Envelope Modulation for Concurrent WUS and Data Transmission

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Solution Overview

Problem

Wake-up receivers (WURs) in IoT devices have low power consumption but suffer from poor performance in terms of sensitivity and selectivity, leading to interference issues and limited range, which affects their ability to efficiently wake up main transceivers for data transmission.

Innovation Solution

Modulating the envelope of data packets to concurrently transmit a wake-up signature (WUS) with user data, using techniques like Amplitude Shift Keying (ASK), which allows for efficient channel usage and reduces interference, enabling better performance and integration with legacy systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a WUR is used to reduce power consumption, then energy efficiency is improved, but sensitivity and selectivity deteriorate

Engineering Contradiction:

Improvepower consumptionVSAvoidsensitivity and selectivity

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces an intermediary mechanism by modulating the envelope of data packets to embed WUS information. This allows the WUR to detect wake-up signals through envelope detection without requiring complex demodulation, thereby maintaining low power consumption while improving detection reliability. The envelope modulation acts as a mediator that bridges the gap between simple detection capability and reliable signal recognition.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the modulation parameter from conventional complex modulation to envelope modulation. By varying the envelope of the data packet according to the WUS bits, the system enables the WUR to detect wake-up signals through simple envelope detection, improving sensitivity without significantly increasing power consumption. This parameter change transforms the detection mechanism to better suit the capabilities of low-power receivers.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If envelope modulation is used to transmit WUS concurrently with data, then channel efficiency is improved, but link performance for data users deteriorates

Engineering Contradiction:

Improvechannel efficiencyVSAvoidlink performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies partial action by using only the envelope variation of the data packet to carry WUS information, rather than modifying the entire signal structure. The main data modulation remains intact, and only the amplitude envelope is varied to encode wake-up bits. This minimal intervention approach maintains data transmission quality while adding wake-up functionality, thus preserving link performance for data users.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent segments the transmission function into two independent layers: the data transmission layer (using conventional modulation) and the wake-up signal layer (using envelope modulation). This segmentation allows both functions to operate simultaneously without interfering with each other, improving channel efficiency while maintaining the reliability of data transmission for awake receivers.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If WUR operates independently with poor selectivity, then device complexity is reduced, but interference susceptibility increases

Engineering Contradiction:

Improvereceiver complexityVSAvoidinterference susceptibility

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of poor selectivity into a benefit by using envelope detection. Since envelope detection is inherently broad-band and insensitive to frequency offsets, it naturally rejects narrowband interferers that are not modulating their envelopes. The WUR's simple structure, previously seen as a liability, becomes an advantage by being immune to many types of interference that would affect more sophisticated receivers.

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 approach enhances the performance of WURs by reducing interference and improving sensitivity, allowing for efficient spectrum use and seamless integration with existing networks, while maintaining negligible impact on link performance for primary data users.

Implementation Method 1

The WUS modulates the envelope of the data packet, resulting in, for example, Amplitude Shift Keying (ASK)

Methodology Applied

Scientific EffectAmplitude Shift Keying: Phase Modulation

Data Source

PatentUS10893473B2Envelope modulation for concurrent transmission of a wake-up signal and user data

Publication Date: 2021.01.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

In one aspect, a transmitting device forms an OFDM signal comprising a plurality of OFDM symbols and carrying user data targeted to a main transceiver of one or more receiving devices. The transmitting device modulates the OFDM signal with a wake-up signature (WUS) targeted to awake-up receiver (WUR) of a receiving device other than the one or more receiving devices. The modulating is performed so as to superimpose a modulation of signal power on the OFDM signal, the resulting variations in signal power conveying the wake-up signature. The modulated OFDM signal is transmitted, where a receiving device receives the OFDM at its WUR. The receiving device detect a WUS modulated in the OFDM signal that is targeted to a wake-up receiver of a receiving device other than the one or more receiving devices. The receiving device wakes up its main transceiver in response to the detecting.