WINSYS 2006 Abstracts
CONFERENCE
Area 1 - Wireless Information Networks
Area 2 - Wireless Networking Technologies
Area 3 - Mobile Software and Services
Area 4 - Wireless Information Policy, Risk Assessment and Management
Title:
A TRANSCEIVER CONCEPT BASED ON A SOFTWARE DEFINED RADIO APPROACH
Author(s):
Admir Burnic, Alex Vießmann, Tobias Scholand, Arjang Hessamian-Alinejad, Guido H. Bruck, and Peter Jung
Abstract:
In this communication, the authors present a software defined radio (SDR) transceiver design, termed FALCON. The FALCON is entirely based on a modular signal processing concept. In particular, the receiver deploys modules which process and generate log-likelihood ratio (LLR) signals, hence, providing the capability of a plug-and-play-type reconfigurability. To the best knowledge of the authors, such a reconfigurability approach has not yet been pursued as consequently before. The authors will present their reconfigurability approach in this communication. The FALCON currently deploys commercial radio frequency (RF) front-ends provided by Atmel, analog and interface boards developed and implemented by the authors and DSP Starter Kits (DSK) with TI TMS320C6416 DSPs, provided by Texas Instruments. The hardware/software integration has been done in the laboratory of the authors as well as the development of all the signal processing modules, which have been realized in C language tailored for the TMS320C6416 DSPs (digital signal processors). The authors describe the FALCON and present measurement results. For an easy comparison of these results with widely published simulation results the authors will consider UMTS/W-CDMA. It will be shown that the FALCON provides superb performance.

Title:
AN ARCHITECTURAL FRAMEWORK FOR HETEROGENEOUS NETWORKING
Author(s):
Glenford Mapp, David N. Cottingham, Fatema Shaikh, Pablo Vidales, Leo Patanapongpibul, Javier Balioisian and Jon Crowcroft
Abstract:
The growth over the last decade in the use of wireless networking devices has been explosive. Soon many devices have multiple network interfaces, each with very different characteristics. We believe that a framework that encapsulates the key challenges of heterogeneous networking is required. Like a map clearly helps one to plan a journey, a framework is needed to help us move forward in this unexplored area. The approach taken here is similar to the OSI model in which tightly defined layers are used to specify functionality, allowing a modular approach to the extension of systems and the interchange of their components, whilst providing a model that is more oriented to heterogeneity and mobility.

Title:
ACK RATE CONTROL STRATEGY AT THE LINK LAYER TO ENHANCE TCP OVER 3G LINKS
Author(s):
Juan J. Alcaraz and Fernando Cerdán
Abstract:
When TCP is carried over 3G links, overbuffering and buffer overflow at the RLC layer degrades its performance. In order to prevent these undesired interactions, we propose an algorithm to control the rate of the acknowledgements (ACK) traversing the RLC entity at the network side. Since the sending rate of a TCP source is determined by the arrival rate of the ACKs, the basic idea of this scheme is to adjust the inder-departure time of the ACKs in the uplink direction, according to the congestion level of the downlink buffer. By means of extensive simulation experiments, we disclose the influence of each parameter on TCP performance. We provide several configurations that improve end-to-end goodput while reducing the delay. The operation of the algorithm is deterministic; it does not require changes in 3G specifications nor in TCP itself, and preserves TCP end-to-end semantics.

Title:
EVALUATION OF AN ORTHOGONAL SFBC CHANNEL ESTIMATION SCHEME FOR MIMO OFDM WIRELESS SYSTEMS
Author(s):
Athanasios D. Marousis and Philip Constantinou
Abstract:
This paper presents the design and evaluation of a channel estimation scheme that is efficient by means of both the mean square error (MSE) of channel estimation/tracking and its incorporation in a real MIMO system. The evaluation has been performed over the spatial channel model developed for MIMO simulations according to 802.16e case of 3GPP.25.996, taking also into account all IF and RF stages in the communication chain. Orthogonality has been applied in space-frequency dimension for both preamble and pilot symbols, as well as for the data symbols, with the application of Alamouti’s scheme. In 4G multicarrier systems that use space-time-frequency coding, orthogonal design turns into a key factor for the performance of the system since the channel has to remain about constant during the transmission of one orthogonal block, something which becomes quite challenging in highly time-variant propagation channels. Furthermore, space-frequency block coding (SFBC) becomes more efficient as the number of subcarriers increases (802.16e, 802.20, etc).The modified channel estimation scheme applied to MIMO transceiver is also efficient in minimization of the processing requirements at the receiver side by estimating only those channel properties that have been changed assuming that the general channel conditions (low/high mobility) are known. The results presented refer to the normalized MSE of the channel estimator and the overall performance evaluation (BER) of the system in various propagations channels, data rates and forward error correction modes.

Title:
A NEW SIGNAL DETECTION METHOD FOR TR-UWB - By Time Delayed Sampling & Correlation (TDSC)
Author(s):
Muriel Muller, Yang Ni, Roger Lamberti and Charbel Saber
Abstract:
This paper introduces a new signal detection method for Low cost, Low power and Low complexity (L3) TR-UWB systems for medium to low data rate applications such as sensors networks. This new detection method is based on a time_to_space conversion realizable by an analog waveform sampler. This method overcomes the major difficulties in a traditional TR-UWB detection methods based on wide band delay lines. Finally the relaxed timing precision needed in symbol synchronization contributes further to lower the system power consumption. This concept has been validated by simulation with real data from experimental setup. The results will be presented and compared also with other solutions.

Title:
HANDOVER OPTIMIZATION FOR HOST AND NETWORK MOBILITY
Author(s):
Hai Lin, Houda Labiod, Guo Zhi Wei and Anne Wei
Abstract:
Mobile IP and NEMO (network mobility) provide continuous connectivity to the Internet to a node or a mobile network when moving from one access router to another. Because of link switching delay and IP protocol operation, packets destined to mobile nodes or mobile networks can be delayed or lost during the handover period. This paper proposes solutions to improve the performance of handover in the context of Mobile IPv6 and NEMO. We introduce a new control entity for both MIPv6 and NEMO to manage the traffic between access routers and mobile nodes or mobile routers, to provide low-latency and low packet loss for real-time services during the handover.

Title:
AN ALGORITHM TO ENHANCE THE NETWORK SELECTION PERFORMANCE IN IN AN INTEGRATED UMTS/WLAN ENVIRONMENT
Author(s):
Abolfazl Nazari, Naser Yazdani and Naser Rezayi
Abstract:
Future wireless networks are presumed to be multi-access networks, in order to benefit from the advantages of any radio access technology. Regarding this fact, the network selection mechanism can play a crucial role in overall network functioning. In general, interworking between 3G cellular networks and WLAN is considered as a feasible approach toward next generation wireless networks. In this paper, we propose a mechanism that uses statistical information of WLAN traffic to measure its capabilities to ensure QoS for the requested service. Then, a network selection algorithm can use this measurement and user preference to select the best radio access technology. We investigated the performance of our algorithm through simulation of transferring video traffic in WLAN. Our results show that the proposed algorithm has an acceptable performance and, in about 95 percent of the times, a user that opt WLAN as his/her access network will have the requested.

Title:
ENVIRONMENTAL ACQUISITION IN MOBILE NETWORK SIMULATION
Author(s):
David Buchmann, Dominik Jungo and Ulrich Ultes-Nitsche
Abstract:
The type or class of an object is not always sufficient to decide on its runtime behaviour. In many cases, the context of the object is also important. Environmental acquisition is a concept to handle context in information models. We explore the use of environmental acquisition for the management of computer network configuration and for network simulation. Physical location or subnet membership can be seen as environment for a computer in a network. For the simulation of networks, environmental acquisition will be especially useful to model mobile devices moving from one area into an other. The concept is illustrated using the network configuration management project Verinec.

Title:
ANALYTIC HIERARCHY PROCESS AND ITS APPLICATION TO GRADE OF TRAFFIC SERVICE FOR CELLULAR NETWORK
Author(s):
Kentaro Hoshi, Sadahiko Kano, Yoshitaka Takahashi, Shigeru Kaneda and Noriteru Shinagawa
Abstract:
In a cellular network, several traffic control services are previously provided. Above all, when the network becomes congested e.g. world-cup ticket-reservation, THREE traffic control scenarios are proposed. In this paper, applying an AHP (Analytic Hierarchy Process) approach enables us to obtain a solution which scenario is best/worst among these traffic control scenarios, from user’s view point. Firstly, we construct a web site on which cellular network users can simply answer a questionnaire regarding grade of traffic services via internet. We then formulate a pair-wise comparison matrix (p.c.m.) through this questionnaire result for an individual respondent. We next calculate the maximum eigenvalue of the p.c.m., which leads to CI (consistency index). Via this CI value, we can see how well the respondent answers logically. Through this process, we obtain all CI values for all questionnaire respondents. We propose a decision making technique for questionnaire respondents group through these individual CI values. Taking the geometric mean of p.c.m. elements we obtain the weighted eigenvector for the maximum eigenvalue of this geometric mean p.c.m., namely priority (users’ dissatisfaction) vector. From the priority vector, we can see how well/badly these traffic control scenarios operate.

Title:
WEIGHTED CRITICAL PATH ROUTING PROTOCOL FOR MOBILE AD HOC NETWORKS
Author(s):
Ihab El Kabary, Amal Elnahas and Said Ghoniemy
Abstract:
In this paper we present a hybrid adaptive ad hoc routing protocol, named Weighted Critical Path Routing (WCPR) protocol that strives to incorporate the merits of both reactive and proactive ad hoc routing schemes. The genuine aspect of WCPR is that it initially starts-off as a conventional reactive Dynamic Source Routing (DSR) protocol. The network traffic is monitored in attempt to gradually discover pairs of highly interactive nodes in the network. Critical Paths are constructed between these pairs of nodes and proactively safe guarded. The established CPs are treated differently depending on the amount of traffic consumed by each. The aim of our work is to achieve low latency between highly active pairs of nodes, thus increasing the overall performance of the network without dramatically increasing the routing overhead. WCPR is evaluated through simulation experiments and compared to DSR, a pure reactive protocol. Results showed that WCPR outperforms DSR in terms of delay with minimal increase in overhead.

Title:
QOS MONITORING AND FAULT DETECTION USING CALL DETAIL RECORDS - A Different Approach that has Come to Add Value
Author(s):
Gean Davis Breda and Leonardo de Souza Mendes
Abstract:
This paper deals with an algorithm to monitor the QoS and consequently to detect the occurrence of failures in wireless and wireline systems, communications systems. It’s a new approach based on the analysis of data stored in Call Detail Records (CDR), which are tickets that contain data describing information related to the system elements involved, such as time and duration of the call, phone types and numbers, SS7 signaling, etc. The tickets are generated in PSTN switches or over VoIP gateways, for the case of Internet Protocol Detail Record (IPDRs). Our main goal is to show, analyze and classify this algorithm according its performance and use.

Title:
LOCALISED AD HOC ADDRESS AUTOCONFIGURATION VIA CLUSTERING IN NOMADIC AD HOC NETWORKS
Author(s):
George Metaxas, David Hutchison and Nicholas J. P. Race
Abstract:
Densely populated urban environments provide unique nomadic movement patterns. People tend to move in groups across predefined paths, with low intra-group movement, giving rise to Nomadic Ad hoc Networks (NANETs). NANETs, which are a constrained subset of Mobile Ad hoc Networks (MANETs) in terms of mobility, are sufficiently dynamic in nature to present significant challenges in the design of even the most common tasks such as packet routing or name resolution. An intriguing issue relates to the automatic configuration of IP addresses to constituent nodes that will allow data exchange. The underlying physical group structure can be utilised in the network layer as a basis for an address autoconfiguration mechanism, which would yield low and localised signalling traffic overhead coupled with a subnet optimisation. This paper discusses the AALM IPv6 address autoconfiguration mechanism, developed to provide the aforementioned characteristics.

Title:
AN EMBEDDED MOBILE HOME AUTOMATION SYSTEM
Author(s):
Chin E. Lin, Chien-Liang Lin and Chih-Ching Li
Abstract:
This paper proposes a home appliance automation system in design and realization. This system is accomplished by embedded boards, radio frequency (RF) transceivers, microprocessors, switching circuits, sensor circuits and GSM (Global System for Mobile Communication) modules. This system mainly consists of two subsystems for home appliance control and home security monitor. In the home appliance control, we combine RF and WAP (Wireless Application Protocol) technologies for controlling home appliances, where RF is for home network and WAP is for remote interconnect to home network via mobile communication. For all security concern or emergency occasion, a SMS (short message service) may automatically be generated from the microprocessor and sent to assigned cell phone number. The proposed system would not only offer personal mobility and life convenience, and also provide home security for better living environment.

Title:
MOBILE AND COMPUTER COMMUNICATIONS THROUGH COLOUR SIGNALS – AN APPROACH NOTE
Author(s):
Rajarshi Sanyal
Abstract:
This paper proposes a technology for realizing a mobile network based on colour signals , which does not require the Mobile Switching Centre as a core network element. This implies that the mobile network conceived by this technology does not require any switching functionality and the call processing is actuated by a colour server which synthesizes color signals and transreceives the data as video broadcast signal. The proposed system is based on adaptive colour technology. Unlike the existing methods of switching or time multiplexing, this is dependent on a process that can be best described as a multicast method based on colour clamping. Each Mobile Station is identified by , and can clamp on to, a specific hue (tinge) and a band of saturation level (how much white is mixed with the colour).The Voice information is trancoded within this band of saturation level which is tied up with the specific hue that has been assigned to the mobile subscriber and is further carried by the chrominance signal. The broadcast chrominance signal in a specific PLMN brings the paging and other signalling information for the particular mobile station (in terms of colour) over the Air Interface . The same technology can be used for realizing a Wireless Computer Network which is not based on the existing network topologies . The identity of the node (i.e. the IP Address, subnet mask ,MAC Address and other associated parameters of the computer and the peripherals) can be addressed in terms of digitized colour information and can be broadcast in the UHF by a digital video transreceiver. There is no switching involved in the whole process .The color server formulates the chrominance signal which carries the data information for each and individual nodes within the band of saturation level assigned for the node. The technology does not put an upper cap/limit on the number of users that can be accommodated in the network , without sacrificing the Quality of Service.

Title:
MULTICAST KEY AGREEMENT PROTOCOL FOR MOBILE AD HOC NETWORKS
Author(s):
André Boumso, Boucif Amar Bensaber, Ismail Biskri and Samir Khali
Abstract:
In this paper we address the problem of Multicast secure data over a multihop wireless ad hoc network. Many protocols that have been proposed are not really convenient for mobile ad hoc networks. We propose a key agreement protocol that aims to solve problems that are specific to ad hoc networks such as mobility, unreliable links, and multihop communication cost. The main idea is to focus on group dynamics and complete node mobility in ad hoc environment to develop an adaptive protocol that is suitable for the network and group changes. Doing so, we extend and adapt the proposed Tree based Group Diffie-Hellman (TGDH) protocol to pure mobile ad hoc network. Our method promotes the use of a fully balanced tree and eliminates the broadcasting of the entire tree as it appears in TGDH. We introduce a probabilistic value that gives the state of group dynamism. We simulated our protocol using C++ code and some results are presented in this paper and currently other simulations are going on the Network Simulator ns environment under various mobility, group size, and group dynamic scenarios.

Title:
PERFORMANCE MEASUREMENT OF CAR-TO-CAR AD-HOC NETWORKS IN THE REAL WORLD
Author(s):
Taehwan Kim, Woojin Han, Jinhyuk Lee, Dowon Hyun and Juwook Jang
Abstract:
This paper shows the performance of car-to-car ad-hoc networks in the real world. Actually there are many irregular driving environments, so we have established some scenarios about inter-vehicle communications can happen in our actual life. And we have measured the transmission characteristics such as throughput, delay and packet loss rate of the system for each case. We have installed laptops with IEEE 802.11b wireless LAN and software for the ad-hoc network and packet transmission at each car. A test-bed has been implemented to support TCP/UDP packet transmission on wireless ad-hoc environment such as AODV (Ad-hoc On Demand Distance Vector) and OLSR (Optimized Link State Routing). Scenarios we have used in this experiment present which algorithm of ad-hoc routing and transmission is suitable in real driving environment and how performance metrics change according to different circumstances.

Title:
ADAPTIVE END-TO-END LOSS DIFFERENTIATION SCHEME FOR TCP OVER WIRED/WIRELESS NETWORKS
Author(s):
Chang-hyeon Lim, Jin-hyuk Lee, Tae-hwan Kim, Woo-jin Han, Do-won Hyun and Ju-wook Jang
Abstract:
We improve a well-known TCP throughput enhancement scheme over heterogeneous networks of wired/wiress paths. The scheme (Westwood+) adjusts the congestion window using the estimate of currently available bandwidth instead of halving the window in the event of a packet loss, enhancing the TCP throughput. Our scheme infers the cause of packet loss(if it is due to congestion or regular bit errors over wireless paths) from the changes of the RTT values. We adapt the RTT threshold used for determining the cause of packet loss to the current congestion level. For example, we increase the RTT threshold for a packet loss to be regarded as due to congestion when the congestion level of the path is estimated to be low. This avoids unnecessary halving of the congestion window on packet loss due to regular bit errors over wireless path in a more precise way than previous schemes. Compared with the Westwood+, our scheme improves the TCP throughputs by 29% and 55% on 1 Mbps and 10 Mbps paths, respectively. The fairness degradation is negligible.

Title:
AUTOMATED SLA NEGOTIATION FOR WIRELESS UBIQUITY - A Secure Approach
Author(s):
Les Green
Abstract:
This document explores the financial system for automatically negotiated service level agreements. Focus is placed on billing and a solution is proposed based on autonomous, negotiating agents. Security, nonrepudiation and authentication issues are addressed, along with the role of speculation and aggregation within the system.

Title:
PROBABILITY OF OVERLOAD OCCURRENCE IN A SINGLE CELL WCDMA SYSTEM
Author(s):
Marko Porjazoski and Borislav Popovski
Abstract:
A WCDMA (Wideband Code Division Multiple Access) system capacity usually is defined as maximum number of simultaneous users satisfying QoS (Quality of Service) requirements. Radio interface characteristics put a limit on number of supported users with specified QoS requirements. This paper presents the evaluation of single cell WCDMA system capacity in multi service environment, considering no power constraints in uplink. Furthermore it exposes the influence of number of users in the cell, traffic sources activity, traffic intensity and QoS requirements on overload probability in single cell WCDMA system.

Title:
USERS’ DISSATISFACTION PERFORMANCE FOR MOBILE COMMUNICATION NETWORK - An AHP Approach
Author(s):
Kei Oguchi, Yoshitaka Takahashi, Kentaro Hoshi, Shigeru Kaneda and Yoshikazu Akinaga
Abstract:
In this paper, we deal with a mobile communication network via an AHP (Analytic Hierarchy Process) approach. To apply the AHP approach, we first consider three hierarchies; goal, dissatisfaction, and traffic control schemes (spatial distribution, time distribution, and traffic reduction). We then assume practical situations where network congestions occur; a terrible earthquake, a large firework, and a popular ticket reservation. Based on these situations we propose an internet AHP questionnaire. Analyzing the AHP questionnaire results, we finally evaluate users’ dissatisfaction regarding these traffic control schemes. Namely, we show how badly traffic control schemes perform for mobile communication network from users’ point of views.

Title:
HIERARCHICAL AND PSEUDO-RANDOM EIRA CODES BASED ON BIBDS AND PRIMITIVE INTERLEAVERS
Author(s):
Jesús Miguel Pérez Llano and Víctor Fernández Solórzano
Abstract:
This paper describes a method based on hierarchical matrices and primitive generators that allows low cost coder and decoder implementations. The hierarchical approach is well suited for decoder implementation and, in addition, the method has been applied to eIRA structures which have demonstrated a reduced coder implementation complexity. Despite the added structure to eIRA original codes, the architecture presented shows similar BER performance. To achieve this, BIBDs have been used to avoid length-four cycles and primimitive generators contribute to get a pseudo-random construction. Moreover, the reduction of low weight codewords and near codewords are considered in order to reduce error-floors.

Title:
SMART ANTENNAS IN UMTS LCR-TDD - Implementation of RSS Beamforming
Author(s):
Peter JungArjang Hessamian-Alinejad, Achim Seebens, Tobias Scholand, Admir Burnic, Guido H. Bruck and Peter Jung
Abstract:
In this communication a novel beamforming scheme is presented, which is based on regular spatial sampling (RSS) of signals. RSS beamforming allows low-complexity algorithms for smart antennas, while at the same time improving the performance of those systems. An implementation concept is presented, which shows the feasibility of implementing RSS beamforming on today’s readily available hardware platforms.

Title:
DIRECTIONAL SPECTRUM MODELLING IN INHOMOGENEOUS FORESTS AT 20 AND 62.4 GHZ
Author(s):
Telmo R. Fernandes, Rafael F. S. Caldeirinha, Miqdad O. Al-Nuaimi and Jürgen Richter
Abstract:
This paper presents a radiowave propagation model for inhomogeneous forests based on the Radiative Energy Transfer theory (RET) model. This model, which is a discretised version of the RET, is able to simulate the behaviour of radiowaves inside a forest which contains various types of vegetation and free space gaps. The forest is divided into square non-overlapping cells, each one with different propagation characteristics. The propagation properties of each cell rely on specific propagation parameters, which are extracted from vegetation using a measurement method which is also described. The model performance is assessed through comparison between predicted values and directional spectrum measurements carried out in an isolated inhomogeneous forest at 20 and 62.4 GHz. This forest, located in South Wales, is formed by 6 different species of trees of various sizes and leaf types. The measurements were performed with the trees in-leaf.

Title:
MMSE-BASED RECEIVER BEHAVIOUR IN HANDOVER SITUATIONS - Study of Intercell Interference
Author(s):
João Carlos Silva, Nuno Souto, Francisco Cercas and Rui Dinis
Abstract:
This paper focuses on the use of an equalization-based receiver for WCDMA (Wideband Code-Division Multiple Access) in an inter-cellular environment, for handover studies. The receiver is based on the MMSE (Minimum Mean Square Error) algorithm and uses the UMTS (Universal Mobile Telecommunications System) HSDPA (High Speed Downlink Packet Access) standard as a basis, alongside the reference UMTS environments

Title:
IMAGE TRANSMISSION WITH ADAPTIVE POWER AND RATE ALLOCATION OVER FLAT FADING CHANNELS USING JOINT SOURCE CHANNEL CODING
Author(s):
Greg H. H°akonsen, Tor A. Ramstad and Anders Gjendemsjø
Abstract:
A joint source channel coder (JSCC) for image transmission over flat fading channels is presented. By letting the transmitter have information about the channel, and by letting the code-rate vary slightly around a target code-rate, it is shown how a robust image coder is obtained by using time discrete amplitude continuous symbols generated through the use of nonlinear dimension changing mappings. Due to their robustness these mappings are well suited for the changing conditions on a fading channel.

Title:
SCATTERING COEFFICIENTS OVER 3-D FLAT DIELECTRIC SURFACES
Author(s):
Iñigo Cuiñas, Manuel García Sánchez, Ana V. Alejos and David Martínez
Abstract:
Indoor radio channel planning tools implement different models to simulate propagation mechanisms as transmission or reflection. Specular reflection formulation is commonly used instead of more complex scattering models, as that is easier programmed as well as it is faster than scattering. In this work, results from measurements are presented, and modelled by means of traditionally reflection procedures, as well as by applying scattering pattern computations. Beckmann’s scattering model is used as it was formulated, and then modified to take into account antenna pattern effects in the measurements. Comparison between measurements and simulations are also presented, showing good agreement.

Title:
MEASURED MIMO CAPACITY ENHANCEMENT IN CORRELATED LOS INDOOR CHANNELS VIA OPTIMIZED ANTENNA SETUPS
Author(s):
Andreas Knopp, Mohamed Chouayakh, Robert Schwarz and Berthold Lankl
Abstract:
Our premise in this paper is to investigate the available channel capacity of MIMO systems in correlated transmission channels for various antenna arrangements differing in their suitability in order to construct high - rank LOS channels. Hence, a measurement campaign with a fast 5×5 - MIMO channelsounder was carried out in a typical, medium - scale, in - room office scenario giving the opportunity to virtually evaluate the results for arbitrary M × N - MIMO systems (M and N can be chosen 5 at maximum) by antenna selection and combination. We use linear antenna arrays and vary their antenna spacings and orientations relative to each other to generate theoretically more or less suitable cases in terms of receiving high pure - LOS capacities, indicating the capacity that would be obtained when only considering the LOS signal without reflected waves, and we investigate the impact of such optimization approaches on the real - world channel capacity which is calculated from measured data and further investigated by simulation. The results show a measurable benefit in channel capacity when such optimization is performed, especially for small antenna numbers. Finally, we conclude the investigated optimization approaches being suitable not only in theory to enhance the capacity in correlated channels.

Title:
AN ESTIMATION OF DISTRIBUTION ALGORITHM FOR THE CHANNEL ASSIGNMENT PROBLEM
Author(s):
Jayrani Cheeneebash and Harry C. S. Rughooputh
Abstract:
The channel assignment problem in cellular radio networks is known to belong to the class of NP-complete optimisation problems. In this paper we present a new algorithm to solve the channel assignment problem using the Estimation of Distribution Algorithm. The convergence rate of this new method is shown to be very much faster than other methods such as simulated annealing, neural networks and genetic algorithm.

Title:
OPTIMIZED GAUSS AND CHOLESKY ALGORITHMS FOR USING THE LMMSE DECODER IN MIMO/BLAST SYSTEMS WITH FREQUENCY-SELECTIVE CHANNELS - Reduced-complexity Equalization
Author(s):
João Carlos Silva, Nuno Souto, Francisco Cercas, António Rodrigues, Rui Dinis and Sérgio Jesus
Abstract:
The LMMSE (Linear Minimum Mean Square Error) algorithm is one of the best linear receivers for DS-CDMA (Direct Sequence-Code Division Multiple Access). However, for the case of MIMO/BLAST (Multiple Input, Multiple Output / Bell Laboratories Layered Space Time), the perceived complexity of the LMMSE receiver is taken as too big, and thus other types of receivers are employed, yielding worse results. In this paper, we investigate the complexity of the solution to the LMMSE and the Zero-Forcing (LMMSE without noise estimation) receiver’s equations. It will be shown that the equation can be solved with optimized Gauss or Cholesky algorithms. Some of those solutions are very computationally efficient and thus, allow for the usage of the LMMSE in fully-loaded MIMO systems.

Title:
A TELEPHONY APPLICATION FOR MANETS - Voice Over a MANET-extended JXTA Virtual Overlay Network
Author(s):
Luis Bernardo, Rodolfo Oliveira, Sérgio Gaspar, David Paulino and Paulo Pinto
Abstract:
This paper presents MANET-VoVON, a new Internet application for mobile ad-hoc networks (MANETs) providing voice over virtual overlay networks. A MANET-enabled version of JXTA peer-to-peer modular open platform (MANET-JXTA) is used to support user location and optionally, audio streaming over the JXTA virtual overlay network. Using MANET-JXTA, a client can search asynchronously for a user, and delay the call setup until a path is available to reach the user. The application uses a private signalling protocol based on the exchange of XML messages of MANET-JXTA communication channels. Nevertheless, it is fully interoperable with normal SIP clients through an embedded gateway function. This paper describes a prototype implementation of the proposed application and of the MANET-JXTA, and presents some performance measurements.

Title:
ROUTING IN THE “UMBRELLA” ARCHITECTURE
Author(s):
A. D. Sotiriou, P. Kalliaras, N. Mitrou
Abstract:
Routing in a Peer-to-Peer environment faces a number of challenges, mainly due to its distributed nature. In this paper we evaluate a new distributed hash table architecture that is able to provide efficient routing through a fixed-size table. By introducing a set of base algorithms, multiple replication schemas, virtual nodes and a variable repair mechanism, we are able to ensure successful lookups of published keywords. Along with theoretical analysis of our proposed work, we present extensive simulation results that testify and evaluate our protocol.

Title:
USE OF AGPS CALL DATA RECORDS FOR NON-GPS TERMINAL POSITIONING IN CELLULAR NETWORKS
Author(s):
Semun Lee, Jeongkeun Lee, Taekyoung Kwon, Yanghee Choi, Tae Joon Ha and Tae-il Kim
Abstract:
This paper presents a novel method of user terminal positioning in cellular networks. A pattern matching technology based on received-signal-strength (RSS) from the pilot channels of cell towers has been the most popular network-based positioning method. In response to a position request, a terminal measures RSSs of pilot channels from surrounding cell towers and then the terminal's RSS pattern is compared with a pattern database to find the most correlated one which indicates the position of the terminal. Although the pattern matching method can provide accurate positioning, its database construction and maintenance require a high overhead of periodic labor-intensive pattern collection. In this paper, we propose to exploit the call data records (CDRs) that are uploaded by Assisted Global Positioning System (AGPS) terminals as inputs to the pattern database, which removes or reduces the pattern collection overhead. In AGPS systems, terminals measure satellite signals and cellular network parameters (such as RSS) and relay them to the cellular infrastructure, which in turn calculates the terminal position using both that satellite and cellular network data. The proposed AGPS CDR based pattern matching method takes advantage of the increasing number of AGPS terminals in service: non-AGPS terminals can obtain more precise positioning results in areas where more AGPS calls are generated (e.g. hotspots). To do so, we analyze the characteristics of RSS patterns and AGPS CDRs. Based on the analysis, a pattern-distance metric and an AGPS CDR based pattern matching system are proposed and their performances are evaluated by examining field data of several urban downtown areas of Seoul, Korea. We obtain promising results: the position of the user terminal can be estimated with the accuracy (or, positioning error) at the level of 76.8m and 149.8m for the 67% and the 95% confidence interval, respectively.

Title:
MOCKETS: A NOVEL MESSAGE-ORIENTED COMMUNICATIONS MIDDLEWARE FOR THE WIRELESS INTERNET
Author(s):
Mauro Tortonesi, Cesare Stefanelli, Niranjan Suri, Marco Arguedas and Maggie Breedy
Abstract:
Wireless networking is becoming increasingly important for ubiquitous access to the Internet and the Web. However, wireless networks exhibit significant reliability and performance problems, with frequent disconnections, congestions, and packet losses. For these reasons, the traditional TCP/IP suite, designed for wired networks, offers poor performance and inadequate communication semantics in this scenario. There are several research efforts in both protocols and communication infrastructures aimed at producing solutions better suited to wireless network characteristics. This paper presents Mockets, a novel communication middleware specifically designed for wireless networks scenarios. The Mockets middleware permits to move a communication endpoint from one node to another without interrupting the communication session. In addition, Mockets provides several delivery services with different communication semantics, semantic classification of data, cancellation/replacement of enqueued data, and priority/lifetime assignment to messages. First experimental results in a wireless network scenario show that the Mockets middleware achieves better performance levels than traditional TCP-based infrastructure.

Title:
A CONTEXT-AWARE ARCHITECTURE FOR MOBILE KNOWLEDGE MANAGEMENT
Author(s):
Olaf Thiele, Hartwig Knapp, Martin Schader and Nicolas Prat
Abstract:
In many professional activities (e.g., medical diagnosis, construction, or sales), the ability to retrieve and store knowledge in a mobile situation is crucial. This need, together with the progress of mobile devices, has led to the emergence of mobile knowledge management. The mobile situation imposes specific constraints on traditional knowledge management activities (e.g., knowledge retrieval, presentation ...). Therefore, a key research question for mobile knowledge management is how context should be taken into account. In this paper, we propose a context-aware knowledge management architecture for mobile environments. The key aspect is the Contextualizer middleware that takes care of knowledge storage and retrieval as well as contextually adapted knowledge presentation on mobile devices. In contrast to existing concepts, we suggest a broader approach, where the middleware serves as the mediator to different mobile devices. We implemented the architecture in a fitted use case. Our roadside assistance use case demonstrates the architecture's strength for presenting both text and graphics stemming from several knowledge sources.

Title:
A TOUCH IS WORTH A THOUSAND CLICKS
Author(s):
Zoe Antoniou
Abstract:
The fusion of interaction and discovery technologies can facilitate easy, intuitive and impromptu access to networked entities by users without the need for significant administrative overhead. Due to mobility, complex connectivity and small user interfaces, traditional service discovery methods fail to meet the demands placed by such environments. This paper presents work-in-progress on how NFC-enhanced mobile devices can enable intuitive service discovery by non-expert users in smart environments through simple gestures such as touch. With this new paradigm, physical space becomes an extension of the traditional GUI. An extensible RFID tag record is presented that can be utilised in a variety of scenarios. The proposed approach is further illustrated through a technical realisation based on the UPnP framework. An example use case is selected and the step-by-step process of service discovery and user interaction is described.

Title:
PACKEDOBJECTS
Author(s):
John P. T. Moore
Abstract:
packedobjects is a highly portable, cross platform, data encoding tool. The project is based on the telecommunications standard Packed Encoding Rules (PER). An abstract syntax language is used to define a protocol specification. packedobjects uses the Scheme programming language to represent the protocol specification within a symbolic expression (s-expression). Using an s-expression provides a more dynamic approach over the traditional method of parsing the specification and producing high level language code. The output of applying packedobjects' encoding rules to a protocol specification is a concisely encoded bit stream suitable for application domains such as network games development and mobile application development. The project has been released under the terms of the BSD license.

Title:
M-SHOW:A SYSTEM FOR ACCURATE POSITION ESTIMATION IN MULTI-FLOOR BUILDINGS
Author(s):
Wu Ke, Zheng Zhong, He Liang and Gu Junzhong
Abstract:
This paper presents M-Show, a Wireless LAN based system for locating users inside multi-floor buildings. It makes improvements in the sampling, processing and storing of empirical signals to previous studies, and builds a Fuzzy Empirical Signal Model that gives more credible description of signal distribution. By dividing the map into different sized Intelligent Areas (iAreas), M-Show is able to achieve alterable positioning granularity within the same map. It also unprecedented adopts AP Close Range Pre-Locating strategy to quickly locate the users inside a certain small scope around an AP. In addition, since statistical calculation methods are inefficient in distinguishing vertically overlapping positions on different floors, which is not tackled in previous locating systems, we introduce the Fluoroscopy to rectify the locating result of probability calculation. M-Show is deployed in Shanghai Science and Technology Museum, and experimental results show that with reduced average position query time and lower computation cost, M-Show achieves a high locating accuracy of 93% probability within 3 feet around the user’s actual position.

Title:
EMERGENCY INFORMATION DISSEMINATION IN MOBILE NETWORKS FOR VEHICLES
Author(s):
Ioan Chisalita and Nahid Shahmehri
Abstract:
Due to the unacceptably high number of accidents with severe consequences, in-vehicle safety systems that provide a better service to drivers are needed. One of the key technologies for supporting the development of efficient safety systems is vehicular communication. In this paper we propose a reactive protocol for disseminating emergency notifications to vehicles in traffic. The communication performance and the protocol usefulness for help avoiding accidents are investigated via computer simulations. The results of the evaluation indicate that timely and reliable communication can be provided by the proposed protocol.

Title:
ONTHEWAY: A PREDICTION SYSTEM FOR SPATIAL LOCATIONS
Author(s):
Juan Antonio Álvarez, Juan Antonio Ortega, Luis González, Francisco Velasco and Francisco Javier Cuberos
Abstract:
In ubiquitous computing we need to know the present context in order to interact properly with the nearby smart elements. When we are moving outdoors, mobile devices take a very important role because they provide us with a link between the world outside and ourselves through means of intelligent interfaces. There are a lot of situations in which it would be very useful to know or foresee the future context, i.e. as a geographic environment, in which we could find ourselves in a near future, and at the same time being able to use that information from our devices. Therefore we must preview this location with enough precision and time and be able to use this information from our mobile device. In our ""OnTheWay"" system, we used GPS technology and databases made of past paths taken by a person, in order to predict the next location, once we had begun a new course, comparing the new one with those ones stored. The results were amazing: from the data collected about paths travelled during a month and five days, we got the actual destination in 98% of cases, when we have only made a 30,35% of the total path. Therefore, including statistic and semantic information will allow us to upgrade our results, due to the sedentary human behaviour, the small number of frequently visited locations and the fact that the paths used to arrive to these locations are usually the same.

Title:
FROM ELECTRONIC TO MOBILE LEARNING - How to Make the Most of Existing e-Learning Materials in Wireless Environment
Author(s):
Vladlena Benson and Shafiiq M. Gopee
Abstract:
Continuous advancement of mobile devices and wireless communication technologies can be successfully utilized to complement face-to-face and blended learning methods. In the recent years various educational software systems have accumulated a wealth of learning resources. Proliferation of mobile devices offers new ways for content delivery. The aim of the project described in this paper was to avoid re-development of the existing online teaching resources and investigate their effectiveness in mobile learning. We have surveyed students’ expectations in terms of educational methods and materials students preferred to use ubiquitously in synergy with face-to-face or blended learning. The study provided an impetus towards the development of a J2ME platform conveying existing electronic teaching resources from the LMS to mobile devices. The analysis of students learning effectiveness via mobile devices has shown the benefits of enriching student experience by means of new technology. This paper concludes with a reflection on the user experience and guidelines for conveying and adaptation of the existing online learning materials for wireless delivery.

Title:
MULTIMODAL INTERACTION WITH MOBILE DEVICES - Outline of a Semiotic Framework for Theory and Practice
Author(s):
Gustav Öquist
Abstract:
This paper explores how interfaces that fully utilizes our ability to communicate through the visual, auditory, and tactile senses, may enhance mobile interaction. The first step is to look beyond the desktop. We do not need to reinvent computing, but we need to see that mobile interaction do not benefit from desktop metaphors alone. The next step is to look at what we have at hand, and as we will see, mobile devices are already quite apt for multimodal interaction. The question is how we can coordinate information communicated through several senses in a way that enhances interaction. By mapping information over communication circuit, semiotic representation, and sense applied for interaction; we create a framework for multimodal interaction that can offer some guidance to integration. By exemplifying how a wide range of research prototypes fit into the framework today, it is shown how interfaces communicating through several modalities may enhance mobile interaction tomorrow.

Title:
SENSOR SYSTEM USING INTERNET COMMUNICATION - Measuring via Internet
Author(s):
Miroslav Husak
Abstract:
The paper describes sensor system for measurement and transfer of data via internet. Sensor data are measure on the different places. There is the conception of read up sensor data, data transfer and data display in the paper. The realized system is described for measurement of air temperature, pressure and humidity. Hardware and software of measure device were realized. Eight physical quantities can be measured by basic sensor system. System consisted from 16 configurations input/output for sensor connection. Additionally sensors can be used by the support of software widespread. RS-232 interface was used by simplicity of use. Interface Ethernet can be used by the converter. Control software of whole system was designed. There are many program functions in whole software. All designs were verified by the realized system sample. All declare functions can be displayed on WEB pages. Common software equipment can be used in the view of WEB pages (PDA or mobile phone).

Title:
EVALUATION ISSUES FOR UBIQUITOUS COMPUTING
Author(s):
Jung-Hyun Bae, Soon-il Cha, Seok-Kyo Shin and Jae-Woong Kim
Abstract:
One of the main problem with the evaluation of ubiquitous computing (UC) is that we do not have standards guidelines, or metrics, even though there have been many researches on the individual technical aspects of ubiquitous systems. UC systems differ from standard applications in many ways. Therefore, it is very hard to apply the current working standards or metrics to the evaluation of UC system, which leads us to develop a desirable way to deal with this. This paper suggests the evaluation issues of service and system software to provide ubiquitous computing. Also, we investigate how equally the evaluation scopes we have suggested and the quality characteristics could be matched with the current technological feasibility of the ubiquitous computing systems, so we can see what benefits and the deficiencies of the proposed evaluation scopes would be. Two case studies are considered and these can be seen as the most-likely applications in the current ubiquitous computing environment.

Title:
WIRELESS NETWORK ARCHITECTURE TO SUPPORT MOBILE USERS
Author(s):
Maryna Komarova and Michel Riguidel
Abstract:
Over the past few years there has been an increasing number of commercial enterprises offering public wireless Internet access, and the zones of different network access points overlap. The natural consequence is users’ needs to move between them without an active session interruption. To satisfy this demand, authentication methods that do not require interruption by the user to chose an ISP or enter a login/password are required. It is necessary to maintain a high level of security for both the user’s device and data and for a visited network. Some deployment scenarios may require separate authentication to obtain access to a network and to the Internet, but the resulting authentication increases handover latency. This paper aims to develop an approach for user authentication in a public access wireless LAN, which minimizes risk of attack at network nodes conducted by unauthenticated users, and provides key establishment and strong encryption between a mobile node and an access point. At the same time, the method must not increase overall authentication time. Two protocols, PANA and IEEE 802.11i, correspond to the described conditions. The proposed method combines these protocols. An authorized user is granted network and Internet access as a result of a single authentication process.

Title:
LICENSE TRANSFER MECHANISMS THROUGH SEAMLESS SIM AUTHENTICATION - Rights Management based on SIM Keys
Author(s):
Josef Noll, György Kálmán and Ulf Carlsen
Abstract:
A critical issue in the acceptance of wireless services is the authentication to these services. Service take-up in wireless networks will be limited, unless seamless service access is guaranteed. The success of GSM, and especially of premium services (e.g. SMS, iMode) are based on seamless user authentication to the network and to the services, provided with adequate security. This paper focuses on the current developments in Mobile phone/SIM card based authentication. The mobile phone can be used for physical access (admittance) and service access using near field communication (NFC). It may act as the security device in wireless network access or using the SIM credentials for VPN and Mobile Commerce applications. In combining these authentication mechanisms, the Mobile phone becomes the identity provider in the virtual/electronic world. The paper extends the seamless service access into the digital rights management, suggesting methods on how the rights keys can be managed on the SIM card, while content remains distributed on the customer devices. Final focus is on the requirements for future SIM cards in order to support the suggested methods.