The approval of standards for PLC by the IEEE P1901 (Institute of Electrical and Electronic Engineers) as baseline technology has accelerated HD-PLC’s widespread adoption. This approval has given a big impact to the industry; as a result of setting clear rules to tie the various PLC standards together, the coexistence with IEEE system has been ensured, a standard that differs from existing HD-PLC system.
• HD-PLC Alliance’s booth at International CES 2009
The approval of PLC standard as baseline technology by IEEE P1901 was announced at the main stage and at the front desk
There are several standards for PLC including HD-PLC, but under the current system, data cannot be exchanged when devices with different standards are connected in a network. This is because the signals sent by PLC devices with different standards are deemed as noise. To alleviate this problem, IEEE established P1901 Working Group in June 2005 to develop a standard for PLC.
On the other hand, Panasonic Corp. and Panasonic Communications Co., Ltd., both members of the HD-PLC Alliance, established CEPCA (Consumer Electrics Powerline Communication Alliance), an organization that promotes standardization of PLC in cooperation with manufacturers adopting other PLC standards in June 2006. They drew up a draft proposal for standardization before IEEE took action, and proposed it to IEEE P1901. And this was the proposal that was approved this time.
Device Check via Standard Verification Signals
IEEE P1901 standard specifies that PLC data must include a signal to verify which equipment with PLC standard sent the data. Devices such as the PLC adaptor send verification signals periodically, which is like saying: ‘I (the device) declare that I was manufactured based on this standard’. PLC devices connected to the network checks the flowing data. When the device finds data with signals with standards different from its own, it first detects the existence of PLC devices with other standards. Next, the two devices start communicating by automatically shifting to coexistence mode to avoid interfering with each other. This enables users to connect to the network without having to worry about the different standards, as long as they are using devices that are IEEE P1901-compliant.
This system is effective not only for in-home networks, but also in the future when it will be more common to use PLC through power lines connected to electrical poles instead of using access lines outside the home, such as optical fiber or ADSL. Since there are differences between networks that are indoor and outdoor, it is necessary to connect the two without any problems. This recently approved standard which can connect different types of networks, does not only apply for devices with PLC standards, but also for connecting indoor and outdoor networks, theoretically.
• When PLC is used as an access network to the Internet, interconnecting between in-home networks and outside the home is necessary. IEEE P1901 will enable this type of connection
Moreover, this standard also ensures the compatibility with current PLC devices including HD-PLC. From the compatibility point of view, HD-PLC and other PLC standards are on the same level. However, with WaveletOFDM, a communication technology that HD-PLC adopts, devices use less power when transforming data to be sent using PLC, when compared with other standards. This is why HD-PLC is able to facilitate the speed-up and downsizing of devices.
IEEE P1901 Working Group will fine tune the details of specifications within the next year or so. A draft version of ‘IEEE 1901’ with specifications close to finalization is expected to be released as early as the end of 2009. Around the same time, parts and devices with ensured compatibility are expected to appear on the market. This will allow PLC to go a step further in widening its adoption among users.
