# HD-PLC

HD-PLC (short for High Definition Power Line Communication) is one of the wired communication technologies. It adopts high frequency band (2 MHz~28 MHz) over mediums like powerlines, phone lines, twisted-pair, and coaxial cables. It is the IEEE 1901-based standard.

## Specification and features

There are essentially two different types of HD-PLC: HD-PLC Complete and HD-PLC Multi-hop. They are incompatible.

### HD-PLC Complete

Source:
This is for high speed applications such as TV, AV, and surveillance cameras.
The major technical features include:
* IEEE 1901 full compliant
* QoS by the priority control
* CSMA/CA and DVTP(Dynamic Virtual Token Passing) supported
* Concurrent multi-AV stream, VoIP, and file transfer and file transfer supported using IP packet classification
* Multi-network access at priority CSMA/CA with network synchronization

### HD-PLC Multi-hop

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This is for long-distance applications such as smart meter, building network, factory, energy management, and IoT devices.
The major technical features include:
* ITU-T G.9905 multihop technology

### Common features

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* Uplinking/downlinking through 432 of 26 MHz (between 1.8 MHz and 28 MHz) bandwidth subcarriers with Wavelet OFDM
* Maximum 240 Mbit/s PHY rate
* Multilevel modulation for each subcarrier which suits the properties of the power line transmission channel and allows for the best transmission speed
* Subcarrier masking with the arbitrary number which can comply with the rules in each country
* Forward error correction (FEC) which enables effective frame transmission
* Channel estimation launch system with change detector for cycle and transmission channel
* HD-PLC network bridging compatible to Ethernet address system
* Advanced encryption with 128 bit AES

### 4th-generation HD-PLC (HD-PLC Quatro Core technology)

Source:
We now come to communication speed issues like high-definition video images (4K/8K) or in some cases multi hop technology is not enough to reach an isolated and distant PLC terminal. HD-PLC Quatro Core has been designed to solve these problems. This technology is an improvement on the conventional HD-PLC in both communication distance and speed. It achieves to double conventional HD-PLC's communication distance by adopting a communication band of 1/2 or 1/4 of conventional HD-PLC band and achieves to offer a maximum physical line transmission rate of 1 Gbit/s by using an expanded communication band 2 or 4 times the conventional HD-PLC band.
This evolution of the standard therefore offers either an extended range in a larger building, at the cost of a lower data rate, or a higher data rate, but achievable over shorter distances than in the previous version of the standard.

## Use cases

There are a few strengths of using HD-PLC technology on existing wires.
* Expectable higher speed performance
* Cost reduction on network construction by existed infrastructure
* Support the area where the radio waves is difficult to be reached
* Wire saving by sharing power lines and communication lines
Typical use case include:
* HVAC systems
* Building Automation
* PV panel
* Smart meter
* Street light
* Surveillance camera system
* Video entry system
* Tunnel
* Robot wire saving