Certain aspects of the present disclosure provide techniques for channel access in an unlicensed spectrum. An example method of wireless communication by a user equipment includes receiving a resource grant indicating a plurality of resource candidates for an uplink signal. The method also includes sensing for energy, in response to the resource grant, over one or more of the resource candidates in a first sensing occasion before a transmission occasion of the uplink signal. The method further includes transmitting, during the transmission occasion, the uplink signal using a subset of the resource candidates selected based at least in part on energy sensed in the first sensing occasion.