Frequency Sub-Band Channel Estimation for Coherent Localization

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing frequency hopping methods in wireless communication networks face challenges in achieving phase coherency of the received signal with minimal effort, which is necessary for accurate localization of user equipment, especially in multipath environments.

Innovation Solution

A method and receiver that estimate the transmission channel across multiple sub-bands to reconstruct a coherent phase basis, compensating for relative phase errors between sub-bands, allowing for a broader bandwidth and improved localization accuracy using time and angle of arrival measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If frequency hopping is used to transmit broadband signals, then bandwidth is increased, but phase coherency between sub-bands deteriorates

Engineering Contradiction:
ImprovebandwidthVSAvoidphase coherency
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

An intermediary phase compensation mechanism is introduced between frequency hops. The system estimates phase errors occurring during frequency transitions and applies compensation to restore phase coherency. This mediator (phase compensation algorithm) allows the system to maintain phase stability while utilizing frequency hopping for bandwidth expansion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts phase parameters to compensate for frequency hopping effects. By changing phase correction values based on observed phase errors during frequency transitions, the system maintains coherent phase relationships across different frequency sub-bands while preserving the bandwidth benefits of frequency hopping.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If phase coherency is maintained across frequency hops, then localization accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvelocalization accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-calibration by using its own transmitted signal as a reference. The known training sequence allows the receiver to self-determine phase errors and automatically compensate for them without requiring external calibration equipment or complex manual adjustments, thereby improving localization accuracy while limiting complexity growth.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses a known copy of the training sequence as a reference template. By comparing the received signal against this known copy, the system can extract phase error information and apply corrections. This copying approach simplifies the measurement process while maintaining high localization precision.

Inventive Principle:
Principle #26Copying

3Measurement precision

If bandwidth is extended through multiple sub-bands, then localization precision is improved, but phase error compensation becomes more difficult

Engineering Contradiction:
Improvelocalization precisionVSAvoidphase error compensation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The broadband signal is segmented into multiple narrower sub-bands, each experiencing less phase error during frequency hopping. By processing each sub-band separately and then combining results with phase compensation, the system achieves high localization precision across the full bandwidth while managing the complexity of phase error compensation through division of labor.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3800847B1Channel estimation of frequency sub bands
Publication Date: 2025.08.20 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3800847B1 patent drawingFigure 1
  • EP3800847B1 patent drawingFigure 2
  • EP3800847B1 patent drawingFigure 3

AI summary

The invention concerns a method for receiving and a receiver configured to receive a radio signal (100) carrying information, the radio signal (100) comprising an overall frequency band (foverall) having a first frequency sub band (101) and a second frequency sub band (102). According to the invention, the receiver is further configured to receive during a first time period (T1) a first portion (111) of the information carried by the radio signal in the first frequency sub band (101), and to receive during a second time period (T2) a second portion (112) of the information carried by the radio signal in the second frequency sub band (102). The receiver is further configured to perform a channel estimation (121) of the first frequency sub band (101) in orderto determine a first phase (131) and to perform a channel estimation (122) of the second frequency sub band (102) in order to determine a second phase (132). According to the invention, the receiver is further configured to determine an overall phase basis (133) of the radio signal using the first and second phases (131, 132).