OFDM Modulator Numerology Coexistence via Frequency Segmentation

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Solution Overview

Problem

Current radio communication standards, such as 5G, face challenges in supporting diverse service use cases with different numerologies, leading to inefficiencies in transport capacity and interference between different numerology-based subcarriers.

Innovation Solution

The implementation of OFDM-modulators and OFDM-demodulators with adjustable block lengths and frequency offsets allows for the coexistence of multiple numerologies on a shared subcarrier grid, maintaining orthogonality and enabling efficient migration from 4G/LTE to 5G by interleaving frequency portions and using a main block length of 2048.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If different numerologies with different block lengths are used in parallel sub-bands, then diverse service use cases can be supported, but transport capacity increases due to frequency offsets between different numerologies

Engineering Contradiction:

Improvesupport for diverse service use casesVSAvoidtransport capacity

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The system segments the frequency spectrum into different sub-bands, each accommodating specific numerologies with different block lengths. This segmentation allows diverse service use cases to be supported simultaneously while managing frequency offsets between segments, thereby preventing capacity loss despite the use of multiple numerologies.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the block length parameter of the inverse Fast Fourier Transform based on the specific numerology requirements of different service use cases. By dynamically adjusting this parameter, the system can accommodate diverse services while maintaining efficient transport capacity through optimized frequency offset management.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If different numerologies with different block lengths are used, then service diversity is supported, but subcarrier orthogonality is compromised leading to interference

Engineering Contradiction:

Improveservice diversityVSAvoidsubcarrier interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system applies local quality by assigning specific numerologies with appropriate block lengths to specific sub-bands based on service requirements. This localized approach ensures that each sub-band maintains subcarrier orthogonality for its designated numerology, preventing interference while supporting service diversity across different frequency regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention resolves the orthogonality conflict by introducing a frequency dimension separation. Different numerologies with different block lengths are allocated to different frequency sub-bands, allowing each to maintain its own orthogonality properties without interfering with others, thus supporting service diversity without compromising signal integrity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3337115B1Combining different OFDM numerologies in one band

Publication Date: 2022.03.30 ALCATEL LUCENT SA

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Figure 1d

AI summary

It is proposed an OFDM-modulator (1000) for operating in a radio device (BS; UE) of a cellular radio communications network (RCN), wherein the OFDM-modulator (1000) is configured to: determine a joined sample stream (g0,...,gB-1) in dependence on a first and second egress sample stream (e0,...,eB-1, f0,...,fB-1) for up-converting the joined sample stream (g0,...,gB-1) to a carrier frequency higher than respective subcarrier frequencies.