Patent ID: 8798676

Claim:
A device that is loaded in a mobile communication terminal and is used for wireless communication, comprising: a first transmission and reception circuit that generates a transmission signal to be transmitted in a wireless manner based on transmission data, and processes a received signal that has been received in the wireless manner, the first transmission and reception circuit being connected to one of a first antenna and a second antenna in a switching manner through a first switch, wherein the first antenna is used for signal transmission and reception in the wireless manner, wherein the second antenna is provided to the mobile communication terminal outside of the device, and is connected to a second transmission and reception circuit different from the first transmission and reception circuit for a wireless communication, said second transmission and reception circuit being configured to transmit and receive a signal having a same frequency band as that of a signal that the first transmission and reception circuit transmits and receives, the mobile communication terminal including a second switch being configured to connect the second antenna to one of the first transmission and reception circuit of the device and the second transmission and reception circuit of the mobile communication terminal in a switching manner, wherein the first switch is controlled so as to select the first antenna during a preamble period of a wireless communication frame and a signal strength of a signal received from the first antenna is stored, and the first switch is subsequently controlled so as to select the second antenna during the preamble period of the wireless communication frame and a signal strength of a signal received from the second antenna is stored, wherein the device further comprises a control part that compares the received signal strength of the signal received by using the first antenna and the received signal strength of the signal received by using the second antenna, selects one of the first antenna and the second antenna, which one has a greater received signal strength, and causes the first switch to connect the first antenna to the first transmission and reception circuit when selecting the first antenna, and connect the second antenna to the first transmission and reception circuit when selecting the second antenna, and wherein the first transmission and reception circuit is configured to transmit a transmission frame from a selected antenna when the transmission frame exists.