Abstract: According to one embodiment, a semiconductor switch includes a power supply, a driver, a switch section, and a first potential controller. The power supply includes a first potential generator and a second potential generator. The first potential generator is configured to generate a negative first potential. The second potential generator is configured to generate a positive second potential that a power supply potential is stepped down. The driver is supplied with the first potential and a third potential and configured to output at least one of the first potential and the third potential based on a terminal switching signal. The switch section is configured to connect a common terminal to any one of a plurality of radio frequency terminals according to an output of the driver. The first potential controller includes a divider and an amplifier.

Abstract: Disclosed is a mobile device to calculate an energy efficiency degree corresponding to a ratio of an amount of transmission of a data packet to an expected energy consumption, in response to the transmission of the data packet to a base station, to set a threshold value of the energy efficiency degree, and to determine whether to access a channel of the base station, based on the threshold value of the energy efficiency degree.