A signal transmission/reception method comprising the steps of: receiving, from a base station, configuration information for configuring the operation of a terminal according to a first communication system; obtaining transmission power information on a downlink signal of the first communication system on the basis of the configuration information; and receiving the downlink signal from the base station on the basis of the transmission power information, wherein the downlink signal is transmitted via a downlink carrier of the first communication system, and the downlink carrier is allocated in an FDD mode in a guard-band between an in-band and the guard-band configured for a second communication system.