Nec Corporation

Clarion Co

Kazutomo Kobayashi

Masaru Tomita

Eiichi Iwasa

Takatoshi Kato

Hiroyuki Mano

Hiroki Uchiyama

Yukitsuna Furuya

Tatsuaki Osafune

Yoshihiko Akaiwa

Masanori Taketsugu

Junji Namiki

Takashi Shiraki

Hideyuki Fukuoka

Fumio Akashi

Kojiro Watanabe

Huanxu Pan

Shohei Sato

Shinya Iguchi

An aspect of the invention is an information terminal device includes a widget management unit for managing execution of a widget being a monofunctional program for performing display on the display part of a display device. The widget management unit includes a policy determination unit for determining the operation policy, including operation restriction and priority, concerning a display state at the display device in the widget, and a reliability determining unit for determining the reliability representing the reliability of the widget in the widget. When the state of the movement calculated by a navigation unit becomes a preset state, the widget management unit regulates the display state of the widget according to the operation restriction and the reliability, and performs display, while preferentially displaying guidance state and positional information calculated by the navigation unit.

Information terminal device, information terminal management system, and storage medium in which program is stored

A method for evaluating the performance of a wireless LAN (local area network) system having a single access point and a plurality of transmission terminals, which share the same radio channel, comprises the steps of dividing the plurality of transmission terminals into groups in accordance with radio conditions, calculating a transmission probability and a post-transmission failure probability for each group using a transmission rate, an error rate, and the number of terminals of each group, and calculating a throughput based on the transmission probability and post-transmission failure probability. A characteristic value for packet transmission delay may also be calculated based on the transmission probability and post-transmission failure probability. According to this method, the performance such as the throughput and the packet transmission delay can be evaluated in a wireless LAN system even before the wireless LAN system is constructed.

Method and apparatus for evaluating performance of wireless LAN system

A display control device comprises a navigation unit for generating route guidance data; a small-sized display unit for displaying information concerning audio-system; and a main unit connected via an interface to the navigation unit and the small-sized display unit with a communication cable, said main unit including: recognizing means for recognizing the connection of the small-sized display unit; and control means for sending out a request for route guidance display to the navigation unit when the recognizing means recognizes the connection of the small-sized display unit, and causing the received route guidance data to be displayed through interruption on the small-sized display unit when the route guidance data generated by the navigation unit is received via the communication cable and the interface.

Display control device and method

A display device is provided with a center unit 10 having a center display unit 12, a slave unit 20 having a slave display unit 21 and a communication line for communicatively connecting the center unit 10 and the slave unit 20. When the center control microcomputer 15 of the center unit 10 detects a predetermined operation through a key operating unit 14, the center control microcomputer 15 and the slave control microcomputer 24 make two of the center display unit 12 and the slave display unit 21 provide a linking display as if these display units operate as one display unit.

Display device for audio system including radio tuner

In a radio communications system wherein a common channel is accessed from multiple terminals, any of the terminals is allowed to transmit a packet through the common channel to a base station on a random access mode when the packet received at the base station has a low error rate, and a specified one of the terminals is allowed to transmit a packet on a controlled access mode when the packet received at the base station has a high error rate.

Dual mode multiple access method for common radio channel

A data packet transmitted from a source data terminal is received by a destination data terminal and stored into a receive buffer from which it is withdrawn at a rate which may differ from the rate of transmission of packets from the source terminal. The destination terminal returns an acknowledgment packet in response to each data packet being withdrawn from the receive buffer. The acknowledging packet includes a flow control variable which is incremented by a unit value in response to the data packet being withdrawn from the receive buffer. The source terminal transmits one or more data packets having sequence numbers the largest of which is determined by a maximum number of outstanding data packets awaiting receipt of the acknowledging packet by the source data terminal and the flow control variable contained in the acknowledging packet.

Method for controlling data flow

In response to call requests from a source data terminal, a source earth station establishes first logical channels between it and the source data terminal and establishes logical links from the first logical channels to destination earth stations via a communications satellite. The destination earth stations establish second logical channels from the logical links to the destination data terminals. Each earth station performs flow control on each of the respective logical channels on a per message unit basis and performs flow control on each of the logical links on the basis of per plural consecutive message units to provide high throughput on the satellite channel.

Multipoint satellite packet communication system

In order to effectively avoid cochannel interferences in a multi-station communications system utilizing a plurality of channels in common, the order of transmission channels to be used is determined utilizing a transmission priority assigned to each channel. The subject matter is characterized in that (a) the transmission priority of a selected channel is raised if the selected channel is not used at another station, and (b) is lowered if the selected channel is used at another station. This means that the past use records of the transmission channels are accumulated so that a good channel can be selected with high probability. In other words, a transmission channel with high priority is still ready to be used even if it was not selected in the preceding selection.

Method of determining optimal transmission channel in multi-station

In a multipoint communication system, first polling signals are sequentially and respectively transmitted to terminal stations on a broadcast channel from a central station, asking a request for reservation without waiting for a reply from the terminal stations. A reservation signal is transmitted on a multiple access channel from a terminal station requesting the reservation to the central station in response to the first polling signal addressed to it. A second polling signal is then transmitted on the broadcast channel in response to the reservation signal and the multiple access channel is reserved for a period of time variable in accordance with the reservation signal. A data signal is transmitted from the terminal station requesting the reservation on the reserved multiple access channel in response to the second polling signal.

Multipoint communication system having polling and reservation schemes

In a packet communication system of a multiaccess type in which a single communication medium is used commonly and divided into a plurality of channels, respective users observe states of the channels and the probability of packet transmission to respective channels is controlled in accordance with observed information, respective users are assigned parameters corresponding to respective channels and the probability of packet transmission onto the channels is controlled according to the parameters, a dummy packet is continuously transmitted for a predetermined time at in channels having low utilization factors, for data requiring immediate transmission. In a modification, a setup packet is sent for data requiring immediate transmission. All the users determine whether the received packet is the setup packet and the set the stored parameters. Accordingly, in another modification, a setup packet is transmitted for data requiring immediate transmission and a dummy packet is continuously transmitted in a channel for which the origination setting packet is successful.

Packet communication systems

In a multiple access system for performing packet communication involving sharing of a single communication medium by a plurality of users, the single communication medium is divided into a plurality of channels. Each user monitors the condition of each channel, and probability of packet transmission to each channel is controlled in accordance with a monitored result.

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Tokyo, Japan

Kazutomo Kobayashi