Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Sony Corporation

Nitto Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Hiroshi Doi

Taisuke Matsumoto

Masahiro Mimura

Yoshinori Watanabe

Kazuaki Takahashi

Suguru Fujita

Hirokazu Kobayashi

Hong Cheng Michael Sim

Naganori Shirakata

Yoshitaka Ohta

Poy Boon Tan

Taku Matsuda

Seishi Suzuki

Katsuo Matsumoto

Tetsuya Wada

Yoshinori Gunji

Osamu Ohira

Eiji Tsukahara

Rieko Nakajima

There is disclosed a wireless communication apparatus that does not interrupt synchronous communication but can continuously perform the synchronous communication even when an address duplication occurs between the local wireless communication apparatus and a nearby wireless communication apparatus. A plurality of wireless communication apparatuses constitutes an ad hoc network system where they transmit beacons to each other. In the wireless communication apparatus, an address processing part () generates a first address, which includes a beacon period slot number corresponding to the position-on-beacon-period of a beacon generated by the local wireless communication apparatus, and a second address assigned at random. A beacon processing part () determines whether the second address generated by the address processing part () is coincident with a second address at another wireless communication apparatus. A transmitting part () uses one of the first and second addresses generated by the address processing part () to transmit a frame to the other wireless communication apparatus.

Wireless communication apparatus and wireless communication method

A radio communication method is capable of easily realizing multi-access in an ad-hoc network using a directive radio wave. In the ad-hoc network using the directive radio wave of the method, two PNC functioning as master devices are arranged opposed to each other so that their directivities face to each other. A super frame is time-divided into two sub super frames so that one of the sub super frames is controlled by one of the PNC and the other sub super frame is controlled by the other PNC.

Radio communication method and radio communication device

Provided is a radio communication method capable of optimally using the wide-band communication enabled time while maintaining power saving in an ad hoc network. According to this method, in the ad hoc network using the wide-band communication and a narrow-band communication, transmission and output of the narrow-band synchronization tone signal and the resynchronization tone signal are controlled so that the reach radius of the narrow-band synchronization signal and the resynchronization tone signal exceeds the reach radius of the wide-band signal (milli-wave UWB signal). Thus, when radio communication devices pass by each other, super frame synchronization is completed before reaching the wide-band communication enabled range of the ad hoc network, thereby optimally using the wide-band communication-enabled time.

A wireless communication method wherein the power consumption can be reduced as compared with the conventional one and a wireless communication apparatus can synchronize its super-frame with the super-frame of another wireless communication apparatus in an ad hoc network. According to this method, in the ad hoc network where a plurality of wireless communication apparatuses use broadband signals to data-communicate with each other, a wireless communication apparatus transmits an end tone () for identifying the end of a super-frame (), and when another wireless communication apparatus receives the end tone (), it synchronizes the end of its super-frame () with the end of the foregoing super-frame (). In this way, the super-frames () can be synchronized even without any beacons.

Wireless communication method and wireless communication apparatus

A distributed wireless medium access control protocol is disclosed. According to the disclosed wireless medium access control protocol the medium access time is partitioned into equal sized slots, and a predetermined number of the slots forming a superframe. The protocol defines beaconing devices and passive devices. Each beaconing device designates one of the slots in the superframe as its beacon medium access slot, and broadcasts during that beacon medium access slot a beacon frame to other devices in wireless range of that beaconing device. A beacon frame collision detection and resolution procedure, and a procedure for reserving access time for communication between devices are also disclosed.

Distributed wireless medium access control protocol for ad-hoc networks

Provided is a radio communication method which can reduce the power consumption as compared to the conventional technique while realizing coexistence of a plurality of radio communication methods and can perform synchronization with a super frame of other radio communication device. The super frame has life confirmation slots () through which radio communication devices of various modulation types should transmit tone signals. A radio communication device has a chance to judge whether one or more radio communication devices using a different modulation type exist or no such device exists in the vicinity. If no such device exists, the slot to be used by the radio communication device of the modulation method is reported as a time that can be used by a radio communication group of other modulation method. Thus, by confirming existence of an object in the vicinity by other radio communication device with which communication cannot be performed, communication can be performed by sharing the super frame.

A beacon is transmitted and received among a plurality of terminals STA. A terminal STA which transmits the beacon is assigned as a representative terminal MSTA which manages a group, and a terminal STA which receives the beacon is assigned as a belonging terminal SSTA of the group. The representative terminal MSTA obtains identification information from the belonging terminal SSTA and stores the identification information. Then, when receiving an AP beacon from a management terminal AP, the representative terminal MSTA collectively transmits, to the management terminal AP, the identification information of the representative terminal MSTA and the belonging terminal SSTA. The management terminal AP performs an authentication procedure, by using the collectively transmitted identification information, for each of all of the communication terminals which form the group.

Wireless communication system, communication terminal, management terminal, communication method, and integrated circuit

In the case where a screen divided display is performed on a liquid crystal panel, a change in brightness or chromaticity between sub regions divided may be reduced. A display includes: a display panel; a backlight arranged corresponding to each of sub regions, and selectively illuminating the corresponding sub region, the sub regions being defined by dividing a display region of the display panel into a plurality of parts; a monitoring means for monitoring the light emission state of the backlight corresponding to each of the sub regions; and a display control means for determining a sub region on which an image is to be displayed, on the basis of the monitoring result of the monitoring means, to fit the image into the determined sub region, and controlling a backlight corresponding to the determined sub region to emit light.

Liquid crystal display and display control method for the same

A radio communication device includes a communication data selection unit for selecting from the received radio communication data containing communication time reservation request information in which a time slot for performing data transmission source radio communication device is described and a communication information analysis unit for extracting an identifier of the source radio communication device and the data transmission reservation time slot from the communication time reservation request information in the radio communication data. When the received radio communication data is addressed to the local device, a communication/response information generation unit correlates the identifier to the reservation time slot, records them in a communication reservation table, and generates communication time reservation response information including information of the reservation time slot.

A beacon slot position control section of a radio communication apparatus constituting a radio network system which detects whether empty beacon slots are present in a beacon period. When an empty beacon slot is present before the period in which the radio communication apparatus transmits a beacon, a movable counter starts counting a specified number of super frames. When the count is completed, the radio communication apparatus transmits a beacon of the radio communication apparatus at the earlier empty beacon slot. Consequently, since the empty beacon slots are eliminated and the beacon period is compacted, even if the number of radio communication apparatuses joining the radio network system fluctuates dynamically, the radio communication apparatus can perform radio communication with high efficiency and less waste of consumed electricity.

Radio communication method and radio communication apparatus

A method and device for wireless directional beam-forming transmission. The method for wireless directional beam-forming transmission between a first device and a second device comprises conducting one or more omni-directional transmissions between the first device and a third device; conducting one or more omni-directional transmissions between the second device and the third device; and determining directional information for directional beam forming transmissions between the first and second devices based on the omni-directional transmissions.

Method and device for wireless directional beam-forming transmission

A frame such as a beacon in wireless communication, with a maximum MAC address, hop count, and maximum hop count, described therein is exchanged between nodes. All the nodes measure the number of hops from a node with the maximum MAC address, and exchange the maximum hop count (hmax) out of the numbers with each other. Hop count H(a,b) between arbitrary nodes a and b is expressed by H(a,b)&#x2266;H(a,max)+H(max,b)&#x2266;2*hmax, where hmax is a hop count from node (max) with the maximum MAC address to the farthest node. That is, the number of hops between two arbitrary nodes in the group is always 2*hmax or less. Herewith, a numeric value assuredly exceeding the maximum value out of the numbers of hops between nodes in an ad-hoc network can be propagated in the entire ad-hoc network.

Communication method and wireless communication device having a frame which is exchanged between nodes

A radio communication device includes a beacon reception unit extracting a frame from a received beacon and a frame judgment unit judging whether the extracted frame is one requiring data transmission/reception or one giving notice of a collision with a beacon of another network, a frame constructing unit used when the frame judgment unit has judged that the frame is a collision notification, generating a frame for relaying the collision notification and a movement notification to a new beacon transmission period, and a beacon transmission instruction unit instructing transmission of the frame at the beacon transmission timing. Accordingly, since these notifications can be relayed, all radio communication devices of the same network can move to a new beacon transmission period while avoiding a collision with a beacon from a radio communication device of another network.

A first receiving unit typically receives a control frame in a narrowband channel. A communication data selection unit controls power saving of a second receiving unit performing reception in a UWB channel, based on the control frame. A communication data generation unit generates communication time reservation response information by adding information reporting a normal reception to the received request for communication time reservation, and transmits this information from transmitting units in the narrowband channel, so that a second receiving unit is set to an operating mode only during a time slot when UWB communication is performed, and use of the time slot for performing UWB communication is reported to the radio communication device which has made the communication request and the radio communication devices in the area where transmission is possible.

Growing community of inventors

Kanagawa, Japan

Hiroshi Doi