Do wireless networks employ both Carrier Sense Multiple Access and Orthogonal Frequency Division Multiplexing? If so, what are their corresponding roles? I'm not a professional and I am confused as to which of them makes P2MP communication possible. I always thought WLANs use CSMA to allow different nodes to communicate to the same access point on the same channel, but here I am reading about how every 802.11 standard uses OFDM as its access technology (except 802.11b which uses DSSS instead), allowing multiple devices to communicate with the same AP at the same time.
Is this the right place for PHY-related questions?
EDIT: changed TDM to CSMA to be more accurate.