Method and apparatus for transmitting uplink signal in wireless communication system
A method for transmitting an uplink signal at a UE in a wireless communication system includes, when a virtual cell ID for a reference signal for demodulation of a physical uplink channel is provided, generating a sequence of the reference signal on the basis of the virtual cell ID, and transmitting the generated reference signal to an eNB. A sequence hopping pattern of the reference signal can be determined on the basis of the virtual cell ID.
1. A method for transmitting an uplink signal at a user equipment (UE) in a wireless communication system, the method comprising:
when a virtual identity (ID), n ID PUSCH , for a reference signal for demodulation of a physical uplink shared channel (PUSCH) is provided, generating the reference signal by the UE based on n ID PUSCH ; and
transmitting, by the UE, the generated reference signal,
wherein, when n ID PUSCH is provided, a pseudo-random sequence generator used to determine sequence hopping of the reference signal is initialized according to
c
init
=
⌊
n
ID
PUSCH
30
⌋
·
2
5
+
n
ID
PUSCH
mod
30
at the start of each radio frame based on n ID PUSCH instead of a physical layer cell ID, N ID cell ∈{0, . . . ,503}, and
wherein n ID PUSCH ∈{0, . . . ,509}is provided by a higher layer.
2. The method according to claim 1 , wherein the sequence hopping is applied when sequence group hopping for the reference signal is disabled.
3. The method according to claim 1 , wherein the sequence hopping is applied when a length of the reference signal satisfies M sc RS ≧6N sc RB ,
wherein M sc RS denotes the length of the reference signal and is defined as M sc RS =m·N sc RB ,
wherein 1≦m≦N RB max,UL
wherein N RB max,UL represents a maximum uplink bandwidth configuration and is expressed by an integer multiple of N sc RB , and
wherein N sc RB is a resource block size and is represented by a number of subcarriers.
4. The method according to claim 1 , wherein a base sequence number of the reference signal in a base sequence group of the reference signal is determined according to the sequence hopping.
5. The method according to claim 1 ,
wherein, when n ID PUSCH is not provided, the pseudo-random sequence generator used to determine the sequence hoping of the reference signal is initialized according to
c
init
=
⌊
n
ID
cell
30
⌋
·
2
5
+
(
N
ID
cell
+
Δ
ss
)
mod
30
,
and
wherein Δ ss ∈{0,1,. . . .29}is provided by higher layer.
6. The method according to claim 1 , wherein n ID PUSCH is set to a value making a base sequence of the reference signal for the UE identical to a base sequence for other UE which is paired with the UE for a multiple user multiple input multiple output (MU-MIMO).
7. The method according to claim 1 , wherein the reference signal is transmitted on one single carrier frequency division multiple access (SC-FDMA) symbol in a slot in which the PUSCH is transmitted.
8. A user equipment (UE) for transmitting an uplink signal, comprising:
a receiver;
a transmitter; and
a processor configured to control the receiver and the transmitter, the processor configured to:
when a virtual cell identity (ID) n ID PUSCH for a reference signal for demodulation of a physical uplink shared channel (PUSCH) is provided, generate the reference signal based on n ID PUSCH ; and
control the transmitter to transmit the generated reference signal sequence
wherein, when n ID PUSCH is provided, a pseudo-random sequence generator used to determine sequence hopping of the reference signal is initialized according to
c
init
=
⌊
N
ID
PUSCH
30
⌋
·
2
5
+
n
ID
PUSCH
mod
30
at the start of each radio frame based on n ID PUSCH instead of a physical layer cell ID, N ID cell ∈{0, . . . ,503}, and
wherein n ID PUSCH ∈{0, . . . ,509}is provided by a higher layer.
9. The UE according to claim 8 , wherein the sequence hopping is applied when sequence group hopping for the reference signal is disabled.
10. The UE according to claim 8 ,
wherein the sequence hoping is applied when a length of the reference signal satisfies M sc RS ≧6N sc RB ,
wherein M sc RS denotes the length of the reference signal and is defined as M sc RS =m·N sc RB
wherein 1≦m≦N RB max,UL ,
wherein N RB max,UL represents a maximum uplink bandwith configuration and is expressed by an interger multiple of N sc RB , and
wherein N sc RB is a resource block size and is represented by a number of subcarriers.
11. The UE according to claim 8 , wherein a base sequence number of the reference signal in a base sequence group of the reference signal is determined according to the sequence hopping.
12. The UE according to claim 8 ,
wherein, when N ID PUSCH is not provided, the pseudo-random sequence generator used to determine the sequence hopping of the reference signal is initialized according to
c
init
=
⌊
N
ID
cell
30
⌋
·
2
5
+
(
N
ID
cell
+
Δ
ss
)
mod
30
,
and
wherein Δ ss ∈{0,1, . . .29}is provided by the higher layer.