This object represents the minimum time between the
start of adjacent MPDUs within an A-MPDU. This time
is measured at the PHY service access-point; the
number of bytes between the start of two consecutive
MPDUs in A-MPDU shall be equal or greater than
(MPDU-density*PHY-bit-rate)/8. The encoding of the
minimum time to this object is as follows.
'noTimeRestriction' - no time restriction between the
start of adjacent MPDUs.
'oneEighth' - 1/8 microseconds
'oneFourth' - 1/4 microseconds
'half' - 1/2 microseconds
'one' - 1 microsecond
'two' - 2 microseconds
'four' - 4 microseconds
'eight' - 8 microseconds.