Wake-Up Receiver Synchronization for Low-Power WUS Detection

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently managing power consumption and latency in wireless devices, particularly in 5G devices, due to the need for frequent wake-up cycles and the inefficiencies of current wake-up signal (WUS) designs, which can lead to increased energy consumption and false wake-ups.

Innovation Solution

Implementing a low-power wake-up receiver (WUR) with synchronized wake-up signal (WUS) configurations, including separate synchronization sequences and offset timings, to optimize power consumption and reduce false alarms, ensuring efficient WUS detection and coexistence with main radio operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a wake-up receiver (WUR) is used to detect WUS, then power consumption is significantly reduced, but the clock or oscillator becomes noisier and less accurate

Engineering Contradiction:

Improvepower consumptionVSAvoidclock accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

A synchronization indicator is introduced as an intermediary signal transmitted via FDM between the main receiver and WUR. The main receiver decodes this indicator and passes synchronization information to the WUR, enabling the WUR to synchronize its wake-up detections with network timing without requiring a high-precision local clock

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent introduces a frequency dimension by using Frequency Division Multiplexing (FDM) to transmit the synchronization indicator separately from the main data channel. This allows the WUR to obtain timing information through frequency-based separation rather than relying solely on time-based synchronization methods that would require precise local oscillators

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If the main receiver monitors the WUS, then no additional hardware is needed, but power saving gain is limited

Engineering Contradiction:

Improvehardware complexityVSAvoidpower consumption

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent segments the receiver functionality into two distinct parts: the main receiver that handles data communication and a separate WUR that handles wake-up signal detection. This segmentation allows each component to be optimized for its specific function, with the WUR consuming minimal power while the main receiver remains available for full-capacity data operations when activated

Inventive Principle:

Principle #1Segmentation

3Reliability

If WUS is transmitted with coverage enhancement, then detection reliability is improved, but transmission time increases

Engineering Contradiction:

Improvedetection reliabilityVSAvoidtransmission time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts the synchronization function from the main WUS transmission by introducing a separate synchronization indicator transmitted via FDM. This allows the WUS to be transmitted more efficiently while the synchronization information is provided through a dedicated channel, separating the timing alignment function from the wake-up signal function

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20260082325A1Wakeup signal synchronization

Publication Date: 2026.03.19 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method, system and apparatus are disclosed. A network node is configured to communicate with a wireless device (WD). According to one aspect, a method in a WD includes receiving a wakeup signal (WUS) synchronization sequence from the network node. The method includes synchronizing a wakeup receiver (WUR) of the WD according to the WUS synchronization sequence. The method also includes receiving by the WUR a WUS sequence from the network node.