EDCA backoff procedures and state switches for EMLSR or EMLMR co-affiliated stations

At a non-access point (non-AP) multi-link device (MLD) operating in an active Enhanced Multi-Link (EML) mode initiating a frame exchange with an AP MLD over a first link, by a first STA affiliated with the non-APD and corresponding to a first set of enabled links in which links the EML mode is applied. Initiating the frame exchange includes switching the first affiliated STA from a listening operation state to an enabled frame exchange state, before the first STA invokes an enhanced Distribution Channel Access (EDCA) backoff procedure decrementing a backoff counter to access the link. The active EML mode may be either Enhanced Multi-Link Single Radio or Multi Radio mode (EMLSR or EMLMR). In an alternative embodiment, the first affiliated STA invokes the backoff procedure and is switched to the enabled frame exchange state when the backoff counter has expired. In another embodiment, a first STA in listening operation invokes the backoff procedure decrementing a backoff counter, and upon receiving an initial frame from the AP MLD over a second link of the set, deciding whether to suspend the decrement of the backoff counter.