Wireless Communication With Implantable Medical Device

Abstract

Embodiments are directed to apparatus and methods of minimizing current drain of an implantable medical device during wireless communication with the device, thereby reducing battery depletion of the device. In one embodiment, the implantable medical device comprises a wireless receiver configured to communicate wirelessly with an external transmitter of an external device via a plurality of communication channels each having a different frequency within a frequency band. The wireless receiver comprises a wideband receiver circuit configured to detect a signal from any of the plurality of communication channels at the different frequencies within the frequency band simultaneously. In another embodiment, the external device is configured to communicate wirelessly with the implantable medical device via a preset communication channel, and via an alternate communication channel selected according to an order of priority if the wireless receiver does not detect a suitable signal from the external transmitter using the preset communication channel.

1 . An implantable medical device comprising: 
 a wireless receiver configured to communicate wirelessly with an external transmitter of an external device via a plurality of communication channels each having a different frequency within a frequency band, the wireless receiver comprising a wideband receiver circuit configured to detect a signal from any of the plurality of communication channels at the different frequencies within the frequency band simultaneously.    
     
     
         2 . The device of  claim 1  wherein the frequency hand is between 402 and 405 MHz, and wherein the plurality of communication channels comprise n contiguous channels of (3÷n) MHz each in the frequency band.  
     
     
         3 . The device of  claim 1  wherein the wideband receiver circuit comprises a front end filter configured to filter a signal received from the external transmitter, a low noise amplifier coupled to the front end filter to amplify the filtered signal, a local oscillator producing an output, and a mixer coupled to the low noise amplifier and the local oscillator to multiply the output of the local oscillator with the amplified received signal from the low noise amplifier and generate a mixer output signal.  
     
     
         4 . The device of  claim 3  wherein the wideband receiver circuit comprises a bandpass filter coupled to the mixer which filters the mixer output signal, an intermediate frequency amplifier coupled to the bandpass filter to be driven by an output of the bandpass filter, and a demodulator coupled to the intermediate frequency amplifier to demodulate an intermediate frequency signal from the intermediate frequency amplifier to a baseband signal, and a decoder unit to decode the baseband signal.  
     
     
         5 . The device of  claim 4  wherein the bandpass filter is a third-order filter having a center frequency of about 10.7 MHz, a passband width of about 4 MHz, and a passband ripple of about 0.1 dB.  
     
     
         6 . The device of  claim 3  wherein the wideband receiver circuit comprises a demodulator circuit coupled to the intermediate frequency amplifier which drives a cell in the demodulator circuit to produce a demodulator output.  
     
     
         7 . An implantable medical device comprising: 
 a wireless receiver configured to communicate wirelessly with an external transmitter of an external device via a plurality of communication channels each having a different frequency within a frequency band, the wireless receiver comprising a receiver circuit configured to detect a signal from any of the plurality of communication channels at the different frequencies within the frequency band; and    a wireless transmitter configured to communicate wirelessly with an external receiver of the external device via the plurality of communication channels, wherein the wireless transmitter is configured to transmit a signal to the external receiver via a communication channel which is used by the external transmitter to communicate with the wireless receiver of the implantable medical device as detected by the receiver circuit.    
     
     
         8 . A method for communicating between an external device having an external transmitter and an implantable medical device having a wireless receiver, the method comprising: 
 providing a wideband receiver circuit in the wireless receiver of the implantable medical device configured to communicate wirelessly with the external transmitter via a plurality of communication channels each having a different frequency within a frequency band; and    detecting with the wideband receiver circuit a signal from any of the plurality of communication channels at the different frequencies within the frequency band simultaneously.    
     
     
         9 . The method of  claim 8  wherein detecting with the wideband receiver circuit comprises: 
 filtering a signal with a filter according to the frequency band;    amplifying the filtered signal;    mixing the amplified filtered signal with a local oscillator signal to generate a mixer output signal having a high frequency components equal to a sum of the frequencies of the amplified filtered signal and the local oscillator signal and an intermediate frequency component equal to difference of the frequencies of the amplified filtered signal and the local oscillator signal; and    filtering out the high frequency component to provide an intermediate frequency signal having the intermediate frequency component.    
     
     
         10 . The method of  claim 9  wherein filtering out the high frequency component comprises passing the mixer output signal through a bandpass filter.  
     
     
         11 . The method of  claim 10  wherein the bandpass filter is a third-order filter having a center frequency of about 10.7 MHz, a passband width of about 4 MHz, and a passband ripple of about 0.1 dB.  
     
     
         12 . The method of  claim 9  wherein detecting with the wideband receiver circuit further comprises: 
 amplifying the intermediate frequency signal;    demodulating the intermediate frequency signal to a baseband signal; and    decoding the baseband signal.    
     
     
         13 . A method for communicating between an external device having an external transmitter and an implantable medical device having a wireless receiver, the method comprising: 
 providing a receiver circuit in the wireless receiver of the implantable medical device configured to communicate wirelessly with the external transmitter via a plurality of communication channels each having a different frequency within a frequency band;    detecting with the receiver circuit a signal from any of the plurality of communication channels at the different frequencies within the frequency hand;    identifying a communication channel from which the signal is received by the wireless receiver from the external transmitter; and    transmitting a signal from a wireless transmitter of the implantable medical device to an external receiver of the external device via the identified communication channel.    
     
     
         14 . A medical communication system comprising: 
 an implantable medical device including a wireless receiver and a wireless transmitter; and    an external device including an external transmitter and an external receiver configured to communicate wirelessly with the implantable medical device via a plurality of communication channels each having a different frequency within a frequency band;    wherein the external device is configured to communicate wirelessly with the implantable medical device via a preset communication channel, and wherein the external device is configured to communicate wirelessly with the implantable medical device via an alternate communication channel selected according to an order of priority if the wireless receiver does not detect a suitable signal from the external transmitter using the preset communication channel; and    wherein the order of priority of communication channels selected is based on communication channels used in previous communication sessions in reverse chronological order.    
     
     
         15 . The medical communication system of  claim 14  wherein the external device is configured to communicate wirelessly with the implantable medical device in a present communication session on a last communication channel used in a last communication session immediately preceding the present communication session.  
     
     
         16 . The medical communication system of  claim 15  wherein the external device is configured to communicate wirelessly with the implantable medical device in the present communication session on the last communication channel immediately preceding the present communication session as long as the last communication channel provides a suitable signal which is below a monitoring threshold power level regardless of whether the last communication channel has a lower interference than the other communication channels.  
     
     
         17 . The medical communication system of  claim 14  wherein the implantable medical device is configured to communicate with the external device at a primary predetermined time arranged in a previous communication with the external device.  
     
     
         18 . The medical communication system of  claim 17  wherein the implantable medical device is configured to communicate with the external device at a secondary predetermined time arranged in the previous communication with the external device if the wireless receiver fails to detect wirelessly a suitable signal from the external transmitter at the primary predetermined time.  
     
     
         19 . The medical communication system of  claim 17  wherein the wireless receiver is configured to scan for signals from the external transmitter at preset time periods if the wireless receiver fails to detect wirelessly a suitable signal from the external transmitter at the primary predetermined time.