Communication for implantable medical devices

An implantable device comprising:

• a housing;
• a wireless communication module within the housing;
• a processor disposed within the housing;
• and
• a memory configured to store executable instructions that, when executed by the processor, cause the implantable device to:
• receive a first data block of a defined size;
• monitor the first data block for a first flag indicating whether the first data block is an initial data block in a message or a subsequent data block in a multiple data block message;
• when the first flag indicates that the first data block is the initial data block in the message, monitor the first data block for a fixed device ID, including:
• comparing the fixed device ID from the first data block to one or more stored fixed device IDs, the one or more stored fixed device IDs each uniquely identifying a specific external device;
• and
• identifying a device sending the first data block as a first authorized device when the fixed device ID from the first data block matches a stored fixed device ID of the one or more stored fixed device IDs, the stored fixed device ID corresponding to the first authorized device.

A method of communicating between an implanted device implanted in a patient and an external device external to the patient, the method comprising:

• generating, by the external device, a first data block of a defined size, wherein generating the first data block includes:
• setting a first flag in the first data block indicating whether the first data block is an initial data block in a message or a subsequent data block in a multiple data block message;
• when the first data block is an initial data block in the message, including a fixed device ID in the first data block, wherein:
• the fixed device ID is a pre-assigned ID that uniquely identifies the external device;
• and
• the implanted device stores a list of approved device IDs, each uniquely identifying a different authorized device, and only responds to messages sent from authorized devices;
• and
• transmitting, by the external device, the first data block.