A transmission method based on OFDM power line communication

A technology of power line communication and transmission method, applied in distribution line transmission system, wired transmission system, transmission system, etc., can solve the problems of power frequency discontinuous transmission, no mention of power frequency synchronous transmission method, etc., to achieve power output Low, avoid false tripping, reduce costs

Active Publication Date: 2019-12-13
HI TREND TECH SHANGHAI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So far, the low-voltage low-frequency narrowband power carrier communication (OFDM) standards that have been released internationally, such as: ITUG.9902, ITU G.9903 (G3-PLC), and ITU G.9904 (PRIME), have not mentioned the Frequency synchronous transmission mode, or power frequency zero-crossing non-continuous transmission mode

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  • A transmission method based on OFDM power line communication
  • A transmission method based on OFDM power line communication
  • A transmission method based on OFDM power line communication

Examples

Experimental program
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Effect test

Embodiment 1

[0098]This embodiment provides a zero-crossing differential transmission mode based on G3-PLC (ITU G.9903). Since the noise at the power frequency zero-crossing moment is relatively small, data can be sent at the zero-crossing point, which can Effectively improve the quality of the signal. The differential zero-crossing mode takes the half cycle of power frequency 10ms as the unit (assuming 50Hz AC), and sends data at each zero-crossing moment respectively. The sending method is as follows figure 1 shown. When communicating in differential zero-crossing transmission mode, the first data packet segment consists of a preamble and 1 FCH symbol, and its preamble consists of 8 SYNCPs and 1.5 SYNCMs, in which all subcarriers of the frame synchronization symbol SYNCM The phase is rotated 90 degrees relative to the SYMP. In order to ensure that the subsequent data packet segments are sent synchronously with the power frequency zero-crossing, the first data packet segment must be sen...

Embodiment 2

[0101] This embodiment provides a zero-crossing related transmission mode based on G3-PLC. In this embodiment, when communicating in the related zero-crossing transmission mode, such as figure 2 As shown, the first data packet segment consists of a preamble and 1 FCH symbol, and its preamble consists of 8 SYNCPs and 1.5 SYNCMs, where the phases of all subcarriers of SYNCM are rotated by -90 relative to SYMP Spend. In order to ensure that the subsequent data packet segment (burst) is sent synchronously with the zero-crossing of the power frequency, the first data packet segment (the data packet segment of the zero-crossing transmission time slot) must start sending at the time point of 4.75±0.1ms after the zero-crossing time, all The packet segment of the next zero-crossing transmission slot will consist of 4 OFDM symbols, and the idle interval between two zero-crossing slot data packets (data packets of the zero-crossing transmission slot) is 6.95ms (equivalent to 10 OFDM sy...

Embodiment 3

[0103] This embodiment provides a zero-crossing correlation transmission mode based on ITU G.9902, which is the same as the G3-PLC-based correlation zero-crossing transmission in Embodiment 2, such as image 3 As shown, the first data packet segment is composed of a preamble (preamble) and 1 FCH symbol, and its preamble is composed of 8 (can also be increased to, such as: 8+4=12) SYNCPs and 1.5 SYNCMs, where The phases of all subcarriers of the frame sync SYNCM are rotated by -90 degrees with respect to the SYMP. In order to ensure that the subsequent data packet segment (burst) is sent synchronously with the zero-crossing of the power frequency, the first data packet segment must be sent at 4.72±0.1ms after the zero-crossing time, and all subsequent data packets of the zero-crossing transmission time slot A segment will consist of 4 OFDM symbols, while the idle interval between two zero-crossing slot packets is 7.0ms (equivalent to 10 OFDM symbols), and each packet segment is...

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Abstract

The invention relates to the low frequency narrowband power line carrier communication field and especially relates to a transmission method of OFDM communication and a selection method of a transmission mode. The method is based on a power line in a power line communication system and an OFDM modulation mode is adopted to carry out data communication. The transmission method comprises the following step of in any one period of time, using the power line to carry out continuous sending or discontinuous sending of a data packet, wherein when the discontinuous sending is performed, in a zero-crossing time segment of a power frequency on an alternating current power line, the data packet is transmitted. A periodic noise and a pulse type interference of the power line can be effectively avoided, and an influence of a electric power load on a communication success rate is reduced so that reliable and effective data communication is reached.

Description

technical field [0001] The invention relates to the field of low-frequency narrowband power line carrier communication, in particular to a transmission method based on OFDM power line communication. Background technique [0002] Noise, interference, and access impedance on low-voltage distribution lines usually exhibit cyclostationary characteristics, so the transfer function and signal-to-noise ratio of the channel also exhibit cyclostationary characteristics. , its cycle is usually consistent with the half cycle (zero crossing point) of AC power frequency (such as 50Hz or 60HzAC). There are many factors that affect the quality of power carrier communication, but the most important ones are the complex channel and noise environment on the power line. The periodic impulse noise (impulsive noise) synchronized with the power frequency is one of the most important factors affecting the communication success rate in the low-frequency narrowband power carrier communication. Pre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26H04L27/34H04B3/54
CPCH04B3/542H04L27/2656H04L27/2666H04L27/34
Inventor 张旭明
Owner HI TREND TECH SHANGHAI
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