As featured in Rethink's Wireless Watch
The 450-MHz band, originally used for analog mobile services, has played only a sideline role in digital communications, supporting a scattering of rural CDMA networks round the world. GSM and W-CDMA profiles for the band never gained support, but the interest in low frequencies for smart cities and other internet of things (IoT) applications could revive interest in the spectrum.
Low power, long distance connections are an important part of IoT functions such as smart metering. Some use narrowband or proprietary protocols, while WiFi will also have a role, especially as it moves into UHF and white spaces spectrum below 1-GHz, supporting long ranges and indoor penetration. LTE can claim the same benefits in its 800-MHz and 700-MHz implementations, but the propagation and cost efficiencies in 450-MHz are even better.
That could see the neglected spectrum coming back into use, as highlighted by Ukko Mobile, a Finnish mobile data provider which is boasting the world’s first commercial LTE450 network. This covers 99.9% of the heavily scattered population of Finland and will initially target services to moving vehicles and equipment. It is working with transportation companies like the Finnish National Railways to offer enterprise and M2M services to government and business sectors, though it will also move into residential broadband access for rural, underserved locations such as summer cottages.
Ukko received a 450-MHz licence in May and acquired a CDMA450 network, covering 99.9% of the population, from bankrupt provider Datame. The equipment has been provided by Huawei, which hopes to secure much of the market for migrating CDMA450 networks to LTE. The owners of those frequencies will also be eyeing machine-to-machine business models, while further 450-MHz spectrum will become available in some markets for 4G, notably Brazil.
Antti Pellinen, Ukko’s CEO, said in a recent interview: “Ukkoverkot is clearly in a challenger position in the Finnish mobile market landscape, especially from a frequency resources point of view. Deploying disruptive technology like LTE450MHz is a good technology strategy. It gives us new value for the 450-MHz band in mobile data use. In addition, the coverage properties are truly impressive, with a countrywide network across the whole of Finland (about 340,000 square kilometers) successfully achieved with only a few hundred sites.” A 450-MHz base station covers about twice the area of an 800-MHz version, and up to 20 times that of a 2.6-GHz site.
Swedish challenger Net 1 uses CDMA450 for rural services and M2M, and plans to position itself purely as an M2M connectivity operator, differentiating on security, quality of service and data usage.
The world’s last analog NMT network was switched off in June 2012, in Poland, leaving its operator Orange with the country’s only 450MHz licence. It repurposed the spectrum for CDMA and, according to the CDMA Development Group, gained a twelvefold increase in 3G coverage compared to 1.8-GHz or 2.1-GHz, the usual 3G bands in Europe. This enabled it to expand coverage to 90% of the huge geography of Poland, where 40% live in rural areas. The CDG also says African CDMA450 networks are profitable on ARPUs of less than $5, and it found a new lease of life for itself by working on a specification for LTE450 using non-contiguous spectrum.
There is a logic to using 450MHz more extensively for M2M networks and applications such as PMR (public mobile radio), especially as so many mobile networks are battling for the limited sub-1GHz resources in other parts of the UHF band such as 700MHz.
However, the option has often been ignored in regulatory recommendations regarding UHF, partly because the band is fragmented. For instance, UK watchdog Ofcom concluded in a recent spectrum management strategy document that there is very little interest in using the 450 to 470-MHz frequencies at all (Ofcom removed the work done on this topic from its 2014 report). However, there are PMR and public safety players, in particular, which believe these low frequencies are being unnecessarily sidelined in EU and UK policy.