Canon Kabushiki Kaisha

Kazutoshi Hara

Hiroshi Mashimo

Masanori Nakahara

Fumihide Goto

Tetsuo Ido

Conventionally, when a communication unit needed to apply an authentication process to other communication units, a problem arose in that the communication unit could not be quickly connected to a communication unit near a user and to which the user wishes the communication unit to connect. In this invention, a station measures a range to other communication units in the surrounding area and possesses a trigger, which is initiated by a user, for beginning an authentication process; when initiated, the station selects the nearest communication unit based on the result of the measurement and applies the authentication process to it.

Communication unit, method of controlling communication unit and computer program

Power saving cannot be implemented in the adhoc mode by only the IEEE 802.11 standard. This is because communication partners mutually utilize the power save mode in the adhoc mode, and their states must always be managed. In the adhoc mode, the number of communication partners is not always one, and all stations which join a network are candidates, increasing the load of implementation. To solve this problem, a communication apparatus notifies a change to power save mode by an ATIM packet, RTS packet, or null packet. When the ATIM packet or RTS packet is transmitted, the communication apparatus can notify the partner of a change in mode regardless of whether the partner is in the power save mode. When the null packet is transmitted, the communication apparatus can rapidly notify the partner without waiting for any beacon.

Communication apparatus and communication method

In the power save mode of an IEEE 802.11 adhoc network, a packet loss occurs unless the power save state of a receiving side is detected, failing in communication. However, there is no explicit notification on joining/leaving in/from a network, and it is difficult to detect and manage the state of a partner, including the detection timing. To solve this problem, a terminal always transmits an information notification packet (ATIM packet) in a time during which all terminals can receive it, prior to data transmission regardless of the power save state of a partner. With this mechanism, the terminal also explicitly notifies the partner of a change in the power save state of the terminal.

Method and apparatus for reducing the load of managing the power save state of a partner

A communication apparatus which starts communication using a power-saving function changes, with its communication counterpart, a key for a confidential mode and performs power-saving communication. When terminating the power-saving function, the communication apparatus returns, with its communication counterpart, the key for the confidential mode to the original one. Then, after returning the key for the confidential mode to the original one, the communication apparatus performs an IP address reassignment process.

Communication apparatus having power-saving communication function, and communication method

Data communication using wireless service discovery is continuously provided even if a radio wave condition temporarily deteriorates or movement of an apparatus occurs. If a temporary deterioration in wireless radio wave environment is found in a communication apparatus including a service discovery function, a search is made again at a raised transmission power. Forcible disconnection processing from a higher-level layer is prevented when communication at the network layer level is ongoing.

Communication apparatus and method providing robust service in the presence of deteriorated radio conditions

Method for rapidly shifting a communication apparatus to a power save mode in an adhoc network

In a communication apparatus for wirelessly communicating directly with a communication apparatus that is participating in a network, a filter is set so as to receive only a signal from a communicating party before start of a power-saving control function at the time of standby, the set filter is removed after the power-saving control function for standby is terminated, and a logical address on the network is reset. As a result, when the power-saving control function is utilized, collision of physical addresses is prevented and it is possible to perform data communication without mismatch.

Communication apparatus and method with physical address filter for power-saving control state

A terminal determined to be a communication partner in advance is subjected to transmission power control, and another terminal receives data with the maximum transmission power. Data to be transmitted to a plurality of terminals is also transmitted with the maximum transmission power.

Growing community of inventors

Kawasaki, Japan

Kazutoshi Hara