gigabit home networking (G.hn)
G.hn stands for Gigabit Home Networking. It is a high-speed technology for home networking developed by the HomeGrid Forum and standardized by the ITU-T. Unlike most high-speed technologies, G.hn can be transmitted on all physical in-house transmission media, such as telephone cables laid indoors, power lines and TP cables, coaxial cables and radio frequency.
The G.hn technology was already adopted in 2009 as ITU standard G.9960 and was intended to eliminate existing incompatibilities in home networking. In order to meet the transmission requirements for G.hn, the standardization committees defined three frequency ranges for G.hn. The baseband range for powerline, transmission over telephone cables and category 5 TP cables. This range has bandwidths of 50 MHz and 100 MHz and extends from 2 MHz to 100 MHz. The bandpass range between 100 MHz and 200 MHz, and the RF range, which can be between 300 MHz and 2.5 GHz and has the same bandwidths.
The data rates supported by G.hn are 1 Gbit/s and 2 Gbit/s, respectively. A G.hn network can consist of up to 250 nodes. Multiple profiles can be addressed for a wide variety of applications. High- profile devices with high data throughput and sophisticated management features include residential gateways, while low-profile devices include automation devices with low data throughput.
G.hn uses a carrier frequency method with many subcarriers modulated in Orthogonal Frequency Division Multiplex( OFDM) or in Quadrature Amplitude Modulation( QAM). Whereby the QAM technique can work with up to 12 bits and thus modulate up to 4,096 bit values. The integration of the different transmission media is based on a single transceiver, which is optimized for the different media and parameterized depending on the cable. Thus, OFDM can be used in multicarrier mode on all transmission media, but parameterization also allows the number of subcarriers and their frequency spacing to be changed depending on the media. Similarly, the forward error correction can be changed depending on the transmission medium.
The high data rate of G.hn is exclusively due to the performance improvement of the main components. They have higher bandwidths and better modulation techniques. The techniques used are extremely robust and also allow transmissions on transmission lines subject to noise. In addition to home networking, G.hn is also suitable for small businesses, hotels and conference rooms.
G.hn is supported by the HomeGrid Forum( HGF) and is also used in smart grids.