Junya Nakata

A Multi-Purpose Wireless Network Emulator: QOMET

In this paper we present the design and usage of the multi-purpose wireless network emulator that we develop, QOMET. QOMET implements a two-stage scenario-driven approach to wireless network emulation. We give here the details of the improved model and additional functionality that make it currently possible to use QOMET to convert a real- world scenario to a sequence of network-condition descriptors for a wide range of experiments. QOMET was used on a real network testbed to perform experiments involving emulated 802.11 a/b/g WLAN technology over wired networks for several types of scenarios. We shall illustrate this in the final part of the paper, with emphasis on networked robot emulation.

QOMET: A Versatile WLAN Emulator

In this paper we present the design of QOMET, the wireless LAN (WLAN) emulator that we develop. Our approach to WLAN emulation is a versatile two-stage scenario-driven design. In the first stage a real-world scenario representation provided by the user is converted successively into physical, data link and network layer effects that correspond to the emulated WLAN scenario. The output of the first stage is a description of the network states at successive moments of time, which is used in the second stage to accurately reproduce the wireless environment conditions by means of a wired-network emulator. We give here the details of the overall model that makes it possible to accomplish this conversion in QOMET. We then present our test methodology and illustrate our approach by several experimental results.

QOMB: A Wireless Network Emulation Testbed

In this paper we present QOMB, a testbed we designed and implemented for the evaluation of wireless network systems, protocols and applications. The testbed uses the wireless network emulation set of tools QOMET so as to reproduce in a wired network, in real time, the wireless network conditions corresponding to a given scenario. In this context QOMET also provides support for features such as realistic virtual 3D environments, and node mobility generation. The infrastructure of QOMB is StarBED, the large-scale network experiment testbed at the National Institute of Information and Communications Technology, Hokuriku Research Center, in Ishikawa, Japan. The multi-hop wireless network emulation experimental results related to OLSR performance analysis in mesh networks and MANETs illustrate the main features and the usability of QOMB.

StarBED2: Large-scale, Realistic and Real-time Testbed for Ubiquitous Networks

Nowadays many new technologies are being developed and introduced for Internet, home networks, and sensor networks. The new technologies must be evaluated in detail before deployment. However the above mentioned networks have a large number of nodes and a complicated topology. Therefore it is difficult to analyze such networks using typical network simulators. Accordingly testbeds for these networks must be able to perform accurately emulation of large-scale networks with a complex topology. In order to implement a testbed that satisfies these requirements, we developed a large-scale, realistic and real-time network testbed, StarBED, using hundreds of PCs, and switched networks. We are now implementing StarBED2, which expands StarBED so as to be suitable for emulating ubiquitous networks by introducing several new concepts. In this paper we describe first the present StarBED, its design concept, overall architecture, implemented functionalities, and some of the experiments we performed. Then we introduce StarBED2, its design policy, architecture, and additional components.

Collaborative motion planning of autonomous robots

In disaster areas, office buildings, or at home, multiple autonomous networked mobile robots may act instead of human beings. These robots have to move to their destiantion so as to perform their function. For this purpose they need to be able to recognize the changes in the surrounding environment. They are equipped with a motion-planning method in order to avoid in real time collisions with other robots or obtacles. In this paper we propose a motion planning method based on PRM (Probabilistic Roadmap) algorithm. To evaluate our method, we constructed an experiment platform based on StarBED, which is a large-scale network testbed. By using the virtual environment manager Map Manager, the WLAN emulator QOMET, and the experiment-support software RUNE we are able to perform emulation of large-scale autonomous networked mobile robot systems. The experimental results confirm the usefulness of collaborative motion planning, which results in reaching faster the estimation and in less frequent re-planning.

Active tag emulation for pedestrian localization applications

Active tags are currently used for various tasks in transport and distribution industries, for factory automation or asset tracking. Pedestrian localization is another application of active tags, for which we develop a technique and a practical system. Following preliminary real-world experiments with a system prototype, we continued to develop our active tag based pedestrian localization technique by an emulation approach that is discussed in this paper. We use emulation during development so as to be able to perform large-scale experiments with the pedestrian localization system easily and in a repeatable manner. The experimental results show the good agreement that exists between the real-world pedestrian scenario and the measurements made with the emulated system.

Emulation framework for the design and development of active RFID tag systems

The design and development of active RFID tag systems requires several iterations, and thorough testing in order to ensure that the prototype systems behave as intended. Facilitating these operations contributes significantly to faster product development and to a quicker time to market. The emulation framework that we present makes it easier to carry out the verification and testing related to the design and development of active RFID tag systems. We illustrate the use of this framework during the design and development of an active RFID tag based pedestrian localization system that is being developed by Panasonic Corporation. In this context emulation was successfully used: (i) to identify active RFID tag firmware issues; (ii) to assess the overall performance of the localization system; (iii) to explore the system parameter space so as to identify the values that provide optimum performance; (iv) to extend the range of tested scenarios beyond what could be done through real-world trials.

Distributed Emulator for a Pedestrian Tracking System Using Active Tags

In this paper we introduce a distributed emulator for a pedestrian tracking system using active tags that is currently being developed by the authors. The emulator works on StarBED which is a network testbed consisting of hundreds of PCs connected to each other by Ethernet. The three major components of the emulator (the processor emulator of the active tag micro-controller, RUNE, and QOMET) are all implemented on StarBED. We present the structure of the emulator, how it functions and the results from the emulation of the pedestrian tracking system. The system met the requirements to create a flexible experimental platform to support the development of the pedestrian tracking system. We confirmed the results obtained by running tests corresponding to a real-world experiment.

IEEE 802.15.4 Network Emulation Testbed

IEEE 802.15.4 networks are promising solutions for wireless personal area networks, and in particular for wireless home area networks. IEEE 802.15.4 has numerous applications in fields such as energy management and home automation. However, real-world trials with 802.15.4 devices are difficult because of the characteristics of these devices (small dimensions, wireless communication), and the potentially large size of the network. We present in this paper an IEEE 802.15.4 network emulation testbed that makes possible repeatable and controllable live experiments with 802.15.4-based devices. The testbed is built by extending the functionality of the wireless network emulation testbed named QOMB with 802.15.4 PHY and MAC layer capabilities, as well as 802.15.4 device processor emulation. We illustrate the usability of the 802.15.4 network emulation testbed with a case study of home networking used for automation related to environment control.

StarBED2: Testbed for Networked Sensing Systems

Nowadays many new technologies are being developed and introduced for Internet, home networks, and sensor networks. The new technologies must be evaluated in detail before deployment. However the above mentioned networks have a large number of nodes, and a complicated topology. We developed a large-scale, realistic and real-time network testbed, StarBED, using hundreds of PCs, and switched networks. We are now implementing StarBED2, which expands StarBED so as to be suitable for emulating ubiquitous networks. In this paper we describe StarBED2, its design policy, architecture, and additional components, including the custom experiment- support system, RUNE (real-time ubiquitous network emulation environment). We then show some experimental results obtained in this environment with emulated networked sensing systems.