WirelessPulse-Comsearch E-News - July / August 2003

Comsearch's bi-monthly 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 entitled "Market Trends " - featuring in-depth analysis on industry trends", Case Corner " - featuring relevant industry case studies and "Regulatory Rap " - featuring extensive microwave and satellite regulatory 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 July 2003 issue:

Market Trends: Interoperability in Public Safety  and Homeland Security by Mark Gibson, Sr. Director, Business Development

Case Corner: WLAN Reliability Concerns Comsearch Field Services 

Regulatory Rap: Microwave and Satellite Regulatory News

What's New at Comsearch!

For more information go to www.comsearch.com.

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MARKET TRENDS :

Interoperability in Public Safety and Homeland Security
by Mark Gibson, Sr. Director, Business Development  

Many incidents have occurred over the last several years that call attention to interoperability issues among both Public Safety and Homeland Security wireless users.  In the Washington, DC area alone we can point to the following examples of problems going back over 20 years:

• In 1982, three events underscored the problems with interoperability – the Air Florida plane crash, a derailment of one of DC’s Metro trains, and a hostage-taking at an IBM office in Bethesda.  In each of these incidences, public safety radio systems were rendered practically ineffective due to technology and spectrum limitations.
  
  

• Ten years later in 1992, a tanker fire on the Capitol Beltway, the Washington area’s major artery, tied up traffic in both directions for the better part of the day.  In 1996, an Amtrack train derailed in a Washington suburb.  In these incidents, cellular networks were overrun by calls from stranded motorists and stranded rail passengers, leaving little to no spectrum available for emergency responders.
  
  

• Several other multi-jurisdictional emergency events including a bridge jumper (again on the Capitol Beltway), large building fires, and traffic accidents have rendered both public and public safety wireless systems unreliable and ineffective.  The culminating event was the 9/11 attacks on the Pentagon where firefighters and other emergency personnel had problems communicating due to inadequacies in their wireless networks.

In addition to the above examples, rescue personnel faced grave communications problems when responding to the 9/11 World Trade Center attacks.  Due to interoperability problems, rescue workers did not hear the call to vacate one of the towers before it collapsed.  An estimated 120 fire fighters died when the north tower fell.

Most interoperability problems can be linked to issues involving either incompatible technology or limited spectrum.  Incompatible technology standards across jurisdictions—such as systems that use analog vs. digital technology—is a significant obstruction to efficient and effective communications among emergency workers that can put lives at risk in a crisis situation.  The lack of available spectrum means that public safety responders must contend with congestion and a scarcity of radio channels.  This causes both interference and blockage.  Some estimates indicate that an additional 73.5 MHz of spectrum is needed for public safety use over the next 10 years.

Other barriers to interoperability include poor coordination among regional public safety agencies and a lack of funding.  New wireless technologies often require new equipment—often difficult for state and local public safety agencies to afford.

Several local, state, and national agencies have mobilized to solve these problems.  At the head is the Public Safety Wireless Network Program, or PSWN.  PSWN was formed in 1996 with a mission to “promote effective public safety communications and to foster interoperability among local, state, federal, and tribal communications systems.”  The Department of Justice and the Department of Treasury jointly sponsor this program that works to address issues facing public safety agencies as they work to improve communications interoperability.

Another organization looking at interoperability issues in the Washington, DC area is the Capital Wireless Integrated Network project, or CapWIN.  This is a partnership among Maryland, Virginia, and the District of Columbia to develop an integrated transportation and public safety data and voice communication systems.

Under the Department of Homeland Security is the National Communications System (NCS).  Formed in 1962, the NCS brings together 23 Federal departments and agencies to address the full range of national security and emergency preparedness telecommunications issues.  The NCS incorporates changing legislative, regulatory, judicial, and technical issues in interagency emergency telecommunications planning activities.

There are a host of other committees, organizations, and programs dedicated to addressing the problems of interoperability among both Public Safety and Homeland Security wireless users.  The introduction of new technologies and the availability of new spectrum allocations is key to these efforts. Recent terrorist attacks, security threats and dynamic world events give a new urgency to these critical issues. __________________________________________

CASE CORNER:

WLAN Reliability Concerns
Proper Network Design and Installation Significantly Improve Performance
Comsearch field Services

INTRODUCTION
The deployment and installation of wireless LANs requires strict attention to both the existing RF environment and to access point locations.  Because many wireless LANs operate in the 2.4 GHz ISM band, they are open to interference from the multitude of other wireless devices operating in this popular portion of the electromagnetic spectrum.  In addition, RF signals in the 2.4 GHz range suffer serious degradation if the access points are not properly located.

This study represents a typical case where a wireless LAN was receiving interference from a multitude of sources.  These interference problems were amplified due to the non-optimal placement of the access points.  Comsearch performed a series of diagnostic measurements at our clients’ offices in order to identify the source of suspected interference to the 2.4 GHz wireless LAN.  Based upon these measurements, and upon inspection of the wireless LAN, we made a series of recommendations for mitigating the interference and for improving the operation of the wireless LAN.

BACKGROUND
For over two years, users of a 2.4 GHz LAN at our clients office reported unexplained, intermittent system failures or system degradation.  Certain areas in the office seemed to experience more frequent failure or degradation than others.  Figure 1 shows a plot of the office floor plan.  

The central part of the main office area tended to experience problems randomly during the workday, while the conference room at the far east end of the complex rarely had problems.  The two conference rooms in the central part of the complex had the worst problems, including system dropouts every few minutes throughout the day.  After unsuccessful attempts to identify the source of these problems, Comsearch was called in to find the cause of the problems and suggest a remedy.

PROCEDURES
Upon arrival at our customer’s site, Comsearch field engineers performed a walk-through inspection of the system and the environment.  They also performed a physical examination of the system installation.  In addition, office personnel who used the system were interviewed to ascertain how the degradation problems were manifested.

As a result of these efforts, our engineers monitored the 2.4 GHz LAN in select locations of the office complex using diagnostic test equipment.  The monitoring locations are depicted on the floor plan in Figure 1.

RESULTS
Based upon the walk-through, interviews, and measurements, it was determined that a microwave oven located in the kitchen/break room adjacent to the main office area was leaking RF energy when in use.  This oven operated at 2450 MHz (50 MHz).  The levels detected were in excess of  -35 dBmi.  Figure 2A shows a spectrum plot of these levels near the break room door with the oven ON.  Figure 2B shows a spectrum plot of the RF environment at the same location with the oven OFF.

During a series of tests it was determined that when the oven was in operation, all users dropped offline throughout the building except those in the most distant conference room.

RF sweeps of the office spaces further revealed the existence of a point-to-point microwave system located south of the building and operating at 2452 MHz with a bandwidth of 15 MHz.  Figure 3A shows a spectrum plot of this signal.  This signal caused problems for office users linked to WLAN Access Point #1 who were near the southwest wall windows and furthest from the access point antennas.  

It was also noted that the two access points were not positioned properly to provide full coverage in the office spaces.  These access point antennas were too far above the suspended roof (approx. 18”) to provide adequate coverage.  Figures 4A & B show Access Point #1 and its location respectively.  Figures 5A & B show Access Point #2 and its location respectively.  It was also noted that there were foil-wrapped HVAC ducts in the plenum that were attenuating and reflecting the signals both to and from the access points in the central areas of the office.  These ducts as well as the plenum area are shown in Figures 4B and 5B.  

RECOMMENDATIONS
Based upon the inspections and measurements, Comsearch made the following recommendations:

1. The microwave oven in the break room should be replaced with a new unit.  RF leakage from microwave ovens tends to increase with time as the door seals age, and a new oven should have minimal leakage.
   
    

2. The office areas that were experiencing problems from the 2452 MHz Digital Microwave System (mainly those areas on the southwest side of the office that use Access Point #1) can greatly reduce the degradation by lowering or closing the metal window blinds.  Figure 3B shows a spectrum plot of the signal from the microwave systems with the blinds closed.
   
    

3. Finally, the access point antennas were located too far above the suspended ceiling such that their signals were substantially attenuated by the HVAC ducting, ceiling tiles, piping, and other metal in the plenum area.  Lowering these antennas closer to the ceiling would greatly increase the effective coverage in the office spaces, and should reduce the impact from the digital microwave signal on the south wall by increasing the desired signal.  In addition, it was recommended that the access points themselves be relocated closer together to increase coverage in the central areas of the office.  Suggestions of alternate access point locations are shown on Figure1.

Our clients’ offices represent a typical situation where sufficient attention must be given to access point locations for a wireless LANs — specifically one operating in the 2.4 GHz ISM band.  The presence of microwave ovens and microwave telecommunications systems, and the imprecise location of the access points, coupled with other potentially system-degrading problems inhibit the full-scale usage of WLAN systems.

CONCLUSIONS
The proper design and installation of wireless LANs requires more than simply placing and connecting access points and turning them on.  As we can see, the local RF environment should be studied to uncover propagation concerns, to identify the existing environment, and to optimize the location of the access points.  And with the increased deployment of wireless LANs in hospitals, airports, schools, office complexes, etc., we expect to see more instances of interference into these wireless networks.  The good news is that most interference problems, once identified, are relatively simple to fix.

For more information on WLAN design and implementation, click here.

REGULATORY RAP:

WHAT'S NEW AT COMSEARCH:

Comsearch Offers Spectrum Sharing Services for  PCS Buildouts
The June 2004 build-out deadline for PCS Block C licensees who won spectrum in 1999 is fast approaching.  Comsearch offers a suite of Spectrum Sharing services to help PCS licensees evaluate the interference potential to existing 1.9 GHz microwave incumbents.  Click here to find out more about our Spectrum Sharing Interference Studies, Cost Sharing Studies and Prior Coordination Notification (PCN) Services.

Become Eligible to Win a $250 Gift Certificate – Complete the Comsearch 2003 Web Survey
Based on feedback from our 2002 Customer Web Survey, we have been working to improve and enhance the Comsearch web site.  Our goal has been to clearly represent the industries/markets that we serve and to provide simple menu options that allow users easier access to critical information. 

In an effort to help us gauge the effectiveness of the new web design architecture, content, and online tools, we ask that you take a moment to complete our latest Web Survey by Friday, August 22, 2003.

Everyone who completes the survey in its entirety by Friday, August 22^nd, will be entered in a drawing for a $250 American Express Gift Cheque.  
Click here to participate.

Andrew Corporation Acquires Allen Telecom  Effective July 15, 2003.
Andrew Corporation (NASDAQ: ANDW), a leader in the wireless telecommunications market, has completed its merger with Allen Telecom. As part of Andrew we are now able to provide you with total end-to-end solutions—the entire base station RF footprint—as well as the services and solutions that we have always offered to you. Click here to learn more...

Comsearch Offers Online Interactive Solutions Subscription Packages
Interactive Solutions are designed to help streamline and expedite the planning, design, and management of RF spectrum.  Comsearch’s new interactive services, applications, and engineering tools allow online users to perform RF interference analysis, frequency assignment and coordination, FCC license application preparation, data monitoring, and more.  Click here for more information. 

Comsearch Protection Clients Receive FREE Standard Package Access to Comsearch Interactive Solutions
For more information on Comsearch Interactive Solutions, click here.

Follow these 3 easy steps to activate your Comsearch Interactive Services Account:

• Step 1: Go to www.comsearch.com. 
  Click on the Interactive Solutions Login button in the upper right corner and create an account.

• Step 2: Contact Comsearch by email at: customersupport@comsearch.com or by phone at 800-318-1234 to activate your subscription.

• Step 3: Begin your online access to Comsearch Interactive Solutions!

Activate your Subscription Package today!  You have everything to gain by accessing the industry's most accurate, comprehensive data, tools, and regulatory and engineering reports—available exclusively through Comsearch Interactive Solutions.

Comsearch Releases Latest Version of its Network Design Tool – iQ·link^® V8.1
Comsearch is pleased to announce the general availability of the latest version of its premier fixed network planning software, iQ·link Version 8.1.  The iQ·link software suite supports the end-to-end engineering design, operation and maintenance for both point-to-point (P-P) and point-to-multipoint (PMP) fixed microwave networks.  Implemented by operators and vendors throughout the world, iQ·link has been used to successfully engineer over 200,000 links operating over the full range of microwave frequencies and applications.

Version 8.1 of iQ·link adds a number of significant features and capabilities to this world-leading software package.  To support link engineering, Version 8.1 includes new features such as an Automatic Frequency Planning (AFP) module, support for Automatic Transmit Power Control (ATPC), and Correlated Fading.  Version 8.1 also includes new and improved windows for a number of engineering and database interfaces.  Additionally, iQ·link Version 8.1 adds the ability to support GIS data in the Erdas Imagine format as well as support for GeoTIFF formatted files.

The iQ·link software is a Unix-based engineering tool suite operating on Sun workstations and using an Oracle relational database.  The software can be provided as either a stand-alone engineering toolset or can be accessed via a web-based interface from a neutral host server.  Either option provides the end-user with the full capabilities of this premier fixed network microwave planning software solution.

Click here for more information on iQ·link.

Comsearch Prior Coordination Notices Go Electronic!
Comsearch is implementing electronic distribution of all Prior Coordination Notices (PCNs) in the fourth quarter of 2003.  Click here to learn more and submit your email address and contact information by September 12, 2003.

For 20 years, Comsearch has provided instructional material and software demonstrations to support two courses offered through USTTI—“Radio Frequency Spectrum Management” and “Spectrum Management in the Civil Sector.”  These courses cover a wide range of topics regarding the efficient use and management of radio spectrum.  The software demonstrations illustrate computerized solutions used in the engineering, spectrum management, coordination, and efficient design of fixed microwave networks and point-to-multipoint WLL systems.  Issues dealing with spectrum-sharing considerations between mobile PCS and fixed microwave networks are also addressed.

The latest course, conducted on July 22, 2003, included twenty-two participants representing 17 different countries.  All students are currently employed in senior positions in their respective country’s government telecommunications division.  The participants for this course represented a true global presence with students from Afghanistan, Bahrain, Bhutan, Bosnia and Herzegovina, Botswana, Cameroon, El Salvador, Ghana, Republic of Kazakhstan, Kenya, Kyrgyz Republic, Lithuania, Moldova, Nigeria, Nepal, Tajikistan, and Uzbekistan.

These courses are also sponsored through the US Department of Commerce National Telecommunications Information Administration (NTIA) and Federal Communications Commission (FCC) divisions.  The knowledge and expertise that the course participants receive will assist them in addressing both technical and managerial telecommunication issues in their home country.  These courses provide a foundation for the acceleration of the telecommunications infrastructure in foreign countries promoting both economic and social growth.

Comsearch WirelessPulse Distributed Quarterly
In an effort to bring you more relevant industry trend stories and applicable case studies that can help you keep abreast of your market and apply real world solutions to your business, Comsearch will publish the WirelessPulse e-newsletter on a quarterly basis. 

Comsearch will send our subscribers Regulatory Rap News Flash notices should there be a release of pertinent news to our clients between the quarterly issues of the WirelessPulse.

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