Masaaki Ohnishi

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.

Regional Wireless Network Platform for Context-Aware Services and Its Implementation

Nerve Net is a concept of regional wireless access platform where multiple service providers can provide their own services with the shared use of the network and sensors, making various context-aware services practical. It works as the nervous system of the human beings. Densely located, interconnected access points with database and data processing unit will provide mobility to terminals without a location server and will enable secure sensor data transport on a highly reliable, managed mesh network. The motivation, concept, architecture, system configuration, and preliminary performance results of Nerve Net are introduced.

Fast route switching of a managed wireless mesh for regional network infrastructure

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 with commercial L2 switches. Performance evaluation showed that route switching after a link failure 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.

Incremental Distributed Construction Method of Delaunay Overlay Network on Detour Overlay Paths

In wide-area disaster situations, wireless mesh networks lose data communication reachability among ar- bitrary pairs of base stations due to the loss of routing information propagation and synchronization. This paper uses a Delaunay overlay approach to propose a distributed networking method in which detour overlay paths are incremen- tally added to a wireless mesh network in wide-area disaster situations. For this purpose, the following functions are added to each base station for wireless multi-hop communication: obtaining the spatial location, exchanging spatial location messages between base stations, transferring data based on spatial locations of base stations. The proposed method always constructs a Delaunay overlay network with detour paths on the condition that a set of wireless links provides a connected graph even if it does not initially provide reachability among arbitrary base stations in the con- nected graph. This is different from the previous method that assumes a connected graph and reachability. This paper therefore also shows a new convergence principle and implementation guidelines that do not interfere with the existing convergence principle. A simulation is then used to evaluate the detour length and table size of the proposed method. It shows that the proposed method has scalability. This scalability provides adaptable low-link quality and increases the number of nodes in wide-area disaster situations.

Capacity determination for deployment of managed mesh networks

We start systematical analysis on the performance of managed mesh network (MMN), which provides communication function in the concept of community service platform in a local region. Towards the performance evaluation framework for MMN, we herein analyze the capacity provision of one base station (BS) under the constraints of physical transmission rate and available spectrum using queueing theory. In the related work of capacity analysis on mesh network, most of them have not put effort on the determination of exact capacity, or they investigated backhaul mesh network, which is different from MMN. Some other researchers investigated the architecture similar to MMN, but they have not investigated actual traffic processed in the transmission queue. Our modeling solves these problems and determines the exact capacity provided by each BS in an MMN. At the same time, we perform extensive simulations to verify the correctness of our modeling under a set of scenarios with different main parameters. After model verification, we apply our modeling results to a city and show how the capacity of one user at peak time changes with the deployment cost.

Delaunay overlay network construction method for super-wide area disaster situations

We develop the data transfer system on a connected network consisting of simple wireless mesh base stations which can be immediately deployed at the disaster-stricken areas at the super-wide area disaster. This system requires the mechanism to correspond a dynamic change of disconnection and connection of links, an ad-hoc network construction with easy operation, and a scalable and reachable wireless mesh network construction. To realize this system, we forward to implement Delaunay overlay network construction method for super-wide area disaster situations, which is the local distributed construction method based on geographical positions. And the behaviors check of this implementation was checked.

PDAF: Proactive Distributed Authentication Framework for Regional Network

We are designing a regional network for New Generation Network (NWGN), which is a future network vision. Regional network needs strong security protections to enable it to be robust under various attacks, such as impersonation attack, replay attack, and illegal modification. To disable these attacks, we identify the design requirements and then propose a proactive and distributed authentication framework (PDAF), where a novel entity called regional network key server (RNKS) is introduced for ID/key generation in this network. By the proposed PDAF, the automatic trustworthy registration, distributed access authentication, handover authentication and mutual authentication can be achieved by end devices, and meanwhile trustworthy information dissemination and transmission can be realized for networking devices without involving trust third parties (TTPs).

Design and implementation of a proactive distributed authentication framework (PDAF)

We are designing authentication framework for a regional network with concerns on fast authentication and disaster robustness. To achieve this goal, we previously proposed a proactive and distributed authentication framework (PDAF). In this paper, to enhance the robustness of PDAF, we add temporary registration and authentication procedures in a disaster scenario and the distributed regional network key server (RNKS) mechanism. Meanwhile, we optimize PDAF messaging through reducing redundancy to improve the performance. The proposed PDAF is a fully distributed design, which is intrinsically more robust than the existing authentication framework. In particular, we implement the PDAF over an existing regional network and measure the performance of PDAF. This shows that network scale and offered traffic load do not influence the PDAFs authentication time, which is usually around 31 ms under our experiment environment, because neighboring networking devices directly authenticate end devices.