The Defense Case for C-Band

By | July 13, 2007 | Satellite News Feed, Telecom

C-Band spectrum, as well as being used for commercial purposes, is also vital in terms of certain defense strategies. The U.S. The Department of Defense (DoD) “has many radars and weapon systems that operate in this band” Ken Carrigan, senior systems engineer, U.S. Navy talks to Via Satellite about why satellite players should hang onto C-Band spectrum.

Via Satellite: What is your whole take on the demands for C-Band spectrum resources and competing arguments of telecoms and satellite players? Is there a compromise that can be reached, or is it a case of one or the other? Is there a middle ground between WiMAX and satellite, for example?

Carrigan: The quest of ITU trying to harmonize allocation of spectrum for IMT and IMT-Advanced did/does not adequately address users in the band, nor does it adequately address the deployment of satellites and systems mutually operating in the band in the future. It seems to be driven by political/commercial might, rather then compatibility of systems operating in the bands presently. Studies have shown, test performed, and results already conclude that IMT deployed will cause degradation and loss of satellite terminal operation to users if operated in the same band. Moreover, IMT base units radiating over 1Watt isotropically will impact satellites users over 100km distance. C/S-Band IMT is not compatible with C/S band Satellite terminals. The middle ground would be for IMT units not to operate 100km from Satellite terminals. This is not only impractical, but with mobile WiMAX (802.16e) deployed in C-Band, it would be impossible to enforce such a standoff distance. No middle ground exists, its all or none. Where C-Band IMT is deployed, C-Band satellite terminal will loose, and thereby vendors and manufacturers of C-Band satellites and terminals will suffer major financial loss.

Via Satellite: One of the arguments being mooted is the importance of C-Band in developing countries for communications. What would be the ramifications for these territories if this C-Band capacity was assigned to terrestrial mobile players rather than satellite?

Carrigan: Wrong question or argument. C-Band is NOT the only band to deploy IMT communications. C-band is optimized for satellites, not only in its broad coverage or foot print, but also less effected by heavy rain, foliage, smog, and atmospherics, where Ku would suffer loss. Satellite service in C-band is very necessary and they can not move to alternative bands for this ideal link margin. IMT does not need this type of quality. 

Via Satellite: In your own opinion, how likely is it that satellite players are going to lose some of this C-Band capacity, particularly to the WiMAX industry? While many believe satellite has a strong case, is it likely that despite these strong arguments, that the telecoms players will use their muscle to gain access to this spectrum?

Carrigan: Exactly, muscle. Commerce seems to be playing a major role in selling of spectrum, while commercial markets for WiMAX are feasting on new spectrum for new markets. It a feeding frenzy out there, and WiMAX ‘back-haul’ is overly hyped. The bandwidth or connect rates of current WiMAX units only provide 1-2 mbps at best for 1 subscriber unit. For more subscriber units connected to the same sector on base unit they will have to share this link. It will be a hard sell for WiMAX, as cell phone industry is ramping up their bandwidth/speeds to surpass current 3G WiMAX. Also the radius for a WiMAX base station is not 30 miles as previously stated. As an example WiMAX base at 23dBm with a sector and receive subscriber antenna of 16dB and receiver set for maximum throughput (64QAM) provides only 3-4 mile radius uninterupted coverage. Hype, and disappointment.

Via Satellite: How does the C-Band issue impact an organization such as the Department of Defense (DoD)? What role can you play in this whole debate and lobbying process?

Carrigan: While the U.S.A has a single vote in the 160 member ITU, we hope that our single votes carriers other countries to vote in the same way. The DoD has many radars and weapon systems that operate in this band and are mission critical to our National Defense. We have been slowly giving up spectrum over the years but in this C-Band, radars have nowhere else to move. As this band is also ideal for satellites, it is also ideal for radars. We work hard on host nation frequency coordination for many of our system and operate these system world wide. We have raised this WiMAX issue to top levels of DoD and currently there is a mandate to stop all new acquisitions in the 3.4-3.6 GHz band.

Via Satellite: Can you give a timeline of what is going to happen over the rest of the year? Is satellite’s debating position now stronger than it has been over the last few months? Is the message about the strengths of satellite’s argument in C-Band getting through? Or is there still a lot of hard work to be done?

Carrigan: I believe this issue is rising in many different forums and is being discussed at conferences and at the ITU. It is very serious. We are, will be, testing  many of our systems currently using C-Band including radars and satellite terminals and actual impacts are being assessed. ITU studies and modeling efforts were deemed unacceptable or unbelievable and did not do a good job convincing ITU not to sell off this spectrum. More testing will be conducted by the end of this year and following years showing and proving that IMT system are not compatible in this band. More work is being done.

Via Satellite: What are your thoughts on this issue and what do you see as the key points in the satellite argument here? Do you think satellite players should keep the entire C-Band spectrum?

Carrigan: Yes. Two reasons. 1) Satellite users have built an infrastructure costing billions of dollars and were there first. 2) C-Band is ideally suited for satellite communication as noted above. This is also true for radars and weapon systems that DoD has developed over many years and is vital to not only U.S. national security, but are also deployed world over to Defend Freedom.

Via Satellite: If we are having this conversation in early 2008, what do you expect to have happened in the whole C-Band arena?

Carrigan: This issue will not go away by 2007 for sure. The ITU is bent on selling more and more spectrum for broadband wireless access (BWA). It is our intent to try to steer ITU out of C-band and to show why C-Band is not optimal for IMT or IMT advanced. The range and coverage provided at lower frequencies are optimal for WiMAX mobile deployment, as it has better coverage, longer range, cheaper development costs, faster deployment, NLOS and LOS coverage, and not impeded by rain, or foliage. Stay out of C-Band. I also firmly believe that WiMAX 802.16-2004 back-haul will become obsolete when mobile WiMAX (802.16e) gets deployed, much like 802.11g superseded 802.11b. In the near future 802.11n will be replacing 802.11b,g and a.

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