Wireless terminal, transmission power control method, and wireless base station

A method for controlling transmission power of a terminal that includes a plurality of antenna elements, the terminal performing radio communication with a base station, the base station including:

• a plurality of transmission points each including at least one antenna element;
• and a signal processing unit connected to the plurality of transmission points, the method comprising:
• estimating path-loss between each of the plurality of antenna elements and the plurality of transmission points;
• summing, in each of the plurality of antenna elements, the path-loss of each of the plurality of transmission points;
• calculating a first coefficient for each summed path-loss based on a table describing a pre-defined positive relationship, wherein each first coefficient having a value between or equal to 0 and 1,
• calculating a power control weight for controlling transmission power of each of the plurality of antenna elements based on the summed path-loss,
• wherein a coefficient of the power control weight is calculated using the calculated first coefficients in a linear system in such a way that the greater the path-loss estimated, the greater the transmission power;
• and
• transmitting a reference signal multiplied by both the power control weight and a beamforming weight,
• wherein the terminal performs calculations in accordance with an equation
• r=αHs+z.

A base station including:

• a plurality of transmission points each including at least one antenna element;
• and a signal processing unit connected to the plurality of transmission points, the base station comprising:
• a processor that:
• estimates path-loss between the base station and a plurality of antenna elements of a terminal,
• sums, in each of the plurality of antenna elements, the path-loss of each of the plurality of transmission points,
• calculates a first coefficient for each summed path-loss based on a pre-defined positive relationship, wherein each first coefficient has a value between or equal to 0 and 1, and
• calculates a power control weight for controlling transmission power of each of the plurality of antenna elements based on the summed path-loss, wherein a coefficient of the power control weight is calculated by using calculated first coefficients in a linear system;
• and
• a transmitter that transmits a reference signal multiplied by both the power control weight and a beamforming weight to the terminal,
• wherein the processor performs calculations in accordance with an equation
• r=αHs+z.