Apple's latest iPad will not connect to many LTE networks in Europe, because it only supports the 700-MHz and 2.1-GHz frequency bands, a fact that has upset consumers in a number of markets. In Sweden, for example, where LTE has been rolled out in different bands, a consumer group last month said it has received complaints from users and is considering an investigation into Apple’s marketing of the new tablet.

The iPad issue has for the first time drawn mass-market attention to spectrum fragmentation and the future challenges it poses to manufacturers and end-users as an increasing number of LTE devices come to market.

One resolution to this regional conundrum could be the eventual implementation of the surprise decision by the World Radiocommunication Conference 2012 to open up the 700-MHz spectrum band to markets in Europe, Africa and the Middle East; the band is already available for use by mobile communications in North America and Asia-Pacific. This raises the possibility for the first time of a globally harmonised spectrum band that could provide a coherent ecosystem for LTE devices.

Of course, this is easier said than done: 700-MHz spectrum is a valuable resource for the broadcast sector in Europe, for example, and the battles over the first digital dividend in the 800-MHz band are still fresh in the minds of mobile and broadcast players alike. Nevertheless, there is growing pressure to make more spectrum below 1 GHz available for mobile broadband as usage grows.

“The stage is set for the right spectrum to be available for this sector,” said Dr Hamadoun Touré, Secretary-General of the International Telecommunication Union (ITU) at a roundtable at Mobile World Congress in February. Dr Touré describes the sub-1-GHz bands as “killer spectrum”.

The mobile industry has a great deal to gain: 700-MHz spectrum could help to overcome a number of hurdles facing the LTE market at present, with roaming, cheaper services and a better device ecosystem high on the agenda. The question is whether the spectrum can be freed up quickly enough, and if global players can agree on a suitable 700-MHz band plan that would promote a global ecosystem for devices.

According to Frederic Pujol, head of radio technologies & spectrum practice at iDate, the debate over the “second digital dividend” will be fiercer than the first as it will involve more players and come up against more resistance. “I anticipate the same process, but it will be more complicated,” he says.

As things stand, European operators are being assigned frequencies in the 800-MHz and 2.6-GHz bands for LTE use, while US and Canadian operators utilise the 700-MHz and 2.1-GHz bands. 3G networks will thus continue to play a huge role in enabling roaming for LTE devices. “LTE roaming is really a mess right now,” says Pujol. “LTE international roaming is a big worry for mobile operators, especially those in Asia.”

Pujol supports the decision by the WRC-12 to open up the 700-MHz spectrum band for mobile services in ITU Region 1, which includes Europe, Africa and the Middle East. Opening up the 700-MHz band for Region 1 was not originally on the agenda for WRC-12, and was initially resisted by policy and regulatory body the European Conference of Postal and Telecommunications Administrations (CEPT).

“CEPT faced a difficult situation at the beginning of the conference with a request from Arab and African countries for a mobile allocation in the 700-MHz [band] - an extended digital dividend,” said Eric Fournier, chairman of the Conference Preparatory Group of the Electronic Communications Committee, which is part of CEPT, in a statement. “Since this proposal was not corresponding to an agenda item of WRC-12, CEPT unanimously opposed this proposal at the beginning of WRC-12,” he noted.

By the end of the conference, CEPT had agreed a compromise that would effectively allow African and Arabic countries to use the 700-MHz band (694 MHz-790 MHz) for mobile communications with immediate effect, but would delay the opening of the band in Europe until after the next WRC in 2015.

The delay to 2015 is to enable the necessary technical studies to be concluded regarding the availability and assignment of the new band, according to Janette Stewart, senior manager at Analysys Mason. “This ‘second digital dividend’ in ITU Region 1 is adjacent to the first digital dividend at 800 MHz (from 790-862 MHz), which was put into place at the previous WRC in 2007,” she said in a research note.

Stewart notes that three principal factors led to the decision to allocate this second digital dividend: it enables countries in Africa and the Middle East (where parts of the 800-MHz band are used for other systems and services) to proceed with awarding digital dividend spectrum in the 700-MHz band; the 700-MHz band provides additional bandwidth that can be used to accommodate mobile broadband services in Europe; and the 700-MHz allocation in Europe raises the prospect of harmonisation with other ITU world regions.

“However, implementing the new 700 MHz allocation within ITU Region 1 will create a number of challenges, acknowledged by the ITU-R (ITU Radiocommunication Sector) in its decision that the new allocation should not come into force until 2015,” she commented.

The key to a fully harmonised use of the 700-MHz band lies in the choice of a band plan that would arrange spectrum allocations within the frequency band to ensure devices can move seamlessly from one region to another, iDate’s Pujol explains. He believes the best available approach would be to adopt the 2x45 MHz band plan proposed by the Asia-Pacific Telecommunity (APT) (see chart).

“If the WRC-15 agrees to reallocate this band to mobile broadband services, I think the CEPT and probably Africa and the Middle East would try to adopt the APT band plan in order to make sure there would not be a limitation of devices and chipsets,” he says.

Pujol points out that the APT band plan is likely to be adopted by the main countries in the Asia-Pacific, and is also very likely to be used in Africa and the Middle East given the power of Chinese manufacturers such as Huawei and ZTE in those regions. The benefits this could have for the device ecosystem provide a powerful argument in favour of the APT approach.

One thing is certain: markets in Region 1 will want to avoid the fragmented situation that has emerged in the US as a result of its 700-MHz band plan. The US was forced to adopt a very specific plan that takes into account legacy issues, but the end result is that smaller US operators face huge obstacles in exploiting their 700-MHz licences because of the difficulty in obtaining devices that work in their particular spectral arrangements.

“During the original 700-MHz auction [in 2008], the spectrum was portrayed as ‘prime real estate’,” says Brett Calder, director of wireless at Globecomm, a US company that is helping small and rural operators in the US to find a business model that will enable them to launch LTE services in the 700-MHz band. “It was said to be better than 800 MHz or 1800/1900 MHz,” but that turned out not to be the case because of the way the frequency band was set up for the regional carriers, meaning that separate products have to be developed for different band classes, he says. Essentially, the market’s larger carriers got a better spectral arrangement than the smaller players. And when it comes to the procurement of mobile devices, size matters.

“It has been tremendously stressful for small carriers,” says Calder. “They have been sitting on licences for four to five years now…there is no ‘universal’ 700 MHz here - it depends where you are in the frequency band.”

Indeed, last month T-Mobile USA called on US telecoms regulator the FCC to ensure there is full interoperability between all LTE networks operating in the 700-MHz spectrum bands.

“Requiring interoperability throughout the band will promote roaming among commercial wireless providers and enhance public safety use of the 700 MHz broadband spectrum,” said Kathleen O’Brien Ham, VP federal regulatory affairs at T-Mobile USA, in a letter to the FCC. “While devices using LTE technology can accommodate multiple bands, there is a practical limit to the number that can be accommodated,” she added, noting that carriers operating outside the 700-MHz band “may be required to choose among 700-MHz licensees for roaming partners, rather than potentially roaming with all 700-MHz licensees.”

Calder believes it is even possible that some companies could be forced to return their licences within the next 12 months.

The rest of the world could certainly avoid this level of fragmentation if there is significant collaboration between the different regions: As Analysys Mason’s Stewart says, “international harmonisation of the 700-MHz band could be achieved, but not without detailed co-operation between the different ITU regions, given the current divergence in 700-MHz deployments between the US and parts of the Asia–Pacific.”

However, 700 MHz is only a medium- to long-term solution to harmonisation issues, iDate’s Pujol notes, as allocations in many markets will not take place for years, and some markets will be more opposed to opening up this band for mobile communications than others.

Robert Ercole, senior director of spectrum regulation at the GSM Association, points out that LTE is just starting out in Europe, and that on a European level at least there is a wide availability of spectrum in the 2.5/2.6GHz band. “Even harmonising at a regional level is better than nothing,” he says.

In his view, the fact that there was a big debate at the WRC-12 about the second sub-band is a general indication that countries are now interested in trying to harmonise their spectrum allocations. “People recognise the importance of harmonisation,” Ercole says. “That’s a positive outcome: they don’t want a patchwork of frequencies.”