Frequency Hopping Simulation via Channel Shifting

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Solution Overview

Problem

Current communication system simulation and testing methods, particularly for frequency hopping spread spectrum systems, are complex and costly due to high computational requirements and bandwidth needs, often necessitating expensive equipment and approximating channel fading, which limits accuracy and adaptability.

Innovation Solution

A low complexity frequency hopping simulation method that shifts the channel profile instead of the signal, splitting the hopping function between baseband processing and RF carrier elevation, reducing computational operations while maintaining accuracy, and utilizing a baseband and channel model combination to simulate frequency diversity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional RF channel simulation is used for frequency hopping spread spectrum systems, then simulation accuracy is maintained, but device complexity and cost increase significantly

Engineering Contradiction:
Improvesimulation accuracyVSAvoidsimulation equipment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the frequency hopping simulation into two parts: baseband processing that handles only the necessary signal transformations, and RF carrier elevation that handles the frequency translation. This segmentation allows each component to operate at optimized complexity levels, avoiding the need for full-bandwidth RF simulation while maintaining accuracy for frequency hopping scenarios.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a simplified baseband model that copies only the essential characteristics of the RF channel behavior needed for frequency hopping simulation. Instead of simulating the complete RF channel with full bandwidth, the baseband model replicates the relevant fading and attenuation effects, significantly reducing computational requirements while preserving simulation accuracy.

Inventive Principle:
Principle #26Copying

2Measurement precision

If full bandwidth RF channel simulation is implemented, then frequency hopping accuracy is maintained, but computational operations increase

Engineering Contradiction:
Improvefrequency hopping simulation accuracyVSAvoidcomputational efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts only the essential computational operations needed for frequency hopping simulation from the full RF channel simulation. By removing unnecessary full-bandwidth processing and keeping only the critical baseband operations and selective RF carrier elevation, the system achieves frequency hopping accuracy with significantly reduced computational operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If expensive RF channel simulator equipment is used, then simulation reliability is improved, but testing cost increases

Engineering Contradiction:
Improvesimulation reliabilityVSAvoidtesting system cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive, complex RF channel simulator hardware with a more economical baseband processing approach combined with simple RF carrier elevation. This substitution uses lower-cost components that perform the essential simulation functions without requiring expensive high-bandwidth RF simulation equipment, thereby reducing testing system cost while maintaining simulation reliability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP1881624B1Low complexity frequency hopping solution for performance testing system and method
Publication Date: 2010.09.22 MOTOROLA INC
  • EP1881624B1 patent drawingFigure 1~3
  • EP1881624B1 patent drawingFigure 4~6
  • EP1881624B1 patent drawingFigure 7

AI summary

A system and method for low complexity frequency hopping simulation for communication device performance testing is disclosed. A baseband and channel model combination in a baseband processing module (602) of a testing system (600) reduces the required number of computations while retaining accuracy. A simulated channel is generated (612) with a bandwidth required for frequency hopping, and the hopping is simulated by shifting (614) the channel (612) instead of the signal (606). Signal attenuation by the shifted channel (615) is modeled in the baseband processing module (602), and the resulting simulated signal (610) is then up-sampled (628) to the proper frequency for output to the test device (634).