Method for controlling the activity of a base station entity comprising a transmitter chain and a receiver chain, in a mobile communication network by means of a mobile device, wherein the base station entity operates in at least a first and a second operational mode, the method comprising the following steps: when, in a first step, the base station entity operates in the first operational mode, the base station entity transmits radio frequency signals providing a control channel which is received in a radio coverage area of the base station entity by the mobile device and in a second step, when the base station entity changes into the second operational mode, the base station entity -- switches off the transmitter chain for only parts related to certain transmission channels of the base station entity and does not provide the control channel in the radio coverage area of the base station entity, -- temporarily provides an activated broadcast control channel to transmit first reactivation information for some periods of time, -- switches off the receiver chain of the base station entity for a predetermined inactivation time interval, and -- switches on the receiver chain of the base station entity for a predetermined sensitive time interval, wherein the method comprises the further steps: -- the mobile device receives the first reactivation information, the first reactivation information being related to the possibility and/or to the manner for the mobile device to activate the first operational mode of the base station entity starting from the second operational mode of the base station entity, -- in a following step, the mobile device transmits a second reactivation information to the base station entity during the predetermined sensitive time interval of the base station entity, wherein dependent on a reception of the second reactivation information by the base station entity, the base station entity applies the first operational mode, wherein the second reactivation information is a message or signal compliant to a communication on a Random Access Channel, RACH, of the base station entity. when, in a first step, the base station entity operates in the first operational mode, the base station entity transmits radio frequency signals providing a control channel which is received in a radio coverage area of the base station entity by the mobile device and in a second step, when the base station entity changes into the second operational mode, the base station entity -- switches off the transmitter chain for only parts related to certain transmission channels of the base station entity and does not provide the control channel in the radio coverage area of the base station entity, -- temporarily provides an activated broadcast control channel to transmit first reactivation information for some periods of time, -- switches off the receiver chain of the base station entity for a predetermined inactivation time interval, and -- switches on the receiver chain of the base station entity for a predetermined sensitive time interval, -- switches off the transmitter chain for only parts related to certain transmission channels of the base station entity and does not provide the control channel in the radio coverage area of the base station entity, -- temporarily provides an activated broadcast control channel to transmit first reactivation information for some periods of time, -- switches off the receiver chain of the base station entity for a predetermined inactivation time interval, and -- switches on the receiver chain of the base station entity for a predetermined sensitive time interval, wherein the method comprises the further steps: -- the mobile device receives the first reactivation information, the first reactivation information being related to the possibility and/or to the manner for the mobile device to activate the first operational mode of the base station entity starting from the second operational mode of the base station entity, -- in a following step, the mobile device transmits a second reactivation information to the base station entity during the predetermined sensitive time interval of the base station entity, wherein dependent on a reception of the second reactivation information by the base station entity, the base station entity applies the first operational mode, wherein the second reactivation information is a message or signal compliant to a communication on a Random Access Channel, RACH, of the base station entity. -- the mobile device receives the first reactivation information, the first reactivation information being related to the possibility and/or to the manner for the mobile device to activate the first operational mode of the base station entity starting from the second operational mode of the base station entity, -- in a following step, the mobile device transmits a second reactivation information to the base station entity during the predetermined sensitive time interval of the base station entity, wherein dependent on a reception of the second reactivation information by the base station entity, the base station entity applies the first operational mode, wherein the second reactivation information is a message or signal compliant to a communication on a Random Access Channel, RACH, of the base station entity.