Method and apparatus for link adaptation in a mobile communication system

A method for determining a forward data rate and a forward transmission power level in a mobile communication system, comprising the steps of:

• measuring, in an access terminal, a received C/I of a forward pilot channel;
• determining the forward data rate by matching the measured C/I with a reference C/I;
• determining a difference between the measured C/I and the reference C/I as margin information;
• transmitting the determined forward data rate and margin information over a reverse transmission channel;
• and
• decreasing a transmission power level in an access network by power corresponding to the margin information and performing forward transmission at the forward data rate at the decreased transmission power level, upon receipt of the forward data rate and margin information.

A method for determining a forward data rate and a forward transmission power level in an access network of a mobile communication system, comprising the steps of:

• receiving a measured C/I over a reverse link;
• determining a forward data rate by matching the measured C/I with a reference C/I based on a data rate of the packet data;
• determining margin information for determining the forward transmission power level by calculating a difference between the measured C/I and the reference C/I, when the measured C/I is not identical to the reference C/I;
• creating data to be transmitted at the determined forward data rate;
• decreasing the transmission power level using the calculated margin information;
• and
• transmitting the transmission data at the decreased transmission power level.

A method for determining a forward data rate and a forward transmission power level in a mobile communication system, comprising the steps of:

• measuring, in an access terminal, a received C/I of the forward pilot channel;
• transmitting the measured C/I over a reverse DRC channel;
• determining, in an access network, the forward data rate by matching the measured C/I with a reference C/I associated with a data rate of packet data upon receipt of the measured C/I over a reverse link;
• determining margin information for determining the forward transmission power level by calculating a difference between the measured C/I and the reference C/I when the received C/I is not identical to the reference C/I;
• creating transmission data associated with the determined data rate;
• decreasing the transmission power level using the calculated margin information;
• and
• transmitting the transmission data at the decreased transmission power level.

A transmission apparatus for a mobile communication system, for determining a forward data rate using a C/I value measured from the pilot channel and transmitting the forward data rate and a transmission power level over a reverse transmission channel using margin information determined based on a difference between a reference C/I and the C/I, comprising:

• a first multiplexer for time-division-multiplexing the forward data rate and the margin information;
• an encoder for encoding an output of the first multiplexer;
• a spreader for spreading the encoded data rate and margin information;
• and
• a second multiplexer for time-division-multiplexing a reverse pilot channel and an RRI (Reverse Rate Indicator) channel to an output of the spreader.

A transmission apparatus for transmitting a C/I in a mobile communication system, comprising:

• an encoder for encoding a measured C/I;
• a spreader for spreading an output of the encoder;
• and
• a first multiplexer for time-division-multiplexing an output of the spreader, a reverse pilot channel and an RRI channel.