Ntt Docomo, Inc.

Mitsuo Iwanaga

Takehiro Ida

Kazufumi Yunoki

Yukihiko Okumura

Kunio Yoshikawa

Etsuhiro Okamoto

Nobukazu Uno

Wataru Matsuno

Yasushi Sakamoto

The present invention provides a mobile station which can perform communication using a specific communication system such as HSDPA and HSUPA, with priority, and a communication system selection method thereof. The mobile station for performing communication using a specific communication system includes: a transmission/reception unit for receiving broadcast information from a plurality of communication base stations; an acquisition unit for acquiring a plurality of pieces of cell information on cells which the mobile station can camp on and on a communication systems which can be used in the cells; and a control unit for selecting one cell where the specific communication system can be used from the plurality of pieces of cell information acquired by the acquisition unit, and performing processing for the mobile station to camp on this cell. By using this mobile station, communication using a specific communication system such as HSDPA or HSUPA can be performed with priority.

Mobile station and communication system selection method

In a transmission power control method, a receiver receives user data transmitted intermittently from a transmitter to a receiver and control data transmitted continuously from the transmitter to a plurality of receivers including the receiver via a DPDCH and a CPICH, respectively; and generates, when the receiver is receiving the user data from the transmitter via the DPDCH, a command for controlling transmission power of the transmitter of a DPDCH in a manner that an SIR of a received signal of the DPDCH by the receiver becomes equal to a target SIR, and generates, when the receiver is not receiving the user data from the transmitter via the DPDCH, a command for controlling the transmission power of the transmitter of the DPDCH by updating the target SIR by using received quality of the CPICH.

Transmission power control method and apparatus

A communication device comprises a receiver configured to receive a notification of a cipher parameter used for encryption of data and a requested start time at which the encryption starts; and a correction unit configured to determine whether the cipher parameter needs to be corrected in response to the notification having been retransmitted based on the requested start time and an actual start time at which the encryption actually starts, and correct the cipher parameter.

Communication device and communication control method

The present invention provides a mobile station able to shorten the processing time of selecting a serving base station and able to select an appropriate serving base station with which the mobile station communicates. Mobile phonereceives an advertisement message from a peripheral base station, until state of communication path to the peripheral base station remains above a reference level over the predetermined time period, 'Treselection', wherein the reference level is calculated by adding the parameter 'Qhyst' to state of communication path to the current serving base station. After detecting peripheral base station, mobile phoneignores the detection that the condition of changing base stations is fulfilled for another peripheral base station, until data storage area is updated in accordance with an advertisement message from the peripheral base station

Mobile station and base station selection scheme

A mobile phoneaccording to the present invention stores first broadcast information received from a base station Bin correspondence with first cell information in a storage unitWhen the mobile phonereceives second cell information from a base station Bit determines whether there is previously stored cell information identical with the second cell information, in a cell information storage tableWhen the result of the determination is that it is stored, the mobile phonereads out the first broadcast information and transfers to a cell according to the first broadcast information. When it is not stored, the mobile phone receives second broadcast information and transfers to a cell according to the second broadcast information. Namely, the mobile phonemakes the cell transfer according to minimum data within a range in which a cell as a potential transfer target can be identified.

Mobile communication terminal, broadcast information storing method, cell transfer method, and mobile communication system

A smaller number of frequencies are dynamically defined, from which a frequency to be used is first searched, failing which, all the frequencies available to a particular mobile communication system are searched, thereby frequency search is efficiently performed with a reduced power consumption.

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Yokohama, Japan

Mitsuo Iwanaga