Time-Based Scrambling for Wake-Up Signal Detection

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Solution Overview

Problem

Current wireless communication systems face challenges in reliably detecting wake-up signals (WUS) due to inter-cell interference and overlapping WUS sequences, leading to false detections and power wastage, especially in 5G networks where accurate detection is crucial for efficient battery management and data transmission.

Innovation Solution

The implementation of a time-based scrambling sequence that phase-shifts the WUS by multiplying the WUS base sequence with a time-varying scrambling sequence, generated using parameters such as cell ID, subframe indices, and Gold sequences, to differentiate and scramble WUS sequences, thereby reducing false detections and improving detection reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If WUS sequences are transmitted without scrambling in dense networks, then transmission simplicity is maintained, but false detections increase due to inter-cell interference and overlapping sequences

Engineering Contradiction:
ImproveWUS detection reliabilityVSAvoidscrambling sequence generation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by introducing time-based parameters (subframe index, slot index, symbol index) to generate scrambling sequences. The scrambling sequence varies over time according to these parameters, allowing differentiation of WUS sequences from different cells and reducing false detections while maintaining a systematic generation approach.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the scrambling sequence time-varying rather than static. The scrambling sequence changes dynamically based on time parameters, enabling the system to adapt to different time instances and reduce interference from overlapping WUS sequences in dense network environments.

Inventive Principle:
Principle #15Dynamics

2Reliability

If time-based scrambling sequences are implemented, then false detections are reduced, but processing complexity increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidscrambling sequence processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the scrambling sequence generation into distinct components based on different time parameters (subframe-level, slot-level, symbol-level). This segmentation allows the system to manage complexity by handling each time granularity separately while achieving comprehensive time-based differentiation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses parameter changes to control the scrambling sequence characteristics. By changing parameters such as the subframe index, slot index, and symbol index, the system generates different scrambling sequences at different time points, improving detection accuracy while maintaining a structured approach to complexity management.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If WUS detection is performed frequently to ensure reliable communication, then communication responsiveness is improved, but battery consumption increases

Engineering Contradiction:
Improvecommunication responsivenessVSAvoidUE battery consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent applies the principle of using cheap, short-living objects by employing lightweight scrambling sequences that can be quickly generated and discarded. The time-based scrambling sequences are computationally inexpensive to generate and process, allowing frequent WUS detection without significant energy cost, thus enabling responsive communication while conserving battery life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Object-affected harmful factors

If scrambling sequences are used to differentiate WUS from multiple cells, then inter-cell interference is reduced, but sequence generation complexity increases

Engineering Contradiction:
Improveinter-cell interferenceVSAvoidscrambling sequence generation complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by incorporating cell-specific parameters into the scrambling sequence generation. Different cells use different parameter values (such as cell ID combined with time parameters), which automatically differentiates the scrambling sequences from different cells and reduces inter-cell interference while maintaining a systematic generation process.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3777351B1Facilitating scrambling of wake-up signal sequences
Publication Date: 2022.12.14 QUALCOMM INC
  • EP3777351B1 patent drawingFigure 1
  • EP3777351B1 patent drawingFigure 2
  • EP3777351B1 patent drawingFigure 3

AI summary

Aspects directed towards wake-up signal (WUS) scrambling sequence design are disclosed. In one example, a time-based scrambling sequence that facilitates a phase shift in time may be generated according to a time parameter associated with a WUS or a paging occasion (PO). A scrambled WUS may be generated by multiplying a WUS base sequence by the time-based scrambling sequence, and subsequently transmitted to at least one scheduled entity. In another example, a scrambled WUS may be received from a scheduling entity. A time-based scrambling sequence associated with the WUS may be identified in which the time-based scrambling sequence facilitates a phase shift in time and corresponds to a time parameter associated with a WUS or a PO. The WUS may be descrambled according to the time-based scrambling sequence. Other aspects, embodiments, and features are also included.