Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

METHOD OF ESTABLISHING A COMMUNICATIONS LINK BETWEEN IMPLANTED DEVICES

IP.com Disclosure Number: IPCOM000128967D
Publication Date: 2005-Sep-23
Document File: 4 page(s) / 269K

Publishing Venue

The IP.com Prior Art Database

Abstract

This disclosure covers the use of internal timers to coordinate inter-device communications intervals and a method of dealing with time interval uncertainty. Specifically, implanted devices check for a wake up command on a frequent interval, such as each minute, but only for a brief period. During the check process, the devices determine whether they are being commanded to fully awaken. Wakeup will be initiated by an external or implanted coordinating device on an interval determined by external parameters.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 41% of the total text.

METHOD OF ESTABLISHING A COMMUNICATIONS

LINK BETWEEN IMPLANTED DEVICES

Establishing a communications link between two or more human implanted devices is a particularly difficult problem since implanted devices with internal power sources tend to be highly energy limited.  One particular communications implementation that can take advantage of this methodology uses ultrasonic waves for carrying data.  This disclosure covers the use of internal timers to coordinate inter-device communications intervals and a method of dealing with time interval uncertainty.  Specifically, the implanted devices check for a wake up command on a frequent interval, such as each minute, but only for a brief period.  During the check process, the devices determine whether they are being commanded to fully awaken.  Wakeup will be initiated by an external or implanted coordinating device on an interval determined by external parameters.

There are a number of methods that may be used to wake time coordinated remote devices.  The method described herein is similar to previous methods except that once the relative time intervals of remote devices is known by the communications coordinator, intervals are communicated back to the remote devices and used for time based correction.  Time based correction may be implemented by adjusting the oscillator frequency or by adjusting an oscillator divider if the oscillator runs at approximately a multiple of the rendezvous intervals.  The correction factor is stored in each remote device and the coordinator only needs to issue a single wake up command with a duration dependent on known oscillator uncertainties.

There are factors that affect the long and short-term certainty of a time reference.  Example factors are component aging, ambient temperature, oscillator operating voltage and so on.  A simple method of correcting long-term drift is to periodically recalibrate using the methods described above.  Short-term drift due to factors like electron induced oscillator noise, particularly at low currents, will make uncorrelated stochastic variations between references in each device.

Short-term variations may be compensated for by progressively increasing the wakeup command duration based on time elapsed since the last coordinated communication.  In particular, remote devices can reset their time clocks either on command by the coordination device or by keying on a received data feature such as the ending of the wakeup command, thereby resetting inter-device time uncertainty periodically.  Time reference uncertainty and budgeted energy for communications will determine the maximum interval between communications for timing resynchronization.

A key aspect of a communications bus is to be able to perform rapid introduction of a new component to the system.  There are three methods of doing this.  The first method, illustrated in Figure 1, uses an external device 100 to wake a communications coordinator 120 and remote devic...