Microwave Reflector Link for Wearable Power Reduction

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Solution Overview

Problem

Current WiFi transceiver technology is not suitable for wearable devices due to high power consumption, as it requires a power amplifier to generate sufficient power for transmission, which is inefficient and not compatible with the limited battery resources of these devices.

Innovation Solution

A reflective link system that eliminates the need for a power amplifier in the transmitter chain, using a microwave reflector to modulate and reflect microwave power, reducing power consumption by a factor of 10 to 100 times and improving data rate or transmission distance by canceling ambient reflections through CDMA signal spreading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a power amplifier is used in the transmitter chain to generate sufficient power for WiFi transmission, then transmission power is improved, but power consumption increases by a factor of 10 to 100 times

Engineering Contradiction:

Improvetransmission powerVSAvoidpower consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

Instead of generating power locally at the wearable device, the patent inverts the approach by having a base station transmit power wirelessly to the wearable device, which then reflects this received power back to the base station for communication. This eliminates the need for a power amplifier at the wearable device, reducing power consumption by a factor of 10 to 100 times while maintaining transmission capability.

Inventive Principle:

Principle #13The other way round (Inversion)

2Use of energy by moving object

If a power amplifier is eliminated from the transmitter chain, then power consumption is reduced, but transmission power and data rate are insufficient

Engineering Contradiction:

Improvepower consumptionVSAvoiddata rate

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent introduces a reflector as an intermediary component at the wearable device that receives wireless power from the base station and reflects it back with modulation. This intermediary approach enables communication without requiring a power amplifier at the wearable device, maintaining low power consumption while achieving sufficient data rates through the reflected signal.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs CDMA spread spectrum techniques to change the parameters of the reflected signal, spreading it across a wider bandwidth. This parameter change allows the system to achieve sufficient data rates and transmission quality without requiring high peak power, thereby maintaining low power consumption at the wearable device.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If ambient reflections are present in the communication channel, then signal interference increases, but CDMA signal spreading can cancel these reflections to improve transmission

Engineering Contradiction:

Improveambient reflection interferenceVSAvoidcommunication reliability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent converts the harmful effect of ambient reflections into a beneficial outcome by using CDMA spread spectrum techniques. The desired signal is spread across a wide bandwidth with a unique code, while ambient reflections remain unmodulated or differently modulated. At the receiver, correlation with the known code selectively recovers the desired signal while rejecting the unmodulated ambient reflections, thereby improving communication reliability despite the presence of reflective environments.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

This solution enables wireless communication systems that consume significantly less power, making them suitable for wearable devices and enhances data rate and transmission distance by mitigating the adverse effects of ambient reflections.

Implementation Method 1

A reflective link system that eliminates the need for a power amplifier in the transmitter chain, using a microwave reflector to modulate and reflect microwave power

Methodology Applied

Scientific EffectElectromagnetic reflection: Reflection

Implementation Method 2

improving data rate or transmission distance by canceling ambient reflections through CDMA signal spreading

Methodology Applied

Scientific EffectSignal spreading:

Data Source

PatentUS10763587B2Microwave reflector link, and CDMA-spread spectrum reflector apparatus for reduction of unmodulated ambient blockers in reflected data links

Publication Date: 2020.09.01 CALIFORNIA INST OF TECH

AI summary

A system, apparatus and method are disclosed for communicating between a short range wireless (WLAN) user device, such as a wearable, phone, or tablet, with a base station. Traditional low power communication (e.g., WLAN, WiFi, Bluetooth, cellular links, etc.) involve an inefficient amplification process of a signal from the WLAN user to the base station, whereby significant power must be expended in the WLAN user device making it unsuitable in many applications. A reflector link paradigm is disclosed in which the user device communicates by modulating the extent of signal reflected back to the base station. An enhanced reflector is also disclosed which overcomes adverse effects of ambient reflections.