Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Panasonic Intellectual Property Corporation of America

Iii Holdings 12, LLC

Taisuke Matsumoto

Hirokazu Kobayashi

Hiroshi Doi

Masayuki Kumazawa

Masahiro Mimura

Makoto Funabiki

Shinkichi Ikeda

Toyoki Kawahara

Kazuaki Takahashi

Suguru Fujita

Kazunobu Konishi

Eiichi Muramoto

Takahiro Yoneda

Hong Cheng Michael Sim

Ichiro Takei

Masashi Kobayashi

Akiyoshi Tanaka

Yasuhiko Watanabe

Yasunari Kimura

Funabiki Makoto c/oMatsushita Electric IndCo Ltd Ltd

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 receiving terminal is provided that prevents a load on a network near a receiving terminal from increasing when a retransmission request is made to a plurality of other terminals, and enables the probability of being able to compensate for a lost packet by means of a retransmission packet to be increased. In a receiving terminal that transmits a retransmission request for compensating for a lost packet lost in a network, a measurement section measures a time period corresponding to a distance in the network between the receiving terminal and a plurality of receiving terminals, a calculation section calculates for each of the receiving terminals a float (spare time period) found by subtracting the current time and a time period measured by the measurement section from a playback time at which a retransmitted packet is played back, and a decision section decides retransmission request transmission timing and a retransmission request transmission destination for each of the receiving terminals based on the calculated floats.

Receiving terminal and receiving method

In radio communication, especially in a centralized network, a commonly faced problem is the issue of the coexistence between a plurality of networks and different networks use different network timing parameters with no synchronization to one another. Thus, a device of one network usually has a difficulty in communication with a device of another network whether or not both are in a radio communication range. This results in causing unwanted mutual interference because when two or more networks operate in the same operation space, a device belonging to a certain network has a difficulty in letting a device belonging to another network know about the existence of the device belonging to the certain network. A means for enabling the first device to communicate with the second device is presented and the operation in the current channel is stopped and the current channel in operation is opened with respect to the second device and the other devices in the network of the second device by the established communication means.

Method for opening channel which is used in radio communication device and radio communication system

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

In a mobile network system composed of plural mobile networks and a home agent, the home agent inquires mobile routers in a mobile network whether or not a terminal is connected, if detecting the absence of the terminal, when data addressed to the terminal arrives at a home network of the terminal in the mobile network. Responding to this inquiry, the mobile routers search whether or not the terminal is connected to the own mobile networks. If the terminal is connected, the mobile routers inform the home agent of the presence of the terminal. When receiving this notice, the home agent transfers data addressed to this terminal to a mobile router as a notice source. This process, even if a terminal moves to a mobile network having a same network prefix as that of the home network, allows transferring a packet accurately to the terminal.

Mobile router, home agent, and terminal position management method

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 data transmitting apparatus makes it possible to send out a retransmitting packet at early timing even when a delivery tree structure is unclear. A transmitting terminal device including this data transmitting apparatus is includes a retransmitting request receiver that receives a data retransmitting request, a receiving terminal device relevancy updater that stores a past history of the number of reception of a retransmitting request transmitted from a first data receiving device and a past history of the number of reception of a retransmitting request sent from the other data receiving devices, wherein the subject of the retransmitting request sent by the other data receiving devices is the same as the object of the retransmitting request sent by the first data receiving device, and a retransmitting destination selector that estimates a delivery tree from the history stored by the receiving terminal device relevancy updater when the retransmitting destination selector receives the retransmitting request from the first data receiving device and selects, another data receiving device positioned downstream of the first data receiving device in the estimated delivery tree.

Data transmitting apparatus and data retransmitting method

In a mobile network system composed of a mobile network with a mobile router and a terminal interconnected, and of a home agent, when the mobile router connects to an external network, the mobile router informs the home agent of path information to the mobile network including the mobile router. Receiving the path information, the home agent inquires the mobile router in the home network whether or not the mobile router connects to the mobile network informed. Then, the home agent advertises path information to this mobile network only when the mobile router connecting to the mobile network does not exist. Accordingly, the home agent can rapidly switch to an optimum path to the external network.

Path control method and home agent

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

In a case where internal links connected to plural mobile routers in a mobile network respectively have unique network identifiers initially set, the mobile router, when receiving a network identifier different from the initial setting advertised from another mobile router, selects either one of the network identifier initially set to the self and that advertised, as a network identifier of the internal link connected to the self. Then, if the one selected is identical to that initially set, the mobile router advertises the network identifier to within the mobile network and registers it in a home agent. If not identical, the mobile router registers the one advertised in the home agent as a network identifier of the internal link connected to the self.

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Kanagawa, Japan

Taisuke Matsumoto