Method and device for multi-user detection with simplified de-correlation in a CDMA system
View Patent ↗A simplified de-correlation method in CDMA multi-user detection comprises: a. receive wireless symbols S; b. obtain a channel correlation matrix R, take a part from R to get a partial correlation matrix R P ; c. do inversion operation to the partial correlation matrix R P , then obtain matrix V (m) ; d. recover original data symbols D from received symbols S by V (m) that the location of original data symbols D corresponds to.
1. A simplified de-correlation method in TD-SCDMA multi-user detection comprising:
receiving wireless symbols S;
obtaining a channel correlation matrix R, taking one part from the channel correlation matrix R and getting a partial correlation matrix R P of the channel correlation matrix R;
performing an inversion operation to the partial correlation matrix R P , and then obtaining a matrix V (m) using an inverse version of the partial correlation matrix R P ; and
recovering original data symbols D from the received symbols S using the matrix V (m) .
2. A simplified de-correlation method in TD-SCDMA multi-user detection of claim 1 , wherein said partial correlation matrix R P ={r i,j }, i,j=1 . . . (2P+1)K, where said partial correlation matrix R P is a submatrix of the channel correlation matrix R on diagonal, said K is the user number in one time slot, and said P is the symbols number earlier than or latter than current symbols and have influence to current symbols.
3. A simplified de-correlation method in TD-SCDMA multi-user detection of claim 2 , wherein said V (m) ={v i,j (m) }, where v i,j (m) =(R P −1 ) i+(m−1)K,j , i =1. . . K,j=1. . . (2P+1)K,m=1 . . . 2P+1.
4. A simplified de-correlation method in TD-SCDMA multi-user detection of claim 2 , wherein 1≦K≦16.
5. A simplified de-correlation method in TD-SCDMA multi-user detection of claim 1 , wherein the location of original data symbols D have three situations:
1) when 1≦n≦P, V (m) =V (n) , D (n) can be recovered as {circumflex over (D)} (n) =V (n) S P (n)
2) when P+1≦n≦N−P, V (m) =V (P+1) , D (n) can be recovered as {circumflex over (D)} (n) =V (P+1) S P (n)
3) when N+1−P≦n≦N, V (m) =V (2P+1+n−N) , D (n) can be recovered as {circumflex over (D)} (n) =V (2P+1+n−N) S P (n) , said {circumflex over (D)} (n) is the estimation of original symbol, said n is location of chip.
6. A simplified de-correlation method in TD-SCDMA multi-user detection of claim 5 , wherein said P is an integer and said N is 22.
7. A simplified de-correlation method in TD-SCDMA multi-user detection of claim 6 , wherein said P is 2.
8. A simplified de-correlation method in TD-SCDMA multi-user detection of claim 1 , wherein:
When P+1≦n≦N−P, received wireless symbols S can be defined as
S
P
(
n
)
=
(
s
⋒
1
(
n
-
P
)
,
s
⋒
2
(
n
-
P
)
,
…
,
s
⋒
K
(
n
-
P
)
︸
n
-
P
th
symbols
of
all
K
users
,
…
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s
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1
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n
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,
s
⋒
2
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n
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,
…
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s
⋒
K
(
n
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︸
n
th
symbols
of
all
K
users
,
…
,
s
⋒
1
(
n
+
P
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,
s
⋒
2
(
n
+
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)
,
…
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⋒
K
(
n
+
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)
︸
n
+
P
th
symbols
of
all
K
users
)
,
where said Ŝ 1 (n−P) , Ŝ 2 (n−P) , . . . , Ŝ K (n−P) is (n−P) th symbols of all K users, said Ŝ 1 (n) , Ŝ 2 (n) , . . . , Ŝ K (n) is (n) th symbols of all K users, said Ŝ 1 (n+P) , Ŝ 2 (n+P) , . . . , Ŝ K (n+P) is (n+P) th symbols of all K users;
When 1≦n≦P, received wireless symbols S can be defined as
S
P
(
n
)
=
(
s
⋒
1
(
1
)
,
s
⋒
2
(
1
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,
…
,
s
⋒
K
(
1
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︸
1
st
symbols
of
all
K
users
,
…
,
s
⋒
1
(
n
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,
s
⋒
2
(
n
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,
…
,
s
⋒
K
(
n
)
︸
n
th
symbols
of
all
K
users
,
…
,
s
⋒
1
(
2
P
+
1
)
,
s
⋒
2
(
2
P
+
1
)
,
…
,
s
⋒
K
(
2
P
+
1
)
︸
2
P
+
1
th
symbols
of
all
K
users
)
,
where said Ŝ 1 (1) , Ŝ 2 (1) , . . . , Ŝ K (1) is 1 th symbols of all K users, said Ŝ 1 (n) , Ŝ 2 (n) , . . . , Ŝ K (n) is (n) th symbols of all K users, said Ŝ 1 (2P+1) , Ŝ 2 (2P+1) , . . . , Ŝ K (2P+1) is 2P+1 th symbols of all K users;
When N +1−P≦n≦N, received wireless symbols S can be defined as
S
P
(
n
)
=
(
s
⋒
1
(
N
-
2
P
)
,
s
⋒
2
(
N
-
2
P
)
,
…
,
s
⋒
K
(
N
-
2
P
)
︸
N
-
2
P
th
symbols
of
all
K
users
,
…
,
s
⋒
1
(
n
)
,
s
⋒
2
(
n
)
,
…
,
s
⋒
K
(
n
)
︸
n
th
symbols
of
all
K
users
,
…
,
s
⋒
1
(
N
)
,
s
⋒
2
(
N
)
,
…
,
s
⋒
K
(
N
)
︸
N
th
symbols
of
all
K
users
)
,
where said Ŝ 1 (N−2P) , Ŝ 2 (N−2P) , . . . , Ŝ K (N−2P) is N−2P th symbols of all K users, said Ŝ 1 (n) , Ŝ 2 (n) , . . . , Ŝ K (n) is n th symbols of all K users, said Ŝ 1 (N) , Ŝ 2 (N) , . . . , Ŝ K (N) is N th symbols of all K users.
9. A UE system in TD-SCDMA comprising:
a correspond calculate equipment to define a partial correlation matrix R P of a channel correlation matrix R;
a draw out and inversed matrix equipment to define new matrix V (m) using the partial correlation matrix R P ; and
a matrix-vector multiplication to multiply received wireless symbols S by said matrix V (m) .
10. A UE system in TD-SCDMA of claim 9 further comprising K matching filters and K buffer storages that are connected to said K matching filters one by one.