Electronic Design
Defining Broadband

Defining Broadband

Broadband, of course, refers to high-speed Internet access. We had Internet access initially in the early to mid-1990s with dial-up phone services. Data speeds rapidly increased to the maximum possible on most plain-old telephone system (POTS) networks.

But at roughly 53 kbits/s for the best modems, that access was never fast enough. Some telecos offered something called ISDN that provided up to 128 kbits/s, though it wasn’t available everywhere and was very expensive. Next came DSL and cable.

The telcos offered DSL, as it delivered higher speeds on the standard POTS twisted-pair lines. DSL data rates were initially only 256 kbits/s but gradually increased to 512 kbits/s, 768 kbits/s, and eventually well over 1 Mbit/s.

Today with advanced versions like ADSL2+, data rates of more than 10 Mbits/s are achievable. Most DSL rates are lower, but up to 6 Mbits/s is commonly available. Some areas with VDSL can deliver up to 50 Mbits/s over short distances.

Cable TV companies found they could provision one or more of their 6-MHz TV channels for data, so they began offering fast Internet access. Rates of 1 Mbit/s or 2 Mbits/s were common, with more available. I tested my cable connection recently, and it hit a download peak of 13.9 Mbits/s, although that slows as traffic on the cable increases.

Cable can deliver up to 50 to 100 Mbits/s by bonding channels, but the price is high. And that’s essentially where we are today. Most U.S. consumers get their broadband connection by cable or DSL. In the U.S., cable service dominates the broadband connection market. DSL is a close second. That’s not the case in Europe and other parts of the world, where DSL rules the broadband market.

Over the years, several other options have become available. For example, some rural areas without DSL or cable are served by a satellite link. It can generally provide a downlink with a speed up to 500 kbits/s. Uplink is by telephone line, so it’s as slow as dial-up.

Some communities have tried to implement broadband over powerline (BPL), which puts orthogonal frequency-division multiplexing (OFDM) on the ac high-voltage lines, and activating a service for consumers. This generated massive radio interference, though, so it was curtailed.

Some utilities did solve the interference problem and offered service. Unfortunately, BPL never could offer the high speeds easily available on DSL or cable lines. Most BPL services have now been abandoned. In fact, the much touted BPL system in Manassas, Va., recently closed down.

A real achievement in broadband expansion has been the gradual rollout or fiber-optic services. Some telcos and cable companies do offer direct fiber to the home (FTTH). The best example is Verizon and its FiOS service, and about 17 million homes have it. FiOS achieves common download speeds of 50 and 100 Mbits/s, and it’s available at a premium cost.

In other areas, companies have installed passive optical networks (PONs), which are economical and can easily offer up to 1-Gbit/s service for a price. Most PONs offer less but can deliver at least 100 Mbits/s to a home for Internet service and Internet Protocol television (IPTV). Fiber is the ultimate answer to the broadband distribution question, but it is expensive and requires either digging or running fiber on available poles.

Additionally, we have wireless high-speed Internet service. The nation’s 3G data networks can easily deliver up to several megabits of downlink to laptops, smart phones, or home PCs. And with 4G Long-Term Evolution (LTE) in the wings for later this year and beyond, we can look to the cellular companies to expand their wireless broadband offerings. That will be boosted in part for the offering of femtocells, the small home basestations that bring a superior 3G or 4G experience to the cellular customer. Sprint and Clearwire already offer WiMAX-based 4G broadband wireless service, which is now in rollout mode.

As for what speed defines broadband, there is no standard or rule. It is almost whatever anyone says it is. The government initially defined it as anything faster than 200 kbits/s, but that has been abandoned. While the FCC didn’t formally define broadband, the plan does state that new broadband systems should deliver at least a 4-Mbit/s downstream data rate. That seems reasonable, even for modern wireless services.

However, the stated real goal is to ensure that at least 100 million U.S. homes have affordable access to 100 Mbits/s downstream and 50 Mbits/s upstream. With roughly 121 million homes in the U.S., that pretty much includes everyone. The goal is achievable, but it will take time and lots of new capital investment. And will most people want it, need it, or pay for it?

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