Systems, methods, and instrumentalities are provided to implement data transmission, comprising: receiving a first signal from an access point (AP) indicating that a primary channel is associated with a first frequency band associated with a first period of time; determining by an IEEE 802.11 station (STA) that a channel condition associated with a secondary channel is better than a channel condition associated with the primary channel; reserving the primary channel associated with the first frequency, wherein the reserving of the primary channel comprises occupying or reserving the primary channel during the first period of time; and sending data over the secondary channel while the primary channel is occupied or reserved.