HARQ Peak Suppression for OFDMA PAPR Reduction

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Solution Overview

Problem

5G NR technology faces challenges in reducing peak-to-average power ratio (PAPR) in OFDMA signaling, leading to increased power consumption and reduced efficiency of power amplifiers due to high PAPR values, which complicates accurate data recovery with higher-order constellations.

Innovation Solution

A method is implemented in wireless communication devices to detect and suppress peaks in data signals exceeding a threshold amplitude, transmitting amplitude-suppressed signals and peak suppression information, which helps in reducing PAPR and improving power efficiency by combining peak suppression information with additional coded bits during HARQ processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If OFDMA signaling techniques are used to support multiple users, then system capacity and user support are improved, but peak-to-average power ratio increases leading to higher power consumption and reduced amplifier efficiency

Engineering Contradiction:

Improveuser support capacityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes the problematic peak amplitude samples from the OFDMA signal. By identifying samples exceeding a threshold and setting them to zero or reduced values, the high PAPR components are taken out of the signal, leaving a modified signal with lower peak power that maintains the multi-user support capability of OFDMA.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the amplitude parameter of specific signal samples by applying clipping or compression functions. The amplitude of peak samples is modified to reduce PAPR while attempting to preserve the underlying data information, thereby changing the signal's power distribution characteristics without altering the fundamental OFDMA structure that enables multi-user support.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If OFDMA signaling techniques are used to support multiple users, then system capacity is improved, but power amplifier efficiency decreases due to high PAPR

Engineering Contradiction:

Improvesystem capacityVSAvoidamplifier efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If peak amplitudes are suppressed to reduce PAPR, then power consumption is reduced, but data accuracy and error vector magnitude deteriorate

Engineering Contradiction:

Improvepower consumptionVSAvoiddata recovery accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent employs feedback mechanisms where the receiver detects errors in the clipped/compressed signal and requests retransmission of affected data bits. The transmitter uses this feedback to identify which samples were modified and retransmits the original or corrected data, allowing the receiver to reconstruct the accurate signal while the transmitter benefits from reduced PAPR in the initial transmission.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary error detection and correction mechanism that mediates between the distorted received signal and the original transmitted data. Through error detection codes and selective retransmission, the system recovers the accurate data that was degraded by the peak suppression process, acting as an intermediary that restores information integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If higher-order constellations are used to increase data rate, then throughput is improved, but error vector magnitude increases requiring larger power amplifier operating range

Engineering Contradiction:

Improvedata rateVSAvoiderror vector magnitude

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary peak suppression processing to the signal before transmission, proactively reducing PAPR to prevent the power amplifier from operating in its non-linear region. This preliminary action ensures that even with higher-order constellations requiring precise amplitude representation, the amplifier operates within its linear range, thereby maintaining low EVM and high reliability while achieving high data rates.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11539565B2Hybrid automatic repeat request (HARQ) techniques for reducing peak-to-average power ratio (PAPR)

Publication Date: 2022.12.27 QUALCOMM INC

AI summary

This disclosure provides methods, devices and systems for reducing PAPR in wireless communications. Some implementations more specifically relate to suppressing the amplitudes of a data signal that exceed a threshold amplitude level. The data signal may represent transmit (TX) data associated with a hybrid automatic repeat request (HARQ) process. In some implementations, a transmitting device may detect one or more peaks associated with the data signal. The transmitting device may reduce the amplitudes of the samples associated with the detected peaks to produce the amplitude-suppressed data signal. The transmitting device may further generate peak suppression information indicating the amplitudes of one or more of the samples associated with the peaks. In response to receiving a NACK message, the transmitting device may transmit, to the receiving device, the peak suppression information, one or more coded bits representing the TX data (associated with the HARQ process), or any combination thereof.