WirelessPulse-Comsearch E-News - March 2006

Comsearch's quarterly e-newsletter for professionals in the wireless industry.

Our engineers use the latest technology in the dynamic wireless market and consistently publish up-to-date information through white papers, case studies and informative articles. With the publication of WirelessPulse, we are able to pass along this information to you, our valued clients and prospects.

WirelessPulse features three industry news sections, the first with our "Feature Article" - in-depth analysis on industry trends, "Case Corner" - featuring relevant industry case studies and "Regulatory Rap" - featuring extensive spectrum management news. We have added "What's New at Comsearch! " so that we can keep you informed of what's going on at Comsearch.

In the March 2006 Issue

FEATURE ARTICLE
Incumbent Relocation Issues and Options for the
1710-1755/2110-2155 MHz AWS Spectrum
by Brian Downs
Director Software Products, Comsearch

CASE CORNER
It Doesn't Have to Squeal to Cause a Problem - Interference from Cellular Amplifiers
by Jim Branin
Field Services, Comsearch

REGULATORY RAP
Spectrum Management News

WHAT'S NEW AT COMSEARCH!

FEATURE ARTICLE

Incumbent Relocation Issues and Options for the
1710-1755/2110-2155 MHz AWS Spectrum
by Brian Downs
Director Software Products, Comsearch

Streaming video, music on demand, radio broadcasts, and TV programming being downloaded to your wireless phone, PDA, or mp3 player are just scratching the surface of new applications that could flourish if radio spectrum were not a limiting factor. Well, after over a decade of numerous FCC proceedings, spectrum reallocations, and even the passage of Congressional legislation, additional spectrum to support mobile wireless applications is finally coming. In January, the FCC issued a Public Notice1 announcing their intentions to auction Advanced Wireless Services (AWS) licenses in the 1710-1755 and 2110-2155 MHz bands beginning June 29, 2006.

Of course, radio spectrum is a precious commodity. And, vacant spectrum allocations are virtually non-existent, especially in frequency bands with propagation characteristics capable of supporting handheld mobile devices and services. The 1.7 and 2.1 GHz bands are no exception. In fact, the existing breadth of fixed and mobile systems currently provided in these bands by federal government agencies, state and local governments, private industry and common carriers sets up perhaps the most complex spectrum reallocation scenario ever created by the FCC. Although complex, the reallocation and transition to new wireless applications and services can be fluid and interference-free, thus protecting the existing public service and national security applications currently deployed in this spectrum.

Similar to the Personal Communication Services (PCS) in the 1850-1990 MHz band that began in the mid 90’s, AWS licensees can deploy new systems and roll out services in the 1.7/2.1 GHz bands provided they do not interfere with existing users. During the rollout of PCS systems, Comsearch developed successful interference analysis methodologies, techniques, and coordination procedures to help promote transitional sharing of spectrum between existing fixed microwave and new mobile services. Comsearch has leveraged this expertise to create new spectrum sharing products, such as iQ.clearXG™, and services to facilitate an interference-free and rapid deployment in this new AWS spectrum allocation. This paper will explore spectrum sharing and relocation issues associated with this AWS spectrum reallocation.

AWS ALLOCATION

The FCC has reallocated the 1.7/2.1 GHz spectrum into 6 paired AWS channel blocks (A through F) where the base stations will transmit in the 2.1 GHz band while the lower powered mobile devices will transmit in the 1.7 GHz band. The FCC will auction these 6 channel blocks by 3 different geographic areas resulting in a total of 1,122 AWS geographic area licenses. The geographic boundary areas vary in size with 12 Regional Economic Area Groupings (REAG’s), 176 Economic Areas (EA’s) and 734 Cellular Market Areas (CMA’s).[1] Figure 1 illustrates the AWS spectrum channel blocks and existing utilization by incumbents.

INCUMBENTS

Based on Comsearch’s proprietary database, common carriers and private industry (including state and local governments) operate approximately 5,700 fixed microwave paths in the 2110-2150 MHz band. The 2150-2155 MHz band is allocated for fixed point-to- multipoint applications, and there are approximately 150 licensed site-based protected systems in this band.

According to the National Telecommunications and Information Administration (NTIA), the 1710-1755 MHz band consists of 2,240 frequency assignments used by 12 different federal agencies to support fixed microwave, transportable (or temporary fixed) systems, and both land and aeronautical mobile systems.[2] The distribution of these frequencies by type of wireless application is listed in Figure 2.

Figure 2: 1710-1755 MHz Frequency Utilization[2]

RELOCATION REQUIREMENTS AND INCUMBENCY ISSUES

In the 1.9 GHz bands, the PCS channel split mirrored the 80 MHz transmit to receive frequency separation used by the incumbent microwave systems. This was done to facilitate sharing and relocation, given that both transmit stations of a microwave link would fall into the same PCS channel block. However, as shown in Figure 3, the AWS block pairings fall into two separate bands, each band used by a different set of operators: mobiles in the 1.7 GHz band, and base stations in the 2.1 GHz band.

There are numerous sharing and relocation complications introduced by this dissimilar band split. The upper and lower bands contain completely different types of incumbent systems, which will require separate interference analyses and relocation considerations. Yet, when determining the optimum transmit frequencies within the AWS channel blocks, the results of both interference analyses must be considered together. For example, a channel with fewer encumbrances in the 1.7 GHz band may require additional relocation costs in the 2.1 GHz band.

A discussion of the issues associated with each band is provided in the following sections.

2110-2150 MHz Band
The relocation rules for this band follow those adhered to by the PCS licensees. If interference is predicted into incumbent systems operating in the 2.1 GHz band, then the AWS licensee can either alter their design to avoid the interference, or negotiate with the operator to relocate their system to another frequency band or media. The interference analysis methods and criteria developed for PCS have proven successful during the transition of the 1.9 GHz band from private fixed microwave to mobile systems. The FCC acknowledges this success and has adopted relocation rules for fixed microwave systems operating in the 2110-2150 MHz band as specified in FCC Rule Part 101, subpart B.

Unlike the PCS bands, where the existing users consisted solely of private microwave licensees, the incumbent operators in this portion of the AWS band contains both common carriers and private licensees. A new relocation dynamic is introduced because, while there are fewer common carrier links and licensees to contend with, some of these common carrier licensees are likely to be competitors of the future AWS licensees.

The FCC chose to eliminate the voluntary negotiation period and proceed directly to the mandatory negotiation period. During this period, the incumbent cannot refuse to negotiate and both parties are required to negotiate in “good faith”. Similar to PCS, the mandatory period for public safety links is longer allowing them 3 years to negotiate, while all others are provided 2 years. Approximately 25% of all links in this band are classified as public safety. The FCC mandated the same reimbursement cap used in the PCS band - $250,000 per paired fixed microwave link, and an additional $150,000 if a new or modified tower is required.

2150-2155 MHz Band
The 2150-2155 MHz band is used by the BRS, formerly known as the Multipoint Distribution Service (MDS). Historically, this spectrum has been used for fixed point-to-multipoint systems to deliver video programming to subscribers within a protected service area (PSA). Today, many of these licensees also provide high-speed Internet access to their subscribers. There are approximately 150 licensed BRS facilities operating in this band, and the FCC has designated spectrum in the new 2.5 GHz BRS band to support the relocation of these facilities. The FCC is still deliberating on the interference protection criteria and triggers to initiate relocation of these facilities.

1710-1755 MHz Band
The 1.7 GHz spectrum, currently occupied by federal government fixed and mobile systems, presents a number of issues that may impact overall relocation and subsequent AWS deployment timelines.

Even though the relocation and negotiation used in the PCS band was considered successful with commercial incumbents, one can only imagine the contractual and bureaucratic complexities that AWS licensees would face if required to negotiate relocation with 12 different federal agencies. Fortunately, the process is different in the 1.7 GHz band.

Instead, Congress passed the Commercial Spectrum Enhancement Act (CSEA) creating a spectrum relocation fund from AWS auction proceeds. This fund will cover the relocation costs of these federally-operated systems. CSEA required the NTIA to estimate costs and a timeline to relocate systems in the 1710 – 1755 MHz band. Last December, the NTIA published estimated costs of $935.9M to relocate systems with 2,240 frequency assignments based on the estimated schedule summarized in Figure 4.[2]

Figure 4: 1710-1755 MHz Frequency Assignments[2]

TRANSITIONAL SHARING

Clearly, this estimated relocation schedule spanning over four years underscores the need for transitional sharing of this spectrum between federal government incumbents and AWS licensees. Transitional sharing of the spectrum allows AWS licensees to implement early phases of their system before all incumbents are relocated, and without causing interference into the existing systems.

Public Law 108-494 Sec. 203(C) allows the FCC to grant a license prior to official termination of the federal entity’s authorization, contingent upon the licensee not causing interference until the entity’s authorization has been terminated by the NTIA. This rule allows for transitional sharing. And, transitional sharing will be a viable option in most markets because potential interference into federal government systems will come from the AWS mobile devices, which operate at very low powers. Interference into incumbent systems is more likely to come from the higher powered AWS base stations at 2.1 GHz, which is not an interference concern into the federal government systems operating at 1.7 GHz.

However, with the exception of coordination procedures with 16 DOD protected facilities specified in FCC Rule Part 27.1134[3], there is no process established by the NTIA or FCC to address transitional sharing between AWS and federal government systems. Transitional sharing with all federal systems is realistic, however, a similar notification process would further facilitate this process by establishing communication channels between AWS licensees and federal agencies.

Moreover, an obstacle to determining sharing potential is the availability of data for the federal government systems. Much of this data is classified and only limited data is available for public review and analysis. Comsearch is working directly with the NTIA and federal agencies to collect more detailed data or to derive the technical parameters necessary to perform thorough interference analyses. This will allow AWS licensees determine if spectrum sharing is feasible for each proposed AWS base station and its associated mobile subscribers.

CONCLUSION

On June 29, the FCC will begin to auction six channel blocks for Advanced Wireless Systems licenses. This spectrum reallocation creates a challenging transition environment due to the variety of systems and operators currently using this band. The four year estimated relocation schedule published by the NTIA emphasizes the need for transitional sharing with federal facilities. And, establishing coordination procedures with federal agencies could create communication channels that can support the transitional sharing of spectrum. The FCC recognizes that existing interference analysis methodologies and algorithms have proven successful for similar spectrum reallocations. And, the FCC requires AWS operators to protect existing 1.7 and 2.1 GHz fixed microwave systems in accordance with procedures specified in TIA TSB Bulletin 10-F[4]. Comsearch has been actively engaged in this spectrum reallocation on a number of fronts and can assist both incumbent users and new AWS operators. We can assess this spectrum prior to and after the auction, perform spectrum sharing and interference analyses using our Spectrum Sharing software tool, iQ.clearXG, and coordinate with incumbents to facilitate an interference-free and rapid transition.

[2] 1710 – 1755 MHz Spectrum Relocation Information, National Telecommunications and Information Administration, report posted on web site (www.ntia.doc.gov), December 28, 2005.

[3] Service Rules for Advanced Wireless Services in the 1.7 GHz and 2.1 GHz bands, Federal Communications Commission, Report and Order, WT Docket No. 02-353, Released November 25, 2003.

[4] TIA Telecommunications Systems Bulletin 10-F, "Interference Criteria for Microwave Systems", May 1994, (TSB 10-F) provides standards and engineering methods for protecting Fixed microwave stations from harmful interference.

CASE CORNER

It Doesn't Have to Squeal to Cause a Problem - Interference from Cellular Amplifiers
by Jim Branin
Field Services, Comsearch

As many public speakers have found, placing a microphone too close to the PA speakers can be deafening when audio feed back occurs. The scenario that follows can best be described as an RF version of audio feedback. It also has the potential to cause many problems and, if you consider a dropped call deafening, have similar results.

Comsearch Field Services was contacted last October by a Cellular (GSM) provider in the Midwest to assist in identifying a suspected interference source at one of their tower sites. The tower was put into service several years ago and has had the problem intermittently since then. The “interference” caused an unexplained increase in dropped calls, usually for periods of several hours on various weekend days.

An omni-directional antenna was originally installed on the tower. At a later date it was replaced with three sectorized antennas. Once this change was made, the periods of excessive dropped calls occurred only on the northwest sector antenna. It should be noted that the provider’s other antennas in the area did not experience this problem.

During the two consecutive weekend periods spent at this location, we were unable to identify the source of the interference because the system experienced no excessive dropped calls during these times. However, the most likely sources of the type of interference experienced were anticipated to be either ham radio Operators, CB base stations running linear amplifiers or a vehicle-mounted cellular amplifier/repeater system.

A few weeks later, the source of interference causing excessive dropped calls was finally identified at a separate location. The verified interference source was indeed a vehicle-mounted cellular amplifier system.

Over the last two months, the client identified more than twenty instances of this type of unit causing excessive dropped calls in their network. In every case, the interference was caused by an improperly installed system. Figure 1 shows the RF spectrum when a cellular amplifier is installed correctly. Figure 2 shows the RF spectrum when installed incorrectly.

Comsearch has conducted preliminary research and testing related to these units. There are multiple manufacturers of this type of unit that supply systems for vehicles, marine installations, and home installations.

The home units consist of an internal antenna connected to an amplifier with up to 60 dB of gain that is connected to an external antenna. We have not yet researched the marine units.

The vehicle systems fall into two separate categories. Some have the phone directly connected to the amplifier, with up to 40 dB of gain, that then is connected to an antenna on the outside of the vehicle. We have not tested this type of system. Another type of vehicle system that we did test consists of an internal “strip antenna” connected to the amplifier with up to 38 dB gain that connects to an external vehicle antenna. These units are advertised as not needing a physical connection to the phone.

The GSM/PCS compatible units have an uplink range of 824-849 MHz and 1850-1910 MHz. Their downlink range is 869-894 MHz and 1930-1990 MHz. The interference to the tower receivers occurs when the internal antenna is mounted too close to the external antenna. This results in spurious emissions that cover the entire 824-849 MHz and 1850-1910 MHz bands. The spurious signals from the amplifier are 20-30 dB stronger than the amplified handset levels. The result is excessive dropped calls when the vehicle is near the cell tower (within one mile usually). The phone does not have to be on or even in the vehicle for this interference event to occur.

The manufacturer of the specific unit we tested was somewhat vague concerning the proper separation between the antennas, citing at least 5 feet and as much as 20 feet. (How many pickup trucks could have this much separation unless you mounted the external antenna on the tailgate?)

We have known for some time that cell phones and PCS phones emit harmonics. This is not a problem with handsets that emit less than one watt. However, it would be a problem if they operated at 3 watts. In 1997 and 1998, we documented two cases where 3 watt cellular bag phones caused interference into C-band earth station antennas receiving digital on the upper transponders via the phone’s 5th harmonic.

The testing we performed showed that the 5th harmonic from an 850 MHz GSM phone utilizing one of these properly operating vehicle amplifiers would be strong enough to cause interference to the upper four transponders of the satellite C-band if receiving digital video. The interference would be even stronger with an improperly installed unit.

Further testing verified that a PCS phone connected to this type amplifier would emit 2nd harmonics strong enough to interfere with the lower five transponders in the satellite C-band if receiving digital video. Even further testing is called for since we suspect that the 3rd harmonic of one of these units, improperly installed and being used with a GSM (824-849 MHz) phone, might cause interference into an 802.11b system if the vehicle were parked close enough to the system.

Comsearch’s Field Services group is committed to solving interference issues and will, no doubt, find themselves busier as telecommunication continues to evolve. Click here to find out more about Comsearch's comprehensive field services.

REGULATORY RAP
Spectrum Management News

MICROWAVE

Wireless Telecommunications Bureau Announces Deployment of "AUTO-TERM" - The automated feature in its Universal Licensing System (ULS) that identifies unconstructed stations resulting in automatic termination of licenses. (DA No 06-45) DA-06-45A1.pdf

Federal-State Joint Board Staff Releases Monitoring Report - This report reflects information on the telephone industry filed with the Federal Communications Commission (FCC) through May 2005. (Dkt No 98-202, 96-45) DOC-262993A1.pdf DOC-262986A1.pdf DOC-262986A2.pdf DOC-262986A3.pdf DOC-262986A4.pdf DOC-262986A5.pdf DOC-262986A6.pdf DOC-262986A7.pdf DOC-262986A8.pdf DOC-262986A9.pdf DOC-262986A10.pdf DOC-262986A11.pdf DOC-262986A12.pdf DOC-262986A13.pdf

Wireless Telecommunications Bureau Enhances the Commission's ULS to Implement Electronic Filing for Pleadings - (DA No 06-125) DA-06-125A1.pdf

Modernization of the FCC's Competitive Bidding Rules and Procedures - Several modifications to the competitive bidding rules adopted. (Dkt No 05-211) FCC-06-4A1.pdf

FCC Issues 12th Annual Report to Congress on Video Competition - The FCC adopted its 12th Annual Assessment of the Status of Competition in the Market for the Delivery of Video Programming. DOC-263763A1.pdf DOC-263763A2.pdf DOC-263763A3.pdf DOC-263763A4.pdf

FCC Examines Need for Tougher Privacy Rules - The FCC launched a proceeding to examine whether additional security measures could prevent the unauthorized disclosure of sensitive customer information held by telecommunications companies. (Dkt No 96-115, RM-11277, FCC No. 06-10)
FCC-06-10A1.pdf FCC-06-10A2.pdf FCC-06-10A3.pdf FCC-06-10A4.pdf FCC-06-10A5.pdf

FCC Adopts Plan to Establish a Public Safety and Homeland Security Bureau - The new Bureau is designed to provide a more efficient, effective, and responsive organizational structure to address public safety, homeland security, national security, emergency management and preparedness, disaster management, and other related issues.
DOC-264395A1.pdf

SATELLITE

FCC Modifies Spectrum Reservations in the 2 GHz Mobile Satellite Service Band
The FCC adopted an Order that reassigned spectrum to two 2 GHz satellite operators so that they have 20 MHz each. The FCC modified the spectrum reservations of TMI Communications and Company Limited Partnership (TMI) and ICO Satellite Services (ICO), such that they are each assigned a total of 20 MHz of spectrum in the 2 GHz mobile satellite service (MSS) band, or 10 MHz in the uplink band and 10 MHz in the downlink band. The FCC reasons that modifying these two spectrum reservations will facilitate ICO's and TMI's provision of public safety and rural broadband services, and allow them to compete effectively in the market for mobile telecommunications services.

Direct Broadcast Satellite (DBS) Service Auction Nullified
Rainbow DBS Company LLC (“Rainbow DBS”) and EchoStar Satellite L.L.C. (“EchoStar”), won three DBS licenses. Rainbow DBS won a license to operate on 32 channels at the 175º W.L. orbital location and a license to operate on 32 channels at the 166º W.L. orbital location. EchoStar won a license to operate on 29 channels at the 157º W.L. orbital location. Both winning bidders timely submitted long-form applications and paid their winning bids in full.

On June 21, 2005, the United States Court of Appeals for the D.C. Circuit held that in Northpoint Technology, Ltd. v. FCC the DBS auction was unauthorized. In light of this holding, the Commission adopted a freeze on all applications for new DBS authorizations to use the 12.2-12.7 GHz band and associated feeder links in the 17.3- 17.8 GHz band pending Commission consideration of the appropriate processing rules for applications to provide DBS in the United States, and sets forth refund procedures.

Globalstar LLC to Operate Ancillary Terrestrial Component Station
The FCC authorized Globalstar LLC to operate ancillary terrestrial component stations to provide services integrated with services provided via the Globalstar Mobile Satellite Service system. GLLC holds an FCC space-station license for the Globalstar “Big LEO” MSS system, which provides service in the United States and abroad via non-geostationary-orbit satellites, using the 1610-1621.35 MHz band for transmissions from mobile earth stations to satellites and the 2483.5-2500 MHz band for transmissions from satellites to mobile earth stations. An affiliated company, Globalstar USA LLC, holds an FCC blanket license for operation of Globalstar mobile earth-station terminals and is responsible for provision of Globalstar MSS services to end users in the United States.

FCC’s International Bureau Announces Appointment of Robert G. Nelson to Chief, Satellite Division
The International Bureau announced the appointment of Robert G. Nelson to the position of Chief, Satellite Division in the International Bureau. Bob Nelson previously was Chief of the Satellite Division's Engineering Branch.

Justice Department Green Lights SES Global's Acquisition of New Skies
The U.S. Department of Justice has completed its review of SES Global's acquisition of New Skies Satellites, effectively giving permission for the deal to go through. The acquisition was announced on Dec.14, 2005. The deal still has to receive the blessing of the FCC and Germany's Federal Cartel Office to proceed, plus the backing of New Skies' shareholders. New Skies expects its acquisition by SES Global to close in the second quarter. The deal will create the world's second largest Fixed Satellite Services operator behind a combined Intelsat-Panamsat.

What's New at Comsearch!

Comsearch Selected, for the 9th Year in a Row, to Serve as the Official Spectrum Manager for CTIA WIRELESS 2006 in Las Vegas, NV, April 5-7, 2006
In its ninth consecutive year as official spectrum manager at CTIA WIRELESS, Comsearch will ensure that the radio frequencies used in demonstrations by exhibitors do not interfere with each other and other licensed wireless operations in the area. This year’s show presents new challenges with demonstrations using UMTS, WiMax, and Digital Video Broadcasting-Handhelds (DVB-H) technologies, in addition to the GSM and CDMA technologies common to the show. Click here for more information on Comsearch’s Frequency Coordination for Trade Shows.

Advanced Wireless Service (AWS) Panel Discussion at CTIA Wireless 2006
Join Comsearch for a panel discussion at CTIA WIRELESS 2006 on Incumbent Relocation Issues and Options for AWS.

The most important auction of mobile wireless spectrum in over a decade will take place this year.

CTIA WIRELESS 2006 Show
Las Vegas Convention Center
Las Vegas, Nevada USA
Thursday, April 6, 2006
Room: N110
Time: 11:30 a.m. – 12:45 p.m.

The most important auction of mobile wireless spectrum in over a decade will take place this year.

AWS spectrum is currently occupied by federal government, commercial fixed microwave, and broadband radio service communications systems — creating a complicated scenario of coexistence and relocation. Comsearch, an industry leader on spectrum management, will host a discussion of issues surrounding the relocation of these incumbents by AWS licensees. The panel will answer key questions that every bidder should know.

• Who are the players and what are their roles?
• What are the implications of the FCC rules for spectrum sharing, relocation and reimbursement considerations?
• How do I evaluate existing systems in the 1.7/2.1 GHz bands that need relocating?
• How do I analyze potential spectrum interference between government and non-government systems and protect all parties?

Don’t miss this important discussion to help you capture the opportunities of AWS. For more information contact us at 800-318-1234 or customersupport@comsearch.com or visit us at the CTIA WIRELESS Show at Booth #2022.

Comsearch Extends Special Show Offer at NAB 2006
Visit Comsearch at Booth #C8147 and take advantage of our special show offer to new clients for FCC Prior Coordination Protection Services.

Comsearch Presenting at AAMI 2006 Conference & Expo
Join Mark Gibson, Senior Director, Business Development for Comsearch, as he presents "Taking Control of your Wireless Spectrum" at Association for the Advancement of Medical Instrumentation (AAMI) 2006 Conference & Expo in Washington, DC on June 25. Wireless technologies are revolutionizing 21st century healthcare. However, the full potential of wireless cannot be realized without properly managing the wireless spectrum. Managing the heavily-encumbered spectrumscape in today's wireless hospital presents new challenges across the enterprise.

All wireless stakeholders are faced with the task of wringing the most out of this non-renewable resource. Mark Gibson will provide insight, case studies, interference mitigation tools, and guidelines for taking control of your wireless spectrum. Visit us at Booth #802. For more information on the AAMI 2006 Conference & Expo, click here.

Comsearch Offering a FREE Microwave Training Class on April 10, 2006
The goal of this course is to provide an understanding of principles of microwave path design, intended for the technical or non-technical telecommunications professional that is interested in learning more about the design of point-to-point microwave communication systems. No previous technical knowledge or experience is necessary, although a basic knowledge of engineering-level mathematics is helpful.

Contact us

Archives

Text only / Printer friendly

Subscribe

Unsubscribe

Update my subscriber info

Forward to a friend

If you have been forwarded WirelessPulse by a friend or colleague and wish to subscribe
yourself then click here and enter your details. CLICK HERE TO SUBSCRIBE