Dynamic Waveform Selection for RACH and Autonomous Uplink

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Solution Overview

Problem

Wireless communication networks face interference and reduced performance due to increasing demand for mobile broadband access, leading to congested networks and degraded signal quality, particularly in scenarios where user equipment (UE) lacks sufficient channel information for waveform configuration.

Innovation Solution

User equipment (UE) is enabled to select between Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) and Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) waveforms for RACH procedures and autonomous uplink transmissions, based on measured path loss and preconfiguration, to optimize waveform selection and resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If UEs use a fixed waveform configuration for uplink transmissions, then device complexity is reduced, but adaptability to different channel conditions deteriorates

Engineering Contradiction:
Improvewaveform configuration complexityVSAvoidwaveform adaptability to channel conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic waveform selection where UEs can switch between DFT-S-OFDM and CP-OFDM waveforms based on measured path loss and channel conditions. The UE determines which waveform to use for RACH procedures and autonomous UL transmissions by comparing measured path loss against thresholds, enabling adaptive behavior rather than fixed configuration.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the waveform parameter based on channel conditions. Specifically, it modifies the waveform type (DFT-S-OFDM vs CP-OFDM) according to path loss measurements and network configuration, allowing the system to optimize performance by selecting appropriate waveform parameters for different transmission scenarios.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If UEs select waveforms dynamically based on channel conditions, then communication efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvedata throughputVSAvoidwaveform selection complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent performs preliminary waveform selection before actual data transmission. The UE measures path loss and determines the appropriate waveform in advance for RACH procedures and autonomous UL transmissions, ensuring optimal communication efficiency is achieved before data transfer begins rather than during transmission.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent enables UEs to autonomously select waveforms based on their own path loss measurements and preconfigured thresholds without requiring complex network coordination. The UE independently determines which waveform to use for uplink transmissions, reducing overall system complexity while maintaining adaptability.

Inventive Principle:
Principle #25Self-service

3Use of energy by moving object

If DFT-S-OFDM waveform is used for power-limited users, then power efficiency is improved, but interference management capability deteriorates

Engineering Contradiction:
Improvepower amplifier efficiencyVSAvoidinterference
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent changes the waveform parameter based on channel conditions and power requirements. For power-limited users, it selects DFT-S-OFDM to maximize power amplifier efficiency, while for users with better channel conditions or higher power availability, it selects CP-OFDM for improved interference management and spectral efficiency.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3542500B1UL waveform during RACH procedure and autonomous UL transmission
Publication Date: 2021.01.06 QUALCOMM INC
  • EP3542500B1 patent drawingFigure 1
  • EP3542500B1 patent drawingFigure 2
  • EP3542500B1 patent drawingFigure 3A

AI summary

Systems and methods herein determine whether an uplink RACH request and/or an uplink autonomous message will be sent using Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM), Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM), or another waveform. Other aspects, embodiments, and features are also claimed and described.