Method and apparatus for antenna selection in a diversity antenna system for communicating with implantable medical device

A system for communicating with an implantable medical device, the system comprising:

• a diversity antenna system including a plurality of antennas configured to transmit an outgoing signal to the implantable medical device and to receive an incoming signal from the implantable medical device;
• a transceiver adapted to transmit outgoing data frames by modulating the outgoing signal and to receive incoming data frames by demodulating the incoming signal, the outgoing data frames and the incoming data frames each being a unit of data including a header, a payload, and a trailer;
• an antenna interface circuit coupled between the diversity antenna system and the transceiver, the antenna interface circuit including a switch circuit adapted to connect an antenna of the diversity antenna system to the transceiver according to an antenna selection signal;
• and
• an antenna control circuit adapted to produce the antenna selection signal, the antenna control circuit including:
• a fading detector coupled to the transceiver, the fading detector adapted to detect a transmission failure deemed to be associated with a null and including a response failure detector adapted to detect a response failure being a data transmission error in at least one response frame of the incoming data frames, the at least one response frame responding to a transmission of a frame of the outgoing data frames;
• an antenna selector coupled to the fading detector, the antenna selector adapted to adjust the antenna selection signal for connecting a different antenna of the diversity antenna system to the transceiver in response to a detection of the transmission failure including the response failure;
• and
• an antenna switching timing circuit coupled between the antenna selector and the switch circuit, the antenna switching timing circuit adapted to hold the antenna selection signal such that the switch circuit does not change the connection between the antenna and the transceiver while a frame of the outgoing data frames is being transmitted or a frame of the incoming data frames is being received.

A system for communicating with an implantable medical device, the system comprising:

• a diversity antenna system including a plurality of antennas configured to transmit an outgoing signal to the implantable medical device and to receive an incoming signal from the implantable medical device;
• a transceiver adapted to transmit outgoing data frames by modulating the outgoing signal and to receive incoming data frames by demodulating the incoming signal, the outgoing data frames and the incoming data frames each being a unit of data including a header, a payload, and a trailer;
• an antenna interface circuit coupled between the diversity antenna system and the transceiver, the antenna interface circuit including a switch circuit adapted to connect an antenna of the diversity antenna system to the transceiver according to an antenna selection signal;
• and
• an antenna control circuit adapted to produce the antenna selection signal, the antenna control circuit including:
• a fading detector coupled to the transceiver, the fading detector adapted to detect a transmission failure deemed to be associated with a null and including a signal strength failure detector adapted to detect a signal strength failure of at least one of the incoming signal and the outgoing signal;
• an antenna selector coupled to the fading detector, the antenna selector adapted to adjust the antenna selection signal for connecting a different antenna of the diversity antenna system to the transceiver in response to a detection of the transmission failure including the signal strength failure;
• and
• an antenna switching timing circuit coupled between the antenna selector and the switch circuit, the antenna switching timing circuit adapted to hold the antenna selection signal such that the switch circuit does not change the connection between the antenna and the transceiver while a frame of the outgoing data frames is being transmitted or a frame of the incoming data frames is being received.

A method for operating a telemetry system communicating with an implantable medical device, the method comprising:

• transmitting an outgoing signal to the implantable medical device and receiving an incoming signal from the implantable medical device using a diversity antenna system including a plurality of antennas, wherein transmitting the outgoing signal includes transmitting outgoing data frames by modulating the outgoing signal, and receiving the incoming signal includes receiving incoming data frames by demodulating the incoming signal, the outgoing data frames and the incoming data frames each being a unit of data including a header, a payload, and a trailer;
• selecting an active antenna from the diversity antenna system according to an antenna selection signal;
• detecting a transmission failure deemed to be associated with a null, the transmission failure including an incoming frame failure being a data transmission error in at least one frame of the incoming data frames, wherein detecting the transmission failure comprises detecting a comma indicative of a receipt of a frame of the incoming data frames during a predetermined time window and indicating the incoming frame failure if the comma is not detected during the predetermined time window;
• adjusting the antenna selection signal for selecting a different active antenna of the diversity antenna system in response to a detection of the transmission failure including the incoming frame failure;
• holding the antenna selection signal such that a switching from the active antenna to the different active antenna does not occur while a frame of the outgoing data frames is being transmitted or a frame of the incoming data frames is being received;
• and
• selecting the different active antenna from the diversity antenna system according to the adjusted antenna selection signal.

A method for operating a telemetry system communicating with an implantable medical device, the method comprising:

• transmitting an outgoing signal to the implantable medical device and receiving an incoming signal from the implantable medical device using a diversity antenna system including a plurality of antennas, wherein transmitting the outgoing signal includes transmitting outgoing data frames by modulating the outgoing signal, and receiving the incoming signal includes receiving incoming data frames by demodulating the incoming signal, the outgoing data frames and the incoming data frames each being a unit of data including a header, a payload, and a trailer;
• selecting an active antenna from the diversity antenna system according to an antenna selection signal;
• detecting a transmission failure deemed to be associated with a null, the transmission failure including a response failure being a data transmission error in at least one response frame of the incoming data frames, the at least one response frame responding to a transmission of a frame of the outgoing data frames;
• adjusting the antenna selection signal for selecting a different active antenna of the diversity antenna system in response to a detection of the transmission failure including the response failure;
• holding the antenna selection signal such that the selecting the different active antenna does not occur while a frame of the outgoing data frames is being transmitted or a frame of the incoming data frames is being received;
• and
• selecting the different active antenna from the diversity antenna system according to the adjusted antenna selection signal.

A method for operating a telemetry system communicating with an implantable medical device, the method comprising:

• transmitting an outgoing signal to the implantable medical device and receiving an incoming signal from the implantable medical device using a diversity antenna system including a plurality of antennas, wherein transmitting the outgoing signal includes transmitting outgoing data frames by modulating the outgoing signal, and receiving the incoming signal includes receiving incoming data frames by demodulating the incoming signal, the outgoing data frames and the incoming data frames each being a unit of data including a header, a payload, and a trailer;
• selecting an active antenna from the diversity antenna system according to an antenna selection signal;
• detecting a transmission failure deemed to be associated with a null, the transmission failure including a signal strength failure of at least one of the incoming signal and the outgoing signal;
• adjusting the antenna selection signal for selecting a different active antenna of the diversity antenna system in response to a detection of the transmission failure including the signal strength failure;
• holding the antenna selection signal such that the selecting the different active antenna does not occur while a frame of the outgoing data frames is being transmitted or a frame of the incoming data frames is being received;
• and
• selecting the different active antenna from the diversity antenna system according to the adjusted antenna selection signal.

A system for communicating with an implantable medical device, the system comprising:

• a diversity antenna system including a plurality of antennas configured to transmit an outgoing signal to the implantable medical device and to receive an incoming signal from the implantable medical device;
• an external system controller;
• a transceiver adapted to transmit outgoing data frames by modulating the outgoing signal and to receive incoming data frames by demodulating the incoming signal, the transceiver including:
• a plurality of receiving modules each having an input coupled to one antenna of the diversity antenna system and an output;
• and
• a switch circuit to connect the output of one receiving module of the plurality of receiving modules to the external system controller according to a receiving path selection signal;
• and
• an antenna control circuit adapted to produce the receiving path selection signal, the antenna control circuit including:
• a signal quality assessment circuit coupled to the transceiver, the signal quality assessment circuit adapted to produce an indication of quality for the incoming signal processed by each receiving module of the plurality of receiving modules;
• a receiving path selector coupled to the transceiver, the receiving path selector adapted to adjust the receiving path selection signal based on the indications of quality for the incoming signal produced for the plurality of receiving modules;
• and
• a path switching timing circuit coupled between the receiving path selector and the switch circuit, the path switching timing circuit adapted to hold the receiving path selection signal while a frame of the outgoing data frames is being transmitted or a frame of the incoming data frames is being received.

A method for operating a telemetry system communicating with an implantable medical device, the method comprising:

• transmitting an outgoing signal to the implantable medical device and receiving an incoming signal from the implantable medical device using a diversity antenna system including a plurality of antennas, wherein transmitting the outgoing signal includes transmitting outgoing data frames by modulating the outgoing signal, and receiving the incoming signal includes receiving incoming data frames by demodulating the incoming signal;
• processing the incoming signal through a plurality of processing paths each coupled to one antenna of the diversity antenna system;
• detecting an indication of quality for the incoming signal processed by each processing path of the plurality of processing paths;
• and
• selecting a processing path of the plurality of processing paths based on the detected indications of quality associated with the plurality of processing paths, the processing path selected while a frame of the outgoing data frames is not being transmitted and a frame of the incoming data frames is not being received.