Method for generating reference signal sequence in multi-antenna wireless communication system and apparatus for same
The present application discloses a method in which a base station transmits a reference signal sequence in a wireless communication system. In detail, the method comprises the steps of: generating a pseudo-random sequence using a first m-sequence and a second m-sequence; generating the reference signal sequence using the pseudo-random sequence; and transmitting the reference signal to a mobile station via antenna ports different from one another. The second m-sequence has an initial value containing parameters for discriminating reference signal sequences among users.
1. A method of transmitting a user equipment (UE) specific reference signal sequence by a base station (BS) in a wireless communication system, the method comprising:
generating the UE specific reference signal sequence based on a pseudo-random sequence defined by a first m-sequence and a second m-sequence;
transmitting the UE specific reference signal sequence to a UE,
wherein an initial value of the first m-sequence is a fixed value,
wherein an initial value of the second m-sequence is determined using a cell identity,
wherein the cell identity is configured based on a transmission mode of the BS,
wherein the pseudo-random sequence is represented as c(n) and is defined by following equation A:
c ( n )=( x 1 n+N C )+ x 2 ( n+N C ))mod 2
x 1 ( n+ 31)=( x 1 ( n+ 3)+ x 1 ( n ))mod 2
x 2 ( n+ 31)=( x 2 ( n+ 3)+ x 2 ( n+ 2)+ x 2 ( n+ 1)+ x 2 ( n ))mod 2, [Equation A]
where N C =1600,
wherein the first m-sequence is represented as x 1 (n) and is initialized with x 1 (0)=1, x 1 (n)=0, n=1, 2, . . . , 30, and
wherein the second m-sequence is represented as x 2 (n), and
wherein an initial value of the second m-sequence is represented by
(└ n s /2┘+1)·(2 n ID +1)·2 16 +k,
wherein k is an indicator indicated by a physical downlink control channel (PDCCH),
where n s is a slot number within a radio frame and n ID is the cell identity.
2. The method of claim 1 , wherein the UE specific reference signal sequence is represented as r(m) and is defined by following equation B:
r
(
m
)
=
1
2
(
1
-
2
·
c
(
2
m
)
)
+
j
1
2
(
1
-
2
·
c
(
2
m
+
1
)
)
,
m
=
0
,
1
,
…
,
12
N
RB
PDSCH
-
1
,
〈
equation
B
〉
where N RB PDSCH is a number of resource blocks allocated to a Physical downlink shared channel (PDSCH).
3. A base station (BS) in a wireless communication system, the BS comprising:
a processor for generating a user equipment (UE) specific reference signal sequence based on a pseudo-random sequence defined by a first m-sequence and a second m-sequence; and
a Radio Frequency (RF) module for transmitting the UE specific reference signal sequence to a UE,
wherein an initial value of the first m-sequence is a fixed value,
wherein an initial value of the second m-sequence is determined using a cell identity,
wherein the cell identity is configured based on a transmission mode of the BS,
wherein the pseudo-random sequence is represented as c(n) and is defined by following equation A:
c ( n )=( x 1 n+N C )+ x 2 ( n+N C ))mod 2
x 1 ( n+ 31)=( x 1 ( n+ 3)+ x 1 ( n ))mod 2
x 2 ( n+ 31)=( x 2 ( n+ 3)+ x 2 ( n+ 2)+ x 2 ( n+ 1)+ x 2 ( n ))mod 2, [Equation A]
where N C =1600,
wherein the first m-sequence is represented as x 1 (n) and is initialized with x 1 (0)=1, x 1 (n)=0, n=1, 2, . . . , 30, and
wherein the second m-sequence is represented as x 2 (n), and
wherein an initial value of the second m-sequence is represented by
(└ n s /2┘+1)·(2 n ID +1)·2 16 +k,
wherein k is an indicator indicated by a physical downlink control channel (PDCCH),
where n s is a slot number within a radio frame and n ID is the cell identity.
4. A method for receiving a user equipment (UE) specific reference signal sequence at a UE in a wireless communication system, the method comprising:
receiving the UE specific reference signal sequence from a base station (BS); and
demodulating a Physical downlink shared channel (PDSCH) based on the UE specific reference signal sequence,
wherein the UE specific reference signal sequence is generated based on a pseudo-random sequence defined by a first m-sequence and a second m-sequence,
wherein an initial value of the first m-sequence is a fixed value,
wherein an initial value of the second m-sequence is determined using a cell identity,
wherein the cell identity is configured based on a transmission mode of the BS,
wherein the pseudo-random sequence is represented as c(n) and is defined by following equation A:
c ( n )=( x 1 n+N C )+ x 2 ( n+N C ))mod 2
x 1 ( n+ 31)=( x 1 ( n+ 3)+ x 1 ( n ))mod 2
x 2 ( n+ 31)=( x 2 ( n+ 3)+ x 2 ( n+ 2)+ x 2 ( n+ 1)+ x 2 ( n ))mod 2, [Equation A]
where N C =1600,
wherein the first m-sequence is represented as x 1 (n) and is initialized with x 1 (0)=1, x 1 (n)=0, n=1, 2, . . . , 30, and
wherein the second m-sequence is represented as x 2 (n), and
wherein an initial value of the second m-sequence is represented by
(└ n s /2┘+1)·(2 n ID +1)·2 16 +k,
wherein k is an indicator indicated by a physical downlink control channel (PDCCH),
where n s is a slot number within a radio frame and n ID is the cell identity.
5. The method according to claim 4 , wherein the UE specific reference signal sequence is represented as r(m) and is defined by following equation B:
r
(
m
)
=
1
2
(
1
-
2
·
c
(
2
m
)
)
+
j
1
2
(
1
-
2
·
c
(
2
m
+
1
)
)
,
m
=
0
,
1
,
…
,
12
N
RB
PDSCH
-
1
,
〈
equation
B
〉
where N RB PDSCH is a number of resource blocks allocated to a Physical downlink shared channel (PDSCH).
6. A user equipment (UE) in a wireless communication system, the UE comprising:
a Radio Frequency (RF) module for receiving a UE specific reference signal sequence from a base station (BS); and
a processor for demodulating a Physical downlink shared channel (PDSCH) based on the UE specific reference signal sequence,
wherein the UE specific reference signal sequence is generated based on a pseudo-random sequence defined by a first m-sequence and a second m-sequence,
wherein an initial value of the first m-sequence is a fixed value,
wherein an initial value of the second m-sequence is determined using a cell identity,
wherein the cell identity is configured based on a transmission mode of the BS,
wherein the pseudo-random sequence is represented as c(n) and is defined by following equation A:
c ( n )=( x 1 n+N C )+ x 2 ( n+N C ))mod 2
x 1 ( n+ 31)=( x 1 ( n+ 3)+ x 1 ( n ))mod 2
x 2 ( n+ 31)=( x 2 ( n+ 3)+ x 2 ( n+ 2)+ x 2 ( n+ 1)+ x 2 ( n ))mod 2, [Equation A]
where N C =1600,
wherein the first m-sequence is represented as x 1 (n) and is initialized with x 1 (0)=1, x 1 (n)=0, n=1, 2, . . . , 30, and
wherein the second m-sequence is represented as x 2 (n), and
wherein an initial value of the second m-sequence is represented by
(└ n s /2┘+1)·(2 n ID +1)·2 16 +k,
wherein k is an indicator indicated by a physical downlink control channel (PDCCH),
where n s is a slot number within a radio frame and n ID is the cell identity.