As more LTE (Long Term Evolution) networks go live across the globe, operators have started planning to offer data roaming, and reusing spectrum is seen as one of the best chances of getting worldwide coverage, according to speakers at the LTE Forum conference this week in Stockholm.
So far, operators have launched about 17 commercial networks in countries including Austria, Germany, Japan, Sweden and the U.S., according to data from industry organization GSA (Global mobile Suppliers Association). Add to that another 140 networks that operators have committed to building, and LTE can be considered the fastest-growing mobile system ever, GSA president Alan Hadden said at the conference.
A year ago, roaming on LTE didn't make much sense, but the growing interest in the technology is changing that, according to Andrés Suazo, head of Tele2's 4G Network Project. Tele2 has launched commercially in Sweden, using a network it shares with Telenor, and is testing LTE in Estonia, Latvia, Lithuania and the Netherlands.
From a roaming perspective, the advantage of LTE compared with previous technologies is that it will eventually have a truly global reach. But just like existing GSM networks, different parts of the world use different frequencies to roll out the technology. That makes developing products able to access the Internet using either LTE -- starting with USB modems -- more complicated, especially for users traveling to different continents.
One band that has the potential to offer LTE roaming across several continents is 1.8GHz, which more than 350 operators have already been allocated and now mainly use for GSM voice, according to Hadden.
The world's first commercial LTE network on 1.8GHz was launched by Mobyland in Poland in September last year. At Mobile World Congress in February, Australia's Telstra announced that it would launch LTE on 1.8GHz by the end of the year. Other operators that have also shown an interest include Elisa in Finland, Deutsche Telekom in Germany and StarHub in Singapore.
"What we are seeing today is a lot of interest [in 1.8GHz] from operators in Europe, Asia-Pacific and also in Brazil," said Frédéric Pujol, head of radio technologies and spectrum practice at IDATE Consulting and Research.
Frequencies below 1GHz provide good indoor coverage, and are also a good fit for expanding LTE coverage to rural areas. But there is no particular band below 1GHz that is widely used globally. And while operators have spectrum available in, for example, 2.6GHz band, which allows them to offer higher speeds, it comes at the cost of diminished indoor performance. Meanwhile, the 1.8GHz band can offer users and operators a good compromise of speed and coverage.
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