Enhanced channel state information (CSI) communication method and apparatus
A system and method includes: sending a channel state information-reference signal CSI-RS to a second terminal device, where a frequency-domain bandwidth of the CSI-RS is the same as a frequency-domain bandwidth of a resource pool, the resource pool is a time-frequency resource set included in a sidelink SL bandwidth part BWP, the resource pool includes one or more consecutive sub-channels in frequency domain, one sub-channel in the resource pool includes one or more consecutive physical resource blocks PRBs, and the resource pool is determined based on a periodic bitmap in time domain. According to the method and apparatus in the embodiments of this application, a first terminal device can obtain channel state information CSI of each sub-channel in the resource pool, and allocate a resource based on the CSI of each sub-channel in the resource pool, improving a communication capacity in an SL scenario.
1 . A communication method, comprising:
sending a channel state information-reference signal (CSI-RS) from a first terminal device to a second terminal device, wherein
a frequency-domain bandwidth of the CSI-RS is the same as a frequency-domain bandwidth of a resource pool to send the CSI-RS over the entire resource pool, the resource pool is a time-frequency resource set comprised in a sidelink (SL) bandwidth part (BWP), the resource pool comprises one or more consecutive sub-channels in a frequency domain, one sub-channel in the resource pool comprises one or more consecutive physical resource blocks (PRBs), and the resource pool is determined based on a periodic bitmap in a time domain; and
the CSI in the CSI-RS is carried in a media access control control element (MAC CE), and a quantity of bytes occupied by the MAC CE is related to a quantity of sub-channels in the resource pool.
2 . The method according to claim 1 , wherein the method further comprises:
sending first indication information to the second terminal device, wherein the first indication information is used to indicate the second terminal device to send CSI, and the first indication information is comprised in 2 nd stage sidelink control information (SCI).
3 . The method according to claim 2 , wherein the first indication information is further used to indicate that the frequency-domain bandwidth of the CSI-RS is the same as the frequency-domain bandwidth of the resource pool.
4 . The method according to claim 1 , wherein the method further comprises:
sending second indication information to the second terminal device, wherein the second indication information is used to indicate that the frequency-domain bandwidth of the CSI-RS is the same as the frequency-domain bandwidth of the resource pool.
5 . The method according to claim 4 , wherein the second indication information is comprised in radio resource control (RRC) signaling.
6 . The method according to claim 1 , wherein the CSI in the CSI-RS comprises at least one of the following:
a wideband channel quality indication (CQI) index corresponding to the frequency-domain bandwidth of the CSI-RS; or
CQI values of one or more sub-channels in the resource pool, wherein a CQI value of one sub-channel in the resource pool corresponds to a CQI index of one sub-channel in the resource pool.
7 . The method according to claim 1 , wherein the MAC CE comprises 1+[y/4] bytes, [x] is a round up symbol, and y is the quantity of sub-channels in the resource pool.
8 . The method according to claim 1 , wherein a power control factor β CSI-RS,1 of the CSI-RS satisfies the following relationship:
β
CSI
-
RS
,
1
=
β
DM
-
RS
,
1
PSSCH
*
W
Y
*
n
layer
PSSCH
Q
p
,
wherein
β DM-RS,1 PSSCH is a power control factor of a physical sidelink shared channel (PSSCH), Wis a quantity of sub-channels of a PSSCH bandwidth, Y is the quantity of sub-channels in the resource pool, Y≥W, n layer PSSCH is a quantity of scheduled layers of the PSSCH, and Q p is a quantity of ports of the CSI-RS.
9 . The method according to claim 1 , wherein a power control factor β CSI-RS,1 of the CSI-RS satisfies the following relationship:
β
CSI
-
RS
,
1
=
β
DM
-
RS
,
3
PSSCH
*
n
layer
PSSCH
Q
p
;
and
β
DM
-
RS
,
3
PSSCH
=
β
DM
-
RS
,
2
PSSCH
*
W
*
Z
W
*
(
Z
-
Q
p
)
+
Y
*
n
layer
PSSCH
,
wherein β DM-RS,3 PSSCH a power control factor of a physical sidelink shared channel (PSSCH) on a symbol PSSCH configured to transmit the CSI-RS, β DM-RS,2 PSSCH is a power control factor of the PSSCH on a symbol not configured to transmit the CSI-RS, W is a quantity of sub-channels of a PSSCH bandwidth, Z is a quantity of PRBs comprised in one sub-channel in the resource pool, Y is the quantity of sub-channels in the resource pool, Y≥W, n layer PSSCH is a quantity of scheduled layers of the PSSCH, and Q p is a quantity of ports of the CSI-RS.
10 . A communication method, comprising:
receiving a channel state information-reference signal (CSI-RS) from a first terminal device, wherein
a frequency-domain bandwidth of the CSI-RS is the same as a frequency-domain bandwidth of a resource pool to send the CSI-RS over the entire resource pool, the resource pool is a time-frequency resource set comprised in a sidelink (SL) bandwidth part (BWP), the resource pool comprises one or more consecutive sub-channels in a frequency domain, one sub-channel in the resource pool comprises one or more consecutive physical resource blocks (PRBs), and the resource pool is determined based on a periodic bitmap in a time domain; and
the CSI in the CSI-RS is carried in a media access control control element (MAC CE), and a quantity of bytes occupied by the MAC CE is related to a quantity of sub-channels in the resource pool.
11 . The method according to claim 10 , wherein the method further comprises:
receiving first indication information from the first terminal device, wherein the first indication information is used to indicate a second terminal device to send CSI, and the first indication information is comprised in 2 nd stage sidelink control information (SCI).
12 . The method according to claim 11 , wherein the first indication information is further used to indicate that the frequency-domain bandwidth of the CSI-RS is the same as the frequency-domain bandwidth of the resource pool.
13 . The method according to claim 10 , wherein the method further comprises:
receiving second indication information from the first terminal device, wherein the second indication information is used to indicate that the frequency-domain bandwidth of the CSI-RS is the same as the frequency-domain bandwidth of the resource pool.
14 . The method according to claim 13 , wherein the second indication information is comprised in radio resource control (RRC) signaling.
15 . A communication apparatus, comprising:
a transceiver, configured to send a channel state information-reference signal (CSI-RS) to a second terminal device, wherein
a frequency-domain bandwidth of the CSI-RS is the same as a frequency-domain bandwidth of a resource pool to send the CSI-RS over the entire resource pool, the resource pool is a time-frequency resource set comprised in a sidelink (SL) bandwidth part (BWP), the resource pool comprises one or more consecutive sub-channels in a frequency domain, one sub-channel in the resource pool comprises one or more consecutive physical resource blocks (PRBs), and the resource pool is determined based on a periodic bitmap in a time domain; and
the CSI in the CSI-RS is carried in a media access control control element (MAC CE), and a quantity of bytes occupied by the MAC CE is related to a quantity of sub-channels in the resource pool.
16 . The apparatus according to claim 15 , wherein
the transceiver is further configured to send first indication information to the second terminal device, wherein the first indication information is used to indicate the second terminal device to send CSI, and the first indication information is comprised in 2 nd stage sidelink control information (SCI).
17 . The apparatus according to claim 16 , wherein the first indication information is further used to indicate that the frequency-domain bandwidth of the CSI-RS is the same as the frequency-domain bandwidth of the resource pool.
18 . The apparatus according to claim 15 , wherein the transceiver is further configured to send second indication information to the second terminal device, wherein the second indication information is used to indicate that the frequency-domain bandwidth of the CSI-RS is the same as the frequency-domain bandwidth of the resource pool.
19 . The apparatus according to claim 18 , wherein the second indication information is comprised in radio resource control (RRC) signaling.