Transmission rate control method and radio base station

A transmission rate control method in which a radio base station controls a transmission rate of uplink user data to be transmitted from a mobile station, comprising:

• notifying, from the mobile station to the radio base station, at a predetermined timing, a happy bit set to a first value, when the mobile station determines that a buffering time during which the uplink user data is buffered in a transmission buffer does not exceed a predetermined time, assuming that the mobile station continues to use a transmission rate corresponding to a current granted value notified by the radio base station;
• determining, at the radio base station, a maximum allowable increment for the current granted value being notified to the mobile station, in accordance with the happy bit notified from the mobile station;
• calculating, at the radio base station, as an allowable value to be notified to the mobile station, a granted value obtained by increasing the current granted value by an increment amount not more than the maximum allowable increment amount;
• notifying, from the radio base station to the mobile station, the granted value calculated at the radio base station, by using a transmission rate control channel;
• transmitting, from the mobile station, the uplink user data, at the transmission rate corresponding to the granted value notified from the radio base station;
• and
• wherein in the determining, the radio base station determines the maximum allowable increment amount for the current granted value, in accordance with an average value of happy bit notified, within a predetermined time period, from the mobile station.

A radio base station used in a mobile communication system in which a mobile station transmits uplink user data at a transmission rate corresponding to a granted value notified from the radio base station, comprising:

• a granted value determining unit configured to determine a maximum a granted value that can be notified to the mobile station, in accordance with the happy bit notified from the mobile station, and to calculate, as an allowable value to be notified to the mobile station, a granted value not more than the maximum granted value;
• and
• a granted value notification unit configured to notify, to the mobile station, the granted value calculated by the granted value determining unit, by using a transmission rate control channel, wherein
• the happy bit is set to a first value when the mobile station determines that a buffering time during which the uplink user data is buffered in a transmission buffer does not exceed a predetermined time, assuming that the mobile station continues to use a transmission rate corresponding to a current granted value notified by the radio base station;
• and
• wherein the granted value determining unit determines the maximum granted value that can be notified to the mobile station in accordance with an average value of happy bit notified, within a predetermined time period, from the mobile station.

A radio base station used in a mobile communication system in which a mobile station transmits uplink user data at a transmission rate corresponding to a granted value notified from the radio base station, comprising:

• a granted value determining unit configured to determine a maximum allowable increment amount for a current granted value being notified to the mobile station, in accordance with the happy bit notified from the mobile station, and to calculate, as an allowable value to be notified to the mobile station, a granted value obtained by increasing the current granted value by an increment amount not more than the maximum allowable increment amount;
• and
• a granted value notification unit configured to notify, to the mobile station, the granted value calculated by the granted value determining unit, by using a transmission rate control channel, wherein
• the happy bit is set to a first value when the mobile station determines that a buffering time during which the uplink user data is buffered in a transmission buffer does not exceed a predetermined time, assuming that the mobile station continues to use a transmission rate corresponding to a current granted value notified by the radio base station;
• and
• wherein the granted value determining unit determines the maximum granted value that can be notified to the mobile station, in accordance with an average value of happy bit notified, within a predetermined time period, from the mobile station.