DSL technology specialists continue to labor toward achieving speeds in the hundreds of megabits per second range. Ikanos Communications said it has fabricated a chipset that can support data delivery at up to 200 Mbps. Meanwhile, Genesis Technical Systems is demonstrating an approach that could boost DSL speeds to 400 Mbps.
One of the key impediments in DSL transmission is the unpredictability of crosstalk across wires. Vectoring is a means of reducing, if not eliminating, crosstalk. Ikanos has introduced a VDSL chipset, with accompanying software, with its take on vectoring, which the company calls NodeScale Vectoring.
Ikanos’ Velocity-3 chipset with NodeScale Vectoring supports up to 384 copper lines in a fiber terminated installation (FTTx). The company claims that Velocity-3 identifies and cancels VDSL crosstalk from all lines in the vectored group, independent of binder, cable or chassis.
Improving a DSL installation could cost as little as one-tenth the cost of deploying a pure fiber solution to individual home, Ikanos calculates.
The technology is being tested by Huawei.
Han Yufa, general manager of the Access Network Product Line for Huawei, said, “Due to the random nature of crosstalk which occurs throughout the entire cable bundle, the potential of VDSL2 performance can only be realized when full Node-Level vectoring is applied across all the cables connected to the node. Huawei’s target is to protect the customer’s investment by eliminating the crosstalk of the existing copper plant using a flexible and future-proof architecture. We have been working with Ikanos for the past two years and now we are glad to see Velocity-3’s achievement on its way.”
Separately, Genesis Technical Systems announced the launch of a technology it is calling DSL Rings, which the company said can deliver 400 Mbps over existing copper, again a cheaper option than a full fiber installation.
Genesis Technical Systems’s rings appear to be almost directly analogous to HFC nodes. The company explained that bonded pairs are used to obtain maximum bandwidth from the central office (CO) to the pedestal/distribution point (DP). These signals are terminated in what Genesis Technical Systems is calling a converged node (CN), which acts as the gateway node for the subscriber ring. Each node can add, drop and pass through traffic. Each ring can consist of a group of 2 to 15 houses (the company recommends a maximum of 12).
The VDSL2 based transmission curve restarts at each node. In most cases the distances back to the pedestal and then to the house are less than 750 feet, the company said. VDSL2 bandwidth at this distance is up to 200 Mbps.
Because of the ring network topology, there are two paths in and out of each home in the ring, or node, so the aggregate of a maximum 200 Mbps from both directions renders the 400 Mbps the company said the system is theoretically capable of.
The greater the number of subscribers on the ring, the greater the bandwidth pool available due to the greater number of pairs available due to the greater number of pairs available for bonding from the pedestal to the CO, the company explained.
As with all DSL technology, transmission rates are dependent on distance, and cutting the distances will also contribute to boosting data rates.
