An extremely high throughput (EHT) station (STA) configured for trigger based (TB) transmission may decode an trigger frame (TF) received from an access point (AP). The TF may include an assignment of resources comprising one or more 20 MHz channels. The EHT STA may determine which of the one or more assigned channels are available for transmission and which of the allocated channels are unavailable when the EHT STA is assigned more than one 20 MHz channel. The EHT STA may encode a EHT TB PPDU in response to the trigger frame. The EHT TB PPDU may be encoded to include an EHT preamble followed by a data field. The EHT preamble may be encoded to indicate channel availability. The EHT STA may generate signaling to cause the EHT STA to transmit the encoded EHT TB PPDU only on the assigned channels that have been determined to be available.