US9270501B2ActiveUtilityA1
Method for removing signal interference based on multiple input multiple output
Est. expiryDec 30, 2033(~7.5 yrs left)· nominal 20-yr term from priority
H04L 25/021H04L 25/0242H04B 7/0452H04L 25/0202H04L 25/0391H04L 25/03955H04B 7/0626H04B 7/0417H04B 7/0632H04B 7/0456
61
PatentIndex Score
1
Cited by
19
References
10
Claims
Abstract
Disclosed is a method for removing signal interference in a MIMO-based interference removing apparatus including transmitting a reference signal to at least one receiver; if channel information is estimated by the receiver, receiving the estimated channel information from the receiver as a feedback signal; and producing transmission pre-coding matrix, beam forming matrix, and weighted matrix using the received channel information. Further, the method includes transmitting information containing the transmission pre-coding matrix, the beam forming matrix, and the weighted matrix by including them in a pilot signal to the receiver, and the MIMO-based interference removing apparatus comprises at least one transmitter.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A method for removing signal interference in a MIMO-based interference removing apparatus, the method comprising:
transmitting a reference signal to at least one receiver;
if channel information is estimated by the receiver, receiving the estimated channel information from the receiver as a feedback signal;
producing a transmission pre-coding matrix, a beam forming matrix, and a weighted matrix using the received channel information; and
transmitting information containing the transmission pre-coding matrix, the beam forming matrix, and the weighted matrix by including them in a pilot signal to the receiver,
wherein the MIMO-based interference removing apparatus comprises at least one transmitter.
2. The method of claim 1 , wherein upon receiving the pilot signal, the receiver produces a received beam forming matrix and transmits it to the transmitter.
3. The method of claim 1 , wherein the transmitter comprises at least one wireless AP or at least one relay and the receiver comprises at least one wireless terminal.
4. The method of claim 1 , wherein said producing transmission pre-coding matrix, beam forming matrix, and weighted matrix using the received channel information comprises:
initializing the transmission pre-coding matrix with respect to the transmitter and the receiver;
calculating the beam forming matrix with respect to the transmitter and the receiver;
calculating the weighted matrix with respect to the transmitter and the receiver;
calculating the transmission pre-coding matrix in case of constraining a transmission power of the transmitter, or the transmission pre-coding matrix in case of constraining a transmission power of the receiver; and
repeatedly performing the calculations until the weighted sum mean square error (MSE) of the weighted matrix converges on a predetermined threshold value.
5. The method of claim 1 , wherein the beam forming matrix is calculated by the following equation:
U [k,i] =Φ [k,i]−1 H i [k,i] V [k,i]
wherein Φ [k,i] represents a covariance matrix of the signal that is received by the receiver, H i [k,i] represents a channel matrix between the transmitter and the receiver, V [k,i] represents a transmission pre-coding matrix for the receiver.
6. The method of claim 5 , wherein the channel matrix is calculated by the following equation:
H i [k,j] ={tilde over (H)} i [k,j] +Δ i [k,j]
where {tilde over (H)} i [k,j] denotes an estimated channel matrix, Δ i [k,j] matrix, and the elements of the channel matrix and channel estimation error matrix are complex
Gaussian random variables whose mean is zero (0) and variance is σ e 2 .
7. The method of claim 5 , wherein the covariance matrix is calculated by the following equation:
Φ
[
k
,
i
]
=
(
σ
n
2
+
σ
e
2
∑
(
1
,
j
)
tr
{
V
[
1
,
j
]
V
[
1
,
j
]
H
}
)
I
+
∑
(
1
,
j
)
H
j
[
k
,
i
]
V
[
1
,
j
]
V
[
1
,
j
]
H
H
j
[
k
,
i
]
H
where
σ e 2 denotes a variance value of noise influenced on the receiver, and where σ 2 n denotes a variance value of baseline noise.
8. The method of claim 7 , wherein the transmission pre-coding matrix is calculated by the following equation:
W [k,i] =( I−V [k,i]H {tilde over (H)} i [k,i]H Φ [k,i]−1 {tilde over (H)} i [k,i] V [k,i] ) −1
where W [k,i] denotes the weighted matrix.
9. The method of claim 8 , wherein the transmission pre-coding matrix is calculated by the following equation in cases where a transmission power of the transmitter is constrained:
V
[
k
,
i
]
=
(
∑
(
i
,
j
)
μ
[
1
,
j
]
H
~
i
[
1
,
j
]
H
U
[
1
,
j
]
W
[
1
,
j
]
U
[
1
,
j
]
H
H
~
i
[
1
,
j
]
+
σ
e
2
∑
(
i
,
j
)
μ
[
1
,
j
]
tr
{
W
[
1
,
j
]
U
[
1
,
j
]
H
U
[
1
,
j
]
}
I
+
λ
i
I
)
-
1
×
μ
[
k
,
i
]
H
~
i
[
k
,
i
]
H
U
[
k
,
i
]
W
[
k
,
i
]
where μ [k,i] denotes the priority of the receiver, λ i denotes a Lagrange Multiplier of the transmitter, which selects a value satisfying
∑
k
=
1
K
i
tr
{
V
[
k
,
i
]
V
[
k
,
i
]
H
}
≤
P
i
,
and P i denotes an upper limit of the transmission power of the transmitter.
10. The method of claim 8 , wherein the transmission pre-coding matrix is calculated by the following equation in case where a transmission power of the receiver is constrained:
V
[
k
,
i
]
=
(
∑
(
i
,
j
)
μ
[
1
,
j
]
H
~
i
[
1
,
j
]
H
U
[
1
,
j
]
W
[
1
,
j
]
U
[
1
,
j
]
H
H
~
i
[
1
,
j
]
+
K
i
P
i
σ
e
2
tr
{
μ
[
k
,
i
]
W
[
k
,
i
]
U
[
k
,
i
]
H
U
[
k
,
i
]
}
I
+
σ
e
2
∑
(
1
,
j
)
tr
{
μ
[
1
,
j
]
W
[
1
,
j
]
U
[
1
,
j
]
H
U
[
1
,
j
]
}
I
)
×
μ
[
k
,
i
]
β
H
~
i
[
k
,
i
]
H
U
[
k
,
i
]
W
[
k
,
i
]
where β denotes a power normalization factor and K i denotes the number of the receivers related to the transmitter.Cited by (0)
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