Methods, systems, apparatuses, and devices are described for contention resolution techniques for medium access using a spatial dimension, a frequency dimension, or a combination of the both. A wireless station may determine that an access timer associated with backoff operations has expired. The wireless station may identify a domain index associated with the frequency domain, the spatial domain, or a combination. The wireless station may access the wireless medium according to the identified domain index. The wireless station may, prior to sending other transmissions, transmit a trigger frame including information associated with the resources of the wireless medium that are reserved for communications. Other wireless stations may share the medium and use the free resources.