Flexible resource partitioning for multi-hop IAB on unlicensed spectrum band
In a wireless system including multiple network nodes using unlicensed spectrum band(s) to communicate at least over backhaul, a configuration entity performs configuring first time resources to be used by at least a first one of the multiple network nodes for communications at least over backhaul using the unlicensed spectrum band(s). The first time resources have specific downlink resources. The configuration entity also performs configuring second time resources to be used by at least a second one of the multiple network nodes for communications at least over backhaul using the unlicensed spectrum band(s). The second time resources include resources for channel occupancy measurements that are at least within a time period set for the specific downlink resources of the first time resources. The first and second time resources overlap at least in part in time.
1 . An apparatus configured to operate as a second network node among a plurality of network nodes forming a multi-hop topology in a wireless network, the apparatus comprising:
at least one processor; and
at least one non-transitory memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform operations comprising:
access, in the wireless network, a configuration of first time resources and a configuration of second time resources for communications over a backhaul using one or more unlicensed spectrum bands, wherein:
the first time resources are allocated to a first network node of the plurality of network nodes for a first channel access attempt, the first time resources comprising designated downlink resources corresponding to downlink starting symbols of the first network node,
the second time resources are allocated to the apparatus and overlap with the first time resources,
the second time resources comprise resources for channel occupancy measurements performed within a time period of the designated downlink resources,
the second time resources are configured with a first rule that permits the apparatus to perform a second channel access attempt on the one or more unlicensed spectrum bands, and
the first rule permits the second channel access attempt based on a determination that the first channel access attempt has failed;
determining whether the first channel access attempt has failed by performing the channel occupancy measurements within the time period of the designated downlink resources, wherein performing the channel occupancy measurements comprises:
performing a listen-before-talk (LBT) procedure on the one or more unlicensed spectrum bands, wherein the LBT procedure comprises:
initiating a first channel assessment of the LBT procedure during a not-available time period preceding the second time resources, wherein the not-available time period corresponds to a time period aligned with a start of downlink transmission of the designated downlink resources;
performing a final channel assessment of the LBT procedure at a specified time instance that is aligned with the designated downlink resources, the final channel assessment being performed at a second threshold value lower than the first threshold value; and
preventing simultaneous channel access attempts by the apparatus and the first network node by temporarily suspending the LBT procedure via self-deferral to delay the final channel assessment until the specified time instance;
based on a successful completion of the LBT procedure, determine that the first access attempt has failed; and
based on determining the first channel access attempt has failed:
perform the second channel access attempt on the one or more unlicensed spectrum bands during the second time resources; and
based on the second channel access attempt obtaining channel access:
initiate a channel occupancy time (COT) by beginning transmission on the second time resources;
communicate over the backhaul on the second time resources; and
continue the COT into next-occurring first time resources without exceeding a maximum channel occupancy time.
2 . The apparatus of claim 1 , wherein the first time resources and the second time resources are configured to alternate in time between the first network node and the second network node.
3 . The apparatus of claim 1 , wherein a duration of the resources for the channel occupancy measurements is less than or equal to a duration of the designated downlink resources.
4 . The apparatus of claim 1 , wherein the first time resources and the second time resources are further configured
for communications with a user equipment.
5 . The apparatus of claim 1 , wherein the apparatus comprises one of the following:
a base station;
a distributed unit;
an integrated access and backhaul node;
a distributed unit of an integrated access and backhaul donor node; or
a distributed unit of the integrated access and backhaul node.