Radio Precoding for Non-Contiguous Bands with Lower Overhead

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Solution Overview

Problem

In radio communication systems using multiple access methods like DFT-S-OFDM and Clustered-DFT-S-OFDM, the increase in control information required for precoding becomes significant, especially when different precoding is applied for each frequency region, leading to performance degradation.

Innovation Solution

A communication apparatus that sets the same parameter across the entire frequency band for contiguous methods and different parameters for non-contiguous frequency bands, reducing control information while maintaining performance gains.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple precoding is used for non-contiguous frequency bands to improve reception characteristics, then reception sensitivity is improved, but control information amount increases

Engineering Contradiction:
Improvereception sensitivityVSAvoidcontrol information amount
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The frequency band is segmented into multiple bands, and precoding is applied separately to each segment. This allows reception sensitivity improvement through frequency-specific precoding while managing control information by treating each segment independently rather than as a whole.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different precoding parameters are applied to different frequency bands based on their specific channel characteristics. This local optimization improves reception sensitivity in each band while the overall system manages control information efficiently by only transmitting necessary differential parameters.

Inventive Principle:
Principle #3Local quality

2Reliability

If different precoding is applied for each frequency region to improve reception characteristics, then frequency selection diversity effect is enhanced, but notification information increases

Engineering Contradiction:
Improvefrequency selection diversity effectVSAvoidnotification information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The system segments the frequency spectrum into multiple regions and applies precoding independently to each segment. This enables frequency selection diversity by exploiting variations in channel conditions across different frequency regions while controlling notification overhead through efficient parameter representation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes precoding parameters according to frequency region to match local channel characteristics. This improves frequency selection diversity effect while the parameter changes are designed to minimize the amount of notification information required, using differential encoding or selective parameter transmission.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2523374B1Communication apparatus, control program for communication apparatus, and integrated circuit
Publication Date: 2025.09.03 SHARP KK
  • EP2523374B1 patent drawingFigure 1
  • EP2523374B1 patent drawingFigure 2
  • EP2523374B1 patent drawingFigure 3

AI summary

In a radio communication method non-contiguously using a frequency, notification information is reduced, while suppressing an effect on performance. In a communication apparatus which switches between a communication method contiguously using a frequency and a communication method non-contiguously using the frequency, sets a parameter corresponding to each communication method, and performs radio communication, the communication apparatus sets a same parameter to an entire frequency band in the communication method contiguously using the frequency, while dividing a frequency band into a plurality of frequency bands and setting a different parameter for each divided frequency band in the communication method non-contiguously using the frequency. The communication method contiguously using the frequency and the communication method non-contiguously using the frequency mutually have different PAPR (Peak to Average Power Ratio) characteristics.