Dynamic FEC Bypass in UAV Communications

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Solution Overview

Problem

In digital communications systems, particularly for unmanned air vehicles (UAVs), the forward error correction (FEC) decoder function consumes significant power, which is a challenge as it is required for maintaining bit error rate and link performance across multiple wireless links, including user, gateway, and inter-UAV links.

Innovation Solution

The FEC decoder function is dynamically removed from UAVs based on instantaneous link quality, such as Bit Error Rate (BER) and Frame Error Rate (FER), and other parameters like available power and estimated future power consumption, with the option to move it to a gateway terminal during high signal quality conditions, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the FEC decoder function is continuously activated in UAVs to maintain bit error rate and link performance, then communication reliability is improved, but power consumption increases significantly

Engineering Contradiction:
Improvebit error rateVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic FEC decoder activation by monitoring link quality metrics (signal-to-noise ratio, bit error rate) in real-time. The decoder is activated only when link quality degrades below predefined thresholds, and deactivated when link quality is sufficient. This dynamic adaptation resolves the contradiction by making the FEC decoder operational state variable rather than fixed, reducing power consumption during good link conditions while maintaining reliability during poor conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameter of the FEC decoder from a constant on-state to a variable state based on link quality parameters. By monitoring parameters such as signal-to-noise ratio and bit error rate, the system adjusts the decoder activation state accordingly. This parameter-based control resolves the contradiction by aligning decoder operation with actual communication needs rather than continuous operation.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the FEC decoder is moved to a gateway terminal during high signal quality conditions, then power consumption in UAVs is reduced, but device complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidsystem complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent extracts the FEC decoder function from the UAV and relocates it to the gateway terminal under specific conditions (high signal quality). This extraction resolves the power consumption contradiction by removing the power-hungry decoder from the mobile platform when its function is less critical. The system manages this complexity through clear conditional logic that determines when to activate or deactivate the decoder based on link quality metrics.

Inventive Principle:
Principle #2Taking out (Extraction)

3Use of energy by moving object

If the FEC decoder is dynamically removed based on link quality, then power consumption is reduced, but communication reliability may deteriorate under low signal conditions

Engineering Contradiction:
Improvepower consumptionVSAvoidlink performance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the system continuously monitors link quality metrics (signal-to-noise ratio, bit error rate, frame error rate) and uses this feedback to control FEC decoder activation. When link quality deteriorates below thresholds, the feedback loop triggers decoder activation to restore reliability. This closed-loop control resolves the contradiction by ensuring reliability is maintained during poor link conditions while allowing power savings during good conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system applies beforehand cushioning by proactively activating the FEC decoder when link quality metrics indicate deteriorating conditions, before actual communication failures occur. By monitoring trends in signal quality and anticipating degradation, the system activates the decoder in advance to prevent bit error rate escalation, thus maintaining reliability while minimizing unnecessary activation during stable conditions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3400664B1Dynamic forward error correction bypass in a digital communications system
Publication Date: 2020.06.24 GOOGLE LLC
  • EP3400664B1 patent drawingFigure 1
  • EP3400664B1 patent drawingFigure 2
  • EP3400664B1 patent drawingFigure 3

AI summary

A system and method of improving communications is provided. A gateway (120) is communicatively coupled to an end terminal (190) through an unmanned air vehicle (UAV) (150), wherein a first link (140) communicatively couples the gateway (120) to the UAV (150), and a second link (180) communicatively couples the UAV (150) to the end terminal (190). At least one of the gateway (120) and the UAV (150) is configured to determine a signal quality on at least the first link (140) between the gateway (120) and the UAV (150) in a first direction. If the signal quality exceeds a predetermined threshold, a received packet is encoded at the gateway (120) for processing by the end terminal (190). The packet is further tagged with an indicator that the packet should bypass (270) forward error correction (FEC) at the UAV (150).