Two-Dimensional Signal Spreading for Wireless Orthogonality

Solution Overview

Problem

In wireless communication systems, existing modulation and demodulation techniques face challenges in maintaining orthogonality of data symbols across non-ideal channels, leading to difficulties in detecting data symbols due to channel degradation such as fading, especially in multi-carrier waveforms used in 5G communication systems.

Innovation Solution

A method involving the spreading of data symbols across two-dimensional resource domains, specifically using delay-Doppler and frequency-time resource blocks, to enhance radio signal transmission and reception performance through channel spreading and equalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data symbols are transmitted through non-ideal channels (delay spread, Doppler spread, fading), then channel degradation occurs leading to loss of orthogonality, but detection and decoding of data symbols becomes difficult

Engineering Contradiction:

Improvedetection reliabilityVSAvoidchannel degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a two-dimensional resource domain (time-frequency grid) for mapping data symbols, transforming the traditional one-dimensional resource allocation. By spreading data symbols across multiple time-frequency resources and performing channel equalization in the frequency domain, the system compensates for channel degradation effects and maintains orthogonality despite delay spread and Doppler spread conditions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent applies frequency-domain channel equalization to compensate for channel degradation. By changing the domain of processing from time to frequency, the system can effectively counteract the effects of fading and maintain reliable detection of data symbols even in non-ideal channel conditions.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If OFDM scheme is used for modulation and demodulation, then frequency efficiency is improved and implementation is simplified, but orthogonality between data symbols cannot be guaranteed in non-ideal channels

Engineering Contradiction:

Improvefrequency efficiencyVSAvoidorthogonality maintenance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies frequency-domain channel equalization to compensate for channel degradation. By changing the domain of processing from time to frequency, the system can effectively counteract the effects of fading and maintain reliable detection of data symbols even in non-ideal channel conditions.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If channel gain value is low due to channel degradation, then transmission reliability decreases, but successful detection and decoding of data symbols becomes difficult

Engineering Contradiction:

Improvetransmission reliabilityVSAvoiddata symbol detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies frequency-domain channel equalization to compensate for channel degradation. By changing the domain of processing from time to frequency, the system can effectively counteract the effects of fading and maintain reliable detection of data symbols even in non-ideal channel conditions.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11563608B2Method and apparatus for signal modulation and demodulation in wireless communication system

Publication Date: 2023.01.24 ELECTRONICS & TELECOMM RES INST

AI summary

An operation method of a first communication node may include: mapping data symbols to be transmitted to a second communication node of the communication system to resources in a first two-dimensional (2D) domain; pre-processing the data symbols mapped to the resources in the first 2D domain to spread the data symbols on resources in a second 2D domain; mapping the pre-processed data symbols to the resources in the second 2D domain; and performing multi-carrier modulation on the data symbols mapped to the resources in the second 2D domain for each of the resources in the second 2D domain.