Channel access for simultaneous uplink transmissions by multiple communication devices

A method for communicating in a communication channel of a wireless communication network, the method comprising:

• determining, at a first communication device, whether the first communication device is to use a first channel access mode or a second channel access mode for accessing the communication channel when the first communication device is triggered for uplink transmission by a second communication device;
• receiving, at the first communication device from the second communication device, a trigger frame;
• and
• transmitting, from the first communication device to the second communication device, a data unit triggered by the trigger frame, wherein transmitting the data unit includes using the determined one of the first channel access mode or the second channel access mode to gain access to the communication channel.