Masugi Inoue

Design and implementation of a Bluetooth signal strength based location sensing system

In a ubiquitous computing environment, location awareness is a basic necessity. There are various research projects, which discuss the problem of indoor location sensing. We have recognized acceptability, low power consumption, and cost as the key design factors for developing widely deployable location sensing systems. As a good candidate technology that could satisfy these needs, we proposed a location sensing system based on the widely available Bluetooth medium. Location evaluation is preformed by sensing Bluetooth signal strength with a reference model based approach. We discuss problems which arise when the Bluetooth RSSI (received signal strength indicator) is used as a signal strength indicator, and propose a novel access point that supports variable attenuators to overcome these problems. This access point allows the reading of a wider range of signal strengths using RSSI. We show that our approach to location sensing has reduced the error rate about threefold compared to systems which do not use variable attenuator supported access points.

Energy Consumption Measurement of Wireless Interfaces in Multi-Service User Terminals for Heterogeneous Wireless Networks

For future generation mobile networks, we expect that the mobile devices like PDAs, note PCs or any VoIP-enabled communicators will have the feature of being always switched on, ready for service, constantly reachable by the wireless Internet. In addition to high access speed, attractive real-time contents or other expected spectacular features of the future wireless Internet environment, the mobile terminals has to be very much energy-aware to enable literal untethered movement of the user. Mechanisms for network activities like maintaining location information and wireless system discovery, which require regular network access, should be energy-efficient and resource-efficient in general. Cellular systems employ the notion of passive connectivity to reduce the power consumption of idle mobile hosts. In IP based Multi-service User Terminal (MUT) that may have multiple wireless interfaces for receiving various classes of services from the network, there should be an efficient addressing of the energy consumption issue. To devise an energy-efficient scheme for simultaneous or single operation of the wireless interfaces attached to such terminals we should have comprehensive understanding of the power consumption of the devices/modules in various operational states. This paper investigates the power consumption pattern or behavior of some selected wireless interfaces that are good candidates for being part of the future of the multi-service user terminals. We propose a simple model for predicting energy consumption in a terminal attributed to the wireless network interfaces. We measured the actual consumption pattern to estimate the parameters of the model.

An ID/locator split architecture for future networks

The ID/locator split concept has recently been introduced in the standardization activities of ITU-T study group 13 for use in future networks. To contribute to ITU-Ts initiative, we first propose a naming system to configure host-names and identifiers and map them to locators. We then propose a network architecture that is based on the ID/locator split concept and the naming system. The proposed architecture allows the network layer to change protocols and locators without disturbing the upper-layer communication sessions. This capability is helpful for designing efficient solutions for mobility, multi-homing, routing, and security as well as for integrating heterogeneous network layer protocols.

Measurement and usage of power consumption parameters of wireless interfaces in energy-aware multi-service mobile terminals

For IP-based always-on type multi-service user terminals, which may have multiple wireless interfaces, energy-efficiency is a key requirement. It is crucial to take into account the power consumption behavior and delay patterns associated with each state and transitions of the wireless devices to formulate efficient operation of multi-module terminals, especially in services where media/session handover between wireless networks are targeted. This paper investigates the power consumption pattern or behavior of some selected wireless interfaces that are good candidates for being part of the future of the multi-service user terminals. We propose a simple model for predicting energy consumption in a terminal attributed to the wireless network interfaces. We measured the actual consumption pattern to estimate the parameters of the model.

Scalable Mobile Ethernet and fast vertical handover

The 3G cellular system has infiltrated into the market and the next generation wireless system called beyond 3G is discussed at ITU-R. The beyond 3G system integrates various wireless accesses, including 3G and wireless LANs, and provides an all IP wireless solution to services that take advantage of each wireless communication of the system. Current approach to integrate wireless systems localizes wireless dependent functions and integrates all IP network using IP technologies. We propose a scalable mobile Ethernet architecture for the all IP integrated network using MAC layer technologies, such as provider bridge, RPR, and IEEE 802, and the fast vertical handover introducing common radio resource and signaling managements. We discuss network segmentation with mobility management and multicast management for the scalability of the mobile Ethernet by reducing network traffic. We evaluate the network from the viewpoint of scalability. In the evaluation, we understand that the design of the gateway switch of a segment forwarding MAC frames as an anchor point becomes effective in cases where the gateway switch of each segment cannot hold entries for all mobile terminals. We also evaluate the vertical handover as compared to the mobile IPv6 fast handover, and we understand that the fast vertical handover consumes less network resources and is flexible in having an anchor point for handover.

Context-Based Network and Application Management on Seamless Networking Platform

A context-based adaptive communication system is introduced for use in heterogeneous networks. Context includes the users presence, location, available network interfaces, network availability, network priority, communication status, terminal features, and installed applications. An experimental system was developed to clarify the feasibility of using context information to flexibly control networks and applications. The system operates on a seamless networking platform we developed for heterogeneous networks. By using contexts, the system can inform the caller and callee of applications they can access, which are available through the network before communication occurs. Changes in contexts can switch an on-going application to another during actual communication. These functions provide unprecedented styles of communication. A business scenario for a seamless networking provider is also presented.

Mobility Management in HIMALIS Architecture

Mobility is not natively supported in the current Internet because it uses IP addresses as host or session identifiers in the transport and application layers and as locators in the network layer. In the mobile networking environment, a host should be able to change its locator when it moves from one network to another, while keeping the host or session ID fixed. Thus, to provide inherent mobility support in the future Internet, which we call the New Generation Network, we propose HIMALIS (Heterogeneity Inclusion and Mobility Adaptation through Locator ID Separation) architecture. HIMALIS uses separate namespaces for host IDs and locators. It includes a new naming scheme for generating host names and IDs. It uses a logical control network to store and distribute bindings among host names, IDs and locators for supporting mobility. We verify the basic functions of the architecture by implementing and testing it in a testbed system.

A Novel Managed Wireless Mesh Architecture for Community Service Platform

This paper identifies communication system functions and technologies that a local region, individuals living in that region, and various communities to which each individual belongs require and propose a community communication service platform for providing those functions and technologies. To provide a variety of services suited to the characteristics of a region or community, the local region itself or individuals, communities, or organizations that are not the conventional telecommunications carriers should be able to deploy, operate, and manage the communications network within that region and should be able to easily construct and provide various services on it. The proposed system, which is based on open specifications, establishes logical paths with a many-to-many mesh topology on a physical wireless mesh network to implement multiple services each of which uses the paths based on its own policy.

Fast Recovery from Link Failures and Blackout of a Managed Wireless Mesh for NerveNet

A managed wireless mesh for infrastructure-level, stable regional mesh network has been studied. NerveNet, which we have been proposing, is a concept of future regional platform network that covers local regions and provides various context-aware services with the shared use of sensors and actuators. The managed wireless mesh developed for materializing NerveNet features auto-configuration of multiple, different routes between any two base stations for high capacity and reliability. The managed wireless mesh of ten base stations was implemented on PCs and commercial L2 switches. Performance evaluation showed that route switching after one or two link failures had been detected was completed in no later than 70 milliseconds while it takes a few to tens of seconds with existing adhoc routing-based mesh networks. It was also shown that the restart of the network took only about three minutes, enabling urgent recovery of communication in emergency situations.

Sensor-Terminal-Network Cooperative Architecture for Context-Aware Services

A new-generation access network should be able to transport various kinds of dynamically changing sensor information about specific localities or private individuals to different destination servers in a secure manner for processing so that the various processed information can be used in an integrated manner to provide advanced context-aware services. After classifying the various kinds of sensor information related to individuals, we propose a communication architecture in which sensors placed in the environment, mobile terminals owned by users, and the new generation access network operate cooperatively. It features secure transport of sensor information via mobile terminals by establishing communication channels to sensors and the sensor database.