Power Line Communication Noise Mitigation via Dummy Symbol Insertion
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Solution Overview
Problem
Power line communication systems face challenges in transmitting long packets of data over poly-phase power lines affected by impulsive noise synchronous with phase voltages, as existing methods like coding and interleaving are insufficient, especially when noise is synchronous with multiple phases, reducing error correction capability and increasing chip size requirements.
Innovation Solution
The method involves determining time intervals free from impulsive noise to transmit useful data and using dummy data or symbols with higher repetition rates during noisy intervals, employing a novel transmission mode that alternates between data and dummy symbols to improve reliability, specifically using 2-DPSK coded modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coding and interleaving are employed to protect against burst noise, then error correction capability is improved, but chip size increases significantly
Solution Approach 1:
The patent applies periodic action by transmitting dummy symbols at regular intervals during noisy periods. The transmitter inserts dummy symbols periodically in time slots corresponding to noisy intervals, allowing the receiver to identify and discard these dummy symbols while retaining useful data. This periodic insertion pattern enables error correction without requiring complex coding schemes that would increase chip size.
Solution Approach 2:
The patent extracts the harmful noise periods from the transmission timeline by identifying time slots corresponding to noisy intervals. During these extracted periods, dummy symbols are transmitted instead of useful data. The receiver then separates and discards these dummy symbols, effectively removing the impact of burst noise from the data stream without requiring extensive error correction coding.
2Reliability
If interleaving is used to spread errors, then robustness against burst noise is improved, but effectiveness diminishes when noise is synchronous with multiple phases
Solution Approach 1:
The patent implements feedback mechanisms where the transmitter and receiver share information about noisy intervals. The transmitter determines which time slots correspond to noisy periods based on feedback about the power line conditions, and adjusts transmission accordingly by inserting dummy symbols. This feedback loop enables the system to adapt dynamically to multi-phase noise patterns, maintaining effectiveness regardless of which phases are affected.
Solution Approach 2:
The patent applies dynamics by making the transmission strategy adaptive rather than static. The system continuously monitors power line conditions and adjusts its behavior in real-time, inserting dummy symbols during noisy intervals and transmitting useful data during quiet periods. This dynamic adjustment allows the system to maintain robustness against evolving multi-phase noise patterns without relying on fixed interleaving configurations.
3Reliability
If dummy symbols are transmitted during noisy intervals, then data transmission reliability is improved, but transmission time increases
Solution Approach 1:
The patent applies local quality by treating different time slots differently based on their noise characteristics. During noisy intervals, dummy symbols are transmitted to maintain synchronization and enable error correction. During quiet intervals, useful data is transmitted at full speed. This localized adaptation ensures that time is not wasted on redundant transmission during good conditions, while protecting against noise during bad conditions, thus optimizing the overall time-reliability tradeoff.
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 approach enables reliable transmission of long data packets by minimizing the impact of synchronous noise, enhancing error correction and reducing chip size requirements, thus improving communication robustness in noisy conditions.
Implementation Method 1
employing a novel transmission mode that alternates between data and dummy symbols to improve reliability, specifically using 2-DPSK coded modulation
Data Source
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AI summary
The method transmits a long packet of digital data over a poly-phase power line affected by impulsive noise synchronous with phase voltages. Instead of using very complicated coding schemes, starting from the knowledge of the typical power line scenario, useful information is transmitted where noise synchronous with the main signal is absent. Time-intervals of a known or estimated duration during which the poly-phase power line is affected by impulsive noise are determined, and dummy data during the time-intervals, and useful data during other time-intervals free from impulsive noise, are transmitted.