Synchronized Power Line Communication Time Slot Allocation
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Solution Overview
Problem
Conventional power line communication systems face inefficiencies due to asynchronous data transmission, leading to packet loss and increased power consumption, as multiple modems can access the same medium simultaneously, causing collisions and retries.
Innovation Solution
Implementing a synchronized power line communication system that uses zero crossings of the power line waveform as a synchronizing signal to assign specific time slots to each modem, reducing collisions and enabling modems to operate in sleep mode when not transmitting or receiving, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If asynchronous data transmission is used in power line communication systems, then modems can access the medium independently, but packet collisions increase and communication efficiency decreases
Solution Approach 1:
The patent implements periodic time slot allocation synchronized with the power line waveform周期 (typically 50Hz or 60Hz). Each modem is assigned specific time slots within each power line cycle to transmit data, creating a periodic structured access pattern that eliminates collisions while maintaining efficient communication.
Solution Approach 2:
The patent segments the continuous power line communication medium into discrete time slots within each power line cycle. By dividing the transmission opportunity into multiple non-overlapping time segments assigned to different modems, the system prevents packet collisions while allowing multiple modems to access the medium systematically.
2Device complexity
If asynchronous transmission without synchronization is used, then device complexity is reduced, but packet loss increases due to collisions and retries
Solution Approach 1:
The patent uses the existing power line waveform as a self-generated synchronization reference for all modems. Each modem independently detects the power line cycle and aligns its time slots to the same reference points (e.g., zero crossings), eliminating the need for external synchronization signals or complex coordination mechanisms while ensuring all modems operate in sync.
Solution Approach 2:
The power line waveform serves multiple functions simultaneously: it provides both the power transmission carrier and the synchronization reference for data communication. This multi-functionality eliminates the need for separate synchronization channels or additional signaling, reducing device complexity while maintaining reliable synchronized operation.
3Reliability
If modems operate continuously to handle collisions and retries, then communication reliability is maintained, but power consumption increases
Solution Approach 1:
The patent enables modems to operate in periodic sleep-wake cycles aligned with the power line communication time slots. Modems wake up only during their assigned transmission or reception time slots and return to sleep mode otherwise, dramatically reducing power consumption while maintaining reliable communication through the structured time division multiplexing that prevents collisions.
Data Source
AI summary
A method and a device are disclosed including a PLC node having a synchronizer, a modem with a transceiver, and a computing device coupled with a power line for power line data communications. In various embodiments, a coordinator or Data Concentrator Unit (DCU) coordinates the communication of PLC nodes. The PLC nodes are configured to detect a zero crossing of the power line wave form and transmit or receive data within time slots defined with respect to the detected zero crossing. In other embodiments, the time slots may be synchronized using a frame sync signal, an external signal, or polling. In various embodiments, the time slots may be random access or assigned. In some embodiments, the modem and/or node may be placed in a sleep mode when not communicating to reduce power consumption and be awaken when an allocated time slot is approaching.