Dynamic transmit chain availability signaling in wireless devices

A wireless device communicates a transmission capability by determining a number of active transmits chains of the wireless device, determining a maximum number of space-time streams according to the number of active transmit chains, providing a frame with an indication of the maximum number of space-time streams, and transmitting the frame. The wireless devices may provide the indication of the maximum number of space-time streams in an Operating Mode field of High Efficiency Aggregate Control field of the frame. The maximum number of space-time streams may be a maximum number of space-time streams that may be used by the wireless device to respond to a Trigger frame.