Various Approaches Needed to Meet Global Demand for Mobile Spectrum

Serious challenges lie ahead, said Gabrielle Gauthey, executive vice president-global government and public affairs at Alcatel-Lucent. There are about 400 connected devices per square kilometer in the 400 biggest cities, she said. In five years, there will be 13,000 devices, she said. The way spectrum has been allocated will need to be revisited, she said.

Radio spectrum and system capacity are not new problems, said Mark Pecen, vice president-advanced technology at Research in Motion. Balancing the “various requirements” needs to be “balanced” and done “right,” said Phil Laven, chairman of the Digital Video Broadcasting Project. Half of the frequency allocation decisions by ITU and the national regulators are wrong, Laven said, but “it takes us 10 years to know that they are wrong.” That track record means thinking about the future needs to be much more dynamic in terms of modifying “things as they go along,” he said.

Mobile network predictions show that by 2020, traffic will be 500 times larger, said Francois Rancy, director of the ITU Radiocommunication Bureau. Luck and a compelling argument to ITU World Radiocommunication Conferences may boost available spectrum by 50 percent, Rancy said. That means a 100-fold efficiency gain still needs to be found, Rancy said. That can’t come from new modulation techniques, he said.

An IEEE study said that from 1957 to 2008, spectral capacity improved so that about 1 million times more information can be carried over each MHz, Pecen said. Information theoretical models boosted capacity 25 fold, he said, referring to advanced modulation and coding schemes, receiver improvements and interference cancellation. Statistical gains from trunking efficiency and regulatory gains from contiguous spectrum blocks boosted capacity another 25 times, he said. The remaining 1600-fold improvement is attributable to smaller cells, he said.

But more towers means more costs, a developing country participant said. More spectrum is the cheapest solution, the participant said. The main reason WRC-07 allocated to mobile in the 700 and 800 MHz band was because it allowed cheaper coverage of less populated areas, Rancy said.

Regulators must remember the bands are “the only ones to solve the Digital Divide,” Rancy said. Sharing 700 or 800 MHz band base stations in less densely populated areas can help keep costs down, Rancy said referring to the unrealistic expectation of having the multiple operators build out separate networks in rural areas.

If everybody uses a tablet to watch video on demand via mobile, spectrum will run out in 10 years no matter how much spectrum ITU allocates, Laven said. “Most of the demand for spectrum” is based on a huge amount of video being delivered, Laven said. “It’s a real problem,” Laven said. Transferring the mobile Internet into a mechanism for on-demand delivery of individualized TV streams is “prohibitive,” Laven said. WiFi and fixed networks can be used for delivery to home networks, Laven said. “The laws of economics will take over,” Pecen said referring to price discrimination for data rates.

"The very rapid takeoff of data over mobile networks” raises concerns that the amount of spectrum set aside to address the capacity increase may not be sufficient, Rancy said. WRC allocations for 3G made in 1992 required about 10 years to be made available and used, he said. WRC-2000 allocated the 2.6 GHz band, Rancy said, and the band is only starting to be used now, 11 years later. “The system is able to react with a time response of 10 years,” Rancy said. The lag is decreasing, he said. WRC-07 identified the digital dividend bands in 700 and 800 MHz and they are now starting to be used, he said referring to the four-year time lag.

Spectrum can be used in more economical ways, said Marc Furrer, president of the Swiss Federal Communications Commission referring to technological gains, gains from better spectrum management and changing its authorized use. LTE, cognitive radio and infrastructure sharing can help boost efficiencies, he said. Better use of unlicensed spectrum can also help, he said referring to WiFi. “Other mobile services” have to be switched off, he said. A second Digital Dividend will also have to be discussed, he said. Does Switzerland need T-DAB, he asked, citing high cable penetration.

Harmonization is an important issue for handset maker RIM, Pecen said. What’s been happening is the auction of “many, many” non-harmonized, unrelated bands, he said. If 18 bands had to be added to a global phone, a $20 to $30 device for India wouldn’t be possible, he said.

The challenges will “force” a review of the rules that pervade the voice world, Gauthey said. Smaller cells are the solution for “densification,” she said referring to devices becoming more numerous over geographic areas. “Almost indoor cells” should be authorized to offload as soon as possible this data tsunami on a fixed backhaul, Gauthey said.

Femtocells should not be taxed, as they are in some countries, Gauthey said. “The future of wireless is wireline backhaul,” she said. Regulators should allow and foster spectrum sharing, she said, especially in the so-called digital dividend bands. Allow new business models to re-balance the value chain in the face of the “data tsunami,” she said referring to the prevailing business model of 80 percent of revenue coming from voice.

Regulators also need to take a long-term view on spectrum, said Alexander Kuhn with the German Federal Network Agency for Electricity, Gas, Telecommunication, Post and Railway. “Every service wants to go broadband,” he said referring to WRC-12 deliberations. The question of more spectrum demand arises for every radio service used for communications, Kuhn said.

It’s not sensible to have four or five operators build out parallel networks, Kuhn said. There is no real economy for having three or four networks in the 700 MHz LTE bands in rural areas, Gauthey said. National agreements increasingly call for commercial sharing of networks, she said. Sharing also creates incentives, said Kuhn, who also referred to coverage obligations.

Spectrum for safety of flight is one of the foundations for global mobility, Kuhn said. He also promoted the Earth exploration satellite service. Europe aims to increase spectrum for the service at the WRC-15. The political impact of climate change needs to be taken into account, he said. “We need validated data,” Kuhn said referring also to meteorological applications.

Digital terrestrial television is the dominant form of delivery in many countries, Laven said. Terrestrial delivery isn’t important in Germany, Belgium and the Netherlands, he said, but it is in Spain, France, Italy, and the U.K.

There were a lot of white spaces in the time of analog TV, Laven said. Broadcasters used it for program-making, he said. Digital terrestrial TV made it more difficult because the gaps have been filled, Laven said. “There is less opportunity, but there is still some opportunity,” Laven said. Some gaps will be available if used carefully, he said. “Clear rules and clear mechanisms,” are needed, Laven said. Devices that consult a live database based on geographic position can produce a “dynamic process,” Laven said, and would be “an extremely good way” of moving ahead. “A truly dynamic use of the spectrum” is “what we're looking for,” Laven said. We can’t manage with 15-year allocations anymore, Laven said.

The military uses “much too much” spectrum in many countries and “they don’t really use it,” Furrer said. Mobile developments over the last 20 years have been using ex-military spectrum, Rancy said referring to the GSM band, 900 MHz, 1800 MHz, 2 GHz, 2.6 GHz, and 800 MHz where there was military before broadcasting. When WRC-07 started to “eat into” broadcasting to provide mobile service, it was the first time when military service “may not have” been involved in the discussion, he said. Other ostensibly non-military applications use spectrum, Rancy said referring to GPS. “Nobody complains that it is using spectrum,” Rancy said.