, any clustering scheme should be conceived to cope with nodes’ mobility. In this paper, we test, by means of computer simulations, how a carefully designed clustering scheme – i.e. a protocol which correctly takes into account the scenario peculiarities and the fact that organized nodes may move over time – is effective in dominating the network dynamism, no matter what mobility model and mobility rates are chosen.


ID:                   82

Title:                 Modelling for Wireless Sensor Network Protocol Design [invited]

Authors:            Roberto Verdone, Chiara Buratti

Affiliation:         CNIT, IEIIT-BO/CNR, DEIS, University of Bologna, Italy

Email:     ;

Abstract:           Protocol design for a Wireless Sensor Network (WSN) must jointly take many aspects into account, owing to the embedded nature of the devices, and the needs for energy efficiency, scalability, self-organisation and robustness to heterogeneous and unplanned environments: all these are crosslayer issues. As usual for wireless systems, protocol design normally includes a heuristic design phase, followed by validation and optimisation that can be achieved through simulation, mathematical and/or experimental approaches. In the two former cases, models are needed to specify the environment addressed by the researcher: as usual, models should be simple and realistic at the same time, where these two characteristics must be defined according to the target of the evaluation procedure. Models should also be agreed and shared among the scientific world in order to allow the comparability of results achieved by different researchers. In a wider sense, modelling for protocol design should also include the definition of the performance figures that have to be selected to measure protocol optimality, or to benchmark them. Some models have got in the last year a natural consensus, like for instance the geometrical distribution of nodes, often considered to be (statistically) uniformly distributed over a square area. However, other models for WSN protocol design still need to find consensus. This paper addresses this aspect and discusses the relevance of some of the issues not sufficiently accurate when dealing with modelling for WSN protocol design. To provide a solid base to this discussion, some results achieved through different means, both via simulation, mathematical or experimental approaches, are reported in the paper; as a common denominator to the different approaches and algorithms discussed, the performance of WSNs is measured in terms of network lifetime (related to energy efficiency), for which a new definition is given in this paper.


ID:                   54

Title:                 A MAC Protocol for Wireless Ad Hoc Networks with Power Control

Authors:            Sylwia Van den Heuvel - Romaszko, Chris Blondia

Affiliation:         University of Antwerp, PATS Research Group, Middelheimlaan 1, B-2020 Antwerpen

Email:               sylwia.romaszko,

Abstract:           We propose a MAC protocol which achieves better spatial reuse of spectrum thanks to power adjustments based on the number of neighbors in the one-hop neighborhood. Through many simulations we show that our algorithm outperforms the IEEE 802.11 standard, also in high interference environments.


ID:                   74

Title:                 A New Approach for the Throughput Analysis of IEEE 802.11 in Networks with Hidden Terminals

Authors:            Athanasia Tsertou, David I. Laurenson, John S. Thompson

Affiliation:         Signals and Systems Group, School of Engineering and Electronics, The University of Edinburgh, EH9 3JL, Edinburgh, UK

Email:               {a.tsertou, dave.laurenson, john.thompson}

Abstract:           The dominance of IEEE 802.11 in the area of singlehop wireless networks is self-evident and has been supported by both simulation results and analytical modeling. On the contrary, the question as to whether the Distributed Coordination Function (DCF) performs satisfactorily enough in multi-hop networks still remains open. In this paper, we aim to give an initial view of this by introducing an analytical framework for the evaluation of DCF in networks exhibiting hidden terminals. The accuracy of our model is determined by comparison with simulations.


ID:                   7

Title:                 Performance Evaluation of a Wireless LAN Dynamic Multi Channel Allocation Strategy

Authors:            C. Taddia, G. Mazzini

Affiliation:         University of Ferrara, via Saragat 1, 44100 Ferrara, Italy

Email:     ,

Abstract:           In this paper we present a Per-Packet Dynamic Channel Allocation algorithm with QoS support to be applied in a wireless multichannel environment. The strategy has been studied both in a simulative and in a more general analytical perspective. The results, concerning the packet drop probability D and the average number of used channel per non dropped activity U, show a high system efficiency in the resource use, with the possibility to be increased by simply grow the number of available channels; measured trend results linear and this indicates that quite good performance may be obtained by the system really outperforming the classical not cooperative solutions. The drop tends to decrease with the number of available channels, even if it becomes very flat when more than 5 channel are considered. Furthermore we can remark that our Per-Packet algorithm allows a smarter channel reuse in respect with static channel allocation schemes.


Tuesday, 10:30 – 12:30, G.73: Session I-b [Routing Protocols – Part I]


ID:                   29

Title:                 A Novel Bus Lane Scheme for QoS Routing in Mobile Ad Hoc Networks

Authors:            Lin Xiao and Eliane Bodanese

Affiliation:         Department of Electronic Engineering, Queen Mary, University of London

Email:     ,

Abstract:           Ad hoc networks are multihop wireless networks without fixed infrastructure, whose topology changes frequently and unpredictably. How to issue routes in such networks with sufficient and constant bandwidth is a key problem for some real-time services like audio and video services. This paper proposes a novel QoS solution using code division multiple access (CDMA) scheme, named CDMA Bus Lane, which combines the network layer with lower layers together to set up and reserve an interferencefree path dynamically for each real-time flow according to its bandwidth requirements. The bandwidth calculation and the channel spreading code assignment method are introduced particularly in this paper. The code used in the Bus Lane scheme is the Original Variable Spreading Factor (OVSF) code. Also an on-demand routing algorithm has been proposed to calculate and reserve the bandwidth hop by hop from source to destination.


ID:                   49

Title:                 The capacity and packets delivery of MANET On Road: MANETOR

Authors:            Jiang Hao1,2 , Kun Mean Hou1, Jian-Jin Li1, Jean-Pierre Chanet3, Christophe de Vaulx1, Hai-Ying Zhou1,2, Gil de Sousa1

Affiliation:         1 LIMOS Laboratoire UMR 6158 CNRS, Campus des Cézeaux, BP 10125, AUBIERE 63173 CEDEX, France, 2Wuhan University, School of Electronic Information, Wuhan, Hubei, 430079, P.R.China, 3Cemagref, 24 Av. Des Landais, BP 50085 63172 Aubière, France


Abstract:           IVC based on MANET has attracted the interests of many automobile manufactures and researchers. The MANET in IVC is named as MANETOR(MANET On Road). In this paper, the capacity and packets delivery are investigated. Through the theoretical analyse of MANETOR, it is clear that the capacity of MANETOR is limited, and a pipe model allowing to estimating the capacity of MANETOR is proposed. With limited capacity, packets delivery is hard in MANETOR. In fact some communication patterns in MANET, such as broadcasting and cross traffic, will impact the packets delivery in MANETOR. The probability model of packet delivery success is evaluated and three methods to improve the PDR(Packets delivery Ratio) of MANETOR are proposed. And they are proved by simulation in ns2.


ID:                   69

Title:                 Physical Layer-Constrained Routing in Ad-hoc Wireless Networks: A  Modified AODV Protocol with Power Control

Authors:            Gianluigi Ferrari1, Simone A. Malvassori1, Marco Bragalini1 and Ozan K. Tonguz2

Affiliation:         1Universit‑a di Parma, Dipartimento di Ingegneria dell'Informazione, I-43100 Parma, Italy; 2Carnegie Mellon University, Electrical and Computer Engineering Department, Pittsburgh, PA 15213-3890, USA

Email:     ,,

Abstract:           Routing in ad hoc wireless networks is not only a problem of finding a route with shortest length, but it is also a problem of finding a stable and good quality communication route in order to avoid any unnecessary packet loss. In this paper, we propose a modified ad hoc on-demand distance vector (MAODV) routing protocol derived from the AODV routing protocol by considering the bit error rate (BER) at the end of a multi-hop path as the metric to be minimized for route selection. While the performance of MAODV is generally worse than that of AODV, we show that use of distributed power control (PC) dramatically improves the packet delivery ratio with MAODV routing protocol (at the cost of a delay increase), whereas has a negligible effect on the network performance guaranteed by the AODV routing protocol. Our results suggest that MAODV-PC protocol has to be preferred, in terms of packet delivery ratio, in network scenarios with low traffic load and limited node mobility.



ID:                   67

Title:                 Multivariate Analysis of the Cross-Layer Interaction in Wireless Networks Simulations

Authors:            Jean-Michel Dricot, Philippe De Doncker, Esteban Zimànyi

Affiliation:         Computer & Network Engineering Dpt., Université Libre de Bruxelles, Av. Franklin Roosevelt, 50, 1050 Brussels,Belgium


Abstract:           While there exist many papers that compare the performances of different routing protocols for wireless ad-hoc networks, these analysis are often realized using tools from descriptive statistics (curves drawing, means and variances computation, etc.). In this paper we propose the use of multivariate statistics to unveil and characterize the interaction between the input variables of a wireless network simulation. The ANalysis Of VAriance (ANOVA) tool helps us in getting the impact of the four variables that we have studied: routing algorithm, propagation conditions, nodes density, and mobility scheme. Using our methodology we are able to show that not only a single layer of the protocol stack can affect the network operation but also the interactions between two or more inputs of the simulation. An important implication of the study is that the efficiency of the routing algorithm is strongly correlated with the environment (indoor/outdoor) and that the performance analysis of the lower levels of the OSI stack should be conducted by focusing on a single layer. In the same way, wireless networks simulators cannot be considered accurate if they neglect a realistic-enough implementation of the physical layer (i.e., propagation, interference and modulation)


ID:                   78

Title:                 A Cross-Layer Stability-based On-Demand Routing Protocol for Mobile Ad-Hoc Networks

Authors:            Lamia Romdhani, Christian Bonnet

Affiliation:         Institut Eurecom

Email:               {Romdhani, bonnet}

Abstract:           It is widely known that having neighbourhood information can help on optimizing the operations of several protocols including routing and medium access protocols. This work presents a new stability-based routing protocol for mobile ad hoc protocols that effectively determine and use this information. Unlike existing similar protocols, our proposal has two main specific features. First, it is designed for on-demand routing protocols like AODV protocol and second, and most importantly, it uses the cross-layer paradigm to gather some useful measurement from the MAC layer. Hence, we develop adaptive stability metrics to identify stable links in a mobile wireless networking environment based on the analysis of routing protocol periodic messages. Out metrics then only rely on on-line statistical evaluation of observed link durations. Neither do they require information on signal strength, nodes speeds, nodes directions, radio conditions, or spacing of the mobile devices, nor do they depend on the availability of additional hardware such as GPS receivers or a synchronisation of the devices. We demonstrate the ability of the metrics to select stable links with a high probability in a wide range of scenarios using ns-2 simulations.


Tuesday, 13:30 – 15:30, G.73: Session II-b [Routing Protocols – Part II]


ID:                   85

Title:                 Are Ad-hoc Networks Able to Substitute Cellular Networks? A Performance Comparison of Ad-hoc Network Routing Protocols in Realistic Scenarios [invited]

Authors:            1Mesut Gunes, 2Jan Siekermann

Affiliation:         1International Computer Science Institute (ICSI), Berkeley, CA, USA, 2Department of Computer Science, Informatik 4, RWTH Aachen University, Germany

Email:     ,

Abstract:           There are several deployment scenarios for mobile ad-hoc networks discussed in the literature. However, the most results have been made in artificial environments. In this paper we study the performance of state of the art routing protocols for mobile multi-hop ad-hoc networks in an environment which emulates a city downtown. The studied simulation environment differs in three aspects from that of well known: i) The used mobility model emulates a city downtown with several zones and different mobility models. ii) The number of mobile nodes and the number of connections is inspired from real traces. iii) We use duplex-connections.


ID:                   59

Title:                 Inherent Robustness of Reactive Routing Protocols against Selfish Attacks

Authors:            Asad Amir Pirzada and Chris McDonald

Affiliation:         School of Computer Science & Software Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009

Email:               {pirzada, chris}

Abstract:           Mobile ad-hoc wireless networks generally comprise nodes having meagre computation and communication resources. To perform multi-hop communication in a dynamic topology, these nodes execute special routing protocols. Each node performs the function of a a mobile router and directs packets to other nodes in the network. For accurate functioning of the network it is imperative that all nodes execute these routing protocols in a benevolent manner. However, as ad-hoc networks are usually established in a physically insecure wireless environment, the network memberships are violated allowing malicious nodes to also participate in the network. These nodes can launch an array of attacks against different network services including the routing process. In this paper, we evaluate the performance of three well known reactive routing protocols, in a network with varying numbers of malicious nodes. With the help of exhaustive simulations, we demonstrate that the performance of the three protocols varies significantly even under similar attack, traffic and mobility conditions.


ID:                   41

Title:                 Flooding Techniques for Resource Discovery on High Mobility MANETs

Authors:            Rodolfo Oliveira, Luis Bernardo, Paulo Pinto

Affiliation:         Deparamento de Engenharia Electrotechnica, Universidade Nova de Lisboa, Portugal


Abstract:           In this paper, we address high mobility AdHoc networks resource discovery problem. We use a virtual dynamic overlay network to perform broadcast flooding task optimization. Two new flooding techniques are proposed and compared with a global flooding strategy, and, a classical flooding scheme using source routing. Experimental results, obtained by several simulations implemented on ns-2, discourage the use of source routing in high-mobility MANETs, and show that most of the times, flooding-optimization techniques could achieve best successful resource discovery rates than using global or source-routing flooding.


ID:                   56

Title:                 Simulation vs. Emulation:  Evaluating Mobile Ad Hoc Network Routing Protocols

Authors:            Furqan Haq and Thomas Kunz

Affiliation:         Systems and Computer Engineering, Carleton University, Ottawa, Ont., Canada K1S 5B

Email:     ,

Abstract:           In  order  for  simulation  studies  to  be  useful,  it  is  very important that the simulation results match as closely as possible  with  the  testbed  results.  This paper  compares emulated testbed results with simulation results from NS2 and  GloMoSim.  OLSR  was  used  as  a  routing  protocol and NRL Mobile Network Emulator  (MNE)  for  dynamic topology  control  and  manipulation.  Five  Linux  based laptops,  equipped  with  IEEE  802.11b  wireless  network cards were used for testbed implementation. At low traffic rates, testbed results matched closely with the simulation results,  at  higher  traffic  rates,  testbed  results  not  only differed from the simulation results both qualitatively and quantitatively  but  the  simulation  results  from  both  the simulators were barely comparable in some scenarios.


ID:                   20

Title:                 Statistical Analysis of Traffic Measurements in a Disaster Area Scenario Considering Heavy Load Periods

Authors:            Nils Aschenbruck, Matthias Frank, Peter Martini

Affiliation:         University of Bonn, Institute of Computer Science IV, Roemerstr. 164, 53117 Bonn, Germany

Email:               {aschenbruck, matthew, martini}

Abstract:           Catastrophes cause an area of destruction including destroyed infrastructure. These disaster area scenarios are typical usage scenarios for mobile wireless ad-hoc networks (MANETs). The results of simulations used for performance analysis in MANETs strongly depend on the traffic model. In this paper, we perform statistical analysis of data, measured in a civil protection manoeuvre. Based on the analysis we generate traffic and compare it to the measured one by doing simulations of two broadcast routing protocols. Finally, we extend our model to concerning heavy load periods and examine the impact on the simulation results.


Tuesday, 16:00 – 18:00, G.73: Session III-b [Ad Hoc Networks]


ID:                   34

Title:                 Session Initiation Protocol Deployment in Ad-Hoc Networks: a Decentralized Approach

Authors:            Simone Leggio, Jukka Manner, Antti Hulkkonen, Kimmo Raatikainen

Affiliation:         Department of Computer Science, University of Helsinki, Finland

Email:               {simone.leggio, jukka.manner, antti.hulkkonen, kimmo.raatikainen}

Abstract:           Ad-hoc networks constitute a peculiar computing environment, characterized by the lack of centralized support from pre-existing network entities. Applications and protocols designed for centralized environments must be adapted for use in ad-hoc environments. For example, the baseline Session Initiation Protocol (SIP) strongly relies on the presence of an infrastructure, the SIP servers, and cannot therefore be deployed as it is in ad-hoc networks. This paper proposes a solution that enables devices in adhoc networks to use SIP functionalities in a decentralized way. Particularly, we embed a limited set of SIP server functionalities in the end devices to allow distribute session management for SIP end devices, without network support.



ID:                   26

Title:                 Integration of Heterogeneous Ad hoc Networks with the Internet

Authors:            Nico Bayer, Dmitry Sivchenko, Bangnan Xu 1), Sven Hischke 2), Veselin Rakocevic3), Joachim Habermann 4)

Affiliation:         1) T-Systems, SSC ENPS (Technologiezentrum), 64295 Darmstadt, Germany, 2)Deutsche Telekom AG, Friedrich-Ebert-Allee 140, D-53113 Bonn, Germany, 3)School of Engineering and Mathematical Sciences, City University, London EC1V 0HB, UK, 4) University of Applied Sciences Friedberg, 61169 Friedberg, Germany


Abstract:           This paper describes a testbed realized at T-Systems in Darmstadt (Germany) that handles the integration of ad hoc networks with the Internet. The testbed contains a Mobile Gateway that connects an IPv6 based ad hoc network over a cellular network (e. g. GPRS or UMTS) with the Internet. The testbed is also able to handle multiple gateways within the same ad hoc domain. This paper describes several mobility scenarios developed within the testbed, namely inter ad hoc domain mobility, intra ad hoc domain mobility and mobility of the whole ad hoc network. The paper also discusses main issues in the development of the testbed – gateway discovery, seamless mobility and the transmission of IPv6 packets over IPv4 infrastructures.


ID:                   92

Title:                 Towards End-to-End QoS in Ad Hoc Networks connected to Fixed Networks [invited]

Authors:            David Remondo

Affiliation:         Telematics Engineering Dep, Catalonia Univ. of Technology (UPC), Av. Del Canal Olimpic s/n, 08860 Castelldefels (Barcelona), Spain


Abstract:           We evaluate the scalability of a new protocol, named DS-SWAN, designed to support end-to-end QoS in ad hoc networks connected to fixed networks that use DiffServ. When congestion is excessive for the correct functioning of real-time applications, DS-SWAN determines the source of the problem and, if it is the case, allocates more resources to high priority traffic in the ad hoc network. The analysis includes the scalability with respect to the number of real-time traffic sources and node mobility in addition to the impact of best-effort traffic load. Simulation results show an improvement of end-to-end delays and jitter for real-time flows without starvation of background traffic.


ID:                   33

Title:                 Gateway Discovery Algorithm for Ad-Hoc Networks Using HELLO Messages

Authors:            Matthias Rosenschon a, Tilmann Mänz a, Joachim Habermann a, Veselin Rakocevicb

Affiliation:         a FH-Giessen-Friedberg, University of Applied Sciences, Wilhelm-Leuschner-Strasse 13, 61169 Friedberg, Germany, b School of Engineering and Mathematical Sciences, City University, London EC1V 0HB, United Kingdom

Email:     ,,

Abstract:           The connection of ad-hoc networks to the Internet is typically established via gateways. To start an Internet connection, in a first step gateways have to be discovered by the mobile nodes within the ad-hoc cluster. Several algorithms to perform the gateway discovery have been studied in the literature up to now. This paper describes an approach for gateway discovery based on HELLO packets of the AODV protocol. The performance of the new algorithm in terms of the discovery time and the handover delay is compared to the well known methods using NS-2 simulations. Conclusions are drawn from the simulations to further improve the performance of common gateway discovery algorithms.


ID:                   40

Title:                 Distributed Gateways in Multi-Plane Ad hoc Networks

Authors:            Sutthisak Inthawadee and Dobri Atanassov Batovski

Affiliation:         St. Gabriel Telecommunications Laboratory, Department of Telecommunications Science, Faculty of Science and Technology, Assumption University, 682 Soi 24, Ram Khamhaeng Road, Hua Mak, Bang Kapi, Bangkok 10240, Thailand

Email:     ,

Abstract:           The concept of multi-plane ad hoc networks is introduced for two emerging applications, namely, multi-plane three-dimensional indoor topologies and virtual multi-plane routing in dense networks. The connectivity between different planes is established with the use of distributed gateways consisting of a prescribed number of interconnected nodes on each plane. Several typical node configurations are considered analytically as open Johnson’s networks. The load balancing in a distributed gateway consisting of a number of connected nodes in a prescribed topology is considered in terms of the flow equalization of both departing and internal rates for arbitrary arrival rates.


 Workshop Presentations

Wednesday 25 May 2005

Abstracts & Papers


Wednesday, 10:30 – 12:30, B.5: Session I-a [MAC – Part II]


ID:                   88

Title:                 Towards High Speed Wireless Personal Area Network – Efficiency Analysis of MBOA MAC [invited]

Authors:            1Yunpeng Zang, 1Guido R. Hiertz, 2Jörg Habetha, 2Begonya Otal, 2Hamza Sirin and 2Hans-J Reumerman

Affiliation:         1Chair of Communication Networks, RWTH Aachen University, 52074 Aachen, Germany, 2Philips Research Aachen, 52066 Aachen, Germany


Abstract:           A new generation of Wireless Personal Area Networks (WPANs) is intended for high data rate and mul-timedia applications. The MBOA WPAN system, which is standardized by the Multi-Band OFDM Alliance (MBOA), is able to provide data rates up to 480Mb/s over a short distance based on the Ultra-Wideband (UWB) frequency band as well as support the Quality of Service (QoS) for both isochronous and asynchronous traffic. The MBOA system has been considered as one of the most potential solutions for the Physical layer (PHY) and Medium Access Control (MAC) of the next generation of WPANs. In addi-tion to the high PHY data rates, the MBOA system provides also high MAC efficiency, especially for the high speed burst transmission and frames of small size. In this work we concentrate on the analysis of MBOA MAC layer efficiency via calculating the Theoretical Maximum Throughput (TMT). Both the numerical results and simulation results using the WARP2 simulation environment are presented for the efficiency evaluation of MBOA MAC. Index Terms—MultiBand OFDM Alliance (MBOA), Wireless Personal Area Network (WPAN), Medium Access Control (MAC), Distributed Reservation Protocol (DRP), Quality of Service (QoS), Ultra-Wideband (UWB).


ID:                   18

Title:                 Design and Implementation of a Low Cost Energy Efficient IEEE 802.11-based Ad Hoc Network

Authors:            Nikos Pogkas1 and George Papadopoulos 1,2

Affiliation:         1 Department of Electrical and Computer Engineering, University of Patras, Campus of Rio, Greece; 2 Industrial Systems Institute, Rion, Greece

Email:     ;

Abstract:           Network energy consumption is a critical issue in mobile communications and especially so in ad-hoc and sensor networks where small sized battery operated nodes must communicate for a long duration in dynamic network topologies. This paper presents a low cost energy efficient solution for IEEE 802.11 based ad hoc networks. Energy efficiency is achieved by the combination of a low power mode algorithm and a power aware routing strategy in order to reduce communication energy consumption and increase node lifetime. Another objective of the proposed routing strategy is the selection of stable links in order to achieve robust network operation. Simulation studies indicate a reduction in energy consumption and a significant increase in node lifetime whereas the network performance (delivery ratio and routing overhead) is not affected significantly. Finally, the hardware/software architecture of the wireless nodes is presented for a low cost design implementation.


ID:                   89

Title:                 An Application-Tailored MAC Protocol for Wireless Sensor Networks [invited]

Authors:            S. Chatterjea, L.F.W. van Hoesel and P. Havinga

Affiliation:         Department of Computer Science, University of Twente, P.O. Box 217, 7500AE Enschede, the Netherlands

Email:               {supriyo, hoesel, havinga}

Abstract:           We describe a data management framework suitable for wireless sensor networks that can be used to adapt the performance of a medium access control (MAC) protocol depending on the query injected into the network. The framework has a completely distributed architecture and only makes use of information available locally to capture information about network traffic patterns. It allows nodes not servicing a query to enter a dormant mode which minimizes transmissions and yet maintain an updated view of the network. We then introduce an Adaptive, Information-centric and Lightweight MAC (AI-LMAC) protocol that adapts its operation depending on the information presented by the framework. Our results demonstrate how transmissions are greatly reduced during the dormant mode. During the active mode, the MAC protocol adjusts fairness to match the expected requirements of the query thus reducing latency. Thus such a data management framework allows the MAC to operate more efficiently by tailoring its needs to suit the requirements of the application.



ID:                   77

Title:                 Towards a Fully Distributed QoS-Aware MAC Protocol for Multihop Wireless Networks

Authors:            Fethi Filali

Affiliation:         Institut Eurécom, 2229 Route des Crêtes, BP-193, 06904 Sophia-Antipolis, France


Abstract:           In this paper we propose a new MAC protocol designed for multihop wireless networks called QAMP (QoS Aware MAC Protocol). It is a distributed protocol and it supports QoS using a distributed reservation mechanism. Although QAMP could be implemented using a single channel, this paper focus on the QAMP's version using a common reservation channel and at least one data channel. QAMP's performance evaluation results are presented for several scenarios using analytical analysis and ns-2 simulations. We measure the saturation throughput and the delay of QAMP using the analytical analysis and based on the simulations, we show that our proposal outperforms 802.11 as it has a saturation throughput of about 97% of the physical capacity. Keywords: multi-hop wireless networks, medium access control, quality of service, reservation-based protocols, collision-free protocols.


ID:                   46

Title:                 A Statistical Approach to detect NAV Attack at MAC layer

Authors:            K.Sugantha, S.Shanmugavel

Affiliation:         Anna University, India

Email:     ,

Abstract:           This paper proposes and investigates a statistical approach to detect the NAV attack in MAC layer. We present simulation and analytical results showing that the NAV attack can under perform the standard 802.11 MAC protocol. Further no approach has been explicitly specified to detect this attack. This approach is a simpler method to detect NAV attack using Glomosim simulator. In this work we investigate the vulnerabilities and detect the NAV attack.


Wednesday, 13:30 – 15:30, B.5:  Session II-a [Mobile VCE]


ID:                   94

Title:                 Experimental Capacity Analysis for Virtual Antenna Arrays in Personal and Body Area Networks

Authors:            Dries Neirynck, Chris Williams, Andrew Nix, Mark Beach

Affiliation:         Centre for Communications Research, University of Bristol


Abstract:           We report on a channel measurement campaign using body and personal area network devices, placed both in an office and on-body. Inspired by the theoretical work on cooperation between devices, which predicts MIMO-like capacity gains for co-operative systems, the capacity of MIMO and cooperating devices are examined. Significant capacity gain is observed, even under line-of-sight conditions in the body area network. Power imbalance between individual channels due to shadowing or orientation, however, degrades the capacity increase when significant compared to the signal-to-noise ratio.


ID:                   93

Title:                 Performance Evaluation in Time-Synchronized Multi-Piconet Bluetooth Environments

Authors:            Imran Ashraf, Athanasios Gkelias, Leila Musavian, Mischa Dohler, A.H. Aghvami

Affiliation:         Centre for Telecommunications Research, King’s College London, UK


Abstract:          Multiple Bluetooth piconets operating in the globally available 2.4-GHz Industrial, Scientific and Medical (ISM) band are likely to co-exist in a physical environment, supporting applications such as wireless earphones, keyboards etc. An independently operating Bluetooth piconet will inevitably encounter the interference from collocated piconets, which results in individual piconet as well as overall network performance degradation. This paper shows that synchronization among co-existing Bluetooth piconets yields considerable performance improvements as compared to uncoordinated piconets.


ID:                   97

Title:                 A Novel Piconet Coordinator Selection Method for IEEE802.15.3-Based WPAN

Authors:            Yuefeng Zhou, David I. Laurenson, Stephen McLaughlin

Affiliation:         School of Engineering & Electronics, University of Edinburgh Edinburgh, EH9 3JL, UK

Email:               {Yuefeng.Zhou, Dave.Laurenson, Steve.McLaughlin}

Abstract:           Power awareness is an essential component of wireless personal area networks (WPANs), due to the limited energy stored in battery-operated equipment. Moreover, a WPAN has to deal with coexistence problems, since it may simultaneously operate over many types of network. Especially, when UWB, which is a candidate PHY technology for IEEE802.15.3-based WPANs, is applied, decreasing the transmission power is necessary to meet the Federal Communications Commission (FCC) regulation and diminish interference to other communication systems. In a WPAN, the Piconet coordinator (PNC) acts as an important role for central controller of the whole Piconet. As specified in the standard, IEEE802.15.3, the most capable device in a Piconet could be dynamically selected as the PNC in terms of the capacity of devices. However, the standard does not explicitly define the capacity function. In this paper, a novel PNC selection method, named Least Distance Square PNC (LDS-PNC) selection for IEEE 802.15.3-based WPANs is proposed. Using the proposed selection method, the transmission power can be lessened, and the interference area introduced by PNCs can be diminished as well. The simulation results show that it has power-saving and interference mitigation characteristics.


ID:                   96

Title:                 A High Survivability Route Selection Method in Wireless Ad Hoc Networks

Authors:            Yuefeng Zhou, David I. Laurenson, Stephen McLaughlin

Affiliation:         School of Engineering & Electronics, University of Edinburgh Edinburgh, EH9 3JL, UK

Email:               {Yuefeng.Zhou, Dave.Laurenson, Steve.McLaughlin}

Abstract:           Energy limitation is a critical issue in wireless ad hoc networks. Researchers have developed some power-aware mechanisms in routing area to prolong the lifetime of connections in networks. The existed power-aware routing protocols often use residual energy, transmission power, or link distance as the metrics to select an optimal path. The investigation in this paper indicates that these route selections will cause rapid energy exhaustion in parts of the network, thus degrade the survivability of whole network. To average the energy consumption over the network with higher energy efficiency, a novel route selection mechanism, based on novel metrics, the relay capacity and the relay efficiency, is proposed. Simulation results show that this method saves energy with significantly more robust connectivity.


ID:                   98

Title:                 Quality-of-Service (QoS) Framework for Multi-rate Wireless Ad-hoc Network (MWAN)

Authors:            Yow-Yiong Edwin Tan, Stephen McLaughlin, David I. Laurenson

Affiliation:         Institute for Digital Communications, School of Engineering and Electronics, The University of Edinburgh, Alexander Graham Bell Building, Kings Buildings, Mayfield Road, Edinburgh EH9 3JL, U. K.


Abstract:           We propose MWAN, a multi-rate network model to deliver differentiated service in a wireless mobile ad-hoc network (MANET) with varying physical-layer link speed. The proposed architecture is modelled using a multi-dimensional Markov chain to support both real-time and non-real-time applications. It is demonstrated that various types of data arrival process can be modelled by a Markov Modulated Arrival Process (MMAP). Numerical analyzes are drawn to estimate the packet drop probability, effective throughput and packet queuing delay. We validate the scheme by simulating under different link utilizations with IEEE 802.11 Distributed Coordination Function (DCF) ad hoc mode. Analytical and simulation results are compared to determine the accuracy of the presented methods. Increased Quality-of-Service (QoS) performance is achieved for high priority traffic.


Wednesday, 16:00 – 18:00, B.5:  Session III-a [Location Determination]


ID:                   23

Title:                 Knowledge Base Assisted Mapping for an Impulse Radio Indoor Location-sensing Technique

Authors:            Wenyu Guo, Simon L. Thomson, Nick P. Filer, Stephen K. Barton

Affiliation:         School of Computer Science, University of Manchester, Manchester, UK

Email:               {guow, thomsos2, nick, S.K.Barton}

Abstract:           An impulse radio indoor wireless location-sensing technique providing mapping and positioning information without deploying fixed references has been proposed. The environment surrounding an impulse radio network can be reconstructed using times of arrival (TOAs) of dominant impulses from different radio channels measured in individual radios. 2D Mapping and positioning algorithms based on various geometry-related assumptions have been developed for this technique. In order to find the correct assumption and its corresponding algorithm efficiently, a knowledge base, which comprises samples of each typical indoor environment either successfully reconstructed or which appears as a common substructure in most floor plans, is introduced for querying purposes. In this paper, an efficient and representative data format for the knowledge base is investigated, in order to achieve an optimised querying performance. A case study is used to demonstrate how this knowledge base can assist in mapping the surrounding environment and even predicting the upcoming ones.


ID:                   24

Title:                 Enhanced-TDOA Measurement for Ad Hoc Networks Positioning

Authors:            Michael Bocquet, Christophe Loyez, and Aziz Benlarbi-Delaï

Affiliation:         Institut d'Electronique de Microélectronique et de Nanotechnologie, IEMN/IRCICA/DHS/CNRS 8520 University of Lille I Avenue Poincaré - B.P. 69 59652 Villeneuve d'Ascq Cedex FRANCE


Abstract:           To maintain the Ad Hoc network connectivity and to perform efficient energy communication between several mobile stations (MS), optimized routing algorithms need accurate short-range localization or/and positioning data. Due to indoor propagation, multipath may dramatically increase location budget error and ask for innovative solutions allowing accurate time of flight measurement. An original solution, based on a like Ultra Wide Band (UWB) technology, uses millimeter multitone dual transmission acting like a pulse composite signal and a basic millimeter receiver involving Enhanced Time Difference Of Arrival measurements (E-TDOA).


ID:                   37

Title:                 Algorithm for Nodes Localization in Wireless Ad-Hoc Networks Based on Cost Function

Authors:            Jean-Philippe Montillet, Timo Braysy, Ian Oppermann

Affiliation:         Center for Wireless Communications (CWC), University of Oulu, P.O. Box 4500, FIN-90014 University Of Oulu, Finland


Abstract:           A new distributed algorithm is described in this paper for localizing sensor network nodes in Wireless Sensor Networks (WSN). The algorithm shares a common three-phase structure: (1) determine node-beacon distances, (2) build a cost function for every sensor node, and (3) compute the coordinate of the node. The coordinates of the sensor nodes are computed using either the Davidson-Fletcher-Powell Quasi-Newton algorithm or the Direct Method. The algorithm is based on the capacity of the nodes to calculate the Time-of-Arrival (ToA) and Angle-of-Arrival (AoA) with their neighbors. The accuracy of the measurements rely on the use of Ultra Wide Band (UWB) technology. It has been shown that the properties of the UWB signal allow more accurate ToA measurements. In order to simulate the range measurement noise in ToA and AoA measurements, two independent random variables are introduced with two different variances for the ToA and AoA measurements. An extensive set of simulations is performed to assess the accuracy and performance of the algorithm. Also, we demonstrate its ability to localize the nodes in a large WSN.


ID:                   65

Title:                 In-building location using Bluetooth

Authors:            Miguel Rodriguez, Juan P. Pece, Carlos J. Escudero

Affiliation:         Departamento de Electronica e Sistemas, Universidade da Coruna, Campus de Elvina s/n, 15.071. A Coruna. SPAIN


Abstract:           This paper presents a new system for indoor location of a mobile device based on bluetooth technology. Bluetooth access points of a network are used for the location system and to access the network. Location is made by means of the signal strength received from those access points. The signal energy will be measured by the mobile device and it will be transmitted to a central server that calculates its location. Since location is made in a central server, it is possible to consider any kind of algorithm to estimate it. The location system also uses a previous scene analysis by considering a map of received signal strengths.


ID:                   71

Title:                 A Statistical Modelling Based Location Determination Method Using Fusion Technique In WLAN

Authors:            1Reetu Singh, Luca Macchi and Carlo. S. Regazzoni; 2Kostas.N. Plataniotis

Affiliation:         1D.I.B.E, University of Genova, Opera Pia 11a, Genova, Italy; 2Edward S. Rogers department, University of Toronto, Ontario, Canada, MSS3G4


Abstract:           Location information is of paramount importance in context aware Ambient Intelligence (AmI), Smart Space, traffic monitoring, surveillance network and cooperative communications services. This paper describes a Positioning determination solution based on wireless local area network (WLAN) signals. Position determination is based on the statistical modeling of the received signal at any position. This paper presents a probabilistic based statistical modelling approach for location estimation which incorporates fusion strategy in final step to combine efficiently the location individually reported by each WLAN transmitter. The system builds a radio map of the environment. The presented system is easier to implement and provide sufficiently good performance under all conditions. The accuracy with the 90% probability is reported to be 1.85 meters where as average error is reported to be 2.1 meters.


Wednesday, 10:30 – 12:30, G.73: Session I-b [Security + Services]


ID:                   58

Title:                 Circumventing Sinkholes and Wormholes in Wireless Sensor Networks

Authors:            Asad Amir Pirzada and Chris McDonald

Affiliation:         School of Computer Science & Software Engineering, The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009

Email:               {pirzada, chris}

Abstract:           Sensor networks are formed with the help of a large number of wireless nodes, generally with limited energy, computation and transmission powers. Each node helps every other node in the network by forwarding their packets. All is well if such an altruistic attitude is upheld by all participating nodes. However, as these nodes often operate in a physically insecure environment, they are vulnerable to capture and compromise. In addition, the communication medium being wireless, restricts enforcement of rigorous node memberships and so a number of malicious nodes also participate in the network. These nodes, in order to snoop or sabotage, can carry out a variety of attacks against the network including sinkhole and wormhole attacks. In this paper, we present a novel trust-based scheme for identifying and isolating malicious nodes, which launch these two types of attacks in a sensor network.


ID:                   36

Title:                 Secure Communication over Heterogeneous Networks with Clustered Mobile Ad hoc Extensions

Authors:            Dimitrios Vogiatzis, Spyridon Vassilaras and Gregory S. Yovanof

Affiliation:         Athens Information Technology

Email:               {dvog, svas, gyov}

Abstract:           In addition to classical security issues, clustered ad hoc networks face the possibility that some nodes may exhibit uncooperative behaviour. Therefore, misbehaviour detection and reputation mechanisms need to be implemented in order to reinforce node cooperation. In this paper, we address the issue of detecting non-cooperative behaviour during packet forwarding in heterogeneous networks with clustered mobile ad hoc extensions. The proposed solution incorporates end-to-end authenticated acknowledgments for each transmitted packet, combined with explicit authenticated alarms sent by legitimate nodes along the path to the source, every time they encounter a suspicious event. Low computational overhead is achieved by employing an adapted version of the TESLA symmetric key broadcast authentication protocol.


ID:                   39

Title:                 Applying Clustering to a Framework for Generating Trust

Authors:            Javesh Boodnah and Eric M. Scharf

Affiliation:         Queen Mary, University of London

Email:               {javesh.boodnah; e.m.scharf}

Abstract:           This paper addresses the issue of trust within the ad hoc context. Several models which claim to model trust are evaluated and a trust framework is then devised which bases itself on clustering technology. Our model aims at providing trust information about originally unknown nodes while making optimum use of computational capacity, which can be quite scarce in pure ad hoc networks. The use of trust data to generate relationships between nodes is therefore strongly favoured to applied cryptography, which generally involves intensive resource consumption. The method proposed also draws on statistical derivations to propose a condition of normality while attempting to provide definition to behaviour.


ID:                   12

Title:                 Friendly Authentication and Communication Experience (FACE) for Ubiquitous Authentication on Mobile Devices

Authors:            Benjamin Halpert

Affiliation:         Nova Southeastern University, Graduate School of Computer and Information Sciences


Abstract:           Current wireless personal area network (WPAN) standards provide no method for two previously unacquainted parties to authenticate to one another in a trusted manner upon first encounter. The paper details the research leading up to the development of Friendly Authentication and Communication Experience (FACE). The FACE methodology will be developed to be independent of wirelessly enabled mobile device types, such as smartphones, personal multimedia devices, personal digital assistants (PDAs), and mobile gaming platforms. FACE will enable individuals that have never met before to communicate in a trusted manner on the first attempt. FACE development will advance human interaction via wirelessly enabled mobile devices.


ID:                   9

Title:                 A Presence-Enabled Mobile Service System For Integrating Mobile Devices With Enterprise Collaborative Environment

Author:             Xueshan Shan

Affiliation:         Avaya Labs Research, 1033 McCarthy Blvd., Milpitas, CA 95035, U.S.A.


Abstract:           Mobile worker’s presence and availability at mobile devices can be very crucial in enterprise collaborative environment due to the not-always-on nature of the mobile devices. We identify the key challenges in tracking the presence status of mobile device and user and in the integration of mobile devices with enterprise collaborative environment. We present the design ideas of a Presence-Enabled Mobile Service (PEMS) system that uses a device-resident Mobile Presence Agent (MPA) to automatically determine and update the presence of a mobile device and its user and securely integrates the presence information with enterprise collaborative environment via Web Services and SMS for the synthesis of user’s availability. A prototype system and its implementation are presented to verify the design concepts and the feasibility of the PEMS system.


Wednesday, 13:30 – 15:30, G.73: Session II-b [Routing Protocols III]


ID:                   75

Title:                 A Simplified Model for Neighbor Discovery in Bluetooth Networks

Authors:            Salvatore Gallo, Laura Galluccio, Alessandro Leonardi, Giacomo Morabito, Sergio Palazzo

Affiliation:         Dipartimento di Ingegneria Informatica e delle Telecomunicazioni, University of Catania, Italy

Email:               {sgallo, lgalluccio, aleonardi, gmorabi, palazzo}

Abstract:           The self-organization in ad hoc networks requires the definition of new quality-of-service (QoS) parameters, which are often in contrast with each others. For example, the spontaneous neighbor discovery is the process allowing communication nodes to discover each other. However, the velocity of discovery is paid in terms of energy consumption and, consequently, an appropriate tradoff has to be achieved. Analytical models can be utilized to represent the node behavior and optimize their performance. Adopted standards, like Bluetooth (BT), unfortunately may be rather complex and their performance computation may require many computational resources and a lot of time. In this paper a strategy to simplify the performance study in BT environment is derived. The accuracy of the simplified model is assessed comparing the performance results obtained through its use to the performance results obtained by simulation.


ID:                   104

Title:                 On the Scalability of Internet Gateway Discovery Algorithms for Ad hoc Networks

Authors:            Mona Ghassemian, Vasilis Friderikos, A. Hamid Aghvami

Affiliation:         Centre for Telecommunications Research, King’s College London, UK


Abstract:           The aim of this work is to evaluate the scalability of methods applied to interconnect ad hoc networks to the Internet. We describe some of the solutions proposed for Internet connectivity in ad hoc networks. We define scalability space, absolute, relative and weak relative scalability terms. The scalability comparison of these mechanisms is presented by means of analytical modelling with respect to different parameters such as number of mobile nodes, rate of link changes and rate of traffic sessions per each mobile node. To optimise the total amount of overhead generated by the discovery protocols, we propose a feedback control algorithm to adapt period and transmission range of gateway advertisements.


ID:                   64

Title:                 Routing Strategy For Bluetooth Scatternet

Authors:            Christophe Lafon, and Tariq S. Durrani

Affiliation:         Digital Signal Processing Department of Electronic and Electrical Engineering, University of Strathclyde, Glasgow Scotland UK


Abstract:           Bluetooth has been introduced into the marketplace as a new short-range radio technology to form small wireless systems called piconet. Nowadays an enhanced concept requests to be elaborated to enlarge these wireless networks referred as scatternet. In this paper we propose a hierarchical scatternet concept adapted for large amount of devices connected along each other with a predefined routing strategy. All Piconets are coordinated according to a tree structure and are perfectly synchronised to a Leader. In the proposal structure, the number of devices present in a scatternet can be up to 400. The scatternet formation algorithm is developed specially to allow fast piconet switching, and to provide a dense scatternet that offers optimal bandwidth and low latency, with no interference between different piconets. A routing method is presented for inter-piconet communication, with the Leader becoming the head of the server and with Master and (Child)Master forwarding services that are given by any devices present in the scatternet. The goal is to facilitate the proximity and fluidity of communication by creating a new synchronise piconet without adding interferences.


ID:                   8

Title:                 Novel Multicast Protocol For Mobile IP Networks

Authors:            Yewen Cao and Khalid Al-Begain

Affiliation:         School of Computing, University of Glamorgan, CF37 1DL Wales, UK

Email:      ,

Abstract:           Ever-increasingly attentions are drawn to the provision of multicast service over mobile IP networks. Multicast over mobile networks have to face against the scalability problem. In the paper, a new mobile multicast scheme, called mobile scalable recursive multicast is proposed. Our approach is based on the concept of dynamic ranching node-based multicast tree, where a pair of branching node messages (BNMs) is used to gradually and dynamically construct a branching node-based multicast tree and recursively delivers multicast packets between branching nodes by unicast. Another pair of mobility control messages (MCMs) is used to implement the destinations mobility management. In our scheme, only branching nodes router (BNRs) keep the multicast state about their next BNRs and mobility information about destinations, and the process of join/leave of members of a multicast session is carried out locally. Our scheme is scalable and with low join/leave latency.


ID:                   1

Title:                 A comparison based overview of destination distance sequence vector routing (DSDV) and mobile ad hoc on demand data delivery protocol (MAODDP)

Author:             Humayun Bakht

Affiliation:         School of Computing and Mathematical Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK


Abstract:           Mobile ad hoc network is an autonomous system of mobile nodes establishing ad hoc or short live network without the intervention of any fixed infrastructure. Routing in these types of network is an unresolved issue. Effort is going on to establish an effective routing mechanism for mobile ad hoc networks. Proposed protocols for mobile ad hoc network can be categorized into two types i.e. table’s driven and on-demand routing protocols. Destination sequence distance vector routing is one of tables driven earliest proposed algorithms.  DSDV maintains the consistent overview of the network. DSDV requires participating nodes broadcast updates after a regular interval of time. Most of the tables driven type protocol is either a extension or modified form of DSDV. Mobile ad-hoc on demand data delivery protocol follows an intermediate approach in compression with tables driven and on demand routing protocols. The key feature of MAODDP is to establish the route and deliver the data simultaneously at the same time one after the other. This paper is an effort to describe the detail functioning of these protocols. This paper also covers an analytical and discussion section to compare the various aspects of these protocols with each other.


Wednesday, 16:00 – 18:00, G.73: Session III-b [Ad Hoc & Sensor Networks]


ID:                   50

Title:                 Retransmission Scheme with Code Sense for VSF/DS-UWB Ad-hoc Network

Authors:            Wataru HORIE, Yukitoshi SANADA and Mohammad GHAVAMI

Affiliation:         Dept. of Electronics and Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama 223-8522 Japan; Centre for Telecommunications Research, King’s College London, University of London, 26-29 Drury Lane London WC2B 5RL, UK

Email:               {whorie, sanada},

Abstract:           In order to extend the communication range of UWB systems, multi-hop transmission is essential. However, since the number of hops increases, the packet loss increases as well. In this paper, to improve the reliability of the connection and make up for the packet loss, the retransmission scheme with code-sense for DS-UWB ad-hoc network is investigated and evaluated.


ID:                   60

Title:                 Influence of directional antennas in STDMA ad hoc network schedule creation

Authors:            Imanol Martinez, Jon Altuna

Affiliation:         Signal Theory and Communications Department, Mondragon Unibertsitatea, Mondragon, Guipuzcoa, Spain

Email:               {imartinez, jaltuna}

Abstract:           The Spatial reuse Time Division Multiple Access (STDMA) ad hoc networks take advantage of the electromagnetic spectrum reuse to increase the global capacity of the network. The schedule creation takes into account different variables. One of them, the Signal-Interference plus Noise Ratio (SINR) generates that the geographical distribution of nodes influences a lot the behavior of the network. The usage of directional antennas in this kind of networks improves the spatial reuse and consequently the capacity of the network. In this article the schedule in a STDMA network is analyzed using antennas with different lobe angles. The created frame lengths for different connectivities are analyzed as well as the number of links/nodes per slot or the spatial reuse that it is achieved comparing to the one in a Time Division Multiple Access (TDMA) network. Results are presented for link-based and node-based assignment methods.


ID:                   61

Title:                 Evaluation of Cooperative Task Computing for Energy Aware Wireless Networks

Authors:            Anders Brødløs Olsen, Frank H.P. Fitzek, Peter Koch

Affiliation:         Department of Communication Technology, Aalborg University, Niels Jernes Vej 12, 9220 Aalborg Øst, Denmark

Email:               {abo,ff,pk}

Abstract:           In this paper we propose cooperation on task-set computation for cooperative groups of mobile wireless terminals. Energy consumption for future generation terminals is important, calling for new innovative concepts to alleviate the present evolution of evermore energy hungry terminals. Related to cooperative concepts a novel energy conservation method is proposed, which we will refer to as D2VS. Our proposed method uses abstractions of traditional multi-processor environments, where terminals are considered as processing units connected by short range wireless networks. Energy conservation is obtained by the well known method of dynamic voltage scaling, which has proven to generate near optimum energy schedules of task sets. Our simulation experiments show that up to 40% energy reduction on two cooperating terminals is obtainable. This is compared to a single energy aware terminal.


ID:                   73

Title:                 Performance Evaluation of TCP in an Integrated WPAN and WLAN Environment

Authors:            Isameldin M. Suliman, Janne Lehtomaki, and Ian Oppermann

Affiliation:         Centre for Wireless Communications, P.O. Box 4500, 90014 University of Oulu, Finland


Abstract:           Short-range low power radio frequency systems such as Bluetooth and UWB enable the deployment of wireless personal area networks (WPAN). A WPAN can interface to larger networks to provide broader network access and Internet connectivity. We evaluate the performance of TCP over an integrated WLAN and WPAN system using a real network testbed. The end-to-end throughput is found to increase, when the window size is increased. However, for large window sizes, measurement results revealed that a wide range of round trip times (RTTs) is experienced. With small window sizes, the variability in the RTT is smaller. The measurements showed that in an integrated network long RTT delays and frequent duplicate acknowledgements lead to an increase in the number of packets transmitted unnecessarily. We study the effect of the number of active short-range devices (Bluetooth in this case) in a piconet. The results show that as the number of active slaves present in the WPAN increases, the bandwidth received by slaves exchanging data decreases. This behaviour is attributed to the Bluetooth scheduling mechanism which uses the round robin polling method. The main finding of our experiments is that for Bluetooth to be successful in enabling WPAN, the time slot allocation scheme should be efficient and fair. Finally, the issue of fair bandwidth allocation among multiple TCP streams is also investigated. The results show that for small number of TCP connections, the bandwidth is fairly distributed. However, as the number of simultaneous TCP connections increases, bandwidth distribution seems to become somewhat less fair.


ID:                   68

Title:                 BLUESIC: context-aware information system for tourism, based on Bluetooth technology

Authors:            Juan Pece, Carlos Fernández, Carlos J. Escudero

Affiliation:         Departmento de Electrónica y Sistemas, Universty of A Coruña, Campus de Elviña s/n, A Coruña, España

Email:      ,,

Abstract:           In this paper it is introduced Bluesic, a new context-aware information system for tourism based on Bluetooth technology. The system has been designed for mobile devices, such as phones or PDAs. Information is provided by a web application using some parameters, such as location and kind of device, to filter and to adapt the requested information. The access to the system is made through Bluetooth access points, which are distributed in around a place of interest (building, city …). When a user (tourist) arrives to a place of interest with Bluesic, he/she gets connected to the system across the corresponding Bluetooth access point. This way, the system knows the access point giving service and, therefore, the location of the request origin. A client application, designed for the system, shows the information to the tourist in his mobile device


Workshop Presentations

Thursday 26 May 2005 – Abstracts & Papers


Thursday, 13:30 – 15:30, B.5: Session II [Hardware Demo + Other]


ID:                   4

Title:                 Reliability Enhancement Strategies for Wireless Communication System

Author:             Stefanos Skoulaxinos

Affiliation:         School of MACS, Heriot-Watt University, Edinburgh, UK, EH14 4AS


Abstract:           This paper presents the development of a wireless communication system, the Long Range Identification Tag, built and tested in Heriot Watt University. The design commences in Spin, a high level model checking tool optimized for the verification of distributed systems. The abstract software model is synthesized automatically to HDL (Verilog/VHDL) and subsequently downloaded to the targeted FPGA platform. To enhance autonomous capacity of the device, run-time fault tolerance schemes such as watchdog timers and forward error correction routines are also developed. The wireless application is finally tested under a lab emulated EMI scheme and system survivability is examined and quantified. The principal objective of the paper and the associated research project (launched in 2002) is to investigate how a number of high-level reliability enhancement strategies can be utilized to promote more dependable embedded applications.


ID:                   22

Title:                 Wireless Temperature Sensor Using Bluetooth

Authors:            Qingshan Shan, David Brown

Affiliation:         Dept. of Creative Technologies, Portsmouth University, UK


Abstract:           Convenient and reliable temperature monitoring systems are increasingly demanded in vehicle refrigerators. However, difficulties exist in wiring between temperature recorders and sensors in vehicles such as trailer-tractor. To solve this problem, this paper provides a novel solution: wireless temperature sensors using Bluetooth. A prototype of the wireless temperature sensors has been developed. The technologies and mathematical models used are presented in this paper.


ID:                   32

Title:                 Transfer Sensor Data on a motor vehicle with GPRS Modem and CAN bus

Authors:            Dan Feng, ChengTao LU, Ke ZHOU, Fang WANG

Affiliation:         Key Laboratory of Data Storage System, Ministry of Education, Huazhong University of Science and Technology, Wuhan 430074, P. R. China


Abstract:           A Fault Monitoring and Detection System (FMDS) combines the technology of CAN bus and communication technology of GPRS, has been applied in a kind of loading vehicle for remote fault diagnoses. Data is collected from many sensors by CAN bus and transmitted to the remote diagnoses system by GPRS modem. The implementation of the system is described and the reliability of the communication is analyzed. It also applies to the local industry data transfer.


ID:                   25

Title:                 Persistent Bidirectional Peer Traffic in Fix-network augmented Broadband Wireless Access

Authors:            Robert Hsieh, Jari Iinatti

Affiliation:         University of Oulu, Centre for Wireless Communications, FI-90014 University of Oulu, Finland

Email:     ,

Abstract:           Currently, the Internet is experiencing the grid accelerated file transfer phenomenon (swarming). It has gained immense popularity and dominance through BitTorrent and has thus far accounted for a substantial amount of the total Internet traffic. In this paper, we borrow ideas liberally from the literature to argue that the use of swarming protocol for traffic/content delivery within the wireless networking milieu is inefficient. We generalize the problem into the delivery of persistent bidirectional peer traffic in wireless hierarchical topology, and further argue that current approaches for fix network augmented broadband wireless access (e.g. 802.11x) has left the problem ill-addressed. A novel system architecture is sketched to rectify such a shortcoming. Hence, the purpose of this short position paper is to stimulate ideas and proposals that may result into important avenues of future research.


ID:                   38

Title:                 Channel Model at 868 MHz for Wireless Sensor Networks in Outdoor Scenarios

Authors:            J.M. Molina-Garcia-Pardo, A. Martinez-Sala, M.V. Bueno-Delgado, E. Egea-Lopez, L. Juan-Llacer, J. García-Haro

Affiliation:         Department of Information Technologies and Communications, Polytechnic University of Cartagena, E-30202, Spain

Email:               {josemaria.molina, alejandros.martinez, mvictoria.bueno, esteban.egea, leandro.juan, joang.haro}

Abstract:           Wireless Sensor Networks (WSN) are formed by a large number of sensing nodes at the ground level. These devices are monitoring and measuring physical parameters from the environment. Simulation is used to study WSN, since deploying test-beds supposes a huge effort. However simulation results rely on physical layer assumptions, which are not usually accurate enough to capture the real behaviour of WSN. In this work several measurement campaigns are performed in three different scenarios: an open quasi-ideal area, a university yard and a park. The main contribution of this work is that a two slopes lognormal path-loss near ground outdoor channel model at 868 MHz is validated, and compared to the widely used one slope model. This model is useful for simulations because its computational cost is low.


Thursday, 16:00 – 17:00, B.5: Session III [Other]


ID:                   72

Title:                 Insight Analysis into WI-MAX Standard and its trends

Authors:            H. Córdova, P. Boets, L. Van Biesen

Affiliation:         Vrije Universiteit Brussel (Dept ELEC/TW); Pleinlaan 2; B-1050 Brussels (Belgium)

Email:               {hcordova, pboets ,lvbiesen}

Abstract:           This paper presents the features of the Worldwide for Microwave Interoperability Access (WiMAX) technology and pretends to establish some valid criterions for future trends of possible applications of WiMAX. A discussion is given by comparing Wireless Fidelity (Wi-Fi) and WiMAX. Several references have been included at the end of the article for those willing to know in detail about certain specific topics.


ID:                   63

Title:                 Relative Proximity Estimation in a Confined Small-Scale Environment

Authors:            Wei-Khing For 1,2 See-Kiong Ng 1 Xiaoming Bao 1 Woon-Seng Gan 2

Affiliation:         1 Institute for Infocomm Research, 21 Heng Mui Keng Terrace, Singapore 119613, 2 Nanyang Technological University, Singapore 639798

Email:               {stuwkf,baoxm,skng}

Abstract:           Recent advances in genomic research and biotechnology have led to an increased level of technological sophistication in today’s biology laboratories. With the promising current advances in pervasive computing, we can expect ubiquitous smart services to be deployed in smart bio-laboratories of the future to simplify the increasingly complex experiments that are now becoming routine. In this paper, we investigate the provision of location aware computing through K-Nearest Neighbor (KNN) relative proximity estimation. Our results show that K-NN can provide low-cost and reliable relative proximity estimation services, even in a challenging small-scale confined environment such as a smart bio-laboratory operating in the common IEEE 802.11b based wireless network environment.


 Workshop Papers

not attending – Abstracts & Papers


ID:                   6

Title:                 Wireless Sensor Actor Networks And Routing Performance Analysis

Authors:            Dung Van Dinh1), Minh Duong Vuong1), Hung Phu Nguyen2), Hoa Xuan Nguyen3)

Affiliation:         1) Research Institute of Posts and Telecoms (RIPT), 2) Post and Telecommunications Institute of Technology (PTIT), 3) Hanoi University of Technology (HUT)


Abstract:           With recent advances in micro-electromechanical systems technology, wireless communications, and digital electronics, the research on wireless sensor networks becomes a “hot” topic. Wireless sensor and actor network (WSAN) is referred to a group of sensors and actors linked by wireless medium to perform sensing and acting tasks. This paper is to present a comprehensive review of recent research achievements on WSANs, open research issues, and the simulation based actor-to-actor routing protocols performance analysis. The review is followed the layers of sensor networks: application, transport, network, link, transmission, and management (power, mobility, task). The performance analysis is considered for three popular ad-hoc networks routing protocols and investigated with respect to the routing packet delay and end-to-end throughput. As a result, the DSR protocol is proposed to handle actor-to-actor communications.


ID:                   57

Title:                 Probabilistic Geographic Routing Protocol for Ad Hoc and Sensor Networks

Authors:            Tanya Roosta

Affiliation:         Department of EECS, UC Berkeley


Abstract:           In this paper, we present Probabilistic Geographic Routing (PGR), a novel approach for the problem of power-aware routing in wireless ad hoc and sensor networks. Our protocol uses only local information to probabilistically forward the packet to the next hop. Every node relies on a beaconing process to keep track of the changes in the set of its neighbors. In order to forward a packet, the node selects a subset of its neighbors. These candidate nodes are then assigned a probability proportional to their residual energy and the link reliability. We simulated PGR in NS-2 and compared the performance to two existing protocols, GPSR and Probabilistic Flooding. Based on the simulation results, PGR improves the throughput by 40%, increases the lifetime of the network by 30%, and decreases the overall end-to-end delay. In addition, we have implemented PGR on a real sensor network test-bed to verify our protocol.


ID:                   5

Title:                 Performance issues of Voice over Wireless LAN (VoWLAN) and comparing it with Wired LAN

Authors:            Ashish Bhatia

Affiliation:         International Institute of Information Technology, India


Abstract:           The emerging next generation networking environment presents an IP based core interconnecting many wireless radio access networks providing ubiquitous access to end users through a vast variety of wireless devices.VoIP over wireless LAN is freeing the telephone from cord is an obvious next step. The convergence of voice and data networks enables new applications and cost reduction. There are number of factors that inhibit wide spread adoption of VoWLAN.Data was reviewed on voice quality effects of excessive latency and jitter, degraded voice quality, poor convergence, interrupted voice service, roaming latency, security problem, retransmission and dropped packets, low capacity and reduced number of calls, voice and data coverage and power coverage environments. The subjective was to find out if VoIP works well enough in wireless LAN to be useful. For this comparison of the behavior of voice over IP in a 100MB/s Ethernet is done and quality of service parameters is measured in both environments. These days wireless environment is getting more and more important so the objective in concern of voice data was to discover if it is possible to do telephone calls in a wireless LAN with voice over IP with good enough speech quality.


ID:                   43

Title:                 Security Enhancement in the NTP Protocol Using Fuzzy Techniques

Authors:            S.Radha, M.S.Jayapriya

Affiliation:         Sri Siva Subramaniya Nadar College of Engineering, Old Mahabalipuram road, SSN nagar-603110, Tamil Nadu, India.

Email:     ,

Abstract:           AdHocNetworks are a new generation of networks offering unrestricted mobility without any underlying infrastructure. Primary applications of Ad Hoc networks are in military, tactical and other security sensitive operations, where the environment is hostile. Hence, security is a critical issue. Due to the nature of Ad Hoc networks, conventional security measures cannot be used. New techniques of security measures are essential for high survivability networks. The performance of the network will be severely affected, in the presence of compromised nodes, which cause undetermined and unpredictable complex failures. This project is mainly to identify the misbehaviors caused by some malicious node for NTP (Node Transition Probability) protocol, and eliminate them from the network. The performance analysis is done based upon two cases .In first case the complete network topology is studied and based upon it a threshold value is fixed to detect the malicious activity and eliminate it. In the second case a fuzzy model is introduced so that automation of threshold can be done for anamoly detection of malicious nodes in network with varying topology. In contrast to the case one -- intrusion detection models for ad hoc networks we have implemented an efficient and bandwidth-conscious framework that takes into distributed nature of ad hoc wireless network management and decision policies.


ID:                   79

Title:                 IEEE 802.15.4/ZigBeeTM Compliant IF Limiter and Received Signal Strength Indicator for RF Transceivers

Authors:            Rajshekhar Vaijinath, Ashudeb Dutta and T K Bhattacharyya

Affiliation:         Advanced VLSI Design Laboratory, Indian Institute of Technology Kharagpur-721302 (India)


Abstract:           This paper presents a low-voltage, low-power CMOS circuit for an intermediate frequency (IF) limiting amplifier and received signal strength indicator (RSSI). Using a single 1.8-V supply voltage, simulated results demonstrate the input dynamic range is larger than 80 dB and a sensitivity of around -80dBm. A low intermediate frequency of 2 MHz is chosen for our application. Power dissipation is 6mW and the input referred noise is 16µV.The prototype is implemented using a 0.18µ CMOS technology. This architecture is designed for RF transceivers complying IEEE 802.15.4/ ZigBeeTM.


ID:                   51

Title:                 Virtual Cellular Infrastructure For Mobile Ad hoc Network

Authors:            Muthu Chidambaranathan.P, Sundaresan S

Affiliation:         Department of electronics and communication engineering, National institute of technology, Tiruchirappalli-620015, India


Abstract:           In this paper, we introduce a protocol which develops a dynamic infrastructure for wireless mobile ad hoc network. The architecture and operation of dynamic infrastructure is similar to conventional cellular network infrastructure. In this protocol, a mobile terminal (MT) is elected by a set of MTs to act as their temporary base station within their base station area based on residual battery power. MTs elected as base stations (BS) are used to track other MTs in the ad hoc network. The dynamic infrastructure routing protocol utilizes the mobility tracking mechanism to route packets from an MT to another MT in the network. This protocol is more efficient then any existing ad hoc routing protocols in terms of energy and load balancing. The infrastructure based ad hoc mobile network is less congested and fast converging to network topology change. This scheme provides different medium access control, band width allocation policies and quality of service (QoS) guaranteed communication in ad hoc networks. It performs well in interactive and multimedia service in ad hoc network.


ID:                   66

Title:                 Effective Link Capacity of Imperfect Reconfigurable Wireless Networks

Authors:            Ulrico Celentano, Savo Glisic

Affiliation:         Centre for Wireless Communications, P.O. Box 4500, FIN-90014, University of Oulu, Finland


Abstract:           This paper presents a model for the link service capacity that an imperfect adaptive radio link provides to upper layers. As the main contribution of this paper, the model includes a number of imperfections in the link adaptation chain, as well as implementation implications. The average goodput is expressed also in compact form and its dependence on the impairments is discussed using analytical, numerical, and simulations results. The model integrates physical channel, transceiver characteristics, and imperfections in a flexible way, by independent, separate matrices.


ID:                   62

Title:                 Improving the Performance of Probabilistic Flooding in MANETs

Authors:            M. Bani Yassein, M. Ould Khaoua, L. M. Mackenzie and S. Papanastasiou

Affiliation:         Department of Computing Science, University of Glasgow, Glasgow, G12 8RZ, U.K.

Email:               {muneer, mohamed, lewis, stelios}

Abstract:           Broadcasting in mobile ad hoc networks has traditionally been based on flooding, which swamps the network with large number of rebroadcast packets in order to reach all network nodes. The appropriate use of probabilistic broadcasting can reduce the number of packet transmission, effectively alleviating the problem of contention. In particular, a good probabilistic broadcast protocol can achieve higher saved rebroadcast and higher reachability. This paper presents a new probabilistic approach that dynamically adjusts the rebroadcasting probability as per the node distribution and node movement. This is done based on locally available information and without requiring any assistance of distance measurements or exact location determination devices. We evaluate the performance of our approach by comparing it with simple flooding as well as a fixed probabilistic approach. The results show that the new algorithm exhibits superior performance in terms of both the reachability and saved rebroadcasts.


ID:                   76

Title:                 On demand Temporary Route Recovery For Frequent Link Failures In Adhoc Networks

Authors:            S.Radha,  M.Tharanian, K.K.Thyagharajan

Affiliation:         Sri SivaSubramaniya Nadar College of Engineering, Old Mahabalipuram road, SSN nagar,Kalavakkam-603110, Chennai, Tamil Nadu, India

Email:     ,,

Abstract:           Adhoc  network  is  a  collection  of  wireless  mobile  nodes  dynamically  forming  a  temporary  network  without the use of  existing  network  infrastructure or centralized  administration. Each node acts as a router by itself and forwards all the packets which it receives. There is a frequent link failure in adhoc Networks, which causes packet to be lost or packets doubt to reach destination. In this scenario a different mechanism and a scheme is proposed and implemented to make the important time critical data like real time or voice data to reach the destination without any loss. The mechanism used is a special propagation which propagates a unique kind of route discovery for real time application scenario to send the time critical data safely. The scheme used is temporary route recovery builds a temporary path between the nodes during link failure.The important node then forwards the buffered packets to the destination without any loss which is on-demand based on type of information a node forwards. Special buffer is allocated for the nodes marked important during special propagation. The significant nodes are assumed and simulated by using a simulation tool GloMoSim. This extensive model is compared with standard models performance metrics such as throughput, retransmission and end-to-end delay are analysed.


ID:                   55

Title:                 On the evaluation of TCP in MANETs

Authors:            Stylianos Papanastasiou, Mohamed Ould-Khaoua, Lewis M. Mackenzie

Affiliation:         Department of Computing Science, University of Glasgow, Glasgow, UK G128QQ

Email:               {stelios,mohamed,lewis}

Abstract:           Past research efforts have denoted the problematic behaviour of traditional TCP agents in MANET environments and have proposed various remedies across the networking stack. However, there has not been an overall performance evaluation of different TCP agents under varying mobility conditions which takes into account past experiences in MANET evaluation. This work aims to rectify this shortcoming through detailed evaluation of prevalent TCP variants in different topology settings over the AODV routing protocol. Subsequent results reveal the performance merits of TCP Vegas and NewReno in MANETs with respect to Reno which is further explored and accounted for. Finally, insight is provided through extensive tracing on the interaction of TCP with the routing protocol.


ID:                   45

Title:                 Performance Evaluation of UWB Sensor Network with Aloha Multiple Access Scheme

Authors:            Romeo Giuliano1 and Franco Mazzenga2

Affiliation:         1 RadioLabs Consorzio Universit`a Industria, Via del Politecnico 1, 00133, Rome, Italy, 2 University of Rome Tor Vergata, Via del Politecnico 1, 00133, Rome, Italy

Email:     ,

Abstract:           The performance of a multi-hop Ultrawideband (UWB) sensor network based on Aloha multiple access technique is evaluated in terms of the average link outage probability and the overall network throughput for different coverage radius of the UWB sensor device. The architecture of the considered sensor network is based on the creation of multi-hop routes using intermediate nodes for each source-destination pair. Packets transmission at each node follows a Poisson distribution with assigned normalized traffic. Performances are obtained using a novel semi-analytical procedure that allows to account for multiple access interference and realistic propagation conditions. The proposed calculation procedure can be used for sensor network design based on Aloha with multi-hop as well as for analysis of an existing installation.


Centre for Telecommunications Research, King's College London, University London 2005.