The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Recent years have seen a great deal of research into Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communications, which will contribute to advances in driving support systems. In contrast to V2I communications, V2V communications offer the advantage of not requiring infrastructure, but introduction of such systems is not expected to be effective unless there is sufficient penetration...
Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) adopted in IEEE 802.11 WLAN suffers from serious problems of hidden terminal and exposed terminal. This will get worse if the environment becomes highly dense. The rise of channel interference among stations (STA) and the deterioration of the total network throughput as the result of these terminal problems need to be mitigated. A possible...
Network traffic for sharing contents is significantly increasing. The cache network is a desirable architecture to reduce traffic and to improve reliability of contents retrieval. “Breadcrumbs” is one of the promising techniques to find cached contents in a distributed manner. Thanks to Breadcrumbs, users can retrieve a content without managing where the cache exists. This demo shows a contents sharing...
In severe disaster environments, wireless sensor networks (WSNs) need to be tolerant to spatial node failure due to external factors such as bomb attack and river overflow. The aim of this paper is to realize data-gathering WSNs that keep the data collection ratio as high as possible while keeping system lifetime as long as possible. This paper proposes not only a multipath data gathering protocol...
In Vehicle-to-Vehicle (V2V) communications, broadcast is expected to disseminate information to other vehicles efficiently. However, due to shadowing of buildings, especially in urban areas, the V2V communications at an intersection is unreliable. Thus it is difficult to disseminate information to all directions at an intersection. Moreover, most of existing protocols which consider intersections...
Public WLANs based on IEEE802.11 standard are now widely deployed. In an environment offering several APs (Access Points), a UTE (User Terminal Equipment) needs to choose which AP to associate with. Conventionally, the UTE associates with the AP with the strongest RSSI (Received Signal Strength Indicator). This simple approach, however, can degrade the efficiency of network utilization since the UTE...
Two-dimensional communication system (2DCS) is a novel communication system which utilizes surface of sheet as communication medium. 2DCS provides wireless power supply as well as safely and high-speed data transmission to sensor devices. However, how to suppress the standing wave effect to a minimum is still an open issue for 2DCS. In this study, we explore how the power distribution on sheet medium...
In this paper, we propose an integer programming formalization to optimize elevator operations under such an ideal condition that all information on passengers who arrive during the planning period is known in advance. The basic idea which inspired the formalization is the concept of trip, which represents a uni-directional (upward or downward) movement of an elevator and forms a trajectory of an...
This paper addresses the problem of fair radio resource partitioning between the cell-edge and cell-center regions in the context of the downlink of a SISO-OFDMA cellular system. Although, a plethora of studies concerning OFDMA-based radio resource allocation exists, it is, however, imperative to accord special attention to the proper design of network resource partitioning variables in order to ensure...
Femtocell is an emerging technology that promises increased network capacity and enhanced indoor coverage at a low capital and operational cost. However, macrocell network performance depreciates when macrocell users (mUEs) are located indoors with femtocell base stations (FBSs), and these users are not allowed access to the FBSs (closed access). This is a critical issue that needs to be addressed...
In this paper, computational results by programs which implement the value iteration, a representative of dynamic programming methods, for a computer with a Graphics Processing Unit (GPU) are displayed to demonstrate the potential speedup brought by many-core computers. That implementation is motivated by two expectations: one is that computing a part of data required in a dynamic programming method...
The maritime MANET (Mobile Ad-hoc Network) system using 27MHz/40MHz bands was developed under the technical committee of the Japanese Ministry of Internal Affairs and Communications for “development of technical examination services concerning frequency crowding.” The maritime MANET is based on AODV (Ad-hoc On-demand Distance Vector) with a transmission power control. After three years study including...
We propose a single-chip ultralow-power sensor node processor with a synchronous media access control (MAC). It is comprised of a transceiver, i8051 micro processor, and dedicated MAC processor. The test chip occupies 3 × 3 mm2 in a 180-nm CMOS process, including 1.38 M transistors. The power is 58.0 µW under a network environment.
To extend an available period of wireless sensor networks, transmission power control is regarded as one of the promising schemes. In most of the previous studies on the transmission power control, it is assumed that a transmitter has power consumption of O(dm), where d and n denote a maximum communication distance and a pass loss factor. This assumption would substantially hold under the condition...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.