The explosion of cellular services in the late '90s provided a harsh wake-up call for mobile satellite operators dreaming of providing voice and data services to the professional business traveler. Inter-carrier roaming agreements — which satellite operators couldn't replicate at the time — provided cellular subscribers with access to a dial tone regardless of where home was, and competition between equipment manufacturers drove down handset sizes. At the same time, prices plummeted as carriers ordered new phones in the millions each year.

“[When] the cellular market overtook the satellite market, it really took off,” said Vijay Venkateswaran, vice president of wireless products and services for Mobile Satellite Ventures (MSV). “The technology got fundamentally smaller. There was more investment; there was a lot of growth potential. [Handsets] got smaller and cheaper. If you think about it, it got cheaper to deploy cell towers than to launch a satellite. The business case for satellite was surpassed by [cellular] technology.”

Ted O'Brien, vice president of the Americas for Iridium Satellite, agreed. “The market we were initially talking about, the professional traveler who could go to any city with a virtual phone, … we never got economy of scale,” he said. “We were a bulkier, more expensive alternative [than cellular].”

In the ensuing years, communities came to expect the availability of cellular service and individuals grew accustomed to simply pulling handsets that fit in the palm of their hands out of a pocket and dialing a number to reach someone, no matter where they were located. But recent natural disasters have sharpened awareness of cellular network vulnerabilities to the forces of nature.

“Prior to [Hurricane] Katrina, the first responder community wasn't as [aware] as it is today, as it relates to mobile communications and the vulnerability to circumstances such as Katrina,” O'Brien said. Katrina showed that even when towers and antennas are able to survive an event of such magnitude, ground-based systems can be vulnerable to flooding — including the terrestrial-based networks that support wireless communications.

Now, public safety agencies recognize the need for alternative communications paths when terrestrial infrastructure isn't available — as often is the case when a major disaster occurs — and they want many of the same conveniences from alternate providers that cellular has delivered, including ease of use and smaller handsets. This is the audience that satellite is now prepared to serve.

But first responders aren't the only ones who need always-on communications. Verizon Business recently added satellite services to its portfolio to better serve enterprises.

“We recognize the need that enterprises are becoming more mobile, they need to be in communication 24/7, regardless of where they are,” said Stephanie Souder, product marketing manager for emerging technologies. “Enterprise customers have huge demand for business continuity, to have a backup for communication during a natural disaster.”

Verizon Business has partnered with Thrane & Thrane to offer a family of portable and rugged satellite equipment using Inmarsat's Broadband Global Area Network (BGAN). Two satellites currently provide coverage over 85% of the world's land mass to customers in 196 countries; when the third is launched later this year, BGAN will effectively cover everything “except the North and South Poles,” Souder said.

Thrane & Thrane's BGAN terminals range in weight from 3 to 4 pounds, and in size from an open paperback book to a larger laptop. All are designed for ease of use, incorporating a compass and software that together guide the user in pointing the flat-panel antenna in the proper direction to acquire the service. The terminals also are equipped with standard RJ-11 phone and RJ-45 Ethernet jacks.

“You plug in your phone, you plug in your PC, you have your office ready to go,” Souder said. “It's plug-in dial tone.” Some terminals provide Bluetooth capability, and the larger 700 model has an embedded Wi-Fi access point.

Meanwhile, Iridium's satellites are much more akin to cellular service in several respects. “Our satellites, in contrast to any other system, are very low in orbit, lower than any other operator,” O'Brien said. “We're at less than 500 miles in altitude. Geostationary operators are at 24,500 miles up. That's how we get away with these relatively small handsets and data modems that we have.” Users of the system don't have to worry about pointing an antenna in any direction other than up because there's always a satellite moving into range; a constellation of 66 satellites blankets the globe with full coverage, including the North and South Poles.

Being closer to the earth means a shorter transmission hop, without significant delay, between handset and satellite, unlike the traditional round trip of 49,000 miles between a mobile handset and geostationary satellite. Calls on the lower-flying Iridium satellites are quickly passed from satellite to satellite in a series of crosslinks, similar to the way calls are handed off between cellular towers.

Because it was designed from the ground up with voice service in mind, the Iridium network mimics the way a U.S. mobile phone network works, with calls originating and terminating in the same way. Iridium phones even have their own area code.

“You don't have to dial a particular way, there's no city code or country code to worry about — you dial it the same way and the call will connect to subscribers,” O'Brien said. “The preponderance of [emergency relief] people aren't communicators for a living — they're doctors, they're utility workers — they need something that's universally simple for them to use.”

While ease of use is a laudable goal, it's not the only one. Consequently, MSV is taking a different approach with its next-generation offering.

“We believe in bigger satellites in space,” Venkateswaran said. “We want users to be able to incorporate form-factor improvements found in the cellular world into a satellite handset.”

A typical geostationary communications satellite has a 6- to 6.5-meter dish antenna, a dimension that is being dwarfed by newer models.

“With our new satellites, we will have a 22.5-meter diameter dish,” Venkateswaran said. “That's a three to four times improvement in the size of the dish. From an area perspective, 12 times. A bigger dish is far more sensitive in terms of signaling and better able to close a link with a smaller device.”

Handsets designed to be used with MSV's new satellites will incorporate internal antennas or have an external antenna that is less than 2 inches in length, much smaller than the 4- to 6-inch antennas found on current satellite phones.

“Bigger antennas in space translate to smaller devices [on the ground],” Venkateswaran said. “Now we're talking something more conventional, more attractive. That's revolutionary. That's giving satellite capability with cellular [form-factor] capability.” It also gives MSV the ability to incorporate both cellular and satellite communications capabilities into a single, cell-phone-like handset.

MSV believes cellular/satellite combos are a necessity for public safety officials, according to Venkateswaran.

“Sometimes they keep their sat phone locked up in a cabinet as a device of last resort, but you don't know when a disaster will hit,” he said. “They also want interoperability with the cellular network. The user, if he or she is out of cellular coverage away from a cell tower, will be on satellite. Having an integrated handset with cellular, perhaps ruggedized, is relevant and useful with them. You don't have to trudge back to the office.”

Venkateswaran anticipates a baseline handset will be able to support downlink data rates between 100 to 200 kb/s with 50 kb/s uplink rates, roughly comparable with existing terrestrial 3G data rates. An optional antenna will enable higher data rates.

“We'll be able to provide and support all existing applications,” he said. “Instant messaging, push to talk, Internet and intranet access.”