Many satellite executives believe the potential loss of C-band spectrum to terrestrial players would be catastrophic or disastrous for the industry. There is little doubt that the stakes are high for many satellite players, but is there another option than just winning or losing complete access to the bandwidth? Can the satellite and terrestrial players find a middle ground for sharing C-band spectrum that would satisfy all parties, bring new services to more users and keep revenues flowing for all companies?

WiMax and IMT players are seeking access to part of the C-band spectrum because with the world going wireless, they view use of this bandwidth as key to their future growth. Gaining access to the part of C-band spectrum running from 3.4 gigahertz (GHz) to 4.2 GHz, traditionally the domain of satellite players, would be quite a coup for the terrestrial providers, but there are some officials suggesting that there may be ways to share this section of bandwidth rather than reserving access for one technology at the expense of another.

Compromise Not An Option

While sharing the spectrum seems like a logical method to satisfy as many providers as possible, technical evidence suggests there is no easy way to keep both telecoms and satellite people happy. “Communications companies and governments throughout the world have been reporting numerous incidents where satellite telecom and broadcasting services are being severely disrupted by interference from terrestrial wireless services in the ‘extended’ and standard C-band frequencies — 3.4 to 4.2 gigahertz,” says David Hartshorn, secretary general of the Global VSAT Forum, one of the organizations leading the satellite industry’s efforts to retain exclusive use of the bandwidth.

“From an interference perspective, both in terms of what we call in-band interference and out-band interference, studies have shown that you can’t really coexist in the same geographic areas using the same frequencies,” says Kalpak Gude, vice president for regulatory affairs at Intelsat. “The out-of-band problem is that the deployed satellite infrastructure that exists out there filters signals only at the edges of the 3.4 to 4.2 gigahertz band. This means that if you put a very powerful WiMax transmitter in the 3.4 to 3.6 band, it is not being filtered for customers even if they are looking for signals in the 3.7 to 3.8 bands.

“A WiMax or IMT transmitter could then overload the satellite receiver and wipe out satellite signals in higher portions of the C-band. That is another concern we have been talking to governments about. I don’t think there is a full appreciation for the amount of deployed C-band infrastructure that exists and the costs associated with modifying this deployed base,” says Gude.

This potential disruption of satellite services provides a compelling practical reason why this part of the C-band spectrum should remain with the satellite players, says Robert Ames, CEO of the Satellite Users Interference Reduction Group. “A good example of the case for protecting the C-band spectrum comes in response to the ‘exclusion zone’ in the proposal for WiMax implementation,” he says. “The proposal suggests a minimum 150-kilometer ‘exclusion zone’ around operational earth stations where WiMax devices would not be allowed to operate so as not to interfere with the earth station. However, if you have an earth station in New York City and another in Washington, DC, both establishing a 300-kilometer-wide exclusion zone, the limitation on WiMax coverage would span the East Coast (of the United States) from Connecticut to southern Virginia.”

Ames also cites a real-life example in Latin America in 2006 which demonstrated the difficulties raised when WiMax and satellite coexist in the same spectrum. “Bolivia rolled out a test WiMax network timed with the start of World Cup soccer,” he says. “The interference from the WiMax system impacted about 30 percent of households in Bolivia receiving World Cup coverage via satellite. Needless to say, this resulted in an outcry that led to the immediate termination of WiMax testing.”

Despite examples such as this, it remains a very real possibility that the International Telecommunication Union (ITU) will authorize the terrestrial players to share C-band spectrum. “According to Article 44 of the ITU Constitution, member states shall endeavor to ensure efficient use of spectrum including the application of the latest technical advances as soon as possible,” says Danny Lau, assistant director, operations for the Office of the Telecommunications Authority, the telecoms regulator of Hong Kong. “If a decision was made purely based on this objective, WRC-07 might allocate some spectrum in the C-band to telecom players.”

Discussions are taking place between the Global VSAT Forum and the WiMax Forum to talk about coexistence. “Our organization has held extensive discussions with the WiMax Forum in an effort to come to a mutual understanding of this issue, and, surprisingly, there is not much disagreement regarding compatibility,” says Hartshorn. “Indeed, our organizations agree that adjacent operation of satellite and terrestrial-wireless services in C-band will cause unacceptable levels of interference. Independent tests conducted by various governments have also reached the same conclusion.”

There also seems to be an understanding on the part of the WiMax players about these interference issues.  “The WiMax Forum recognizes that, in some countries, parts of the band in question may not be able to be used for broadband wireless access systems where ubiquitously deployed satellite earth stations use the whole band 3.4 to 4.2 gigahertz,” a WiMax Forum source says. “In some countries or regions the coexistence issues have been studied in depth and recommendations agreed to give guidance to administrations about how the service can coexist.”

However, the WiMax Forum believes in some countries coexistence is an option. “The WiMax Forum believes that both services have a role to play in countries where traditional and reliable wired telecommunications services are not in widespread use,” the source says. “The band in question is already allocated to both terrestrial and satellite services on an international basis and it is for national administrations to determine the extent to which all types of service are used with appropriate regulatory procedures in place and adherence to international coordination procedures for coexistence with services in neighboring countries.”

But Hartshorn is adamant that “terrestrial-wireless interests need to pursue spectrum other than C-band.”

Providing Other Options

Tom Choi, CEO of Asia Broadcast Satellite, believes other spectrum bands are better suited for WiMax players. “WiMax for mobile communications have much better capacity available in S-band, L-band or even in UHF band where there are better link performances. C-band from 3 to 4 gigahertz is simply not good for indoor or mobile coverage when compared with the spectrum available in the 800 to 2 gigahertz range,” he says. “If point-to-point communications is considered for WiMax, 5 to 6 gigahertz should be the choice, as there is plenty of capacity available there and no resistance from the satellite/GSM/broadcasting community. It’s highly unlikely that in countries of Southeast Asia, where C-band is an integral part of communications, that WiMax will win out over satellites.”

Peter Jackson, CEO of AsiaSat, also believes the interference issues will affect more than just the developing countries in Asia, since heavy rainfall limits the use of most other spectrums, and satellite-based telecommunications services “have to use the satellite C-band frequency for all services that demand the high reliability that Ku-band cannot meet. … However, with the low cost of terrestrial fiber, our customers only use satellite where it is impossible to have terrestrial connections, so I would assume these services would have to move to Ku-band and live with the level of service that Ku-band can provide. But Ku-band generally has limited geographic coverage or just serves a single country so a large coverage regional service would be impossible.”

While recognizing the importance of C-band to the satellite industry, iDirect Technologies believes it may have a way to improve the ability of Ku-band to provide services in areas where rain fade is an everyday problem. The company will introduce before the end of the year a DVB-S2 product line with adaptive coding and modulation that will provide customers with bandwidth efficiency improvements.

“We absolutely recognize the interference issues,” says David Bettinger, iDirect’s CTO. “We have experienced them ourselves. … Coming out with DVB-S2 on the outbound channel and then adaptive coding and modulation on the inbound channel. We will have a completely adaptive system that can better handle rain fade and optimize performance. Our belief is that you will be able to use Ku-band service in areas formerly restricted to C-band. The downside is that because there is not a huge Ku-band market in those areas, I’m not sure how much satellite coverage there is and how long we will have to wait for coverage. I’m sure you can get Ku-band across Africa and Asia, but it’s probably underused.”

Bettinger describes the technology as “an iDirect-only solution for an industry opportunity. C-band has very little rain fade problems, which is why it is used in high rain regions. But it doesn’t rain all the time, so with the adaptive coding and modulation available on the outbound channel, when we introduce the inbound channel, then you have a system to adaptively handle rain fade without falling out of network or designing rain fade loss into the network,” he says. He does not envision the solution as a replacement for C-band spectrum, but says, “We are hoping there is a market opportunity by going for the C-band market with a cheaper Ku-band space segment and equipment.”

Robert Bednarek, CEO of SES New Skies, believes the WiMax and telecoms need to look elsewhere for spectrum but also hints that satellite players have to adjust their mindset when protecting their interests. “The satellite industry has had spectrum battles in the past. We have prevailed in some of those by demonstrating the value we bring to the public and we are all able to enjoy the fruits of that labor today,” he says. “We are a big industry. There is a lot of investment in our systems. There are a lot of customers. We span the globe. Perhaps we are not as comfortable with clearly defining and explaining our role as an industry as those in the terrestrial world. Perhaps some in the industry have become more focused on paying debt than creating and running services but this doesn’t remove the obligation for all of us in the satellite industry to speak for the vital services we offer. Any industry that uses spectrum, first must, defend its use of this spectrum, and then work to obtain more spectrum for its expansion. I don’t blame the WiMax and IMT proponents for looking for spectrum; they just need to look for it somewhere else.”

Stop The European Disease From Spreading

While the satellite players appear to be winning the battle in Africa and some parts of Asia, obstacles remain in Europe and some of Asia’s biggest territories ahead of the ITU meeting.

“When talking about the regional groups, the problem here is very much Europe,” says John Lothian, vice president, space development at SES Global.  “You have manufacturers like Nokia in Finland, Ericsson in Sweden and the mobile operators. Because for historical reasons, there is somewhat less intensive use of C-band satellites in Europe, Europe is like a special case. What we are trying to do is avoid the European disease spreading elsewhere. If you look at region one — Europe and Africa — C-band is not the primary satellite band in Europe, but it is in Africa, [where] it is the bread and butter. Another perception people have is that C-band satellites are a dying business and IMT is a growing business, but in fact, C-band in Africa is how you get your broadband via satellite, IP services. It is providing the backbone for communications. We have to recognize that Europe is an oddball in terms of C-band, and we have to try and prevent Europe from spreading its views to other countries.”

Gude says, “Europe may go in their own direction, but even the French, who are big proponents of IMT, recently came out with a proposal and drew the line at 3.8 instead of 4.2. That is a move in the right direction, albeit not sufficient.

“The Koreans and Japanese are somewhat differently situated than the rest of the world, however, and may move in a different direction for IMT services,” says Gude. “I think we are doing a better job of educating governments and customers about the risks associated with IMT/WiMax deployment in the C-band. I think in the lower part of the band, WiMax is likely to continue to be a significant problem for satellite services. Luckily, there is less deployed satellite infrastructure in that part of the band right now, although the out-of-band problem still needs to be addressed.”

Jackson believes certain European regulators have taken a very short-term view. “Unfortunately some European regulators have taken a purely local view and allocated some of the satellite C-band frequency in their countries to WiMax, and that will be difficult to reverse,” he says. “In Asia regulators have now, I believe, recognized the problem and so they are unlikely to follow that example. We will therefore either see two sets of frequencies being used in parallel or the world will slowly change to a single lower frequency than C-band that is more suitable for terrestrial use.”

Bottom Line

The best situation for satellite players is to win the battle for C-band spectrum, but there does not seem to be much of a plan B at this stage. According to satellite industry executives, it appears that even a partial victory for the terrestrial players could have serious consequences for the satellite industry, and while the consequences may not be fatal, it could take years to recover.