This document describes techniques and apparatuses for joint-transmission over an unlicensed frequency band using a user equipment (UE)-coordination set. In aspects, a first UE in a UE-coordination set acts as a coordinating UE. The coordinating UE receives, using a local wireless network connection, uplink data from a second UE in the UE-coordination set. The coordinating UE distributes, using the local wireless network connection, the uplink data to at least a third UE in the UE-coordination set. The coordinating UE receives, from at least one UE in the UE-coordination set, respective results of a clear channel assessment of the unlicensed frequency band. The coordinating UE determines a specified time to begin joint-transmission of the uplink data based on the results and coordinates the joint-transmission by directing the at least one UE to initiate the joint-transmission of the uplink data based on the specified time.