A system includes a first feedpoint and a second feedpoint symmetrically disposed on the left and right sides of an antenna on a small board. A first switch, a second switch, and a third switch are disposed on a mainboard. The first switch, the second switch, and the third switch are controlled through a control instruction so that the system is in a first connection state and a second connection state. Signal strength corresponding to the first connection state and signal strength corresponding to the second connection state are detected, and if the signal strength corresponding to the first connection state is greater than the signal strength corresponding to the second connection state, each switch is controlled through an instruction so that the system is in the first connection state, in which the first feedpoint is working. Otherwise, the second feedpoint is working.