CSI-RS Assisted SRS Frequency Sounding for 5G NR Coverage

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Solution Overview

Problem

Existing 5G NR technologies face challenges in enhancing Sounding Reference Signal (SRS) capacity and coverage, particularly in frequency range 1 and 2, with limitations in flexible triggering, DCI overhead, and interference structure extraction during partial frequency sounding.

Innovation Solution

The proposed solution involves associating Channel State Information Reference Signal (CSI-RS) resources with SRS resources for enhanced interference measurement and precoding, allowing dynamic switching between partial and full frequency sounding through higher-layer signaling or DCI, and configuring SRS resources for partial or full frequency sounding based on configuration information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If full frequency sounding is performed using SRS, then channel state information coverage is improved, but SRS capacity and power efficiency deteriorate

Engineering Contradiction:

Improvefrequency coverageVSAvoidSRS capacity

Core Design Contradiction:

Area of stationary objectVSQuantity of substance

Solution Approach 1:

The frequency spectrum is segmented into multiple parts, with CSI-RS handling downlink frequency sounding and SRS handling uplink frequency sounding. This segmentation allows each signal type to focus on specific functions, improving overall system capacity while maintaining comprehensive frequency coverage through coordinated operation of both signals.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of requiring SRS to perform complete full-band frequency sounding, the system applies partial action by using CSI-RS for downlink sounding and SRS only for uplink sounding or selective frequency portions. This reduces SRS resource consumption while maintaining adequate frequency domain channel state information through the combined approach.

Inventive Principle:

Principle #16Partial or excessive action

2Measurement precision

If SRS resources are increased for full frequency sounding, then channel state information accuracy is improved, but power consumption and resource overhead increase

Engineering Contradiction:

Improvechannel state information accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The measurement function is segmented between CSI-RS for downlink channel sounding and SRS for uplink channel sounding. This division allows each signal to use optimized power levels appropriate for its specific direction and purpose, reducing total power consumption while maintaining measurement accuracy for both uplink and downlink channels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

CSI-RS acts as an intermediary that provides downlink channel state information, which can be used to infer or complement uplink channel information through channel reciprocity. This intermediary approach reduces the need for SRS to independently sound the entire frequency band, lowering power requirements while maintaining accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If aperiodic SRS triggering is enhanced for flexible transmission, then adaptability to interference conditions is improved, but Downlink Control Information overhead increases

Engineering Contradiction:

ImproveflexibilityVSAvoidDCI overhead

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The aperiodic triggering mechanisms for CSI-RS and SRS are merged and coordinated through shared higher-layer configuration parameters. This combining approach allows the system to trigger both downlink and uplink sounding resources simultaneously or in coordinated sequences, improving adaptability to interference while reducing redundant DCI overhead through unified control.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If SRS switching for multiple antennas is implemented, then MIMO capacity is improved, but device complexity and configuration overhead increase

Engineering Contradiction:

ImproveMIMO capacityVSAvoidconfiguration complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The SRS resource configuration framework is designed with multi-functionality to support both single-antenna and multi-antenna SRS switching scenarios. By creating a universal configuration structure that can accommodate different antenna counts and switching patterns through parameter adjustment rather than structural changes, the system achieves high MIMO capacity while minimizing configuration complexity and device overhead.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12634083B2Methods of CSI-RS assisted partial frequency sounding with SRS

Publication Date: 2026.05.19 NTT DOCOMO INC

AI summary

A wireless communication method is disclosed that includes receiving, via downlink control information (DCI) or higher layer signaling, configuration information for a. Sounding Reference Signal (SRS) configuration and configuring one or more SRS resources for partial or full frequency sounding based on the configuration information. In other aspects, a terminal and a wireless communication system are also disclosed.