This disclosure provides methods, devices and systems for synchronized channel access. Some implementations more specifically relate to facilitating coexistence among wireless communication devices that support synchronized channel access and those that do not. A group of access points may schedule periodically recurring, synchronized channel access periods by periodically transmitting quiet elements. The quiet elements establish recurring quiet periods during which legacy devices are not permitted to transmit. In some implementations, an access point may transmit one or more quiet override elements each associated with a respective quiet element and indicating to other access points supporting synchronized channel access that they are permitted to contend for access during the respective quiet period. In some other implementations of synchronized channel access, an access point supporting synchronized channel access that wins contention after one or more consecutive synchronized channel access periods during which no other synchronized access points won contention, may be entitled to an extended TXOP.