Ntt Docomo, Inc.

Shinji Ueda

Takehiro Nakamura

Minami Ishii

Yasuhiro Kato

Sung Uk Moon

Seizo Onoe

Kazunori Obata

Akihiro Maebara

Yutaka Ohto

The object of the present invention is to provide a base station, a mobile stationand a radio network controllerwhich can reduce the load on the radio network controllerduring multicast communication. The base stationsupporting multicast communication comprises a response signal relayconfigured to transfer response signals transmitted from a plurality of mobile stationsto a radio network controller. The response signals respond to a control signal for a multicast group. The response signal relaytransfers only a predetermined number of response signals to the radio network controller. Any following response signals are retained.

Base station, mobile station and radio network controller

A radio communication system includes a radio network controller, base stations and mobile stations. The mobile station includes a response signal transmitter which is configured to transmit a response signal including a group ID identifying a multicast group A to a base station. The response signal responds to a control signal for the multicast group A which the mobile station is joining in. The base station includes a response signal transmitter configured to transmit at least one response signal to the radio network controller. The response signal is selected from at least one response signal transmitted from the mobile station joining in the same multicast group A.

Radio communication system, mobile station, base station and radio network controller

In a mobile communication systemcomprising a control station, a base station, and a mobile station, in which the control stationsets a dedicated channel with the mobile stationvia the base station, the control stationcomprises dedicated channel control means for performing a dedicated channel retention operation in which a second dedicated channel, which is different to a first dedicated channel, is set during communication through the first dedicated channel in such a manner that both the first and second dedicated channels are retained for a predetermined time period after the second dedicated channel is set.

Mobile communication system and control station

Disclosed is a mobile communication system whereby, to reduce the connection time, a mobile station closely located to a base wireless station is permitted to continue to use a common channel for exchanging signals, and to suppress an increase in interference, an individual channel is set for a mobile station located near the edge of a cell, and to obtain a stabilized communication quality and to prevent an increase in the connection time, the probability that the transmission power will reach an upper limit is reduced. When communication between a mobile station and a wireless base station is started, the wireless base station measures the transmission power and the communication quality in the communication with the mobile station and the utilization ratio for a common channel, and compares the obtained values with predetermined threshold values. When the obtained values are lower than the threshold values, the wireless base station continues to use the common channel for signal transmission/reception. On the other hand, when the obtained values exceed the threshold values, the wireless base station sets an individual channel and sets a wireless channel so as to be capable of the continued use of the individual channel for the exchange of signals.

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Yokosuka, Japan

Shinji Ueda