Multi-input and multi-output communication method in large-scale antenna system
View Patent ↗The present invention relates to a multi-input and multi-output communication method in a large-scale antenna system. An MIMO transmission method according to the present invention includes: obtaining statistical channel information on at least one terminal, dividing terminals into a plurality of classes and a plurality of groups based on the statistical channel information, wherein the groups depend on the classes; determining a group beam-forming matrix for each of the divided groups; performing a group beamforming transmission by group based on the group beam-forming matrix to obtain instantaneous channel information; and scheduling terminals based on the instantaneous channel information. Thus, it is possible to decrease the complexity in a scheduling and precoding calculation without an increase in the amount of wireless resources that are required for providing feedback for a reference signal and channel status information.
1. An operation method of a user equipment (UE) in a wireless communication system, the operation method comprising:
receiving, from a base station, information on the number of antennas and a subset of beams which is selected among all possible beams of the base station;
generating a codebook based on the information;
receiving a reference signal (RS) from the base station;
calculating channel state information (CSI) based on the RS by using the codebook; and
reporting the CSI to the base station,
wherein the codebook is generated by using Kronecker product of a horizontal beamforming vector and a vertical beamforming vector.
2. The operation method of claim 1 ,
wherein the codebook is generated based on following equation:
W
g
,
l
(
t
)
∈
{
[
b
H
,
g
,
i
(
t
)
⊗
b
V
,
g
,
h
(
t
)
α
b
H
,
g
,
i
(
t
)
⊗
b
V
,
g
,
h
(
t
)
]
:
i
=
1
,
…
,
b
H
′
,
h
=
1
,
…
,
b
V
′
and
α
=
1
,
-
1
,
j
,
-
1
}
wherein:
b H,g,i (t) is the horizontal beamforming vector,
b v,g,h (t) is the vertical beamforming vector,
αis a co-phasing factor,
i is an index of the horizontal beamforming vector,
h is an index of the vertical beamforming vector,
b′ H is the number of horizontal beamforming vectors,
b′ v is the number of vertical beamforming vectors, and
wherein each of the b′ H and the b′ v is determined based on the information on the number of antennas and the subset of beams.
3. The operation method of claim 1 , wherein the CSI includes at least one of a precoding matrix indicator (PMI), a channel quality indicator (CQI), and a rank indicator (RI).