Renesas Introduces PLC Solution for Voice Communication over Power Lines

Renesas Electronics announces a new voice power line communication (PLC) solution that supports data communication and voice communication in existing power networks. The PLC solution reduces the amount of wiring inside buildings, thereby reducing the implementation and maintenance costs of public address (PA) systems and security systems.

Reduces cabling costs by integrating voice and data communications in the building's power distribution network

Renesas Electronics PLC software modem (R9A06G037), which manages PLC communications, and an RX651 microcontroller (MCU), which controls the processing of the audio codec, are new to the solution. The new solution integrates voice functionality into existing installations at a low cost and enables system manufacturers to enhance security systems. For new installations that include a variety of sensors and voice communications, wiring costs can be reduced by approximately 60 percent, while installation and maintenance costs can be reduced by up to 40 percent.

Facilities such as office buildings have a variety of management systems installed, including climate control systems, lighting, various sensors, building public address systems, and security systems. In the past, each system required its own dedicated line. More recently, the trend has shifted to utilizing existing direct current (DC) power lines in configurations where these communication lines are shared with the power system.

However, attempts to use power lines for voice communications have resulted in poor audio quality due to fluctuating delay times. In order to deal with the issue, the new voice PLC solution uses priority control during audio transmission to virtually eliminate latency fluctuations in voice communications, even when signal control communications and voice communications are operating on the same power lines. This ensures that audio quality remains consistent at all times. In addition, the solution optimally combines the audio priority control function with Renesas Electronics' narrowband PLC technology, allowing the use of signal lines longer than one kilometer without the use of repeaters. By combining data communication and voice communication over existing power networks, the new solution significantly reduces the amount of wiring required for building management systems and helps reduce maintenance costs.

Key Features of the Voice PLC Solution

Enables Priority Control in Audio Transmission, Suppressing Delay Variations and Ensuring Stable Sound Quality

In PLC systems, multiple devices use power lines as a common communication medium, so data conflicts must be avoided. This is similar to the anti-collision function used in wireless communications, where data is transmitted once it is confirmed that no other device is communicating. Renesas Electronics' Voice PLC solution utilizes an optimized anti-collision feature that enables prioritization of devices for "voice" transmission. This minimizes fluctuations in communication delays and ensures stable voice communication without interruptions.

Supports Long-Distance Transmission over One Kilometer without Relays, Allowing Extensive Coverage within Each Installation

PLC systems often include relaying (hopping) mechanisms to extend distance coverage. However, these mechanisms can also lead to increased fluctuations during data transmission. The R9A06G037 PLC chip integrates analog front-end circuitry with a wide dynamic range, variable amplifiers for transmission and reception, and ADC and DAC peripherals. In addition, Renesas Electronics has increased the operating frequency of the DSP used to perform PHY layer processing and added special instructions for PLC processing. These enhancements enable higher sensitivity for very small signals, as well as better immunity to noise generated by power lines, thus ensuring that long-distance communication is achieved. The new Voice PLC solution has been tested and proven to support more than 128 node connections and more than one kilometer of DC power lines without the use of repeaters.

Easy-to-Implement Software Stack Reduces the Time Required for System Development

The software stack allows users to easily select and implement an audio codec with the desired functionality, significantly reducing system development time. The new solution is adapted to a configurable software stack running on Renesas Electronics' RX651 MCU.