Power Line Data Synchronization at Zero Crossings
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Solution Overview
Problem
Low-voltage power line networks face harsh environments with low line impedance, large attenuation, and strong interference, making reliable data transmission challenging in PLC communication systems.
Innovation Solution
A method and device for transmitting and receiving data using power lines, where synchronization signals are sent at zero crossing points with a predetermined format, minimizing interference and ensuring accurate synchronization recognition, thereby improving communication stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If data transmission is performed on low-voltage power lines, then existing power supply lines can be used for communication without rewiring, but the transmission reliability deteriorates due to low line impedance, large attenuation, and strong interference from electrical appliances
Solution Approach 1:
The patent introduces a synchronization signal as an intermediary element that mediates between the transmitter and receiver. This synchronization signal, which includes a specific pattern of high and low level periods, acts as a reference that helps the receiver accurately identify the start and length of data packets amidst the noisy power line environment, thereby improving transmission reliability without requiring system reconstruction
Solution Approach 2:
The patent applies preliminary action by transmitting a synchronization signal before the actual data packet. This synchronization signal is sent in advance to establish the timing reference and signal characteristics that the receiver needs to properly decode the subsequent data packet, ensuring reliable reception even in the harsh power line environment
2Measurement precision
If synchronization signals are transmitted to enable accurate data reception, then data transmission accuracy is improved, but the communication time is increased due to the additional synchronization signal transmission
Solution Approach 1:
The patent uses parameter changes by varying the duration of high and low level periods within the synchronization signal to encode different information (such as signal length indication). This allows the synchronization signal to carry multiple pieces of information in a single transmission, improving recognition accuracy without proportionally increasing transmission time
Solution Approach 2:
The patent merges the synchronization function with the signal length indication function into a single synchronization signal structure. The synchronization signal simultaneously provides timing reference and informs the receiver about the data packet length, combining multiple functions that would otherwise require separate transmissions, thus reducing overall communication time
Data Source
AI summary
A method for transmitting data by using a power line. The method includes: setting i=1 and j=1; receiving an i-th zero crossing signal at a time point ti, and determining, based on the i-th zero crossing signal, a start time when synchronization signals of a j-th data packet are transmitted, the start time when the synchronization signals of the j-th data packet are transmitted being ti+t; transmitting the synchronization signals of the j-th data packet at the start time when the synchronization signals of the j-th data packet are transmitted; transmitting data signals of the j-th data packet in sequence; and determining whether j is equal to M; when j is not equal to M, continuing a data transmission; and when j is equal to M, ending the data transmission, M being a number of data packets into which data to be transmitted is divided.