Ntt Docomo, Inc.

Nec Corporation

Nitto Kagaku Kogyo Kabushiki Kaisha

Ntt Mobile Communications Network, Inc.

Atsushi Fujiwara

Shinji Takeda

Hitoshi Yoshino

Akira Yamada

Yasushi Yamao

Hidenori Aoki

Lan Chen

Toru Otsu

Kengo Yagyu

Yoichi Matsumoto

Koji Omae

Kei Igarashi

Toshifumi Sato

Lei Du

Hirohito Suda

Takatoshi Sugiyama

Tomohiro Dohi

Kanehiko Enomoto

Yoshiaki Satoh

Shinzo Ohkubo

Yasutaka Nakashima

Toshiaki Doi

Akira c/o Ip Department Ntt Docomo Inc Yamada

Hitochi Yoshino

A pair scheduling medium access control method used in a wireless network, comprises the steps of: checking, by a receiving node, whether a transmitting node has data packets to be subsequently sent, according to data packets received from the transmitting node; when the transmitting node has no data packets to be subsequently sent, checking whether the receiving node has data packets to be sent to the transmitting node or not; if the receiving node has data packets to be sent to the transmitting node, then adding a time period required for sending the data packets of the receiving node into an acknowledgement packet to be sent to the transmitting node; after the receiving node receives a Clear to Send packet sent from the transmitting node, sending the data packets in the receiving node to the transmitting node.

Medium access control method and apparatus in wireless distributed network

A wireless communication apparatus is provided. The wireless communication apparatus includes: detection means that detects that there is another wireless communication apparatus around the wireless communication apparatus; comparison means that compares a first reference value managed in the wireless communication apparatus with a second reference value managed in the another wireless communication apparatus; means that corrects the first reference value based on the comparison result; and means that announces the first reference value to the another wireless communication apparatus. Frequencies are set such that a frequency of the wireless communication apparatus becomes same as a frequency of still another wireless communication apparatus to which a radio wave of the wireless communication apparatus does not reach but a radio wave of the another wireless communication apparatus reaches.

Wireless communication apparatus and wireless communication method

A channel allocation method for dynamically allocating channels of a plurality of radio interfaces at each access point included in a mesh network is provided. The method includes the steps of (a) acquiring, at each access point, in-node information about the access point itself, and (b) grouping high-traffic access points in a cluster using a same channel set based on the acquired information.

Channel allocation for access point in mesh network

Provided is a mobile communication system capable of determining a communication path to implement fast communication by multihop connection. A mobile communication system () comprises a mobile station (), at least one relay station (), and a base station () and implements packet transmission from the mobile station () to the base station () through a communication path with an intermediary of at least one relay station () or through a communication path without an intermediary of a relay station. The mobile communication system () is provided with a communication path determiner for determining a communication path with a largest communication speed or a communication path satisfying a required line quality, based on interference levels of respective signals received at a relay station () constituting a communication path between the transmitting station and the receiving station, and at the base station ().

Mobile communication system, transmitting station, receiving station, relay station, communication path determining method, and communication path determining program

A mobile communication system determines a communication path to implement fast communication by multihop connection. A mobile communication system includes a mobile station, at least one relay station, and a base station and implements packet transmission from the mobile station to the base station through a communication path with an intermediary of at least one relay station or through a communication path without an intermediary of a relay station. The mobile communication system is provided with a communication path determiner for determining a communication path with a largest communication speed or a communication path satisfying a required line quality, based on interference levels of respective signals received at a relay station constituting a communication path between the transmitting station and the receiving station, and at the base station.

A wireless communication device, a wireless communication system and a wireless communication method for preventing buffer over flow in the wireless communication device acting as a relay node, and for improving throughput within the whole system are disclosed. The wireless communication device includes an information acquisition unit configured to acquire information on the amount of data relay processing in the wireless communication device and/or a neighbor wireless communication device; a priority calculation unit configured to calculate transmission priority of the wireless communication device, based on the acquired information; and a priority determination unit configured to determine a priority related parameter for data transmission from the wireless communication device, based on the transmission priority.

Wireless communication device, a wireless communication system and a wireless communication method

A wireless communication device that performs packet transmission in accordance with a packet transmission system that performs wireless bandwidth allocation by virtual carrier sensing has a time-point management section that manages the time-point and outputs current time-point information, and a parameter management section that manages a parameter relating to packet transmission right acquisition priority. The parameter management section includes: a parameter holding section that holds, in association with a time-point, a parameter relating to packet transmission right acquisition priority that changes with a different distribution between wireless communication devices located in the same wireless LAN area, in a prescribed period; and a parameter alteration section that reads, from the parameter holding section, the parameter associated with current time-point information and dynamically alters a current parameter relating to packet transmission right acquisition priority in accordance with the parameter thus read.

Wireless communication device and wireless communication method

A mobile communication system capable of determining a communication path to implement fast communication by multihop connection. The mobile communication system includes a mobile station, at least one relay station, and a base station and implements packet transmission from the mobile station to the base station through a communication path with an intermediary of at least one relay station or through a communication path without an intermediary of a relay station. The mobile communication system is provided with a communication path determiner for determining a communication path with a largest communication speed or a communication path satisfying a required line quality, based on interference levels of respective signals received at a relay station constituting a communication path between the transmitting station and the receiving station, and at the base station.

Mobile communication system, transmission station, reception station, relay station, communication path deciding method, and communication path deciding program

A wireless communication apparatus comprises a transmission buffer configured to store packets addressed to one or more communication nodes in the network until a transmission timing; a requesting interval determination unit configured to determine a listen interval for each of the communication nodes based on the amount and/or the priority of packets accumulated in the transmission buffer; and a transmission unit configured to transmit a request frame to each of the communication nodes to request the communication nodes to receive a beacon from the wireless communication apparatus at the determined listen interval.

A radio channel allocation apparatus of a node in a radio communication system which controls to allocate a radio channel between nodes by a virtual carrier sense is disclosed. The radio channel allocation apparatus includes a node information collecting unit which collects information of a neighboring node to which the node can directly transmit data, and a radio channel determining unit that determines a radio channel, which is allocated to a communication link between a node which has transmission inhibition conditions and another node which does not have the transmission inhibition conditions by communications between predetermined nodes. The determined radio channel is a different radio channel from a radio channel between the predetermined nodes, based on node information of the node and the neighboring node.

Radio frequency assigning apparatus, wireless communication system, and radio frequency assigning method

The multi-hop communication system according to the present invention is configured by a radio control stationconnected to a core network, and radio stations-. The radio control stationhas a control signal TX/RX unitwhich transmits/receives the control signal, an information signal TX/RX unitwhich transmits/receives the information signal, and a communication channel controllerwhich transmits a 'usage notification' indicating usage of communication channels managed by the radio control stationto the radio stations-using the control signal. The radio station has a control signal TX/RX unitwhich transmits/receives the control signal, and an information signal TX/RX unitwhich transmits/receives the information signal.

Multi-hop communication system, radio control station, radio station and multi-hop communication method

A wireless communications apparatus used in a wireless communications network consisting of multiple wireless communications apparatuses mutually connected via wireless links includes (a) a buffer configured to temporarily store information received from an adjacent wireless communications apparatus or a user terminal located under the wireless communications apparatus; (b) a routing control information processing unit that estimates a node cost representing traffic at the wireless communications apparatus and a link cost representing a radio condition of the link to determine a transmission route based on cost information reflecting both the node cost and the link cost; and (c) a routing control unit that designates a next hop to which information accumulated in the buffer is to be transmitted according to the determined transmission route.

Wireless communications apparatus, and routing control and packet transmission technique in wireless network

A wireless communication apparatus capable of constructing an ad-hoc wireless network is disclosed to include a transmitting/receiving unit configured to transmit and receive a common broadcast signal; and a transmission interval control unit configured to change transmission interval of the common broadcast signal to be transmitted depending on the number of communication nodes existing in communication range of the wireless communication apparatus or on the wireless resource utilization status.

Wireless communication apparatus and wireless communication system for adjusting the transmission interval in an AD-HOC wireless network

The object is to control interference in a permissible range by applying the CDMA system to signal collision in the conventional CSMA and TDMA base multihop systems and to relax the hidden terminal problem and others to enhance the throughput of the entire system by grouping of channel groups in multihop transmission and by control of transmission based on an interference level from another station. A multihop relay station calculates a desired signal level, for example, from an interference level at its own station of a packet sent from a mobile station, and notifies the mobile station of the desired signal level; and the mobile station calculates a transmission power amount of a packet from the desired signal level, determines whether the packet is transmissible to the station as a source of the desired signal level, and transmits the packet to the source station determined as a packet-transmissible station.

Growing community of inventors

Yokohama, Japan

Atsushi Fujiwara