Power Line Multicarrier Communication Band Synchronization
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Solution Overview
Problem
Existing communication systems face challenges in efficiently utilizing broad frequency bands, particularly in power line communication, due to increased attenuation and level differences between low and high frequency bands, which limits communication speed and dynamic range requirements for AD and DA converters.
Innovation Solution
A communication apparatus and method that synchronizes communication units operating in different frequency bands (2 MHz to 30 MHz and 30 MHz to 80 MHz) using common or separate hardware, minimizing leakage signals by aligning symbol lengths and processing timings, and utilizing a cycle detector for AC power supply synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the frequency band is expanded to include high frequencies (30 MHz to 80 MHz), then the communication rate is theoretically improved, but the attenuation increases and the output becomes relatively restrictive
Solution Approach 1:
The frequency band is segmented into low band (2 MHz to 30 MHz) and high band (30 MHz to 80 MHz), allowing independent processing and optimization of each band to mitigate the effects of attenuation in the high frequency range
Solution Approach 2:
Both low band and high band communication units are merged into a single system that operates simultaneously, combining the advantages of both frequency ranges while managing their respective characteristics through unified control
2Productivity
If the frequency band is expanded to include high frequencies, then the communication rate is improved, but the level difference between low band and high band spectra increases
Solution Approach 1:
The system dynamically adjusts the gain of each band independently using variable gain amplifiers, allowing real-time compensation for the level difference between low and high bands without requiring excessive dynamic range from the AD/DA converters
Solution Approach 2:
Different processing characteristics are applied to different frequency bands, with the low band and high band having separate gain control and processing paths tailored to their specific characteristics
3Productivity
If TDM is carried out using low band and high band simultaneously, then the level difference between bands increases, but the communication capacity is improved
Solution Approach 1:
Variable gain amplifiers dynamically adjust the signal levels of each band during TDM operation, maintaining optimal signal levels despite the alternating use of different frequency bands and reducing the required dynamic range
4Productivity
If FDM is carried out using low band and high band, then signal leakage occurs between bands, but the communication efficiency is improved
Solution Approach 1:
Synchronization signals are transmitted beforehand to establish precise timing relationships between low band and high band communications, enabling the system to prevent signal leakage through proactive timing alignment
Solution Approach 2:
The system uses feedback mechanisms to detect and adjust for timing deviations between bands, maintaining orthogonality and minimizing signal leakage through continuous monitoring and correction
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A communication apparatus carries out multicarrier communication with another communication apparatus through a transmission channel. The communication apparatus includes a first communication unit which carries out communication using a subcarrier at a first frequency band; a second communication unit which carries out communication using a subcarrier at a second frequency band higher than the first frequency band; and a third communication unit which carries out communication by synchronizing the first communication unit with the second communication unit and concurrently using the first and second frequency bands.