SINGAPORE - The Internet may feel like it's everywhere, but large pockets of sky, swathes of land and most of the oceans are still beyond a signal's reach.
Three decades after the first cellphone went on sale - the US$4,000 (S$5,023) Motorola DynaTAC 8000X "Brick" - half the world remains unconnected. For some it costs too much, but up to a fifth of the population, or some 1.4 billion people, live where "the basic network infrastructure has yet to be built," according to a Facebook white paper last month.
Even these figures, says Kurtis Heimerl, whose Berkeley-based start-up Endaga has helped build one of the world's smallest telecoms networks in an eastern Indonesian village, ignore the many people who have a cellphone but have to travel hours to make a call or send a message. "Everyone in our community has a phone and a SIM card," he says. "But they're not covered."
Heimerl reckons up to 2 billion people live most of their lives without easy access to cellular coverage. "It's not getting better at the dramatic rate you think."
The challenge is to find a way to connect those people, at an attractive cost.
And then there's the frontier beyond that: the oceans.
Improving the range and speed of communications beneath the seas that cover more than two-thirds of the planet is a must for environmental monitoring - climate recording, pollution control, predicting natural disasters like tsunami, monitoring oil and gas fields, and protecting harbors.
There is also interest from oceanographers looking to map the sea bed, marine biologists, deep-sea archaeologists and those hunting for natural resources, or even searching for lost vessels or aircraft. Canadian miner Nautilus Minerals Inc said last week it came to an agreement with Papua New Guinea, allowing it to start work on the world's first undersea metal mining project, digging for copper, gold and silver 1,500 meters (4,921 feet) beneath the Bismark Sea.
And there's politics: China recently joined other major powers in deep-sea exploration, partly driven by a need to exploit oil, gas and mineral reserves. This year, Beijing plans to sink a 6-person 'workstation' to the sea bed, a potential precursor to a deep-sea 'space station' which, researchers say, could be inhabited.
"Our ability to communicate in water is limited," says Jay Nagarajan, whose Singapore start-up Subnero builds underwater modems. "It's a blue ocean space - if you'll forgive the expression."
BALLOONS, DRONES, SATELLITES
Back on land, the challenge is being taken up by a range of players - from high-minded academics wanting to help lift rural populations out of poverty to internet giants keen to add them to their social networks.
Google, for example, is buying Titan Aerospace, a maker of drones that can stay airborne for years, while Facebook has bought UK-based drone maker Ascenta. CEO Mark Zuckerburg has said Facebook is working on drones and satellites to help bring the Internet to the nearly two thirds of the world that doesn't yet have it. As part of its Project Loon, Google last year launched a balloon 20 km (12.4 miles) into the skies above New Zealand, providing wireless speeds of up to 3G quality to an area twice the size of New York City.
But these are experimental technologies, unlikely to be commercially viable for a decade, says Christian Patouraux, CEO of another Singapore start-up, Kacific. Its solution is a satellite network that aims to bring affordable internet to 40 million people in the so-called 'Blue Continent' - from eastern Indonesia to the Pacific islands.
A mix of technologies will prevail, says Patouraux - from fiber optic cables, 3G and LTE mobile technologies to satellites like his HTS Ku-band, which he hopes to launch by end-2016. "No single technology will ever solve everything," he said.
Indeed, satellite technology - the main method of connectivity until submarine cables became faster and cheaper - is enjoying a comeback. While Kacific, O3b and others aim at hard-to-reach markets, satellite internet is having success even in some developed markets. Last year, ViaSat topped a benchmarking study of broadband speeds by the US Federal Communications Commission.
And today's airline passengers increasingly expect to be able to go online while flying, with around 40 per cent of US jetliners now offering some Wi-Fi. The number of commercial planes worldwide with wireless internet or cellphone service, or both, will triple in the next decade, says research firm IHS.