A first communication device transmits first bitmap length capability information for the first communication device regarding block acknowledgment procedures, and receives second bitmap length capability information for a second communication device regarding block acknowledgment procedures. The first communication device performs a block acknowledgment procedure, including setting a block acknowledgment transmission window size for the block acknowledgment procedure based on the second bitmap length capability information for the second communication device, and a determination of whether a block acknowledgement frame used in the block acknowledgment procedure is a compressed block acknowledgement (C-BA) frame or a multi-station (multi-STA) block acknowledgement frame.