Congestion control for sidelink transmissions

1 . A method performed by a user equipment (UE) configured for congestion control during sidelink transmissions in a wireless communication network, the method comprising:

determining that the UE is actively receiving in a subset of resources during a time interval;

estimating a congestion control metric for the time interval during which the UE is actively receiving in the subset of resources; and

selecting one or more transmission parameters to use for sidelink transmissions in accordance with the estimated congestion control metric, wherein the selecting comprises:

defining a plurality of thresholds and a plurality of congestion control configurations;

selecting a congestion control configuration among the plurality of congestion control configurations by comparing the number of resources in the subset of resources in which the UE is actively receiving within a time interval to one or more thresholds among the plurality of thresholds; and

selecting the one or more transmission parameters to use for sidelink transmissions in accordance with the selected congestion control configuration.

2 . The method of claim 1 , wherein the subset of resources comprises one or more of:

a first subset of time intervals within the time interval;

a second subset of sub-channels within a configured bandwidth; and

a third subset of the carriers configured for the UE.

3 . The method of claim 1 , wherein the congestion control metric is estimated in relation to the subset of resources in which the UE is determined to be actively receiving during the time interval.

4 . The method of claim 2 , further comprising:

obtaining a subset of a total number of configured sub-channels in which the UE is actively receiving; and

estimating the congestion control metric as a portion of the subset of the total number of configured sub-channels.

5 . The method of claim 1 , wherein estimating a congestion control metric for the time interval during which the UE is actively receiving in the subset of resources comprises estimating one or more of the following:

a congestion control metric in relation to the first subset of time intervals;

a congestion control metric in relation to the second subset of sub-channels; and

a congestion control metric in relation to the third subset of the carriers configured for the UE.

6 . The method of claim 1 , further comprising:

defining a plurality of sets of thresholds;

selecting one set of the plurality of sets of thresholds as a function of the subset of resources in which the UE is actively receiving within a time interval; and

selecting one or more transmission parameter(s) to use for sidelink transmissions by comparing the estimated congestion control metric to the one or more thresholds in the selected set of thresholds.

7 . The method of claim 1 , wherein estimating a congestion control metric for the time interval comprises:

segmenting the time interval into a plurality of measurement windows;

determining respective subvalues for the congestion control metric, for each measurement window; and

estimating the congestion control metric by combining the respective subvalues for each measurement window.

8 . The method of claim 7 , wherein estimating the congestion control metric by combining the respective subvalues for each measurement window comprises:

assigning a weighted factor to each measurement window;

determining respective subvalues with the assigned weighted factor for each measurement window; and

combining the respective subvalues with the assigned weighted factor to obtain the estimated congestion control metric.

9 . The method of claim 8 , wherein the weighted factor assigned to each measurement window is determined based on a time interval associated with the measurement window.

10 . The method of claim 1 , further comprising performing a sidelink transmission using the selected one or more transmission parameters.

11 . The method of claim 1 , wherein the congestion control metric includes one or more of the following: channel busy ratio (CBR), and channel occupancy ratio (CR).

12 . A user equipment (UE) configured for congestion control during sidelink transmissions in a wireless communication network, the UE comprising processing circuitry configured to:

determine that the UE is actively receiving in a subset of resources during a time interval;

estimate a congestion control metric for the time interval during which the UE is actively receiving in the subset of resources; and

select one or more transmission parameters to use for sidelink transmissions in accordance with the estimated congestion control metric, based on:

defining a plurality of thresholds and a plurality of congestion control configurations;

selecting a congestion control configuration among the plurality of congestion control configurations by comparing the number of resources in the subset of resources in which the UE is actively receiving within a time interval to one or more thresholds among the plurality of thresholds; and

selecting the one or more transmission parameters to use for sidelink transmissions in accordance with the selected congestion control configuration.

13 . The UE of claim 12 , wherein the subset of resources comprises one or more of the following:

a first subset of time intervals within the time interval;

a second subset of sub-channels within a configured bandwidth; and

a third subset of the carriers configured for the UE.

14 . The UE of claim 12 , wherein the congestion control metric is estimated in relation to the subset of resources in which the UE is determined to be actively receiving during the time interval.

15 . The UE of claim 13 , wherein the processing circuitry is further configured to:

obtain a subset of a total number of configured sub-channels in which the UE is actively receiving; and

estimate the congestion control metric as a portion of the subset of the total number of configured sub-channels.

16 . The UE of claim 13 , wherein the processing circuitry is configured to estimate the congestion control metric for the time interval during which the UE is actively receiving in the subset of resources by estimating one or more of the following:

a congestion control metric in relation to the first subset of time intervals;

a congestion control metric in relation to the second subset of sub-channels; and

a congestion control metric in relation to the third subset of the carriers configured for the UE.

17 . The UE of claim 12 , wherein the processing circuitry is further configured to:

define a plurality of sets of thresholds;

select one set of the plurality of sets of thresholds as a function of the subset of resources in which the UE is actively receiving within a time interval; and

select the one or more transmission parameters to use for sidelink transmissions based on comparing the estimated congestion control metric to the one or more thresholds in the selected set of thresholds.

18 . The UE of claim 12 , wherein the processing circuitry is configured to estimate a congestion control metric for the time interval based on:

segmenting the time interval into a plurality of measurement windows;

determining respective subvalues for the congestion control metric, for each measurement window; and

estimating the congestion control metric by combining the respective subvalues for each measurement window.

19 . The UE of claim 18 , wherein the processing circuitry is configured to estimate the congestion control metric by combining the respective subvalues for each measurement window based on:

assigning a weighted factor to each measurement window;

determining respective subvalues with the assigned weighted factor for each measurement window; and

combining the respective subvalues with the assigned weighted factor to obtain the estimated congestion control metric.

20 . The UE of claim 19 , wherein the weighted factor assigned to each measurement window is determined based on a time interval associated with the measurement window.

21 . The UE of claim 12 , further comprising radio transceiver circuitry operably coupled to the processing circuitry, wherein the processing circuitry and the radio transceiver circuitry are further configured to perform a sidelink transmission using the selected one or more transmission parameters.

22 . The UE of claim 12 , wherein the congestion control metric includes one or more of the following: channel busy ratio (CBR), and channel occupancy ratio (CR).

23 . A non-transitory computer readable medium storing computer executable instructions that, when executed by processing circuitry of a user equipment (UE) configured for congestion control during sidelink transmissions in a wireless communication network, configure the UE to perform operations corresponding to the method of claim 1 .