Chirp-BOK Modulation for Reliable Power Line Communication
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Solution Overview
Problem
Power-line communication (PLC) systems face challenges in smart grid applications due to time-varying noise levels, unpredictable signal attenuation, and regulatory constraints, limiting their reliability and coverage, especially in low-data-rate communication scenarios required for demand response and load control.
Innovation Solution
The use of quasi-peak (QP) measurement techniques combined with chirp-binary orthogonal keying (BOK) modulation and spread spectrum control signals with a chirp frequency range extending over the QP frequency band to enhance PLC communication reliability and coverage, allowing for low-bitrate sensing and control protocols that meet regulatory emission standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional PLC modulation techniques are used to achieve high data rates, then communication speed is improved, but reliability and coverage deteriorate in low-bandwidth control applications
Solution Approach 1:
The patent changes the modulation parameters by using chirp-BOK modulation instead of conventional PLC modulation. This involves frequency-modulated chirp signals with binary orthogonal keying, where the frequency varies linearly over time. This parameter change enables the system to achieve both low data rates and high reliability by optimizing the signal characteristics for robust transmission through the power line channel.
Solution Approach 2:
The patent employs periodic chirp signals with specific frequency sweep characteristics. The chirp signals are transmitted periodically with controlled frequency variations, creating a periodic action that enhances signal detection and discrimination. This periodic chirp structure allows the receiver to synchronize and reliably detect signals even in the presence of noise and interference.
2Area of stationary object
If transmitted signal power is increased to improve coverage, then communication range is improved, but electromagnetic interference and regulatory compliance deteriorate
Solution Approach 1:
The patent segments the frequency spectrum by using chirp signals that sweep through a defined frequency range rather than transmitting at a single frequency. This frequency segmentation allows the signal to occupy multiple frequency bins during transmission, distributing the energy across the spectrum. As a result, the peak power at any single frequency is reduced, lowering electromagnetic interference while maintaining overall signal energy for improved coverage.
Solution Approach 2:
The patent changes the signal parameters by using frequency-modulated chirp signals instead of constant frequency signals. The frequency varies linearly over time according to the chirp rate, creating a time-varying signal that spreads energy across the frequency spectrum. This parameter change enables the system to achieve better coverage through improved signal processing while complying with electromagnetic interference regulations.
3Adaptability or versatility
If PLC systems operate in challenging electrical environments with time-varying noise, then adaptability is improved, but measurement precision and signal detection deteriorate
Solution Approach 1:
The patent implements feedback mechanisms in the receiver to compensate for time-varying noise and channel conditions. The receiver continuously monitors the signal quality and adjusts its parameters in real-time, using feedback from signal strength and noise level measurements. This feedback loop enables the system to maintain precise signal detection across varying electrical environments by dynamically adapting to changing conditions.
Solution Approach 2:
The patent uses periodic chirp signals with known frequency characteristics that serve as reference patterns for signal detection. The periodic nature of the chirp signals allows the receiver to use correlation and matched filtering techniques to precisely detect and distinguish signals from noise. The periodic structure provides temporal redundancy that enhances signal detection precision in the presence of time-varying interference.
Data Source
AI summary
Described are power line communication (PLC) systems, devices and techniques which are reliable and suitable for use in control applications which can operate with relatively low data rates while complying with governing regulatory rules. Such systems, devices and techniques enable demand-side management of electrical loads in a building or facility or other environment.