OFDMA Duplicate Transmission Using Orthogonal Codes for Low PAPR

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Solution Overview

Problem

Duplicating symbols for transmission in OFDMA signals leads to increased peak-to-average power ratio (PAPR), restricting maximum transmission power and signal quality due to constructive addition of time-domain crests.

Innovation Solution

Applying phase shifts to symbols using Hadamard matrices to generate duplicate transmissions across multiple resource units, reducing constructive interference in the time domain and minimizing PAPR.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If symbols are duplicated for transmission on multiple resource units, then communication reliability is improved, but peak-to-average power ratio increases

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidpeak-to-average power ratio

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent applies phase shift transformations to the duplicated symbols before transmission. By changing the phase parameter of the symbols according to orthogonal codes (such as Hadamard codes), the patent maintains the redundancy benefit for reliability while altering the time-domain signal characteristics to reduce PAPR. This parameter transformation allows the signal to meet power amplifier requirements without sacrificing communication reliability.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If symbols are duplicated for transmission on multiple resource units, then data loss is reduced, but transmission power is restricted

Engineering Contradiction:

Improvedata loss reductionVSAvoidmaximum transmission power

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent transforms the phase parameter of duplicated symbols using orthogonal codes before transmission. This phase transformation reduces the peak power requirements while maintaining the redundant transmission structure that protects against data loss. The receiver can recover the original data by applying the inverse phase transformation and combining the signals from multiple resource units.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If symbols are duplicated for transmission on multiple resource units, then retransmissions are reduced, but signal characteristics deteriorate

Engineering Contradiction:

Improveretransmission reductionVSAvoidsignal characteristics

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies phase shift transformations to duplicated symbols to improve signal characteristics. By transforming the phase parameter according to orthogonal codes, the patent eliminates the constructive interference that causes high PAPR and signal deterioration. The transformed signals maintain their redundancy for reducing retransmissions while exhibiting improved time-domain characteristics suitable for efficient power amplification.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250350415A1Systems for and methods of frequency domain duplicate mode transmission using orthogonal codes

Publication Date: 2025.11.13 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

A system for providing duplicate mode orthogonal frequency-division multiple access transmissions while maintaining a relatively low peak-to-average power ratio. Data to be transmitted is converted to symbols which are duplicated onto a number of resource units. Phase shifts are applied to a number of symbols prior to conversion to the time domain for transmission. The phase shifts can be removed at the receiver prior to decoding the signal to the transmitted data.