Patent ID: 8553550

Claim:
A wireless transmission device that performs wireless data transmission, the wireless transmission device comprising: a wireless transmitting and receiving unit that includes an antenna that transmits and receives data wirelessly; a buffer in which the data that is to be transmitted or has been received by the wireless transmitting and receiving unit is temporarily stored; and an antenna control unit configured to improve characteristics of the wireless transmitting and receiving unit by causing the wireless transmitting and receiving unit to perform one of the following when it is determined that a data amount stored in the buffer falls below a threshold value: (a) processing for selecting, as the antenna, one of a plurality of antennas each having a different directivity, (b) processing for changing the directivity of the antenna by switching a conduction state of a parasitic element arranged close to the antenna, and (c) processing for changing a weighting coefficient for an adaptive array antenna serving as the antenna, wherein the buffer is a Transmission Control Protocol (TCP) buffer in which a TCP packet received by the wireless transmitting and receiving unit is temporarily stored, the wireless transmitting and receiving unit is configured to transmit an ACKnowledgement (ACK) packet to a transmission source of the TCP packet in order to notify the transmission source that the wireless transmitting and receiving unit has received the TCP packet, the antenna control unit is configured to detect a data amount of the TCP buffer by subtracting a window size included in the ACK packet from a capacity of the TCP buffer, and the antenna control unit is configured to calculate the threshold value, by multiplying an application rate by a necessary time period, the application rate being a processing amount per unit time of the data received by the wireless transmitting and receiving unit, and the necessary time period being a time period required to improve the characteristics of the wireless transmitting and receiving unit.