Multiplexed Wake-Up Packet Time Domain Merging

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Solution Overview

Problem

Wake-up radio technologies using on/off keying (OOK) modulation with guard intervals lead to decreased spectrum efficiency as 'silent' parts are not used for transmission, which is a concern as low-energy wireless devices are expected to increase in number.

Innovation Solution

Multiplexing individual wake-up signals into a wake-up packet with time domain multiplexing, using a composite of individual wake-up packets with unique time offsets, and potentially including amplitude shift keying signals modulated according to a partial On-Off-Keying scheme, to increase spectrum efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If guard intervals are used in OOK modulation for wake-up signals, then signal-to-noise ratio is improved, but spectrum efficiency decreases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidspectrum efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Multiple individual wake-up packets are merged into a single multiplexed wake-up packet by combining them in the time domain with different time offsets. This allows multiple devices to be addressed simultaneously within one transmission frame, improving spectrum efficiency while maintaining the guard interval structure for reliable detection

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If multiple individual wake-up packets are transmitted separately, then each device is addressed individually, but spectrum efficiency decreases

Engineering Contradiction:

Improveindividual device addressingVSAvoidspectrum efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

Multiple individually addressed wake-up packets are merged into a single multiplexed packet structure. Each device retains its unique identification and time offset, allowing individual addressing while improving spectrum efficiency by reducing the total number of separate transmissions required

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The solution introduces a time offset dimension to differentiate multiple wake-up packets within a single transmission. By assigning different time offsets to packets destined for different devices, the system can address multiple devices simultaneously without collision, moving from a single-dimension (sequential) approach to a multi-dimensional (parallel with time differentiation) approach

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS11490332B2Multiplexing of wake-up signals

Publication Date: 2022.11.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method of wirelessly providing a multiplexed wake-up packet for waking up a plurality of wireless communication receivers from a low-power state to a normal state is provided. The multiplexed wake-up packet comprises a composite of individual wake-up packets, wherein each individual wake-up packet is addressed to one of the plurality of wireless communication receivers. The method comprises determining a number N of individual wake-up packets of the multiplexed wake-up packet, determining a time offset To(n) for each of the individual wake-up packets, where n=1 . . . N, generating the multiplexed wake-up packet as a time domain multiplexed signal comprising all the N individual wake-up packets with the time offsets To(n), and transmitting the multiplexed wake-up packet. A network node is arranged to perform the method.