Continuous Scatterer Parameter Update for Wireless Channel Estimation

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Solution Overview

Problem

Current channel estimation techniques in wireless communication systems fail to produce accurate estimates, especially for higher order modulations, and struggle to predict channel changes due to vehicle mobility, leading to inadequate interference cancellation and diversity combining.

Innovation Solution

A method for tracking scatterer parameters in a wireless channel by updating existing sets of parameters using signal samples derived from newly received signals, employing continuous sequential updates or integrated Doppler approaches, allowing for more accurate channel frequency response estimation and prediction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional channel estimation techniques are used, then the system operates with existing estimation methods, but the channel estimates are insufficiently accurate for higher order modulations

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidreliability for higher order modulations
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the parameters used for channel estimation from conventional methods to scatterer-based parameters including path delays, Doppler frequencies, and scattering coefficients. By modeling the channel as a collection of scattering objects with specific parameters, the system achieves higher estimation accuracy suitable for higher order modulations while maintaining reliability through continuous tracking of these parameters

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements continuous feedback by tracking scatterer parameters over time and using updated measurements to refine channel estimates. The system continuously monitors path delays, Doppler frequencies, and scattering coefficients, feeding this information back into the estimation process to maintain accuracy in dynamic environments with vehicle mobility

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If conventional channel estimation is used, then the system maintains simplicity, but it cannot predict channel changes due to vehicle mobility

Engineering Contradiction:
Improvechannel prediction capabilityVSAvoidcomplexity of estimation process
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by establishing scatterer parameter models in advance that capture the essential characteristics of scattering objects. By pre-defining parameters such as path delays, Doppler frequencies, and scattering coefficients, the system creates a framework that enables prediction of channel changes due to vehicle mobility without requiring complex real-time computations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces specific parameters (path delays, Doppler frequencies, scattering coefficients) that directly relate to mobile channel behavior. These parameter changes enable the system to adapt to and predict channel variations caused by vehicle mobility, transforming a static estimation approach into a dynamic, predictive model

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the entire calculation process is repeated for each time interval, then accurate scatterer parameters are obtained, but the processing requires significant computational resources and time

Engineering Contradiction:
Improvescatterer parameter accuracyVSAvoidprocessing efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary calculations of scatterer parameters during an initial evaluation period, establishing a baseline model of the scattering objects. This preliminary action allows subsequent updates to focus only on changes from the initial state, significantly reducing computational requirements while maintaining accuracy through incremental updates using new signal samples

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by updating only the necessary scatterer parameters using new signal samples rather than repeating the entire calculation process. The system performs selective updates on parameters that have changed due to mobility, avoiding redundant computations and improving processing efficiency while maintaining measurement precision

Inventive Principle:
Principle #16Partial or excessive action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables improved channel estimation and prediction, enhancing the accuracy of channel estimates for higher order modulations and facilitating better interference cancellation and diversity combining by continuously updating scatterer parameters based on new signal samples.

Implementation Method 1

a transmitted signal reflects off objects (e.g. buildings, hills, etc.) in the environment, referred to herein as scattering objects. The reflections arrive at a receiver from different directions and with different delays.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The complex delay coefficients show fast temporal variation due to the mobility of the vehicle while the path delays are relatively constant over a large number of OFDM symbol periods.

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Data Source

PatentEP2438723B1Continuous sequential scatterer estimation
Publication Date: 2013.08.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP2438723B1 patent drawingFigure 1
  • EP2438723B1 patent drawingFigure 2
  • EP2438723B1 patent drawingFigure 3~4

AI summary

The present invention uses newly received signal samples to update previously determined scatterer parameters, and therefore, reduces the processing effort required for characterizing scattering objects in a wireless channel. Broadly, the present invention determines a first set of scatterer parameters based on signal samples derived from signals received during one or more previous time interval, and determines an updated set of scatterer parameters for a subsequent time interval based on the first set of scatterer parameters and the new signal samples hi one exemplary embodiment, the receiver uses a continuous sequential update process, e.g., a per-symbol-period inverse Prony process, to update the scatters parameters !n another exemplar embodiment, the receiver uses an integrated Doppler approach to update the scatterer parameters.