LTE-A system and uplink power control method thereof
An LTE-A system and power control method for controlling cell interference based on codeword-specific transmission power adjustment with a transmission power control offset parameter. The method includes transmitting a parameter K S signaled by a higher layer and codeword-specific power control parameters from a base station to a terminal; calculating gains at the terminal, using the codeword-specific power control parameters and the parameter K S ; calculating, at the terminal, codeword-specific transmit powers according to the gains; and transmitting, from the terminal to the base station, at least two codewords at the codeword-specific transmit powers.
1. A method for controlling transmit power in a user terminal, the method comprising:
receiving a parameter K S signaled by a higher layer and codeword-specific power control parameters from the base station;
calculating gains using the codeword-specific power control parameters and the parameter K S ;
calculating codeword-specific transmit powers according to the gains; and
transmitting at least two codewords at the codeword-specific transmit powers.
2. The method of claim 1 , wherein the parameter K S is set to one of 0 and 1.25.
3. The method of claim 2 , wherein calculating the codeword-specific transmit powers comprises equaling a sum of the codeword-specific transmit powers of the at least two codewords to a transmit power using a single codeword, if K S is set to 0.
4. The method of claim 3 , wherein calculating the codeword-specific transmit powers further comprises adjusting the codeword-specific transmit powers using an offset parameter λ.
5. The method of claim 3 , wherein calculating the codeword-specific transmit powers further comprises controlling cell interference by adjusting the codeword-specific transmit powers with different offset parameters λ CW#′1 and λ CW#′2 .
6. The method of claim 2 , wherein calculating the codeword-specific transmit powers comprises:
calculating a Transmit power control that is commonly used for calculating both the at least two codewords; and
calculating the codeword-specific transmit powers according to a Modulation and Coding Scheme(MCS) of each the at least two codewords, if K S is set to 1.25.
7. A transmit power control apparatus comprising:
a transceiver configured to perform data communication; and
a controller configured to receive a cell-specific parameter K S given by a higher layer and codeword-specific power control parameters, to calculate gains using the codeword-specific power control parameters and the cell-specific parameter K S , and to transmit at least two codewords at codeword-specific transmit powers calculated with the gains.
8. The transmit power control apparatus 7 , wherein the parameter K S is set to one of 0 and 1.25.
9. The transmit power control apparatus of claim 8 , wherein the controller is further configured to equal a sum of the codeword-specific transmit powers of the at least two codewords to a transmit power using a single codeword, if K S is set to 0.
10. The transmit power control apparatus of claim 9 , wherein the controller is further configured to adjust the codeword-specific transmit powers using an offset parameter λ.
11. The transmit power control apparatus of claim 9 , wherein the controller is further configured to control cell interference by adjusting the codeword-specific transmit powers with different offset parameters λ CW#′1 and λ CW#′2 .
12. The transmit power control apparatus of claim 8 , wherein the controller is further configured to calculate a Transmit power control that is commonly used for calculating both the at least two codewords, and to calculate transmit powers according to a Modulation and Coding Scheme (MCS) of each the at least two codewords, if K S is set to 1.25.
13. A method for transmitting parameters in a base station, the method comprising:
transmitting a parameter K S signaled by a higher layer and codeword-specific power control parameters to a terminal; and
receiving at least two codewords at the codeword specific transmit power from the terminal,
wherein the parameters are used for calculating gains using the codeword-specific power control parameters and the parameter K S , and for calculating the codeword-specific transmit powers according to the gains in the terminal.
14. The method of claim 13 , further comprising:
checking per-codeword received power strengths received from the terminal; and
updating the codeword-specific power control parameters based on the per-codeword received power strengths.
15. A base station for transmitting parameters, the base station comprising:
a transceiver configured to perform data communication; and
a controller configured to transmit a parameter K S signaled by a higher layer and codeword-specific power control parameters to a terminal, and to receive at least two codewords at the codeword specific transmit power from the terminal,
wherein the parameters are used for calculating gains using the codeword-specific power control parameters and the parameter K S , and for calculating the codeword-specific transmit powers according to the gains in the terminal.
16. The base station of claim 15 , wherein the controller is further configured to check per-codeword received power strengths received from the terminal and to update the codeword-specific power control parameters based on the per-codeword received power strengths.