Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Godo Kaisha IP Bridge 1

Keisuke Takeuchi

Rintaro Katayama

Yukiko Takeda

Hidenori Inouchi

Koki Uwano

Tomonori Yamamoto

Takahiro Fujishiro

Kazuyoshi Hoshino

Tadashi Kaji

Osamu Takata

Kenzaburo Fujishima

Shiro Mazawa

Toshiyuki Saito

Shinsuke Suzuki

Masaya Hayashi

Takamitsu Senou

Akira Morita

Akihiko Yoshida

Tetsuhiko Hirata

Hiroaki Nakazawa

Katsunori Takahashi

Shuji Senoo

When a femto cell base station detects an intense uplink interference, the femto cell base station autonomously extends the femto cell so as to raise a probability that a mobile terminal around the original femto cell may be connected to the femto cell base station. If the mobile terminal connects to the femto cell base station, the uplink interference is reduced and total throughput is improved. Additionally, if a resultant effect of interference reduction is low, the femto cell base station returns the mobile terminal, which is connected to the femto cell base station due to the extension of the femto cell, to the original connection destination. If an evaluative criterion meets a predetermined condition, the femto cell base station restores the extended femto cell to the original size. These actions prevent degradation of performance caused by concentration of the connections of mobile terminals to the femto cell base station.

Wireless communication system and method for wireless communication

Timing division multiplexing is conducted between the cells to avoid intercell interference. Transmission timing in a time slot pattern has a given interval. A base station determines the transmission timing based on measured uplink interference power. For example, an uplink time slot pattern in which the measured uplink interference power is smaller is selected. A downlink time slot pattern is assigned so that a response to HARQ is returned at that timing. If traffic is busy, additional time slot pattern may be assigned. In determination of the traffic volume, for example, the queued buffer size, the number of connected terminals, or the number of connections to a higher-level device can be used. Assignment timing can be an initial setup time, or a fluctuation detection time of a channel which can be realized by collection of report information on a downlink communication quality, periodic monitor of uplink interference information.

Base station, interference control method and radio communication system

A method for radio resource control is carried out in a radio communications system including multiple base stations. In this method, a radio resource that can be used by the base stations is divided into multiple first radio resources on the frequency axis. Then one or more of the first radio resources are allocated to a second radio resource for initially transmitting a packet and the other first radio resources are allocated to a third radio resource for retransmitting the packet.

Method for radio resource control and base station using the same

A base station is connected to wired and wireless networks to send a call that is received from the wired network to the wireless network at a predetermined quality of service (QoS), select one or more combinations of a set of modulation and coding scheme, and a radio resource amount that are associated with a QoS set in a newly incoming call, determine the radio resource amount that is equal to or less than a amount of the unassigned radio resources, assign, to the newly incoming call, the combination that is associated with the determined radio resource amount and the QoS set in the newly incoming call, reduce the radio resources assigned to the ongoing call without changing the QoS, and assign, to the newly incoming call, an amount of radio resources released from the ongoing call and modulation and coding scheme associated with this released radio resource amount.

Base station and access control method for cellular wireless communication

Conventionally, different HARQ processesand(subframes Tand T) transmit data packets B and D, respectively. One data packet corresponds to one process and is retransmitted as necessary one by one on a process basis, degrading the usage efficiency of frequency and time resources. To solve this problem, downlink data packets B and D, when needed to be retransmitted, are spatially multiplexed in the different HARQ processesand. The data packets are simultaneously retransmitted to the same terminal as process(subframe T).

Base station, terminal and wireless communication system

An encrypted communication system is provided, in which an encryption key for use in encrypted communication and settings information for the encrypted communication are distributed to each of a plurality of communication devices performing encrypted communication within a group, and in which traffic generated by distributing the encryption key and the like can be reduced. In the encrypted communication system according to the present invention, information including a key for use in the intra-group encrypted communication or a seed which generates the key is distributed to the communication devices belonging to the group that are participating (e.g., logged in) in the intra-group encrypted communication.

Encrypted communication system, communication status management server, encrypted communication method, and communication status management method

In a data communication method and a data communication system, a session control message designating a destination server with identification information unique to application is transferred to the destination via a session management server. When an application program or encrypted communication software on a client issues a connection request designating a destination with identification information unique to application, the client or the session management server automatically converts the identification information into a desired resource identifier identifiable a domain to thereby determine a domain as the destination of the received connection request message.

Data communication method and data communication system

A wireless access terminal, after handoff, adds channel quality information calculated in the wireless access terminal to a header of transmit data and transmits this data until a wireless base station succeeds in receiving at least one or more packets. The wireless base station, when having succeeded in receiving a packet for the first time after the handoff, extracts the channel quality information from a received header to initialize channel quality information inside the wireless base station. Subsequently, the wireless base station autonomously updates the channel quality information in response to success or failure of packet reception and controls the transmission rate.

Wireless communication system, wireless base station, wireless terminal and communication control method of the wireless communication system

Provided is a wireless base station comprising: a power control unit, a reference information acquisition unit and a reference information storing unit, wherein the wireless base station comprises a first control signal receiving unit for receiving a first uplink control signal used by a mobile station connected to the wireless base station and for requesting the power control unit to control the transmission, and a second control signal receiving unit for receiving a second uplink control signal used by a mobile station connected to the neighbor base station and for requesting the power control unit to control the transmission power, and wherein the power control unit controls the transmission power of the downlink signal based on the request to control the transmission power from the first control signal receiving unit and the request to control the transmission power from the second control signal receiving unit.

Base station and wireless communication system

When a receiving apparatus which employs a OFDM-based cellular wireless communication scheme detects as an excessive signal for each frame, the signal having signal intensity exceeding a reference value after a Fourier transform, a gain variable according to an excessive quantity relative to the reference value is used for each frame to control signal intensity such that the amplitude thereof is at most the reference value.

Communication equipment which receives OFDM signal, OFDM-based wireless communication system and method for receiving OFDM signal

A data communication method for forwarding a session control message designating a destination server with an IP address to the destination server via a session management server, wherein, when an application program or encrypted communication software on a client issues a connection request designating a destination server with an IP address, the client or the session management server automatically converts the IP address into a desired resource identifier identifiable a domain, thereby to determine the domain to which the received connection request message should be forwarded.

Data communication method and system

The present invention provides a wireless communication system and a terminal. A base station notifies terminals of an intensity of a received interference power. The terminal controls a transmission power for transmitting data to the base station, which is one of base stations and to which data is to be transmitted, by referencing an intensity of interference power (OSI) notified from base stations to which data is not to be transmitted. The terminal calculates a decision value for increasing/decreasing the transmission power, wherein the decision value is variable according to the current transmission power of the terminal and propagation attenuations between the terminal and the base stations to which data is not to be transmitted, and variably controls the amount of transmission power increase/decrease according to the decision value for increasing/decreasing a transmission power.

Wireless communication system and terminal

Information on whether a prefix is distributable to a MN is held by a CA. The server section of the HA allots prefix information to a MN approved by the CA. When the server section of the HA receives an IKE packet from the MN, the server section generates an IPsec SA after checking the prefix information in the server section. The server section allows an MN location registration request to fulfill the IPsec SA. The CA approves distribution of a prefix to the MN and verifies that the MN is genuine by generating an IPsec SA with the HA by utilizing the prefix distributed by the MN.

Server, terminal control device and terminal authentication method

A system for preventing spoofing to use a service provided on a network. The system holds correlation between a first identifier used by a user of a service provided on a network for first authentication for permitting a user to make connection to the network and a second identifier used for second authentication for permitting the user to use a service, holds correlation between a third identifier assigned to the user permitted to make connection to the network and the first identifier of the user, and checks the correlation between the second identifier and the third identifier contained in the packet for the second authentication.

Growing community of inventors

Kunitachi, Japan

Keisuke Takeuchi