The present invention discloses a semiconductor memory device that includes first and second memory banks. The grading blade can be positioned outwardly of the vehicle to grade a surface beside the vehicle as the vehicle moves forward. If the incoming data unit rate exceeds the predetermined threshold, then a security action is taken, such as generating an alarm or preventing further transport of data units from the external network to the first network. The multiplexer also optionally switches between the transmitter and the receiver during the transmission and the reception. The adaptive antenna beamforming may be used in a millimeter-wave wireless personal area network in one embodiment.