512 the wireless usb device 110 may transmit the session close message to the wireless usb host 100 otherwise in operations s 513 and s 514 the wireless usb host 100 and the wireless usb device 110 may delete the session information thereafter in operation s 515 additional operations are performed to close the data connection fig6 is a flowchart of a session maintenance operation according to an example embodiment of the present invention fig7 is a view of a session status bitmap included in a session status message according to an example embodiment of the present invention referring to fig6 in operation s 600 the wireless usb host 100 periodically transmits a session status message after a creation of a session the session status message transmitted from the wireless usb host 100 includes a session status bitmap as shown in fig7 referring to fig7 the session status bitmap according to an example embodiment of the present invention has 128 bits this value is determined in consideration of a specification of the usb connection therefore a maximum of 128 wireless usb devices may be connected to the wireless usb host 100 each bit represents a session activation status of the wireless usb device corresponding to.