Hitachi, Ltd.

Yuta Muto

Daisuke Ishii

Koji Watanabe

Kenzaburo Fujishima

Masashi Yano

Toshiyuki Saito

Michitaka Okuno

Nodoka Mimura

Tsutomu Hirao

Kouki Uwano

A communication system comprising computers and a management computer, wherein the computers include a communication control unit configured to control a communication using a session of a terminal. The communication control unit manages a database storing in a plurality of pieces of session information. The management computer includes property management information for managing a property of each of the plurality of pieces of session information. The session information migration control unit is configured to: detect a migration trigger of the plurality of pieces of session information stored in a first database; select the plurality of pieces of session information from the plurality of pieces of session information stored in the first database based on the property management information; determine a migration order for the selected plurality of pieces of session information based on the property of the each of the selected plurality of pieces of session information.

Communication system, management computer, and session information migration method

A mobile radio communication system having one or more relay stations and base stations, a gateway, an external device having a route selection function, and a policy control device which selects a main route and a sub route on the basis of residual resources in a radio communication device. The mobile station connected to one radio communication device can select another radio communication device having a large amount of residual resources as a new access point when the one radio communication device cannot be used, to prevent shortage of the radio resources. Also, it is possible to enable a process of selecting the radio communication device as a new access point to be omitted when switching one route to another by determining a sub route as the new access point when a main route is disconnected in advance, to shorten a service disconnection time.

Route selecting device and mobile radio communication system

In a wireless communication system, when data communication is performed between a relay device and a terminal (in a second path), the same amount of data is required to be transferred between a base station and the relay device (in a third path). An amount of wireless communication resources required is obtained by adding an amount inversely proportional to a capacity of each of the second and third wireless transmission-paths. Therefore, the amount inversely proportional to the capacity of the third path is consumed in excess. Based on a channel quality of a first wireless channel between the base station and the terminal, a channel quality of a second wireless channel between the terminal and the relay station, and a channel quality of a third wireless channel between the base station and the relay station, it is determined whether data communication between the base station and the terminal is relayed.

Base station, wireless communication system, wireless resource allocating method, and wireless communicating method

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Yokohama, Japan

Yuta Muto