Rajeev Bansal University of Connecticut ECE, U-1 57,260 Glenbrook Road Storrs, CT 06269 USA (860) 486-2878 (860) 486-2447 (Fax) rajeev@engr.uconn.edu (e-mail)

Keywords: Electromagnetic propagation; satellite communication; antennas; diversity methods

directional receiving-antenna characteristics, allows both satellite and terrestrial signals to co-exist, without interfering with one another.

North-by-north point Where is the Proof?

y last column [l] discussed how polarization diversity, com- M bined with novel signal-processing techniques, was being explored to increase the capacity of congested radio channels in the cellular/PCS bands in urban environments. This column describes the efforts of a small company, Northpoint Technologies (not to be confused with the defunct but better-known Intemet networking company, Northpoint Communications), which wants to use its patented spatial diversity system to allow terrestrial and satellite broadcasts to occur simultaneously on the same frequencies. If successful, the Northpoint technology will enable spectrum capac- ity to nearly double in the bands where it is employed.

Northpoint’s technology is the basis for Broadwave USA, Inc.’s FCC application, filed on January 8, 1999, to offer a new nationwide video and data-distribution system in head-to-head competition with DBS and local-monopoly cable providers. With regulatory approval, Broadwave and its 68 affiliates will offer ser- vice in the 12.2-12.7 GHz band. Broadwave’s technology operates through a network of tiny transmitters, each of which is smaller than a notebook computer and can serve 100 square miles [2].

How Does the North point Technology Work?

In 2000, Congress mandated that the FCC contract with an independent testing organization to conduct a “demonstration of any terrestrial service technology proposed by any entity that has filed an application” to provide service in the spectrum band used by direct-broadcast satellites. Broadwave and two other companies were subject to this requirement.

On April 23, 2001, the Federal Communications Commission released a highly detailed report [4] froin Mitre Corporation on the Northpoint-type terrestrial systems, and invited public comments by May 15, 2001. Sophia Collier, President of Broadwave USA, noted in a press release:

The Mitre report confirms every technical filing that Northpoint has made at the FCC about sharing with DBS. Mitre correctly concluded that satellite-terrestrial sharing requires specialized technology like Northpoint in order to be effective and that, without a system such as Northpoint, sharing cannot work. We were also flat- tered by Mitre’s special mention of our engineers’ abil- ity to predict and prevent interference.

Our company applied for its first experimental license at the FCC in 1995 and we have operated suc- cessfully in three locations and in a wide variety of conditions, including in Washington, DC, during Hurri- cane Floyd. Northpoint technology is highly robust and will be a terrific platform for new lower cost services to be offered throughout the country. If the FCC acts soon, consumers will be enjoying savings by Christmas.”

A good example of how the Northpoint system will work is within the band allocated to direct-broadcast satellites. Nine satel- lites are currently authorized to broadcast from orbital slots 9” apart. All of these satellites broadcast in the full 12.2-12.7 GHz band, but because o i the ability to resolve their 9” seoaration. each satellite’s signal is distinct. A homeowner must poinf the receiving antenna precisely at a specific satellite in order to get a signal. To change to another service, one must re-point the dish [Z]. So What’s the Problem?

Northpoint broadcasls are made from terrestrial bases (tow- ers). Since the geosynchronous DBS satellites are positioned over Technically, it wouldn’t be a problem for Northpoint to use the equator, DBS receiving dishes in the US all point in a southerly another frequency band and avoid the issue of potential interfer- direction. The Northpoint towers will be located north of the ence with the DBS service altogether. But Northpoint wants to receiving areas, and will transmit to dishes pointing north. avoid an auction and get the spectrum for free, just as its rival sat- According to Northpoint, this angular separation, combined with ellite companies do. The rivals see Northpoint as a “bunch of

114 I€€€ Antennas and Propagation Magazine, Vol. 43, No. 3, June 2001

interlopers” [4]. Mcrrill Spiegcl, Vice President for Govemmental Affairs at rival DirccTV, the nation’s largest satellite-television subscription service, told the New York Times, “These players have no intention of deploying anything. They are spending a for- tune lobbying and yet thcy havc no infrastructure to build any- thing,” On their part, Northpoint executives argue that federal law requires that satellite frequencies not be auctioned, and access to those frequencies is the only thing thcir company needs to become a low-cost operator and to promote competition in many under- served marlcets.

What’s Next?

Both Northpoint and its rivals havc hired a rctinue of influen- tial Washington lobbyists. It is impossible to know what the FCC will ultimately decide. The FCC has a new Chairman, and three new members nominated by the B L I S ~ administration to its five-

membcr commission, and they have not indicatcd their position on the issue, yet. Stay tuned.

References

1. R. Bansal, “AP-S Turnstile: Tripole to the Rescue,” IEEE Antennas nnd Propngntiorz Magazine, 43, 2, April 2001, pp. 106- 107.

2. Noi-thpoint Technologies Web sitc: http:// www . northpointtechno I ogy. coin .

3. Mitre Technical Report, “Analysis of Potential MVDDS Inter- ference to DBS in the 12.2-1 2.7 GHz Band” (available at the FCC Web sitc, http://www.fcc.gov/oet/inf/mitrereport .

4. S. Labaton, “An Earthly Idea For Doubling The Airwaves,” The New York Tuxes, April 8, 200 1 . *E

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