Power control of sidelink in unlicensed spectrum in mobile communications
Examples pertaining to power control of sidelink (SL) on unlicensed spectrum (SL-U) in mobile communications are described. A user equipment (UE) communicates in a SL-U. The UE performs a transmit power control (TPC) such that a power spectral density (PSD) limit is not exceeded in communicating in the SL-U.
1 . A method, comprising:
communicating, by a processor of a user equipment (UE), in a sidelink unlicensed spectrum (SL-U); and
performing, by the processor, a transmit power control (TPC) such that a power spectral density (PSD) limit is not exceeded in communicating in the SL-U,
wherein the performing of the TPC comprises performing the TPC with a sidelink synchronization signal block (S-SSB) excluded from a sidelink resource pool of resources used in data, control and feedback channel transmissions,
wherein the performing of the TPC further comprises controlling a PSCCH/PSSCH transmission, and
where the corresponding PSCCH is not transmitted in PSCCH-PSSCH transmission occasion, as:
P PSSCH =min( P MAX ,P MAX,CBR ,min( P PSSCH,D ,P PSSCH,SL ), P MAX,PSD ) [dBm].
2 . The method of claim 1 , wherein the performing of the TPC further comprises controlling a S-SSB transmission power in the SL-U as:
P
S
-
SSB
,
PSD
=
min
(
P
MAX
,
P
O
,
S
-
SSB
+
10
log
10
(
2
μ
·
M
RB
S
-
SSB
)
+
α
S
-
SSB
·
PL
,
P
MAX
,
PSD
)
,
and
P
MAX
,
PSD
=
BW
S
-
SSB
×
PSD
MAX
[
mW
]
or
P
MAX
,
PSD
=
10
*
log
10
(
BW
S
-
SSB
)
+
PSD
MAX
[
dBm
]
,
wherein:
P MAX denotes a pre-configured maximum transmit power,
P O,S-SSB denotes a pre-configured received power target assuming full pathloss compensation for a downlink (DL) pathloss,
α S-SSB denotes an alpha value for the DL pathloss,
M
RB
S
-
SSB
denotes a number of physical resource blocks (PRBs) used for the S-SSB,
BW S-SSB denotes a bandwidth of a S-SSB transmission based on either or both of contiguous resource blocks (RBs) and interlaced RBs, and
PSD MAX denotes a pre-configured maximum limit on the PSD.
3 . The method of claim 1 , wherein the performing of the TPC further comprises controlling a PSCCH/PSSCH transmission, where both PSCCH and PSSCH are transmitted in PSCCH-PSSCH transmission occasion, as:
P
P
S
S
C
H
2
=
10
log
1
0
(
M
R
B
P
S
S
C
H
-
M
R
B
P
S
C
C
H
M
R
B
P
S
S
C
H
)
+
P
P
S
S
C
H
[
dBm
]
,
and
P
PSCCH
=
10
log
1
0
(
M
R
B
P
S
C
C
H
M
R
B
P
S
S
C
H
)
+
P
P
S
S
C
H
[
dBm
]
.
4 . The method of claim 1 , wherein the performing of the TPC further comprises controlling a PSFCH transmission as replacing P MAX in a PSFCH TPC formula defined in a Release-16 or Release-17 of a 3 rd Generation Partnership Project (3GPP) specification by min (P MAX,PSD , P MAX ).
5 . The method of claim 1 , wherein the performing of the TPC comprises performing the TPC with a sidelink synchronization signal block (S-SSB) included in a sidelink resource pool of resources used in data, control and feedback channel transmissions.
6 . The method of claim 5 , wherein the communicating in the SL-U comprises communicating with the S-SSB and a physical sidelink control channel (PSCCH) or physical sidelink shared channel (PSSCH) time-division multiplexed.
7 . The method of claim 5 , wherein the communicating in the SL-U comprises communicating with the S-SSB and a physical sidelink control channel (PSCCH) or physical sidelink shared channel (PSSCH) frequency-division multiplexed.
8 . The method of claim 7 , wherein the performing of the TPC further comprises:
calculating a power of a PSSCH transmission with the PSD limit being one of a plurality of factors used in the calculating; and
determining a linear average over corresponding power contributions of the S-SSB and a frequency-division multiplexed PSSCH.
9 . An apparatus implementable in a user equipment (UE), comprising:
a transceiver configured to communicate wirelessly; and
a processor coupled to the transceiver and configured to perform, via the transceiver, operations comprising:
communicating, via the transceiver, in a sidelink unlicensed spectrum (SL-U); and
performing, via the transceiver, a transmit power control (TPC) such that a power spectral density (PSD) limit is not exceeded in communicating in the SL-U,
wherein the performing of the TPC comprises performing the TPC with a sidelink synchronization signal block (S-SSB) excluded from a sidelink resource pool of resources used in data, control and feedback channel transmissions,
wherein the performing of the TPC further comprises controlling a PSCCH/PSSCH transmission, and
where the corresponding PSCCH is not transmitted in PSCCH-PSSCH transmission occasion, as:
P
P
S
S
C
H
=
min
(
P
MAX
,
P
MAX
,
C
B
R
,
min
(
P
P
S
S
C
H
,
D
,
P
P
S
S
C
H
,
S
L
)
,
P
MAX
,
P
S
D
)
[
dB
m
]
.
10 . The apparatus of claim 9 , wherein the performing of the TPC further comprises controlling a S-SSB transmission power in the SL-U as:
P
S
-
SSB
,
PSD
=
min
(
P
MAX
,
P
O
,
S
-
SSB
+
10
log
10
(
2
μ
·
M
RB
S
-
SSB
)
+
α
S
-
SSB
·
PL
,
P
MAX
,
PSD
)
,
and
P
MAX
,
PSD
=
BW
S
-
SSB
×
PSD
MAX
[
mW
]
or
P
MAX
,
PSD
=
10
*
log
10
(
BW
S
-
SSB
)
+
PSD
MAX
[
dBm
]
,
wherein:
P MAX denotes a pre-configured maximum transmit power,
P O,S-SSB denotes a pre-configured received power target assuming full pathloss compensation for a downlink (DL) pathloss,
α S-SSB denotes an alpha value for the DL pathloss,
M
RB
S
-
SSB
denotes a number of physical resource blocks (PRBs) used for the S-SSB,
BW S-SSB denotes a bandwidth of a S-SSB transmission based on either or both of contiguous resource blocks (RBs) and interlaced RBs, and
PSD MAX denotes a pre-configured maximum limit on the PSD.
11 . The apparatus of claim 9 , wherein the performing of the TPC further comprises controlling a PSCCH/PSSCH transmission, where both PSCCH and PSSCH are transmitted in PSCCH-PSSCH transmission occasion, as:
P
P
S
S
C
H
2
=
10
log
1
0
(
M
R
B
P
S
S
C
H
-
M
R
B
P
S
C
C
H
M
R
B
P
S
S
C
H
)
+
P
P
S
S
C
H
[
dBm
]
,
and
P
PSCCH
=
10
log
1
0
(
M
R
B
P
S
C
C
H
M
R
B
P
S
S
C
H
)
+
P
P
S
S
C
H
[
dBm
]
.
12 . The apparatus of claim 9 , wherein the performing of the TPC further comprises controlling a PSFCH transmission as replacing P MAX in a PSFCH TPC formula defined in a Release-16 or Release-17 of a 3 rd Generation Partnership Project (3GPP) specification by min (P MAX,PSD , P MAX ).
13 . The apparatus of claim 9 , wherein the performing of the TPC comprises performing the TPC with a sidelink synchronization signal block (S-SSB) included in a sidelink resource pool of resources used in data, control and feedback channel transmissions.
14 . The apparatus of claim 13 , wherein the communicating in the SL-U comprises communicating with the S-SSB and a physical sidelink control channel (PSCCH) or physical sidelink shared channel (PSSCH) time-division multiplexed.
15 . The apparatus of claim 13 , wherein the communicating in the SL-U comprises communicating with the S-SSB and a physical sidelink control channel (PSCCH) or physical sidelink shared channel (PSSCH) frequency-division multiplexed.
16 . The apparatus of claim 15 , wherein the performing of the TPC further comprises:
calculating a power of a PSSCH transmission with the PSD limit being one of a plurality of factors used in the calculating; and
determining a linear average over corresponding power contributions of the S-SSB and a frequency-division multiplexed PSSCH.