SRS Waveform Configuration for Full-Bandwidth 5G Positioning

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Solution Overview

Problem

There is currently no method for uplink-based positioning in the 5G NR network, and existing SRS configurations in LTE/UMTS do not efficiently utilize orthogonal dimensions for sufficient UE multiplexing, limiting the accuracy of time of arrival estimates.

Innovation Solution

The proposed solution involves configuring SRS resources to achieve full bandwidth by concatenating comb-2 or comb-4 symbols, using power boosting, symbol repetition, and frequency hopping, and adapting SRS configurations for different positioning technologies like RTT and UTDOA, to maximize orthogonal resources and improve positioning accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional SRS configurations are used in LTE/UMTS, then the system maintains simplicity, but the accuracy of time of arrival estimates is limited due to insufficient UE multiplexing and inadequate utilization of orthogonal dimensions

Engineering Contradiction:
Improvetime of arrival estimation accuracyVSAvoidSRS configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the SRS configuration into multiple comb configurations (comb-2 and comb-4) with different subcarrier spacing and frequency hopping patterns. This segmentation allows the system to utilize multiple orthogonal dimensions simultaneously, enabling better UE multiplexing and improving time of arrival estimation accuracy without overwhelming complexity in a single configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces frequency hopping as an additional dimension beyond traditional time-domain SRS transmission. By hopping across different frequency resources according to configured patterns, the system creates orthogonal dimensions that enable multiple UEs to be multiplexed simultaneously, thereby improving measurement precision while managing complexity through structured frequency allocation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If full bandwidth SRS is transmitted using comb structures, then orthogonal resources are maximized, but the transmission requires concatenation of multiple symbols which increases processing complexity

Engineering Contradiction:
Improveorthogonal resource utilizationVSAvoidSRS symbol concatenation processing
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple comb configurations (comb-2 and comb-4) into a unified SRS transmission framework that achieves full bandwidth utilization. By combining the advantages of different comb structures and using frequency hopping to bridge them, the system maximizes orthogonal resource utilization while managing processing complexity through integrated configuration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic frequency hopping patterns that adapt the SRS transmission across different time slots. This dynamic approach allows the system to achieve full bandwidth utilization through concatenation while managing processing complexity by distributing the transmission across multiple structured hops rather than requiring simultaneous processing of all bandwidth resources.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If SRS resources are configured for positioning, then positioning accuracy is improved, but the configuration requires adaptation for different positioning technologies (RTT, UTDOA) which increases system complexity

Engineering Contradiction:
Improvepositioning accuracyVSAvoidpositioning technology adaptation
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal SRS configuration framework that can support multiple positioning technologies (RTT, UTDOA, and future positioning methods) through a single standardized structure. The frequency hopping and comb configurations are designed to be universally applicable, allowing the same basic mechanism to serve different positioning needs without requiring separate dedicated configurations for each technology.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses parameter changes in the SRS configuration (such as frequency hopping patterns, comb factors, and subcarrier spacing) to adapt the same basic SRS structure for different positioning technologies. By adjusting these parameters rather than creating entirely different systems, the patent achieves versatility across positioning methods while managing system complexity through parameter-based adaptation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3909326B1Methods and apparatuses for positioning based on the sounding reference signal
Publication Date: 2026.03.11 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3909326B1 patent drawingFigure 1
  • EP3909326B1 patent drawingFigure 2
  • EP3909326B1 patent drawingFigure 3

AI summary

A method performed by a user equipment, UE (110, 200) includes obtaining (1202) a Sounding Reference Signal, SRS, configuration from a network node (160) and determining (1204) an SRS waveform and transmitting (1206) the SRS waveform. The SRS waveform is adapted for positioning based on the SRS configuration to have a full bandwidth within a bandwidth applicable for the SRS waveform.