Adaptive multiple antenna transmission method and apparatus in accordance with antenna transmission power in a wireless communication system
The present invention relates to a wireless communication system, and an adaptive multiple antenna transmission method and apparatus in accordance with antenna transmission power are disclosed. A method of performing multiple antenna transmission from a terminal to a base station according to one embodiment of the present invention may include the steps of: determining a reference value for a transmission power of each of a plurality of transmit antennas of the terminal; grouping the plurality of transmit antennas into a first group of transmit antennas and a second group of transmit antennas in accordance with the determined reference value; and transmitting a signal to the base station through at least one of the first group of the transmit antennas and the second group of transmit antennas.
1. A method for performing multiple antenna transmission from a user equipment to a base station, comprising:
determining, by the user equipment for an uplink transmission, a criterion value of transmit power of each transmit antenna of a plurality of transmit antennas of the user equipment;
grouping, by the user equipment, the plurality of transmit antennas into a first group of transmit antennas and a second group of transmit antennas according to the determined criterion value, wherein the first group of transmit antennas has higher transmit power than the second group of transmit antennas; and
transmitting, by the user equipment, a signal to the base station via the first group of transmit antennas and the second group of transmit antennas,
wherein the transmitting includes transmitting the signal to the base station using a precoding matrix configured to transmit a larger number of layer signals via the first group of transmit antennas as compared to the second group of transmit antennas, at least one layer signal being transmitted via each of the first group and the second group of transmit antennas, and
wherein, in the precoding matrix, the number of elements having a value of 0 per column is the same, elements having a value of 0 are not present in the same row, and each column includes only one element having a value of 0.
2. The method according to claim 1 , wherein the criterion value is determined based on outputs of power amplifiers respectively mapped to the plurality of transmit antennas.
3. The method according to claim 1 , wherein the precoding matrix includes a precoding matrix reconfigured by permuting each row of the precoding matrix according to the locations of power amplifiers respectively mapped to the plurality of transmit antennas.
4. The method according to claim 1 , wherein the precoding matrix includes, for rank-2 transmission, a matrix of Equation 1:
[
a
d
b
e
c
0
0
f
]
,
Equation
1
and
includes, for rank-3 transmission, a matrix of Equation 2:
[
a
d
g
0
e
h
b
0
i
c
f
0
]
Equation
2
wherein, in Equations 1 and 2, a, b, c, d, e, f, g, h and i are non-zero complex numbers.
5. The method according to claim 1 , further comprising:
selecting a combination of power amplifiers mapped to one or more transmit antennas of the at least one group of the first group of transmit antennas or the second group of transmit antennas used for transmission of the signal to the base station; and
reporting the combination of the power amplifiers to the base station.
6. A user equipment which performs multiple antenna transmission to a base station, comprising:
a plurality of antennas;
a reception module configured to receive a signal from the base station via the plurality of antennas;
a transmission module configured to transmit a signal to the base station via the plurality of antennas; and
a processor configured to control the user equipment including the plurality of antennas, the reception module, and the transmission module;
wherein the processor is further configured to:
determine, for an uplink transmission, a criterion value of transmit power of each transmit antenna of a plurality of transmit antennas of the user equipment,
group the plurality of transmit antennas into a first group of transmit antennas and a second group of transmit antennas according to the determined criterion value, wherein the first group of transmit antennas has higher transmit power than the second group of transmit antennas, and
transmit a signal to the base station via the first group of transmit antennas and the second group of transmit antennas, wherein the user equipment further comprises:
a memory configured to store a precoding matrix configured to transmit a larger number of layer signals via the first group of transmit antennas as compared to the second group of transmit antennas, at least one layer signal being transmitted via each of the first group and the second group of transmit antennas; and
a precoder configured to perform precoding with respect to a signal to be transmitted to the base station and to output the precoded signal, using the precoding matrix stored in the memory,
wherein the processor is further configured to control transmission of the precoded signal to the base station via the first group of transmit antennas and the second group of transmit antennas, and
wherein, in the precoding matrix, the number of elements having a value of 0 per column is the same, elements having a value of 0 are not present in the same row, and each column includes only one element having a value of 0.