Terayon Communication Systems Inc. is introducing a new software upgrade to its DOCSIS 2.0 cable-modem termination systems that will allow MSOs to increase network productivity for their high-speed access service.
The new TDMAccelerator product is designed to address the conundrum operators face where more advanced modems — such as Data Over Cable Service Interface Specification 2.0 modems — are often limited by the lower-performing modems on the system (such as those that follow the 1.0 spec).
The product effectively segments the data channel by placing all “slower” modems in a slower quadrature phase shift key transport lane, and allowing modems that operator at 16 quadature amplitude modulation (QAM) or higher to operate in “faster” lanes, thus improving network efficiency and customer experience.
“The TDMAcceleraor extracts more bandwidth from the existing DOCSIS 1.0 and DOCSIS 1.1 modem pool,” said Terayon senior director of product marketing Kanaiya Vasani. It enables DOCSIS 2.0 modems to operate at their maximum capacity, he said.
“This makes the upstream more efficient,” he said, allowing operators to go to 16 QAM or even 32 QAM for data. It also reduces the line-card ratio from 1:8 and 1:6 to 1:4, he said.
Overall, the new software can increase network capacity by three times, he added.
The new software has a cost benefit, because operators won’t have to look to split nodes as they increase data penetration or replace legacy modems, if a high percentage of the older units have been deployed.
Most cable operators are rolling out modems that follow both the DOCSIS 1.1 and 2.0 specifications. But many 1.0 units remain in place — and, in some cases, they account for 30% or more of existing modems.
They can be costly to replace, Vasani said, but they also serve as a drag on the system since they force an entire data channel to operate at QPSK, which is 5 Mbps.
Because these modems can’t handle pre-equalization, Vasani said, it forces all modems — including the new 2.0 units — to operate with their equalizers turned off.
The TDMAccelerator segments modems, allowing 2.0 modems to operate at 16 QAM (10 megabits) or higher, while segmenting slower QPSK modems into another part of the spectrum. In effect, the product creates a high-speed passing lane and a slow lane on the same highway, Vasani said.
The software has been tested in a number of systems, including one system that was able to move 87% of its modems to 16 QAM modulation, which resulted in a near doubling of channel capacity, he said.
Terayon also is introducing a product called dB Boost, which provides a 20- to 30-decibel gain for modems that operate in low signal-to-noise ratio environments, such as multiple dwelling units.
The software improves modem efficiency by less data, but more power per bit. The product is designed for DOCSIS 2.0 modems only, Vasani said.
