Optical Channel Estimation Using Component Geometry

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Solution Overview

Problem

Existing optical communication systems require training sequences for channel estimation, which consume temporal and frequency resources and can be distorted by processing steps like DC biasing in OFDM-based systems, especially in scenarios with high mobility or frequent changes in the optical communications channel.

Innovation Solution

Determining the channel estimate by calculating the location, orientation, and transmission/reception characteristics of optical transmitting and receiving components, using methods such as GPS or orientation sensors, and calculating the channel without transmitting training sequences over the optical channel, potentially using RF signals for information exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If training sequences are used for channel estimation in optical communication systems, then channel knowledge can be obtained, but temporal and frequency resources are consumed and channel estimation can be distorted by processing steps like DC biasing in OFDM-based systems

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidtemporal resource consumption
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by determining channel characteristics before actual data transmission begins. The system calculates channel estimates based on pre-determined parameters including locations of transmitting and receiving components, their orientations, and their transmission/reception characteristics. This preliminary channel characterization eliminates the need for time-consuming training sequences during the actual communication phase, thereby resolving the contradiction between obtaining accurate channel knowledge and consuming temporal resources.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If training sequences are used for channel estimation, then channel knowledge can be obtained, but channel estimation can be distorted by processing steps like DC biasing in OFDM-based systems

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidchannel estimation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the channel estimation process from the data transmission process. Instead of estimating the channel during OFDM processing (where DC biasing and other processing steps cause distortions), the system separately determines channel characteristics based on geometric and physical parameters. This extraction eliminates the harmful interaction between channel estimation and signal processing steps, thereby improving both accuracy and reliability of channel knowledge without compromising either.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If training sequences are transmitted over the optical channel for channel estimation, then channel characteristics can be determined, but overhead is increased

Engineering Contradiction:
Improvechannel knowledge acquisitionVSAvoidcommunication overhead
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary approach by using geometric and physical parameters (locations, orientations, transmission characteristics) as mediators to determine channel characteristics. Instead of transmitting training sequences directly over the optical channel, the system uses these intermediary parameters to calculate channel estimates. This intermediary method avoids the overhead associated with training sequence transmission while still achieving accurate channel knowledge, thereby resolving the contradiction between channel characterization and communication overhead.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3864774B1Determining a channel estimate
Publication Date: 2023.06.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3864774B1 patent drawingFigure 1
  • EP3864774B1 patent drawingFigure 2~3
  • EP3864774B1 patent drawing

AI summary

In one example aspect, a method of determining a channel estimate of an optical communications channel between at least one optical transmitting component and at least one optical receiving component is provided, the method comprising determining a location of at least one optical transmitting component, determining an orientation of the at least one optical transmitting component, determining a transmission characteristic of the at least one optical transmitting component, determining a location of at least one optical receiving component, determining an orientation of the at least one optical receiving component, determining a reception characteristic of the at least one optical receiving component, and calculating the channel estimate of the optical communications channel based on the location of the at least one optical transmitting component, the orientation of the at least one optical transmitting component, the transmission characteristic of the at least one optical transmitting component, the location of the at least one optical receiving component, the orientation of the at least one optical receiving component and the reception characteristic of at least one optical receiving component.