Communication method and apparatus
A method includes: determining a start time point of a resource selection window based on a first time point for triggering resource selection, and selecting a transmission resource in the resource selection window. A time interval between the start time point of the resource selection window and the first time point is not less than duration required by a terminal device to perform first-type listen-before-talk (LBT).
1 . A method, comprising:
determining a start time point of a resource selection window, wherein a time interval between the start time point of the resource selection window and a first time point is not less than first duration, the first time point is a time point for triggering resource selection, and the first duration is duration required for a terminal device to perform first-type listen-before-talk (LBT); and
selecting a transmission resource in the resource selection window,
wherein a quantity T 1 of slots corresponding to the time interval between the start time point of the resource selection window and the first time point meets:
when
T
proc
,
1
SL
>
T
,
T
≤
T
1
≤
T
proc
,
1
SL
;
and/or
when
T
proc
,
1
SL
≤
T
,
T
1
=
T
,
wherein
T
proc
,
1
SL
is a predefined first processing duration, and T is a quantity of slots corresponding to the first duration.
2 . The method according to claim 1 , wherein the first duration is determined based on an initial value of a random backoff counter corresponding to the first-type LBT.
3 . The method according to claim 2 , wherein a quantity T of slots corresponding to the first duration meets:
T=┌ (counter*9 e −3 )/2 −μ ┐, wherein
counter is the initial value of the random backoff counter, and u corresponds to a subcarrier spacing.
4 . The method according to claim 2 , wherein selecting the transmission resource in the resource selection window comprises:
selecting the transmission resource in a first resource set in a chronological front-to-back order, wherein the first resource set is a subset of candidate resources in the resource selection window, and the first resource set comprises a candidate resource that is in the resource selection window and that is located after an end time point of the LBT.
5 . The method according to claim 1 , wherein the first duration is determined based on an initial value of a random backoff counter corresponding to the first-type LBT and second duration, wherein
the second duration is a quantity of slots occupied by N reserved resources, or the second duration is determined based on the quantity of slots occupied by the N reserved resources and N first intervals, the first interval is idle duration of a channel after a corresponding reserved resource, the first interval and the corresponding reserved resource are continuous in time domain, the N reserved resources are resources reserved in the first duration, and N is a positive integer.
6 . The method according to claim 5 , wherein a quantity T of slots corresponding to the first duration meets:
T
=
(
⌈
counter
*
9
e
-
3
2
-
μ
⌉
+
∑
1
N
reservation
i
)
,
wherein
counter is the initial value of the random backoff counter, μ corresponds to a subcarrier spacing, and reservation i is a quantity of slots occupied by an i th reserved resource in the N reserved resources.
7 . The method according to claim 5 , wherein a quantity T of slots corresponding to the first duration meets:
T
=
(
⌈
counter
*
9
e
-
3
+
N
×
t
2
-
μ
⌉
+
∑
1
N
reservation
i
)
,
wherein
counter is the initial value of the random backoff counter, μ corresponds to a subcarrier spacing, reservation i is a quantity of slots occupied by an i th reserved resource in the N reserved resources, and t is the first interval.
8 . The method according to claim 5 , wherein the N reserved resources are indicated by M pieces of sidelink control information in a resource listening window, and M is a positive integer, wherein:
a reference signal received power (RSRP) corresponding to each of the M pieces of sidelink control information is greater than a first threshold, and the first threshold is an RSRP threshold used for resource selection; or
a received signal strength indicator (RSSI) corresponding to each of the M pieces of sidelink control information is greater than a second threshold, and the second threshold is an RSSI threshold used for LBT; or
an RSRP corresponding to each of the M pieces of sidelink control information is greater than a first threshold, and an RSSI corresponding to each of the M pieces of sidelink control information is greater than a second threshold.
9 . A communication apparatus, comprising:
one or more processors configured to:
determine a start time point of a resource selection window, wherein a time interval between the start time point of the resource selection window and a first time point is not less than first duration, the first time point is a time point for triggering resource selection, and the first duration is duration required for a terminal device to perform first-type listen-before-talk (LBT); and
select a transmission resource in the resource selection window,
wherein a quantity T 1 of slots corresponding to the time interval between the start time point of the resource selection window and the first time point meets:
when
T
proc
,
1
SL
>
T
,
T
≤
T
1
≤
T
proc
,
1
SL
;
and/or
when
T
proc
,
1
SL
≤
T
,
T
1
=
T
,
wherein
T
proc
,
1
SL
is a predefined first processing duration, and T is a quantity of slots corresponding to the first duration.
10 . The communication apparatus according to claim 9 , wherein the first duration is determined based on an initial value of a random backoff counter corresponding to the first-type LBT.
11 . The communication apparatus according to claim 10 , wherein a quantity T of slots corresponding to the first duration meets:
T=┌ (counter*9 e −3 )/2 −μ ┐, wherein
counter is the initial value of the random backoff counter, and μ corresponds to a subcarrier spacing.
12 . The communication apparatus according to claim 10 , wherein, when selecting the transmission resource in the resource selection window, the one or more processors are further configured to:
select the transmission resource in a first resource set in a chronological front-to-back order, wherein the first resource set is a subset of candidate resources in the resource selection window, and the first resource set comprises a candidate resource that is in the resource selection window and that is located after an end time point of the LBT.
13 . The communication apparatus according to claim 9 , wherein the first duration is determined based on an initial value of a random backoff counter corresponding to the first-type LBT and second duration, the second duration is duration for which the random backoff counter corresponding to the first-type LBT is interrupted by N reserved resources, the N reserved resources are resources reserved in the first duration, and N is a positive integer.
14 . The communication apparatus according to claim 13 , wherein a quantity T of slots corresponding to the first duration meets:
T
=
(
⌈
counter
*
9
e
-
3
2
-
μ
⌉
+
∑
1
N
reservation
i
)
,
wherein
counter is the initial value of the random backoff counter, μ corresponds to a subcarrier spacing, and reservation i is a quantity of slots occupied by an i th reserved resource in the N reserved resources.
15 . The communication apparatus according to claim 13 , wherein a quantity T of slots corresponding to the first duration meets:
T
=
(
⌈
counter
*
9
e
-
3
+
N
×
t
2
-
μ
⌉
+
∑
1
N
reservation
i
)
,
wherein
counter is the initial value of the random backoff counter, μ corresponds to a subcarrier spacing, reservation i is a quantity of slots occupied by an i th reserved resource in the N reserved resources, and t is a first interval.
16 . The communication apparatus according to claim 13 , wherein the N reserved resources are indicated by M pieces of sidelink control information in a resource listening window, and M is a positive integer, wherein:
a reference signal received power RSRP corresponding to each of the M pieces of sidelink control information is greater than a first threshold, and the first threshold is an RSRP threshold used for resource selection; or
a received signal strength indicator RSSI corresponding to each of the M pieces of sidelink control information is greater than a second threshold, and the second threshold is an RSSI threshold used for LBT; or
an RSRP corresponding to each of the M pieces of sidelink control information is greater than a first threshold, and an RSSI corresponding to each of the M pieces of sidelink control information is greater than a second threshold.
17 . A non-transitory computer-readable storage medium, comprising executable instructions, wherein the executable instructions, when executed by a computer, cause the computer to:
determine a start time point of a resource selection window, wherein a time interval between the start time point of the resource selection window and a first time point is not less than first duration, the first time point is a time point for triggering resource selection, and the first duration is duration required for a terminal device to perform first-type listen-before-talk, LBT; and
select a transmission resource in the resource selection window,
wherein a quantity T 1 of slots corresponding to the time interval between the start time point of the resource selection window and the first time point meets:
when
T
proc
,
1
SL
>
T
,
T
≤
T
1
≤
T
proc
,
1
SL
;
and/or
when
T
proc
,
1
SL
≤
T
,
T
1
=
T
,
wherein
T
proc
,
1
SL
is a predefined first processing duration, and T is a quantity of slots corresponding to the first duration.