Apparatus and method for controlling power of reverse channels in a mobile communication system

An apparatus for performing power control on reverse channels by a mobile station transmitting a reverse pilot channel, a reverse traffic channel and a reverse channel quality indicator channel (CQICH) to a base station, the apparatus comprising:

• a control bit detector for receiving a control bit from the base station, and determining whether the received control bit is a ratio control bit indicating a command to increase or decrease a CQICH traffic-to-pilot ratio or a power control bit indicating a command to increase or decrease transmission power of the reverse channels;
• a ratio controller for controlling a CQICH traffic-to-pilot ratio according to the ratio control bit, if the control bit is a ratio control bit;
• and
• a gain controller for receiving the ratio provided from the ratio controller, and controlling transmission gains of the reverse pilot channel, the reverse traffic channel and the reverse channel quality indicator channel according to the power control bit and the provided ratio.

A method for performing power control on a reverse channel quality indicator channel (CQICH) received from a mobile station by a base station in a mobile communication system including the base station for transmitting a power control bit for power control on reverse channels and the mobile station for controlling transmission power of the reverse channels according to the power control bit, the method comprising the steps of:

• (a) determining whether to perform an erasure process by measuring reception power of the reverse channel quality indicator channel;
• (b) accumulating the erasure-determined result for N slots and calculating an erasure rate for the N slots;
• (c) determining a ratio control bit indicating a command to increase or decrease a CQICH traffic-to-pilot ratio according to the erasure rate;
• and
• (d) transmitting the determined ratio control bit to the mobile station.

A method for performing power control on a reverse channel quality indicator channel by a base station receiving a reverse pilot channel, a reverse traffic channel and the reverse channel quality indictor channel from a mobile station, the method comprising the steps of:

• generating a power control bit indicating a command to increase or decrease transmission power of the reverse channels by measuring reception power of the reverse pilot channel;
• determining whether to perform an erasure process by measuring reception power of the reverse channel quality indicator channel, and calculating an erasure rate for N slots according to the reception power of the reverse channel quality indicator channel;
• determining a ratio control bit indicating a command to increase or decrease a CQICH traffic-to-pilot ratio according to the erasure rate;
• and
• transmitting the ratio control bit at one or more selected time slots among a plurality of time slots on a forward channel, and transmitting the power control bits at the other time slots except the selected one or more time slots.

A method for performing power control on reverse channels by a mobile station transmitting a reverse pilot channel, a reverse traffic channel and a reverse channel quality indicator channel (CQICH) to a base station, the method comprising the steps of:

• (a) receiving a control bit from the base station, and determining whether the received control bit is a ratio control bit indicating a command to increase or decrease a CQICH traffic-to-pilot ratio or a power control bit indicating a command to increase or decrease transmission power of the reverse channels;
• (b) if the control bit is a ratio control bit, controlling a CQICH traffic-to-pilot ratio according to the ratio control bit;
• and
• (c) controlling, if the control bit is a power control bit, transmission gains of the reverse pilot channel, the reverse traffic channel and the reverse channel quality indicator channel according to the power control bit and the ratio control bit at a previous time slot.

A method for performing power control on reverse channels by a mobile station transmitting a reverse pilot channel, a reverse traffic channel and a reverse channel quality indicator channel to a base station, the method comprising the steps of:

• receiving a ratio control bit indicating a command to increase or decrease a CQICH traffic-to-pilot ratio at one or more selected time slots among a plurality of time slots on a forward channel;
• controlling a CQICH traffic-to-pilot ratio according to the ratio control bit;
• receiving power control bits indicating a command to increase or decrease transmission power of the reverse pilot channels at the other time slots except the selected one or more time slots;
• and
• controlling transmission gains of the reverse pilot channel, the reverse traffic channel and the reverse channel quality indicator channel according to the power control bit and the ratio control bit of a previous time slot.