Conductive Implant Communication Using Orthogonal Pulse Encoding
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Solution Overview
Problem
Existing implant-to-implant communication systems for medical devices, such as leadless cardiac pacemakers and non-vascular ICDs, are prone to noise interference, leading to misinterpretation of signals and undefined device behavior due to weak signal reception, especially in noisy electromagnetic environments.
Innovation Solution
Implementing a method where implantable medical devices encode and transmit bits using orthogonal pseudo noise pulse sequences in composite bits, allowing for robust conductive communication by encoding each bit as either a first or second pseudo noise pulse sequence, and decoding using in-phase and quadrature channel values to extract the intended data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low frequency conductive telemetry is used for implant-to-implant communication, then communication between LCPs is achieved, but noise interference causes signal misinterpretation and undefined device behavior
Solution Approach 1:
The patent applies preliminary action by incorporating a wake-up pulse before the actual data transmission. This wake-up pulse serves as a preliminary signal that alerts receiving devices to prepare for incoming data, allowing them to synchronize their receivers and adjust their sampling timing accordingly. This preliminary action reduces the impact of noise interference by ensuring receiving devices are properly prepared and synchronized before the actual communication begins.
Solution Approach 2:
The patent implements periodic action through the use of time-division multiplexing with alternating time slots for different communication pairs. The communication system operates in periodic cycles where LCP1 transmits to LCP2 during one time slot, then switches to transmit to the NV-ICD during another time slot. This periodic switching allows each receiving device to expect signals at predictable intervals, improving noise immunity through synchronized reception timing.
2Adaptability or versatility
If conductive telemetry is used for LCP to NV-ICD communication, then communication between different device types is enabled, but weak signal reception increases susceptibility to noise
Solution Approach 1:
The wake-up pulse serves as a preliminary action that enables receiving devices to prepare their receivers in advance. For the NV-ICD, which has weak signal reception capability, the wake-up pulse allows the device to advance its receiver timing and amplify signals before the actual data transmission begins, compensating for its inherently weak reception strength.
Solution Approach 2:
The patent implements feedback mechanisms where receiving devices acknowledge receipt of communication signals. The NV-ICD and LCPs send acknowledgment signals back to the transmitting device, allowing the system to verify successful communication and adjust transmission parameters accordingly. This feedback loop enables the system to compensate for weak signal reception by adapting transmission strength and timing based on actual reception quality.
3Productivity
If time-division multiplexing is used to communicate with multiple devices, then communication efficiency is improved, but timing synchronization becomes more complex
Solution Approach 1:
The wake-up pulse serves as a preliminary synchronization signal that is transmitted before the time-division multiplexed data. This preliminary action allows all receiving devices to synchronize their internal timers and receiver timing to the transmitting device's clock reference. By establishing this common timing reference in advance through the wake-up pulse, the system simplifies the complexity of coordinating multiple time slots for different device pairs.
4Adaptability or versatility
If existing conductive telemetry protocols are used for LCP-LCP communication, then compatibility is maintained, but noise causes undefined device behavior
Solution Approach 1:
The patent applies segmentation by dividing the communication signal into distinct segments: a wake-up pulse segment followed by data transmission segments. The wake-up pulse is transmitted first as a separate segment, allowing receiving devices to synchronize before the actual data begins. This segmentation isolates the synchronization function from the data transmission function, maintaining compatibility with existing protocols while adding noise immunity through the separate wake-up phase.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances communication reliability and noise resistance in noisy environments by ensuring accurate data extraction and synchronization between medical devices, maintaining synchronized therapy and reducing undefined device behavior.
Implementation Method 1
transmitting the composite bit, e.g., using conductive communication
Data Source
AI summary
Devices, systems and methods for improving conductive communication between medical devices, such as leadless cardiac pacers (LCPs) and non-vascular implantable cardioverter defibrillators (NV-ICDs), are described herein. To provide enhanced channel noise resistance, implant-to-implant (i2i) communications can encode bit values as orthogonal pseudo noise pulse waveforms. When a first implantable device is communicating with multiple devices, the multiple data streams for the devices can be encoded as composite bits, with each composite bit including a bit for each of the multiple intended receiving devices, with at least one of each of the data streams encoded as the orthogonal pseudo noise pulse waveforms.