Evaluating Bluetooth Performance as the Support for Context-Aware Applications
We present an experiment relative to the use of the Bluetooth wireless technology to provide network support for context-aware applications. We describe an approach to provide network interconnection using a combination of wireless and wired network technologies. We also describe the steps taken to create a Bluetooth based context-aware application. We, finally, evaluate, using a small test-bed and simulation the overall performance of this technology when adopted in the area of context-aware and ubiquitous computing.
The differences between distributed shared memory caching and proxy caching
The authors discuss the similarities in caching between the extensively studied distributed shared memory systems and the emerging proxy systems. They believe that several of the techniques used in distributed shared memory systems can be adapted and applied to proxy systems.
A MANET Autoconfiguration System based on Bluetooth Technology
The availability of both Wi-Fi and Bluetooth technologies on currently available devices offers the possibility to combine both in order to make the most out of their capabilities. In this paper we propose using Bluetooth technology to solve the configuration problem of the terminals conforming an IEEE 802.11-based ad-hoc network. The main objective of mobile ad- hoc networks (MANETs) is to extend the connectivity range of nodes through packet forwarding, thereby avoiding the use of a fixed infrastructure. However, since configuration of nodes is a complex issue, we provide a fast and reliable solution to auto-configure MANET terminals. Our solution is adequate for the quick setup and deplo…
A New FEC Scheme for Real-time Transmission of High Definition Video over IP Network
Increasing the applicability of ubiquitous computing, minimizing energy consumption and hardware cost are mandatory in real world applications. In this paper we present our platform prototype for ubiquitous computing, which has been implemented based on commercial Bluetooth off-the-shelf components. It allows every object to be augmented with processing and communication capabilities in order to make them "smart". We validate our proposal by evaluating the trade-off between power consumption and performance of the experimental prototype.
Group mobility impact over TCP and CBR traffic in mobile ad hoc networks
We present an analysis of the effect that mobility models have over the performance of a mobile ad hoc network. We concentrate on group mobility because there is a growing attention on the development and evaluation of MANET's approach applied to personal area networks (PANs), especially based on Bluetooth technology. We investigate the effect that the mobility model has on the performance of CBR traffic and TCP traffic. We propose four different group mobility models and describe a mobility pattern generator called grcmob to be used with the ns-2 simulator. We perform a thorough evaluation of a MANET behavior using as a reference the behavior obtained with the random waypoint mobility mode…
Supporting scalable video transmission in MANETs through distributed admission control mechanisms
Emerging multimedia applications over mobile devices are becoming very popular, especially over infrastructure wireless networks such as cellular and WLANs. However, providing this kind of services over infrastructureless networks like ad hoc networks presents many additional problems. One of these problems is how to share resources fairly among the users involved. In this article we propose a QoS framework supporting scalable video streaming in mobile ad hoc networks based on distributed admission control and video traffic awareness. Our framework promotes fairness between video flows in terms of resource consumption. It also guarantees a significant reduction of the idle times experienced…
A low power protocol to broadcast real-time data traffic in a clustered ad hoc network
Energy saving is an extremely important design criteria for mobile ad hoc networks. We present the intra-cluster data-dissemination protocol (Icdp). The Icdp is used to group nodes around a special one, called the cluster leader (CL). The CL centralizes the power management mechanism and acts as a proxy for data transfer between the cluster and the rest of the nodes in the region. When a cluster node enables the power management it goes into "sleep" mode, to minimize power consumption. The CL buffers data frames for power saving stations and delivers them on the stations' request. We periodically distribute the cluster leader role among all the nodes inside the cluster, to not overload a si…
On the Design of Spontaneous Networks Using a P2P Approach and Bluetooth
In this paper, we address the design of spontaneous networks using a peer to peer (P2P) and Bluetooth technology. A spontaneous network is a small infrastructureless network formed when a group of people come together to participate in some collaborative activity. In this work, we develop a base library and application work ground for easy spontaneous networks development. Based on it, we present an experimental application that provides spontaneous networks with context and transparent services to interchange resources between peers. We describe the overall network architecture and present details of the implementation steps taken to create our P2P and Bluetooth based application. Finally …
Evaluating the Performance of Real Time Videoconferencing in Ad Hoc Networks Through Emulation
The validation of new video protocols and applications for mobile ad hoc networks in a real environment is an important task. In this work we present Castadiva, a test-bed architecture that allows validating software solutions for ad hoc networks using low-cost, off-the-shelf devices and open source software. We use this tool to test a videocall using the OLSR protocol in different scenarios, varying the number of hops between the caller and the receiver. The results obtained in this paper show that, for an ad hoc network with a large number of hops, the quality of videocalls suffers a significant degradation even in the absence of mobility.
Modeling of mobility and groups in inter-vehicular MANET-based networks
This paper evaluates the behavior of mobile ad hoc networks when group mobility is involved. We concentrate on group mobility because road vehicles tend to form groups or fleets whose behavior depends on the behavior of the close-by vehicles. We propose four different group mobility models and present a mobility pattern generator, called grcmob that we designed to be used with the ns-2 simulator. We evaluate the performance of vehicular ad hoc networks under a wide number of scenarios using both TCP and UDP data traffic. We show that the number of groups is more important than the number of nodes and that the impact of area size is almost negligible. We also reveal that the mixture of inter…
A Wireless Mesh Network-based System for Hotspots Deployment and Management
In recent years Wireless Local Area Networks (WLANs) or hotspots, as they are commonly known, have emerged as a promising networking platform to extend network connectivity in public venues, providing local coverage for Internet applications on the move in urban areas and rural environments. Wireless hotspots using 802.11-based technology have popped up in corporate offices, coffeehouses, airports, restaurants and bookstores worldwide. For all their utility and ease of use the 802.11 wireless protocol, known as WiFi, has become the mobile connectivity mechanism of choice for business people, travelers, villagers, and everyone else. Unfortunately, even with the protocol's ease of use and its…
Castadiva: A Test-Bed Architecture for Mobile AD HOC Networks
Evaluating and deploying all sorts of protocols and applications designed for wireless ad hoc networks in a real environment is an important and urgent task. Traditionally, all the proposals made rely solely on simulator results. However, as different research groups develop different solutions to solve problems related to these new networks, it becomes more and more important to migrate the proposed solutions to a real environment. In this work we present Castadiva, a test-bed architecture that allows validating software solutions for ad hoc networks using low-cost, of the-shelf devices and open source software. Through a friendly user interface, Castadiva offers the possibility to define …
Evaluation of the Impact of Multipath Data Dispersion for Anonymous TCP Connections
Despite recent research efforts, wireless ad hoc networking technology remains especially prone to security attacks. In this work our contribution focuses on determining the optimal trade-off between traffic dispersion and TCP performance to reduce the chances of successful eavesdropping, while maintaining acceptable levels of throughput. For our experiments we propose a multipath-enhanced version of DSR, and we compare Tahoe, Reno and Sack TCP variants. Results show that multipath traffic dispersion impact on TCP throughput is bounded to a maximum of 25-35%, and that there is only a minimal dependence on the number of routes used, the number of consecutive packets sent on each route, the r…
On the design of pervasive computing applications based on Bluetooth and a P2P concept
As an example of implementing the pervasive computing, we developed an application framework to deploy an easy, spontaneous, and infrastructureless network. We selected the Bluetooth technology with the peer-to-peer (P2P) concept to develop an experimental application which enables peers to exchange their resources. Overall network architecture and the prototype application are presented. We selected a small test-bed and simulation to evaluate the overall performance and system behaviour. We measured and present our findings in term of the duration of inquiry procedure and the throughput, according to various experimental parameters such as physical distance between nodes and their speeds.
Building a research prototype to provide pervasive services in hospitals
Research into the nature of pervasive computing has now been around for more than a decade. Nowadays pervasive applications exploit mobile wireless communication technologies to interconnect computing devices along with various sensing technologies, setting up a new kind of intelligent environment where applications can transparently search and use services without userspsila intervention. However, there are few examples of real world deployment of pervasive computing moving out from academic laboratories into our everyday life. We present BlueHospital - a research prototype that provides context-aware information and location based services to clinicians in hospitalspsila recovery wards. T…