110 may exclude the sensing occasions associated with the first set from the sensing window based on the allowed reservation period.

Then, the first terminal device 110 may sense the sidelink channels in the sensing window, and exclude from the resource selection window one or more candidate single-slot resources that are occupied by other terminal devices. For example, the first terminal device 110 may exclude the occupied candidate single-slot resources from the resource selection window by performing the act at block 350 in FIG. 3.

In turn, the first terminal device 110 may determine resources in the resource selection window excluding the resources that are occupied as the first subset. For example, in the method 300, at block 380, the first terminal device 110 may determine the candidate single-slot resources remaining in the resource selection window as the first subset. In other words, the first terminal device 110 may determine the sensing results as the first subset.

Because the first terminal device 110 handles the first set before sensing, the number of sensing occasions is reduced. Thus, the complexity of sensing is reduced.

As an alternative to the solution of handling the first set before sensing, the first terminal device 110 may handle the first set after sensing. In such embodiments, the first set may comprise resources that will be used for transmission by the second terminal device 120, and the second set may comprise resources that are results of sensing sidelink channels by the first terminal device 110, or resources in the sidelink resource pool. In such embodiments, upon determining the second set comprising the resources that are results of sensing or the resources in the sidelink resource pool, the first terminal device 110 may exclude the overlap from the second set. In turn, the first terminal device 110 may determine the remaining candidate resources in the second set as the first subset.

In some embodiments, the overlap comprises an overlap in time domain. Because the first terminal device 110 may select the target resources in the first subset excluding the overlap in time domain, the first terminal device 110 could mitigate half-duplex issue and consecutive packet loss.

In embodiments where the first set comprises resources that are results of sensing sidelink channels by the second terminal device 120, and the second set comprises one of the following: the resources that are results of sensing the sidelink channels by the first terminal device, or the resources in the sidelink resource pool, the first subset may comprise the overlap between the first set and the second set.

In some embodiments the overlap comprises an overlap both in time domain and in frequency domain. Because the first terminal device 110 may select the target resources in the first subset including the overlap in time domain and in frequency domain, the first terminal device 110 could mitigate half-duplex issue and consecutive packet loss.

In embodiments where the second set comprises the resources in the sidelink resource pool, upon determining the first subset of the second set, the first terminal device 110 may, for example, randomly select the candidate resources in the first subset for the sidelink transmission.

In some embodiments, the determination of the first subset may be performed at a physical layer of the first terminal device 110, and the selection of the target resources for the sidelink transmission may be performed at a higher layer of the first terminal device 110. For the purpose of the selection, the first terminal device 110 may transmit a report about the first subset from the physical layer to the higher layer.

In some embodiments, the first terminal device 110 may determine whether a ratio of the number of candidate single-slot resources in the first subset to a total number of candidate single-slot resources in a resource selection window for the first terminal device 110 is above or equals a threshold ratio. If the ratio is above or equals the threshold ratio, the first terminal device 110 may transmit the report about the first subset from the physical layer to the higher layer.

In some embodiments, the threshold ratio is configurable. For example, the threshold ratio is configurable by a higher layer of the first terminal device 110.

In some embodiments, the threshold ratio may be in the range of 0.1 to 0.5.

In some embodiments, the first terminal device 110 may further determine a second subset of the second set. The second subset comprises the candidate resources in the second set excluding the first subset. In such embodiments, the first terminal device 110 may transmit a report about the first subset and the second subset from the physical layer to the higher layer.

In some embodiments, the first terminal device 110 may determine whether a ratio of the number of candidate single-slot resources in the first subset to a total number of candidate single-slot resources in a resource selection window for the first terminal device 110 is above a configured threshold. If the ratio is below the configured threshold, the first terminal device 110 transmits the report about the first subset and the second subset from the physical layer to the higher layer.

In some embodiments, the first terminal device 110 may transmit a first report about the first subset at a first time point, and transmit a second report about the second subset at a second time point subsequent to the first time point.

Alternatively, the first terminal device 110 may transmit the first report about the first subset in a first predefined field in a signaling, and transmit the second report about the second subset in a second predefined field in the signaling. The second predefined field is different from the first predefined field.

In some embodiments, the first terminal device 110 may prioritize the candidate resources in the first subset to be selected as the target resources. For example, the first terminal device 110 may select the candidate resources in the first subset with a higher probability.

In some embodiments, in order to prioritizing the candidate resources in the first subset to be selected as the target resources, the first terminal device 110 may determine whether the number of the candidate resources in the first subset is above a threshold number. If the number of the candidate single-slot resources in the first subset is above or equals the threshold number, the first terminal device 110 may select the candidate resources in the first subset.

On the other hand, if the number of the candidate resources in the first subset is below the threshold number, the first terminal device 110 may select the candidate resources in the first subset and the candidate resources in the second subset. In this way, more flexibility for the selection of candidate resources may be achieved.

FIG. 4 illustrates a flowchart of an example method 400 in accordance with some embodiments of the present disclosure. For example, the method 400 can be performed at the first terminal device 110 as shown in FIGS. 1-2. It is to be understood that the method