Sunday, January 09, 2011

The Economist: Why LTE can't substitute for fiber

Some believe the Internet will become untethered over the last mile and point to cutting edge wireless transmission technology known as LTE or 4G. The two biggest telcos in the U.S., Verizon and AT&T, are rolling it out (or are about to in the case of AT&T.)

But it won't be able to replace the nation's aging copper cable infrastructure that has grown increasingly difficult and costly to operate reliably. Nor is it likely to provide sufficient capacity for future growth in bandwidth demand -- something that Verizon and AT&T are acutely aware having faced growth pains and capacity constraints with their current generation of 3G wireless.

The Economist explains why:

Already LTE has shown itself good for at least 5Mbps—impressive for a mobile technology still in its infancy (see “Generational change”, December 3rd, 2010). But with peak speeds of 1Gbps theoretically possible, LTE’s next iteration should make downloads of 100Mbps over the airwaves a matter of routine. Developments beyond that could lead to near-gigabit speeds.

Of the two, though, a fixed link like fibre remains the better bet. Sooner or later, even a 4G wireless protocol such as LTE or its country-cousin WiMAX will become overwhelmed by the exponential growth of mobile traffic. By contrast, an optical link to the home could use a multitude of different wavelengths to boost throughput almost indefinitely.

Network World also weighs in:

So the next question about wireless broadband as a substitute. Recall that according to the U.S. Government Centers for Disease Control and Prevention (CDC), 1 in 4 homes has cut the legacy wireline phone cord in favor of wireless-only voice. Could we see wireless substitution rates that high for broadband access? We think not because radio spectrum is a limited resource, and unlike wireless voice networks that have plenty of spectrum to manage voice calls, if 25% of broadband users shifted from wireline access, the demand for wireless broadband would likely exceed available spectrum given today's technology.
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