The growing demand for radio spectrum to accommodate new services and the physical limits on the amount of spectrum available are forcing new users and incumbent services to search for innovative engineering solutions to avoid signal interference.

Broadband and wireless applications , in particular, are boosting the demand for spectrum, which is a relatively finite resource. As a result, new users, especially those with terrestrial services, are increasing the pressure on regulators to make more spectrum available by any means possible, including forcing satellite companies to give up some of the spectrum reserved for satellite services.

New technology is making the old rules used by regulators to allocate bandwidth obsolete, John Janka, a partner in the Latham & Watkins law firm, said during a May 23 presentation at a military satellite conference in Silver Spring, Md.

In the past, the U.S. Federal Communications Commission (FCC) would allocate spectrum, set rules for its use and license individual services, Janka said during the “Military Satellites” conference, which was sponsored by the Institute for Defense and Government Advancement, a New York based non-partisan group that promotes innovative ideas in public service and defense.

Now, regulators are willing to allow flexible use of spectrum and to look for “holes” in existing spectrum use that can be reassigned to new service entrants, Janka said. The result is that incumbent users are asked to prove “harmful interference” would be caused if new services shared their spectrum, he said .

The International Telecommunication Union, a United Nations organization that coordinates international telecommunications networks and services, generally has held a policy of having both incumbent and new users share and coordinate their use of spectrum but the “presumption” has been in favor of existing users, said Tara Giunta, a partner with the Paul, Hastings, Janofsky & Walker LLP law firm.

“That has started to change in an effort to accommodate new services,” Giunta said. “While incumbents bear the initial burden, new entrants are wise to remember that they will quickly become the incumbents of tomorrow. Therefore, it is in the best interests of incumbents, new entrants and consumers for everyone to make reasonable demands and accommodations, and for regulators to facilitate consensus.”

Giunta, previously the managing partner of the Washington D.C. office of the Coudert Brothers LLP law firm, joined Paul, Hastings in March to advise domestic and international companies in all sectors of the telecommunications and technology industries.

Technologies that are driving the change toward spectrum sharing rather than exclusivity include “smart” radios that adapt to the environment in which they operate, the advent of sophisticated antennas that facilitate sharing and spread spectrum techniques that reduce the potential for interference, Janka said.

A trend clearly is emerging that requires incumbents to constrain their operations to certain frequencies, to forgo interference protection in new areas of operation and to employ new receiver designs to ward off interference from startup services, Janka said. The burden is falling on existing spectrum users to increase their efficiency in bandwidth use, he said .

The trend is problematic for satellite companies that need long lead times to develop their services, Janka said . The time required to develop satellite systems often extends beyond an individual regulator’s tenure, he added .

Ten years is not an uncommon length of time for the concept of a satellite system to reach commercial launch, Janka said. In the case of Ka-band services, rules for such enterprises first were adopted in 1983 and the systems only are rolling out now, he added.

Another threat to satellite systems is coming from terrestrial services, which currently are trying to “claw back” 40 percent of the 2 GHz mobile satellite services bandwidth just three years after the first satellite systems were licensed to use it, Janka said.

Satellite services already have been faced with the need to find ways to share spectrum with other technologies. For example, new terrestrial microwave systems are entering the broadcast satellite services and direct broadcast satellite services band, Janka said.

In addition, the mobile satellite services bands are accommodating ancillary terrestrial component services to allow use of certain systems indoors as well as outdoors. Mobile satellite services also are operating in fixed satellite services bands, while non-geostationary satellites are tapping the Ku-band and wireless devices are using the C-band, he added.

“Historically, [mobile satellite services] and [fixed satellite services] uses were designated for use in different frequency bands due to technological incompatibilities,” Janka said. New technologies have been developed that make mobile services’ use of spectrum for fixed satellite services as compatible as sharing solely among users of fixed satellite services, he added. Those technical advances include new tracking antennas, spread spectrum signals and power/pattern tradeoffs.

Pressures also are developing for broadband mobile satellite services. The existing bandwidth is proving to be inadequate for the requirements of such services, Janka said.

In addition, recent and forthcoming allocation and service rule changes will facilitate broader deployment of aeronautical and maritime terminals in C- and Ku-band, Janka said. New rules allow fixed satellite service Earth stations on mobile vessels, and a notice of proposed rulemaking is pending to facilitate the use of fixed satellite service Earth stations on airplanes for services such as Connexion by Boeing, he added.

The FCC previously allowed maritime, aeronautical and land mobile uses of fixed satellite services bands only on a case- by-case basis, with just a secondary priority.

Satellite technology developments to watch for in the future include more intensive spectrum use through spot beams, smaller earth stations that are more readily deployed and more efficient modulation schemes, Janka said.

Paul Dykewicz is a seasoned journalist who has covered the development of satellite television, satellite radio, satellite broadband, hosted payloads and space situational awareness.