Are Lessons From 3G Deployment Being Applied To LTE?

The first 3G network was launched nearly a decade ago. Subsequent 3G deployments were criticised for being too expensive and lacking a single global standard. While the initial Long-Term Evolution (LTE) spectrum auctions have been less expensive, have other key lessons been learned in time for 4G’s rollout?

When the first commercial 3G mobile network was launched in October 2001, its Japanese operator DoCoMo chose the WCDMA standard. Since then, operators have spent billions of dollars establishing 3G offerings across the world and deploying tem on a variety of bands and standards, which include WCDMA, CDMA2000, TD-CDMA, and TD-SCDMA.

Consumers were forced to buy expensive multi-band, multi-standard equipment for establishing universal communication. On the other hand, mobile equipment manufacturers were hit harder.

The multiple standards and frequencies required by 3G meant that all mobile broadband devices required region-specific variants with a different bill of materials for each one to make them cost effective. In fact, multi-standard, multi-frequency transceivers such as Lime’s LMS6002 have only become available in the past couple of years, making universal user equipment a more realistic proposition.

Deploying LTE

The next big roll-out, LTE, is receiving a lot of consumer interest. Tests performed by Epitiro earlier this year suggest typical speeds for LTE networks are around 40 to 50 Mbits/s and latency is exceptionally low, meaning services such as mobile gaming will be truly possible when the deployment moves over to 4G.

This demand from consumers led to TeliaSonera’s 2009 launch of the world’s first LTE networks, across Scandinavia. In the U.S., Verizon has rolled out its LTE network in several cities and airports. Elsewhere, spectrum auctions have taken place or are scheduled, with smaller LTE networks in their infancy.

However, it appears that regulators and the industry as a whole are following the 3G path for the rollout of LTE with an even greater number of frequency bands, albeit with fewer flavours of the standard.

Will There Be Harmonisation?

“The biggest concern facing many operators now is the squeeze on available spectrum,” says Fei Feng, a research analyst at ABI. This has meant that many countries, including Taiwan, have not announced any plans for LTE spectrum allocation.

In the U.S., Verizon and other operators have adopted 700 MHz, although networks running on the 1700-MHz band have also been announced. In Europe, TeliaSonera’s 2009 Swedish LTE deployment was based on 2.6 GHz. The 800-, 900-, and 1800-MHz bands have also been allocated.

A similar pattern can be found in Asia with 700 MHz, 1700 MHz, and 2.6 GHz being assigned. As ABI’s practice director Adita Kaul has also indicated, a challenging issue to tackle will be the ability of LTE devices to work across the various spectrum bands.

To support as many different frequency band allocations as possible, LTE standards allow paired and unpaired spectrum operation using frequency division duplex (FDD) and time division duplex (TDD) techniques. Paired spectrum operation is known as FD-LTE, and unpaired spectrum is known as TD-LTE.

So far, there are 28 FD-LTE networks. While no TD-LTE networks have been established, China Mobile, Bharti Airtel, Softbank Mobile, Vodafone, Clearwire, E-Plus, and Aero2 launched the Global TD-LTE Initiative (GTI) in February.

These move point to the fact that there is no one standard being adopted globally, or even in the same country. Australian operators Telstra and Vivid Wireless, for example, have respectively announced future LTE networks based on FD-LTE and TD-LTE.

Many lessons should be learned from the rollout of 3G. Regulators and operators have not reached a unanimous decision on the spectrum being allocated and standards adopted. In the absence of a worldwide agreement, the device manufacturers and the broadband OEMs once again are asked to engineer around the problem.

This time, however, new multi-band, multi-standard ICs and devices are beginning to find their way into the market, enabling OEMs to keep backward compatibility as well as allowing numerous frequency bands and variations of the standard to be deployed cost effectively.