DFT-s-OFDM Distributed RS Insertion with Adaptive Padding

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Solution Overview

Problem

DFT-s-OFDM's single-carrier nature limits flexibility in allocating control and data information in the frequency domain, especially when implementing 5G NR Reference Signals (RS), which does not allow multiplexing of data information in the same symbol, and increases peak-to-average power ratio (PAPR) at higher carrier frequencies.

Innovation Solution

Implementing post-DFT RS insertion with padding sequence adaptation, where interference is cancelled based on a determined padding sequence structure, and RS are inserted into DFT-s-OFDM symbols using techniques like subcarrier puncturing and interleaving, to reduce PAPR and improve flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Reference Signals are inserted into DFT-s-OFDM symbols using conventional methods, then the single-carrier nature is preserved, but flexibility in allocating control and data information in the frequency domain is limited

Engineering Contradiction:

Improveflexibility in frequency domain allocationVSAvoidsingle-carrier waveform structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the DFT-s-OFDM symbol into multiple parts: data regions, reference signal regions, and transition regions. By dividing the frequency domain resources into separate controllable segments, the system achieves flexible allocation of control and data information while maintaining the single-carrier nature through controlled transitions between segments

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a time dimension to the frequency domain allocation by allowing control information to be multiplexed across multiple DFT-s-OFDM symbols. This enables frequency domain flexibility without compromising the single-carrier property in any individual symbol, as the control-data separation is achieved through temporal multiplexing

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If distributed Reference Signals are inserted in DFT-s-OFDM, then frequency domain flexibility is improved, but Peak-to-Average Power Ratio increases at higher carrier frequencies

Engineering Contradiction:

Improvefrequency domain allocation flexibilityVSAvoidpeak-to-average power ratio

Core Design Contradiction:

Adaptability or versatilityVSPower

Solution Approach 1:

The patent applies local quality by creating smooth transitions only at the boundaries between data and reference signal regions, while maintaining constant envelope characteristics within each region. This localized approach to waveform shaping reduces PAPR spikes at transition points while preserving the frequency domain flexibility benefits of distributed reference signals

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent performs preliminary waveform shaping and transition smoothing during the signal generation stage, before transmission. By pre-configuring the padding sequences and transition regions to have controlled amplitude characteristics, the system prevents PAPR increase from occurring during transmission, especially at higher carrier frequencies where power amplifier efficiency is critical

Inventive Principle:

Principle #10Preliminary action

3Reliability

If control and data channels are allocated different DFT-s-OFDM symbols, then single-carrier nature is preserved, but resource utilization efficiency decreases

Engineering Contradiction:

Improvesingle-carrier waveform integrityVSAvoidresource utilization efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent merges control and data channels within the same DFT-s-OFDM symbol by allocating them to different frequency resources (subcarriers). This allows both control and data to be transmitted simultaneously in a single symbol period, improving resource utilization while maintaining single-carrier integrity through the DFT-s-OFDM processing that ensures constant envelope properties across the combined signal

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20250274326A1Insertion of distributed reference signals in DFT-s-ofdm

Publication Date: 2025.08.28 INTERDIGITAL PATENT HOLDINGS INC

AI summary

Some implementations provide devices, methods and systems for receiving data over a Discrete Fourier Transform-spread Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) waveform. A Reference Signal (RS) configuration message is received. A padding sequence structure is determined based on a received indication. A DFT-s-OFDM symbol is received. Interference is cancelled based on the padding sequence structure. In some implementations, the padding sequence structure includes a constant-envelope sequence, sign-reversed data symbols, phase-shifted data symbols, and/or blank symbols. In some implementations, the RS configuration message includes an RS sequence, a RS length, and/or a subcarrier offset.