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In this issue:

CASE CORNER:
Taking Aim at Costly "Dead Zone" Problems-
Deployment Strategies for In-building Distributed Wireless Systems

MARKET TRENDS:
Visualizing Data

REGULATORY RAP:
Microwave
Satellite

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Case Corner

Taking Aim at Costly "Dead Zone" Problems -
Deployment Strategies for In-building 
Distributed Wireless Systems
by Will Hogg

In today’s wireless environment, it is common for wireless users to experience a dropped signal while in the middle of an important phone call. Attempting to make calls while in shopping malls, airports, tunnels, or other public structures, users often find their calls will not go through due to lack of coverage in a particular area. Wireless carriers and service providers know that dropped calls mean lost revenue, and that “dead zones” can be deadly to their business. The solution to this problem is to eliminate costly dead zone problems and ensure constant coverage for your wireless users. That’s where a distributed wireless antenna system comes in to play.

In-building Distributed Wireless Systems (DWS)

While Distributed Wireless Antenna Systems (DWS) can be more challenging to deploy than a Macro system, they are a great way to provide additional coverage and capacity to your subscriber base while at the same time helping to eliminate lost subscriber-based revenue due to wireless network “dead-zones.” Although dropped calls are the main driving force behind the need for the installation of a Distributed Wireless System (DWS), an additional incentive for installation is that these systems are not only cost effective, but also extremely successful at eliminating dropped calls and dead zones. Given that, it is important to note that the implementation procedures are more stringent when deploying a DWS than with a Macro-site design. This is due in part to various construction issues involved with deploying an in-building DWS. However, the benefits to carriers, service providers, and more importantly, customers, are immense, and far outweigh the stringent implementation procedures required.

For a high caliber in-building DWS to be successful, several key issues must be addressed and specific tasks must be completed prior to deployment. For example, antenna sites used in the DWS must seamlessly integrate into the current Macro system. In addition, interference and capacity direction must also be addressed in order to ensure a successful DWS is deployed. Both of these key elements are often times overlooked when optimizing these systems.

DWS and Integration with TDMA and CDMA based Systems

Most Distributed Wireless Systems are deployed to serve a need based on shortcomings in the existing Macro system. These shortcomings are based on key system problems including coverage dead zones, system interference, and capacity limitation. Coverage dead zones are self-explanatory. There simply is not enough RF energy to meet your system’s link budget in the intended service area. Interference concerns, however, are a bit more involved.

In a TDMA based system, interference can stem from adjacent channel or co-channel interference. It is usually the latter, and is very similar to interference problems that RF engineers face when working on networks on a Macro-level. In a CDMA based system, interference within a DWS is usually based on lack of a dominant pilot (PN) serving the coverage area, which often is due to multiple PNs (or sectors) serving the same area. This is called pilot pollution, and is often faced by RF engineers on the Macro-level.

Additionally, capacity issues can be a major obstacle that must be overcome, especially in areas that are highly congested, such as airports, convention centers, and shopping malls. Traditionally, carriers have felt that constructing additional sites in close proximity to the desired coverage area can easily provide a quick fix for these types of dead zones. However, while these sites do dramatically increase the coverage and capacity to these areas, the carrier cannot guarantee there will be coverage/capacity in the depths of building structures. Carriers are finding that the Macro-site approach is also more costly and takes a significant amount of time as zoning issues alone can stall Macro site development for years.

Expanding coverage to areas where it is non-existent today in order to decrease subscriber churn rate is another underlying factor for installing a DWS. Deployment of a DWS provides added coverage and capacity to areas of poor coverage via the DWS infrastructure. While the infrastructure design is similar between vendors (i.e., Mikom, LGC Wireless, Foxcomm, etc.), there are two primary methods that provide the carrier’s signal into the building or other structure.

Deployment Methodology

In the first method, a repeater is used for the front end of the system. This is because a repeater is less costly than a full Base Transmission System (BTS) and can be easily placed into/onto the building. After the first fiber hub is installed, the rest of the infrastructure is the same, as seen from the repeater or BTS. However, a repeater cannot provide carriers with the additional capacity needed in the building.

This is where the second method comes into play that involves using a Base Transmission System as the front end to the DWS. While this is not the most cost-effective method, it is the most robust solution for deploying a DWS. Using a BTS provides the flexibility to allocate capacity as needed versus taking it from another site. This method also allows engineers to conduct frequency/PN planning on a cluster basis with the rest of the Macro system, allowing the DWS to be seen as its own separate and independent site within the carrier’s system. Additionally, lower-cost microcell BTSs will soon be available from various vendors that will make the equipment footprint area more manageable.

It is clear that Distributed Wireless Systems provide a major advantage in meeting in-building coverage goals. However, implementing these systems can often be intimidating to the inexperienced engineer. There are pitfalls that an experienced RF engineer may fall into due in part to their lack of experience with these types of systems.

When implementing a successful DWS, strict attention must be given to the following key areas:

1. Receiving existing building drawings prior to the initial walk through of the building

2. Access to perform system testing prior to system design

3. Performing optimization/integration testing after the DWS is deployed

In order for the site acquisition specialist and the RF engineer to fully understand the “lay of the land” prior to arriving at the building or structure, it is crucial that they have access to site drawings prior to arriving at the building or structure. All too often problems such as antenna layout, building layout, or equipment room locations are encountered at the site and can be eliminated when preliminary studies of the site drawings are performed prior to arriving at the building. This enables a speedy site walk, and more importantly, enables the RF engineer to decide ahead of time where to perform the path loss measurements and existing signal strength measurements.

Another potential roadblock that may be encountered during the design phase of the System is gaining access to the building or structure in order to conduct system testing of the coverage area. Proper access to the building or site cannot be stressed enough as the determination of antenna locations must be decided upon prior to the actual testing, and validated by doing a site-walk through the building or structure. Access to antenna and equipment locations so that the RF Engineer, site acquisition specialist, and construction manager can validate these locations and determine their viability is crucial to the overall success of the system.

There are numerous instances where assumptions are made in equipment location or antenna cable/fiber runs only to have them fail from a constructability standpoint. Having access to the building helps all parties determine if the design assumptions and ideas can be implemented. Part of the validation process for the design is the actual testing of these locations by performing pathloss test measurements. These tests help the RF engineer determine the RF environment of the building or structure. Part of this validation process should include testing of the existing signal level within the building or structure. This is a crucial step that must be performed to ensure that antenna locations can be verified and logically placed in order to overcome strong signals that may penetrate the system from outside sources. Overcoming the outside system must be achieved if you use a dedicated BTS to ensure the capacity for the building or structure is being provided by the DWS system.

Once the design is complete, and the system has been constructed, the next crucial step involves testing of the actual DWS to ensure that the System integrates seamlessly into the Macro-system. A common pitfall encountered in testing Distributed Wireless Systems is to simply walk around and monitor mobile phone receive power levels. While this may be acceptable at ground level, it becomes critically misleading on higher floors or at higher elevations on the structure where penetration from the outside Macro-system increases to higher levels.

On the higher floors of a building or at higher levels on a structure, it is important to measure DWS interference from the outside system and to properly test the interference from the DWS. However, experience has shown that due to their relatively low power levels, a DWS rarely interferes with the existing Macro system. A critical element that must be addressed for proper operation of the System is to take the necessary steps to make sure that the Macro system does not interfere into the DWS. This can negatively impact the DWS in two ways. First, it can create significant downlink interference into your system, and not enable the DWS to carry the traffic of the building, which is one of its primary coverage requirements.

Second, if the measurements of the existing signal levels are performed completely and accurately, then the antennas should be placed in optimal positions to overcome outside interference. Finally, the last step in the process is to monitor performance statistics to verify that the capacity is distributed where it is most needed. Fortunately these systems are so adaptive that capacity can be re-allocated as necessary.

Summary

The benefits you will experience when deploying a DWS system are easily realized. You stay competitive and provide your customers with what they want—a dominant, capacity-plentiful, wireless service—anytime, anywhere. In addition, you will expand coverage to areas where it is non-existent today while at the same time increase the capacity of your network.

However, there are pitfalls that need to be addressed to ensure these systems are designed and executed quickly, efficiently, and cost effectively. Taking the time to address these issues when deploying a DWS will prove very beneficial to you and your customers. Help eliminate lost subscriber-based revenue, reduce your churn rate, and take dead aim at your wireless network “dead zone” problems by deploying a Distributed Wireless Antenna System today.

A Case Study:
Janelia Farm Technology Park

  In Building System – Design and Performance

Comsearch required solid in-building cellular coverage to accommodate the business needs of its high tech workforce. When the decision was made to move its headquarters from Reston, Virginia to a new facility in Janelia Technology Park in Ashburn, Virginia, it was crucial that existing levels of cellular coverage be maintained to accommodate the needs of Comsearch employees and business partners. Tucked quietly into the Potomac River valley, the location of Janelia Technology Park meant any cellular carrier would have difficulty providing adequate service levels in a cost effective manner. Comsearch’s Engineering Solutions group studied existing service levels to propose a course of action to obtain optimal coverage.

Comsearch determined early on in the data gathering process that the existing coverage from the local national wireless service providers was inadequate, especially on the lower floors of the building. Figure 2 shows the signal strength of one service provider as collected on the second floor of the building. The coverage of this carrier in particular was very weak throughout the building and in most cases the phones were unusable. Observed signal levels of –100 dBm to –105 dBm were typical throughout the entire building, and construction of walls and furnishings caused additional signal attenuation. Comsearch conducted a comprehensive CDMA analysis for this carrier.

Since a majority of the Comsearch employees uses this carrier’s phones, Engineering Solutions decided to design and implement a Distributed Antenna System (DAS) to provide sufficient signal levels to support reliable wireless service. Figure 3 shows the design layout of the in-building distributed antenna system installed at Janelia Farm Technology Park.

The results of the measurements and analysis effort indicated that the in-building distributed antenna system was successful (see Figure 4). The first true test of the system was the move in weekend for Comsearch. The new system allowed move staff to communicate throughout the building and has been on air since providing optimal wireless coverage in all areas of the facility. The Janelia Technology Park in-building Distributed Antenna System has proved to be a valuable solution for Comsearch’s wireless communication needs. Comsearch’s design easily met the carrier’s optimization and performance criteria and has been a total success.

Janelia Farm Technology Park’s successful engineering design process included a comprehensive analysis encompassing all of the following aspects:

1. Pre-design Analysis

   1. Existing Signal Coverage Measurements

   2. Site Survey

   3. Path Loss Test
      
      

2. Design Development

   1. Traffic Analysis

   2. Capacity Requirement

   3. Equipment Specification

   4. System Impact

   5. Design Generation
      
      

3. Equipment Selection

   1. Vendor Capabilities

   2. Costs
      
      

4. System Implementation
   
   

5. Exit Criteria

   1. RF Performance

   2. Forward & Reverse Link Average FER

   3. Percent Dropped Calls

   4. Access Failures

   5. Percent Call Origination/Termination Failures

   6. Ec/Io Performance

   7. Average Channel Element Usage per Call

Market Trends

Visualizing Wireless
by Carol Hahn

In addition to typical network design, these tools can be applied to a variety of planning projects such as:

State / Local Government                                   

Facilities management, as it relates to network development and maintenance, is a constant issue for government entities.  Some government jurisdictions have a very thorough detail of wireless telecommunications in their area, while other jurisdictions may not have collected all the data needed to assess their networks.  And, there are still some government entities that do not have a network defined at all.  GIS data can help these agencies visualize data through the many stages of network development and analysis - allowing governments to see their networks or other wireless networks in their area.  This type of visualization of data will shorten the network planning process and reduce costs due to duplication of resources.   Governments need to know the dynamics of their networks.  The diversity of band applications presents many opportunities to grow and improve local communities and entice businesses into a particular region.  Open pockets in a network may present valuable opportunities for the right investor.  A wide-open area could be the prime target for windmills farm - a growing application in energy design.

Example use: Wind Energy Design

Wind Energy is growing in popularity as a non-traditional, environmentally friendly form of energy.  Windmill farms are being developed at record numbers throughout the world.  A developing issue, however, is the risk of wireless telecommunications

Expanding the Network

Network companies are constantly competing for the biggest and best networks.  Their eyes see the stars, yet budgets impact decisions.  The last issue companies want to arise is lack of coverage.  This is a growing concern in booming areas of the country.  These companies can design the expanding networks to take into consideration population density and coverage area.  GIS tools give network planners the ability to envision how development will affect current and future population conditions.

Type of Data

A great factor in considering the benefits of visualization for network planning is the amount and type of data that is included.  Common attributes are Coordinates, Ground Elevation, Radio and Antenna Equipment, Distance Between Sites, Contact Information, Frequency, and Callsign.

What's next...Competitive Analysis, Satellite Imagery, 
Location Based Services?

Regulatory Rap

MICROWAVE

FCC Budget of $278 Million proposed for Fiscal Year 2003

The President has submitted a budget to Congress that proposes fiscal year 2003 funding for the Federal Communications Commission of $278,092,000 and a proposed staffing level of 1,975 full- time equivalents.  This budget represents an increase of $33M over the FY 2002 appropriation level of $245M. Nearly 25% of the requested FY 2003 increase in the funding level ($8,190,000) will cover mandatory increases for salaries and benefits and other areas and inflationary increases for contract services. The balance of the requested increase ($ 15,066,000) includes funds to continue expansion of electronic filing, improve technical and economic expertise of staff, address life-cycle replacement of technical monitoring and testing equipment, provide infrastructure improvement to the laboratory facility, enhance the Commission’s information technology infrastructure, and enable the Commission to improve its homeland security posture. The complete copy of the Commission’s FY 2003 budget submission is available on the FCC’s web site at: www.fcc.gov.

FCC Releases 3^rd Annual Report on the Availability of High-Speed 
and Advanced Telecommunications Capabilities

The report reflects nearly ten million subscribers to these specialized services.  Full details can be found at: http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-219820A1.pdf.

FCC Designates 4.9 GHz Band for use in Support of Public Safety

On February 14, 2002, the FCC adopted a Second Report and Order and Further NPRM allocating 50 megahertz (MHz) of spectrum in the 4940-4990 MHz band (4.9 GHz band) for fixed and mobile wireless services and designating the band for use in support of public safety. The Commission also sought comment on various issues including licensing and services rules for the 4.9 GHz band. This allocation and designation will provide public safety users with additional spectrum to support new broadband applications such as high-speed digital technologies and wireless local area networks for incident scene management. The spectrum also can support dispatch operations and vehicular or personal communications. Additional information available here: http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-219990A1.pdf.

Ultra-Wideband Technology Approved

On February 14, 2002, the FCC adopted a First Report and Order in Docket 98-153 that permits the marketing and operation of certain types of new products incorporating ultra-wideband (“UWB”) technology. UWB devices operate by employing very narrow or short duration pulses that result in very large or wideband transmission bandwidths. This First Report and Order (“Order”) includes standards designed to minimize interference with existing and planned radio services, particularly safety services. Since there is no production UWB equipment available, and there is little operational experience with the impact of UWB on other radio services, the Commission chose in this First Report and Order to err on the side of conservatism in setting emission limits when there were unresolved interference issues. The Commission intends within the next six to twelve months to review the standards for UWB devices and issue a further notice of proposed rule to explore more flexible standards and address the operation of additional types of UWB operations and technology.  The Order establishes different technical standards and operating restrictions for three types of UWB devices based on their potential to cause interference. These three types of UWB devices are: 1) imaging systems including Ground Penetrating Radars (GPRs), wall, through-wall, medical imaging, and surveillance devices, 2) vehicular radar systems, and 3) communications and measurement systems. http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-220001A1.doc.

Wireless Bureau Seeks Comment on the NTIA Report on Spectrum Use 
by the Energy, Water, and Railroad Industries

On February 14, the FCC requested comment on the U. S. Department of Commerce, National Telecommunications and Information Administration (NTIA) Report entitled “Current and Future Spectrum Use by the Energy, Water, and Railroad Industries.”  Details at: http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-02-361A1.pdf.

FCC Initiates Proceeding to Promote Widespread Deployment of 
High-Speed Broadband Services

On February 14, 2002, the FCC adopted a major rulemaking to promote greater deployment of broadband services. The NPRM is designed to resolve outstanding issues regarding the classification of telephone-based broadband Internet access services and the regulatory implications of that classification. In the Notice, the FCC tentatively concluded the wireline broadband Internet access services – whether provided over a third party’s facilities or self-provisioned facilities – are information services, with a telecommunications component, rather than telecommunications services. Information services include such services as voice mail and email, which ride over telecommunications facilities. The FCC has set the following policy goals: 1. Encourage the ubiquitous availability of broadband access to the Internet to all Americans. 2. Promote competition across different platforms for broadband services. 3. Ensure that broadband services exist in a minimal regulatory environment that promotes investment and innovation. 4. Develop an analytical framework that is consistent, to the extent possible, across multiple platforms.

U.S. Supreme Court Agrees to Review Nextwave Bankruptcy Proceeding

The U.S. Supreme Court has agreed to review the Nextwave proceeding involving the FCC and the PCS licenses impacted by Nextwave’s bankruptcy filing.  This review process could take up to 2 years.  In a related action, Verizon Wireless, Inc. has once again requested the federal appeals court to compel the FCC to return its deposit money.

Nextel Spectrum Plan - Financial Impact Predicted for Private Wireless Users

The Industrial Telecommunications Association (ITA), an industry group opposing Nextel’s Plan, predicts that many business and industrial wireless system users will be hit by high reallocation costs if the proposal successfully makes it through the Washington regulatory rounds. The Nextel proposal is designed to ensure interference-free spectrum for police and fire department communications. If approved by the FCC, the plan would reconfigure the 800-MHz spectrum band to reduce interference. In a letter to the FCC, the ITA stated that the Nextel plan could disrupt "mission-critical communications and impose billions of dollars of costs on American businesses to relocate operational communications systems that are not causing any interference to public safety operations." The Nextel proposal has some support from public safety communications organizations and police and fire chiefs associations. The public safety agencies would have to shift some spectrum assignments, but Nextel said it would provide $500 million to fund the change.  While Nextel has offered replacement spectrum at 700 and 900 MHz, it has not offered funding to reallocate the non-public safety private wireless systems.  The FCC is expected to release an NPRM this month requesting comment on this issue.

FCC Auctions:

Auction 43: 220, 800 and 900 MHz Multi-Radio Service Licenses

Auction closed on January 17, 2002, after 31 rounds.  The 3 winner bidders (AerWav Inc., Nextel Spectrum Acquisition Corporation, and TeleBeeper of New Mexico, Inc.) purchased 27 licenses for a total of $1.55M.  Full details on the winning licenses at:  http://wireless.fcc.gov/auctions/43/releases/da020157a.pdf.

Auction 31:   Upper 700 MHz

Scheduled to begin June 19, 2002.  Twelve 700 MHz Band EAG licenses will be available, designated as:

Block "C" 747-752 MHz, 777-782 MHz
Block "D" 752-762 MHz, 782-792 MHz

 Additional details can be found at http://wireless.fcc.gov/auctions/31/factsheet.html and http://wireless.fcc.gov/auctions/31/releases.html#da012394.

Auction 41:     Lower 700 MHz

Scheduled to begin June 19, 2002. Licenses can be used for Fixed, Mobile, and Broadcasting services in the 698-746 MHz (Lower 700 MHz) band. Several 700 MHz Band licenses will be available, designated as:

Additional information can be located at:   http://wireless.fcc.gov/auctions/44/releases.html.

SATELLITE

FCC Reorganizes the International Bureau

On February 28, 2002, the International Bureau (IB) announced a new structure consisting of three Divisions:  Policy Division, Satellite Division and Strategic Analysis & Negotiations Division.  The Satellite’s Division Chief will still be Tom Tycz, along with Fern Jarmulnek as Deputy Division Chief and John Martin as Senior Engineer.  Robert Nelson will now head the Satellite Engineering Branch and Ron Repasi, former Satellite Engineering Branch Chief, is now the Deputy Division Chief of Engineering for the Policy Division.

IBFS Update

Comsearch has been actively participating in the International Bureau’s development of the IBFS electronic licensing system.  An update on some of the recent system upgrades includes the following:

• Auto-Population of application information based on user FRN number.
• Auto-Population of application technical information for modifications of license based on FCC Call sign.
• Automatic Calculation of various technical portions of the 312 Schedule B: AZEL, Max. EIRP Density, etc.
• Application Save Option - saves the application with the current data to allow you to return later to complete.

These are just some of the proposed changes that would make the system more user friendly and save time in preparing a filing on-line.

ESV NOI

On February 4, 2002, the IB released an Notice of Inquiry on Procedures to Govern the Use of Satellite Earth Stations on Board Vessels in Bands Shared With Terrestrial Fixed Service (IB Docket No.  02-10) http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-18A1.doc. This Notice requests comment on a number of issues related to the licensing of ESVs.  These include the feasibility of licensing the service in general, the appropriate service and band allocations, methods to preclude interference, coordination of the service on a permanent basis, and any other comments from the industry.  Comments will be due 30 days after publication on the Federal Register, which has not occurred as of the date of this newsletter.  The National Spectrum Managers Association (NSMA) has taken an active role in this issue and is expected to spearhead industry response to the NOI.

Earth Station License Terms

On February 28, 2002, as part of an on-going effort regarding the FCC Rule Part 25 Biennial Review (IB Docket No. 00-248), the IB has issued a Report and Order modifying the licensing terms for transmit-receive and receive-only earth stations. See URL:
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-45A1.doc.

FCC Rule Part- 25.121 License term and renewals will now include the following:

1. License Term. Licenses for facilities governed by this part will be issued for a period of 15 years.
   
2. The Commission reserves the right to grant or renew station licenses for less than 15 years if, in its judgment, the public interest, convenience, and necessity will be served by such action.

Service Rules and Policies for Ka-band NGSO

On February 6, 2002, the IB released an NPRM on The Establishment of Policies and Service Rules for the Non-Geostationary Satellite Orbit, Fixed Satellite Service in the Ka-Band (IB Docket No. 02-19). See URL:
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-30A1.doc.

The IB is seeking a way to share the spectrum with at least five pending Ka-band NGSO system applications.  Comments on sharing feasibility and techniques and service rules are requested. Comments are due on or before April 3, 2002, and Reply Comments are due on or before April 18, 2002, (there is a typo in the Federal Register which reads that Reply Comments are due April 3, 2002).

EchoStar - Spot Beam Satellite Approved

On January 15, 2002, the FCC granted EchoStar Satellite Corp. authority to launch and operate a new direct broadcast satellite - EchoStar 7 and co-locate it with EchoStar's existing network of satellites at the 119 degree WL orbital location. Full details can be located at: http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-02-118A1.pdf.

Spectrum Management 2002