Patent ID: 7948362

Claim:
An implantable medical device ( 20 ) comprising: a transceiver ( 203 ) that comprises a first transmitter and first receiver configured to transmit and receive wirelessly transmitted data respectively, wherein said transceiver is turned off or switched into an energy-saving rest state between individual data transmissions a waking unit ( 202 ), which is configured to switch said transceiver ( 203 ) from its turned-off state or its rest state into its fully operational state by a waking signal; wherein said waking unit comprises a second receiver independent of said first receiver wherein said second receiver is a low-power receiver ( 210 ) that requires less energy as said transceiver in said transceiver's fully operational state and a waking control unit ( 206 ), of which said low-power receiver ( 210 ) is configured to monitor multiple predefined frequency ranges in such a way that, in case of a transmission of sufficient signal strength in one or more frequency ranges said low-power receiver ( 210 ) generates an output signal and outputs said output signal to said waking control unit ( 206 ), and of which said waking control unit ( 206 ) is configured to analyze output signals of said low-power receiver ( 210 ) and to output said waking signal to said transceiver ( 203 ), which switches said transceiver ( 203 ) on or to fully operational, if a predefined condition is met or multiple predefined conditions are met; wherein said waking control unit ( 206 ) is configured to output said waking signal to said transceiver ( 203 ) if a condition is met that said low-power receiver ( 210 ) outputs a sequence of output signals which identify that said low-power receiver ( 210 ) has detected a series of data transmissions of sufficient signal strength in various frequency ranges which correspond to a predefined series/sequence of frequencies; and, a transmission control unit ( 204 ), wherein said transmission control unit ( 204 ) has or is connected to a random generator ( 205 ) and is configured, after lapse of a waiting time after said transceiver ( 203 ) is turned on by said waking control unit ( 206 ), to transmit a response signal and to define a time of a transmission beginning after said transceiver ( 203 ) is turned on by said waking control unit ( 206 ) for this purpose in such a way that said time of said transmission beginning corresponds to an ending time of said waiting time, which begins with said waking signal and has a duration which corresponds to a product ZZ·SD of a random number ZZ generated by said random generator ( 205 ) and at least one predetermined average transmission duration SD.