Multicast message communicating method, multicast message communicating system, base station thereof, and mobile station thereof

A multicast message communicating method having a base station for transmitting a multicast message using a multicast channel and a plurality of mobile stations for receiving the multicast message from the base station, the method comprising the steps of:

• (a) receiving transmission power increase request signals from the plurality of mobile stations corresponding to reception powers of the multicast message received by the plurality of mobile stations;
• (b) detecting the reception powers of the transmission power increase request signals received from the receiving portion;
• (c) deciding and generating a transmission power increase request signal or a transmission power decrease request signal for the plurality of mobile stations corresponding to the received powers;
• and
• (d) controlling the transmission power of the multicast message transmitted to the plurality of mobile stations corresponding to the reception powers,
• wherein the steps (a) to (d) are performed by the base station,
• wherein the multicast message and the transmission power increase request signal or the transmission power decrease request signal are transmitted to the plurality of mobile stations, and
• wherein the plurality of mobile stations gradually decrease the transmission powers of the transmission power increase request signals corresponding to the reception powers of the transmission power increase request signal or the transmission power decrease request signal, and the multicast message received from the base station.

A base station for transmitting a multicast message to a plurality of mobile stations using a multicast channel, comprising:

• a receiving portion for receiving transmission power increase request signals from the plurality of mobile stations corresponding to reception powers of the multicast message received by the plurality of mobile stations;
• a reception power detecting portion for detecting the reception powers of the transmission power increase request signals received from said receiving portion;
• transmission power control generating means for deciding and generating a transmission power increase request signal or a transmission power decrease request signal for the plurality of mobile stations corresponding to the received powers;
• and
• a power controlling portion for controlling the transmission power of the multicast message transmitted to the plurality of mobile stations corresponding to the reception powers,
• wherein the multicast message and the transmission power increase request signal or the transmission power decrease request signal cause the transmission powers of the plurality of mobile stations to be increased or decreased, and
• wherein the plurality of mobile stations gradually decrease the transmission powers of the transmission power increase request signals corresponding to the reception powers of the transmission power increase request signal or the transmission power decrease request signal, and the multicast message received from the base station.

A mobile station for receiving a multicast message from a base station using a multicast channel, comprising:

• a receiving portion for receiving the multicast message and a transmission power increase request signal or a transmission power decrease request from the base station;
• a reception power detecting portion for detecting the reception power of the multicast message received from said receiving portion;
• and
• a power controlling portion for comparing the reception power with a predetermined threshold value, stopping transmitting the transmission power increase request signal to the base station when the reception power is larger than the predetermined threshold value, and increasing the transmission power of the transmission power increase request signal when the reception power is equal to or smaller than the predetermined threshold value and said receiving portion receives the transmission power decrease request signal, wherein when said power controlling portion stops transmitting the transmission power increase request signal to the base station, said power controlling portion gradually decreases the transmission power thereof.