Lighting up copper loop

If fibre is not coming to a building or curb near you, it’s time to squeeze more juice out of that copper loop ringing your premises.

Actelis Networks Inc., a 3-year-old company founded by ex-Nortel Networks Corp., 3Com Corp., Fujitsu Ltd. and JDS Uniphase Corp., is looking to “light up” copper by making it as reliable as fibre for delivery of broadband services such as DS-3 and backhaul of large-scale DSL deployments.

Even though the industry is currently fixated on fibre and optical networks as the conduits for big broadband bandwidth, 60 per cent of all office buildings in the U.S. will not be fibre-fed by 2009, says Steve Olen, Actelis senior product manager. The demand for fibre is outstripping the supply.

But the existing copper loop infrastructure lacks the reliability of fibre. Copper was designed for low-bandwidth applications; it has a bit error rate at least twice that of fibre; it has a limited loop reach of 12,000 feet or less; it is prone to frequent pair failures; and has poor noise resiliency.

Actelis’ solution is a patented Spatial Division Multiplexing (SDM) algorithm to provide symmetric full-duplex transport of 10Mbps to 100Mbps, increase the loop reach to 18,000 feet and cut the bit error rate closer to, if not the same as, fibre.

SDM uses multiple copper pairs on a link between transport systems. It parses packets and transmits the fragments over the copper pairs, then reassembles the packet at the destination node.

This results in data that is less prone to corruption than if it were transmitted using TDM, should the connection incur a major noise burst, Olen says. Actelis one-ups this by adding Forward Error Correction to SDM, which results in a packet that’s totally intact even if a major noise burst occurs, Olen claims.

This results in broadband service delivery in one day over an existing infrastructure to homes, buildings and businesses that were beyond the reach of services such as DSL or DS-3.

Actelis is targeting its technology at facilities-based incumbent local exchange carriers – the ones with money to spend. The company just completed an SDM trial with the North Pittsburgh Telephone Company, which realized fibre-like reliability – a bit error rate less than half that of TDM-based copper – for traffic at DS-3 and beyond, Olen claims.

The company is on the Web at