Delivering Gigabit Speeds

English: A gigabit HP-ProCurve network switch ...

English: A gigabit HP-ProCurve network switch in a nest of Cat5 cables. (Photo credit: Wikipedia)

There is a lot of talk about companies like Google and many municipal networks delivering Gigabit speeds to homes and residents. But what is not discussed is the fact is that there are no existing wiring technologies that can deliver the bandwidth for any significant distance. Most people are shocked when they find out how quickly data speeds drop with existing wiring technologies.

Existing wiring is adequate to deliver Gigabit speeds to the smaller homes or to small offices. Carriers have typically used category 5 wiring to deliver data signal, and that technology can deliver 1 Gigabit for about 100 feet from the fiber terminal. But after that the speeds drop off significantly.

Wiring technology was never a significant issue when we were using the wiring to deliver slower data speeds. The same fall-off occurs regardless of the data speeds being delivered, but a customer won’t notice as much when a 20 Mbps data connection falls to a few Mbps as when a Gigabit connection falls to the same very slow speed.

Many carriers are thinking of using the new 802.11ac WiFi technology as a surrogate for inside wiring. But the speeds on WiFi drop off faster than speeds on data cabling. So one has to ask if a customer ought to bother paying extra for a Gigabit if most of it doesn’t get delivered to his devices?

Below is a chart that compares the different technologies used today for data wiring along with a few that have been proposed, like WiGig. The speeds in this table are at the ‘application layer’. That means theoretical speeds but is the easiest number to use in a chart because it is the speeds that each technology touts when being promoted. But you must note that actual delivered data speeds are significantly less than these application layer speeds for every technology listed due to such things as overheads and for the bandwidth due to modulation techniques.

Speeds Chart

The technology that stands out on the chart is ultra-broadband from PulseLink of Carlsbad California. PulseLink uses the radio frequency (RF) spectrum on coaxial cable above 2 GHz and can deliver data rates exceeding 1 Gbps. They are marketing the technology under the name of CWave. This technology uses a wide swath of RF spectrum in the 3 to 5 GHz range. As a result the RF signal is out-of-band (OOB) to both Cable TV and Satellite and will peacefully co-exist with both. Typically RF spectrum above 3 GHz on coax cable has been considered unusable RF spectrum, but due to the unique techniques used Pulse-LINK’s CWave chipset the technology reliably delivers Gigabit data rates while not disturbing existing frequencies used by cable TV and cable modems. Effectively it adds a whole new Ethernet data path over existing coaxial and that needs no new wires when coax is already present.

The differences in the various technologies really matters when you are looking at delivering data to larger buildings like schools and hospitals. As was recently in the news, President Obama announced a ConnectED initiative that has the stated goal of bringing a minimum of 100 Mbps and a goal of 1 Gbps to 99% of students within five years. But there does not seem like any good reason to bring a gigabit to a school if only a tiny fraction of that bandwidth can be delivered to the classrooms. I think that the PulseLink ultrabroadband technology might be the only reasonable way to get broadband to our classrooms.

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