The per antenna capacity of each of the transmitter antennas in a MIMO system are individually determined from measurable information at the receiver end. The napper frame is foldable from a generally planar deplyed orientation about one or more generally longitudinally extending frame folding axes. One of the blowers blows a stale airstream out through the heat exchangers; the other blower blows a fresh airstream in through the heat exchangers. The second operation signal indicates that the n-value of the CAS latency is equal to or greater than the predetermined value and the write latency is variable. An actuating device is further provided and coupled with the plurality of second attachment members.