NASA/TM⎯2004-211529

EMERGING COMMUNICATION 

TECHNOLOGIES (ECT) 

PHASE 3 FINAL REPORT 

Gary L. Bastin, Ph.D. 

ASRC Aerospace Corporation, John F. Kennedy Space Center, Florida 

William G. Harris, PE 

ASRC Aerospace Corporation, John F. Kennedy Space Center, Florida 

Lakesha D. Bates, B.S.E.E., M.S.E.E. 

NASA Graduate Fellowship Student, John F. Kennedy Space Center, Florida 

Richard A. Nelson 

NASA, YA-D7, John F. Kennedy Space Center, Florida 

September 2004 

 
 

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NASA/TM⎯2004-211529

EMERGING COMMUNICATION 

TECHNOLOGIES (ECT) 

PHASE 3 FINAL REPORT 

Gary L. Bastin, Ph.D. 

ASRC Aerospace Corporation, John F. Kennedy Space Center, Florida 

William G. Harris, PE 

ASRC Aerospace Corporation, John F. Kennedy Space Center, Florida 

Lakesha D. Bates, B.S.E.E., M.S.E.E. 

NASA Graduate Fellowship Student, John F. Kennedy Space Center, Florida 

Richard A. Nelson 

NASA, YA-D7, John F. Kennedy Space Center, Florida 

National Aeronautics and 

Space Administration 

John F. Kennedy Space Center, Florida 32899-0001 

September 2004 

 
 

Acknowledgments

Although there is always the risk of inadvertently forgetting someone, the ECT team nonetheless wishes to 

acknowledge especially the assistance and guidance provided by the following individuals, listed 

alphabetically. Without the continued support of these supporters who believed in the value of this project, 

this project could not have accomplished all its goals. 

Name Organization

Erik Denson NASA-KSC 

Temel Erdogan ASRC Aerospace Corporation 

Richard A. Nelson NASA-KSC 

Don Philp ASRC Aerospace Corporation 

Steve Schindler NASA-KSC 

Lisa Valencia NASA-KSC 

Available from: 

NASA Center for AeroSpace Information National Technical Information Service 

7121 Standard Drive 5285 Port Royal Road 

Hanover, MD 21076-1320 Springfield, VA 22161 

 
ECT - Phase 3 

TABLE OF CONTENTS 

No. Description Page 

1.0 Introduction............................................................................................... 1

1.1 Background................................................................................................. 1 

1.2 Objectives ................................................................................................... 2 

1.3 Scope........................................................................................................... 2 

1.4 ARTWG / ASTWG..................................................................................... 2 

2.0 Free Space Optics...................................................................................... 5

2.1 Background................................................................................................. 5 

2.2 Basic FSO Theory....................................................................................... 7 

2.3 Test Description.......................................................................................... 7 

2.4 Test Objectives ........................................................................................... 8 

2.5 Test Setup ................................................................................................... 8 

2.5.1 EDL ANDL Setup..................................................................................... 10 

2.5.2 EDL East Parking Lot Test Setup............................................................. 12 

2.5.3 EDL to SSPF Parking Lots Test Setup ..................................................... 15 

2.5.4 Schwartz Road Test Setup ........................................................................ 17 

2.6 Test Equipment And Software.................................................................. 19 

2.6.1 SONAbeam 622-M ................................................................................... 20 

2.6.2 Laptop ....................................................................................................... 23 

2.6.3 SmartBits................................................................................................... 24 

2.6.4 SONAbeam Terminal Controller Software .............................................. 26 

2.6.5 SmartApplications .................................................................................... 29 

2.7 Test Results............................................................................................... 30 

2.7.1 Results Summary ...................................................................................... 30 

2.7.2 SmartBits................................................................................................... 42 

2.7.3 SmartBits Testing ..................................................................................... 42 

2.8 FSO Security Concerns............................................................................. 43 

2.9 Comparison Of Multi-Beam and Single Beam Systems........................... 44 

2.10 FSO Summary And Recommendations .................................................... 45 

3.0 Ultra Wide Band ..................................................................................... 47

3.1 Introduction............................................................................................... 47 

3.2 Background............................................................................................... 49 

3.3 OFDM Overview ...................................................................................... 49 

3.4 Research Organization.............................................................................. 51 

3.5 Timing Jitter in UWB-OFDM Communication Systems ......................... 51 

3.6 OFDM Technique ..................................................................................... 51 

3.7 Timing Error Effects on System Performance.......................................... 53 

3.8 Timing Jitter and Phase Noise Relationship............................................. 53 

3.9 Tikhonov Approximation of Timing Error............................................... 54 

3.10 Bit Syncronization .................................................................................... 55 

3.11 Analytical Solutions for BER Performance.............................................. 56 

3.12 Conditional Error Probabilities................................................................. 56 

3.13 Manchester Coded Data............................................................................ 57 

 iii
ECT - Phase 3 

3.14 NRZ Coded Data....................................................................................... 57 

3.15 RZ Coded Data ......................................................................................... 57 

3.16 Miller Coded Data .................................................................................... 58 

3.17 Establishing Avg. Error Prob. at the Receiver.......................................... 59 

3.18 Test Case with the PulsON200 Radios..................................................... 61 

3.19 Test Procedures......................................................................................... 62 

3.20 Results Overview...................................................................................... 65 

3.21 BER Effects due to Timing Errors............................................................ 65 

3.22 PulsON200 Test Case ............................................................................... 70 

3.23 Required Equipment and Test Setup ........................................................ 71 

3.24 Test Case Results...................................................................................... 71 

3.25 Assessment of Timing Uncertainties........................................................ 73 

3.26 Analysis of Effects on UWB-OFDM System with High Data Rates ....... 75 

3.27 Summary of Results.................................................................................. 76 

3.28 Recommendations for Future Research.................................................... 76 

4.0 ECT Summary Recommendations For Continued Research............. 78

APPENDIX A: UWB EVK Performance Analysis Tool (PAT) Software................ 80

APPENDIX B: Digital Signaling Formats Applicable T0 FSO And UWB 

Communication Signaling.............................................................................................. 90

APPENDIX C: Q-Function, ERF, AND ERFC, Applicable To Bit Error Rate 

Theoretical Analysis Of FSO AND UWB Communication Systems.......................... 92

REFERENCES................................................................................................................ 94

 iv
ECT - Phase 3 

LIST OF FIGURES 

No. Description Page 

Figure 1-1 ARTWG/ASTWG National Development Strategy....................................3 

Figure 1-2 ARTWG Integration/Interaction Process.....................................................3 

Figure 1-3 Spaceport and Range Environments...........................................................4 

Figure 2-1 Typical Test Setup Using SmartBits with Loop at OTU #2 .......................9 

Figure 2-2 OTU #1 in the ANDL on the North Bench...............................................10 

Figure 2-3 OTU #2 in the ANDL by the South Wall .................................................11 

Figure 2-4 OTU #1 with Laptop Measuring Receiver Performance .........................12 

Figure 2-5 OTU #1 Mounted on an Existing Antenna Trailer ...................................13 

Figure 2-6 OTU Mounted On Fabricated Support Stand ...........................................13 

Figure 2-7 Trailer Mounted OTUs in East EDL Parking Lot (113-Ft Range)...........14 

Figure 2-8 Portable Generator Used for Power During Remote Testing ...................14 

Figure 2-9 EDL to SSPF Parking Lots Test Setup .....................................................15 

Figure 2-10 OTU #2 in the EDL North Parking Lot ..................................................15 

Figure 2-11 OTU #1 in the SSPF Parking Lot............................................................16 

Figure 2-12 View from OTU #2 to OTU #1................................................................16 

Figure 2-13 OTU #2 Parked on West End of Schwartz Rd.........................................17 

Figure 2-14 OTU #1 Parked on East End of Schwartz Rd. ........................................18 

Figure 2-15 OTU #1 with SmartBits and Laptop Connected .....................................18 

Figure 2-16 View from OTU #1 toward OTU #2 at 1.0 Mile Range .........................19 

Figure 2-17 Front of SONAbeam 622-M OTU .........................................................20 

Figure 2-18 SONAbeam Junction Box Open ............................................................22 

Figure 2-19 Pole Mount with OTU, Connection Box & Power Supply Box ............22 

Figure 2-20 Gateway 450 XL Laptop Computer.......................................................23 

Figure 2-21 SmartBits Test Unit................................................................................25 

Figure 2-22 Field Testing with the SmartBits & a Laptop ........................................25 

Figure 2-23 Initialization Page for fSONA Terminal Controller Software ...............26 

Figure 2-24 Comm 1 Status Showing No FSO Connection or Input ........................26 

Figure 2-25 Comm 1 Tx Configuration With System Power At Level 1..................27 

Figure 2-26 Comm 1 Rx Power Level.......................................................................27 

Figure 2-27 Comm 1 Diagnostics with No FSO Lock or Input.................................28 

Figure 2-28 Comm 1 Settings....................................................................................28 

Figure 2-29 Smart Applications Main Page with Card 17 to Card 19 Test Setup.....29 

Figure 2-30 Minimum Receive Power versus Distance ............................................32 

Figure 2-31 Receive Power versus Transmitter Setting @ 1.0 Mile .........................32 

Figure 2-32 Receive Power versus Transmitter Setting @ 1.5 Mile .........................33 

Figure 3-1 De-Multiplexed High Data Rate Of DM Data Stream.............................49 

Figure 3-2 Overlapping Orthogonal Sub-Carriers In OFDM Symbol.......................50 

Figure 3-3 OFDM Symbol.........................................................................................52 

Figure 3-4 OFDM Block Diagram.............................................................................54 

Figure 3-5 Performance Analysis Interface For PulsON 200 Receiver.....................63 

Figure 3-6 Theoretical BER vs Eb/No For PulsON 200 Flip Modulation ................64 

 v
ECT - Phase 3 

Figure 3-7 Representation Of Timing Errors In A Digital Signal .............................66 

Figure 3-8 Representation Of Distortions In A Signal ..............................................66 

Figure 3-9 BERs For Timing Jitter (Manchester Data).............................................67 

Figure 3-11 BERs For Timing Jitter (MILLER Data)...............................................68 

Figure 3-12 BERs For Timing Jitter (NRZ Data)......................................................69 

Figure 3-13 Flip Modulation......................................................................................70 

Figure 3-14 PulsON 200 Evaluation Kit Setup .........................................................71 

Figure 3-15 Flip Modulation Theoretical Curve vs PulsON 200 Data (9.6 Mbps)...73 

Figure 3-16 Manchester Data With Extrapolated PulsON 200 Data.........................74 

 vi
ECT - Phase 3 

LIST OF TABLES 

No. Description Page 

Table 2-1 FSO Industry Comparisons..........................................................................6 

Table 2-2 FSO Test Locations .....................................................................................9 

Table 2-3 SONAbeam 622-M Specifications ............................................................21 

Table 2-4 FSO Factory IP Addresses.........................................................................23 

Table 2-5 FSO Reset IP Addresses............................................................................23 

Table 2-6 Laptop Computer Specifications ...............................................................24 

Table 2-7 Laptop Computer Installation Parameters .................................................24 

Table 2-8 Summary of Test Locations & Objectives.................................................30 

Table 2-9 Summary of Test Types and Data Measurements .....................................30 

Table 2-10 Recommended Receiver Power Levels .....................................................31 

Table 2-11 Summary Of fSONA 622-M Testing.........................................................33 

Table 2-12 SmartBits Throughput Test Parameters.....................................................42 

Table 2-13 Typical SmartBits Through-Put Test.........................................................43 

Table 2-14 Typical SmartBits Packet Loss Test ..........................................................43 

Table 3-1 List Of UWB-Related Abbreviations.........................................................48 

Table 3-2 Analytical Equation Definitions ................................................................60 

Table 3-3 PulsON 200 Collection Of Data Rate Vs Range Test Cases.....................72 

 vii
ECT - Phase 3 

 viii
ECT - Phase 3 

Executive Summary 

________________________________________________________________________ 

The National Aeronautics and Space Administration (NASA) is investigating alternative 

approaches, technologies, and communication network architectures to facilitate building 

the Spaceports and Ranges of the future. These investigations support the Crew 

Exploration Vehicle (CEV) and other associated craft presently under development or 

under consideration in Government, academic, and private sectors. These investigations 

also provide a national centralized R&D forum for next-generation Spaceport and Range 

technology development. Together, these sectors all share the common goal of changing 

the historic risk/reward equation for access to space, with the intent to: 

• Dramatically reduce launch cost 

• Greatly improve launch system reliability 

• Significantly reduce crew risk 

 ix
ECT - Phase 3 

 x
ECT - Phase 3 

1.0 INTRODUCTION

1.1 BACKGROUND 

Emerging Communication Technologies is a multi-year task investigating new 

communication technologies with likely high utility and application for future ranges and 

spaceports. 

In year one, the project was called Range Information Systems Management (RISM). 

This project investigated US ranges and documented their missions, capabilities, and 

infrastructures. A part of this investigation was the history of communication and the 

identification of certain technologies which might offer improved range capabilities in 

the near future. Three emerging technologies were identified: Free Space Optics (FSO), 

Ultra Wide Band (UWB), and Wireless Ethernet (Wi-Fi). All three of these technologies 

address the first mile / last mile communication solution. 

In year two, specific examples of FSO, UWB and Wi-Fi were purchased and evaluated 

for range application. The FSO hardware was an AirFiber 5800 optical transceiver. This 

unit includes an auto-tracking feature that keeps the two units in optical alignment during 

small movements that normally occur to support structures due to solar heating, winds 

and vibration. The units were tested over various distances and through various weather 

conditions. 

The UWB effort in year 2 involved an industry survey, a discussion of UWB theory, and 

the testing of an Evaluation Kit (EVK) from Time-Domain Corporation. Testing 

involved measuring the signal degradation due to range; normal office barriers of 

concrete, metal, partitions, etc.; and interference from microwave ovens, wireless phone, 

etc. 

During year 2, two different Wi-Fi systems were purchased and evaluated. One was an 

802.11b base station by Microsoft. The other was an 802.11g system by D-Link. The 

majority of testing was on the 802.11b system were signal degradation due to range; 

normal office barriers of concrete, metal, partitions, etc.; and interference from 

microwave ovens, wireless phone, etc., were investigated. 

During year 3, the current year, additional details were addressed in detail and are 

documented at length in this report. Specifically, wide-beam, non-tracking FSO 

hardware from fSONA was procured and evaluated in contrast to the narrow-beam, autotracking hardware from AirFiber investigated in year 2. Additionally, OFDM-UWB 

performance limitations were investigated through using the same EVK with the addition 

of new firmware upgrades from Time-Domain Corporation. Likewise, general industry 

trends for achieving first mile / last mile communications were monitored and 

incorporated into this multi-year ECT activity. 

 1
ECT - Phase 3 

 

1.2 OBJECTIVES 

The primary objective for the Emerging Communication Technology (ECT) task is to 

lead the development of a Space Based Range Distributed Subsystem (SBRDS) network 

providing the concurrent features and growth capabilities necessary for future Spaceports 

and Ranges to interconnect Range assets, Range operations, and Range users during 

launch and recovery events, while focusing primarily on the First Mile/Last Mile wireless 

communication extensions to existing, fixed communication infrastructures. 

1.3 SCOPE 

ECT Phase 3 was limited to the following: 

• Investigate one fixed alignment, multiple-beam FSO system 

• Further investigate the capabilities of the Time-Domain upgraded firmware UWB 

system 

• Monitor future range and spaceport architectures and needs 

1.4 ARTWG / ASTWG 

ECT further seeks to multiply the knowledge base of the in-house investigators through 

participation in the active efforts of: 

• ARTWG (Advanced Range Technology Working Group) 

• ARTWG Communication Subgroup 

• ARTWG other Subgroups 

• ASTWG (Advanced Spaceport Technology Working Group) 

• ASTWG Subgroups 

ARTWG is a collaborative NASA/US Air Force/Industry/Academia effort to focus 

interest and investment in Range technologies (Figure 1-1). It is co-chaired by NASA and 

the US Air Force, and comprised of aerospace leaders from industry, academia, and 

national, state, and local governments. ARTWG is a multi-layer organization with 

functional subgroups as its base (Figure 1-2). ARTWG addresses Range (Figure 1-3) 

development needs while its companion organization ASTWG (Advanced Spaceport 

Technology Working Group) addresses Spaceport development needs. 

 2
ECT - Phase 3 

Process: National Development Strategy

Other NASA

Centers

Requirements

Technology

Thrust Areas/

Capabilities

Entrepreneurial

Concepts

Air Force/DOD

Other Government

Agencies Contractors & OEMs

Capabilities

A R T W G / A S T W G

National Technology Roadmaps

Business

Thrust Areas

Technology & 

Business

Thrust Areas

Technology

Thrust Areas/

Capabilities

KSC Spaceport

Technology Center

Focus Areas

2002 2003 2004 2005 2006 2008-2012

COMMAND, CONTROL & MONITORING

TECHNOLOGIES ROADMAP

2007 2013-2020+

TTA: Command

Sensors &

Instrumentation

Spaceport System

Health Management

Generic Software Architecture Standards

Intelligent Control

System

IVHM

ISS/P l d P i

ELV ISS & Payload

Shuttle HEDS

Emerging Spaceports

Autonomous

Onboard

System

Sensor Connectivity Veri.

Non-intrusive Sensing Remote Monitor Real Time 

Space Traffic

Control &

Multi-Parameteric Sensors Nanotech Sensors Monitoring

Distributed

Intelligence

Sensor

System

Enhanced Ver. & Con.

Optimize VHM Software Investigation

Process Spec. Analysis Process/Design Synergy

Seamless 

Ground &

Avionics

Connectivity

Two Shuttle Control

CLCS Launch Capable

Investigate Architecture Proto Development Selection

Highly Reliable Computer Network

Intelligent Data Analysis Expert Control System

Next Generation

Health Man.

Hi Fidelity Training Sim

Near Term Goals Mid-Term Goals Far Term Goals

Hardware Systems

Reliability Simulation

System Checkout Sim

Simulation Technologies

Expert Control System

Expert Control System

Diagnostic

and Control

System

Goals Specific 

to Focus Area

Decrease 

Variable 

Costs:

Baseline=

$25M/Yr

-Near term 

Reduction

-Mid Term

$2.5M/Yr

contrib.

-Far Term

$250k/Yr

contrib.

Decrease 

Fixed Costs:

Baseline=

$175M/Yr

-Near term 

Reduction

-Mid Term

$20M/Yr

contrib.

-Far Term

$2M/Yr

contrib.

Gen 2/3 RLV

Focus Areas

2002 2003 2004 2005 2006 2008-2012

COMMAND, CONTROL & MONITORING

TECHNOLOGIES ROADMAP

2007 2013-2020+

TTA: Command

Sensors &

Instrumentation

Spaceport System

Health Management

Generic Software Architecture Standards

Intelligent Control

System

IVHM

ISS/P l d P i

ELV ISS & Payload

Shuttle HEDS

Emerging Spaceports

Autonomous

Onboard

System

Sensor Connectivity Veri.

Non-intrusive Sensing Remote Monitor Real Time 

Space Traffic

Control &

Multi-Parameteric Sensors Nanotech Sensors Monitoring

Distributed

Intelligence

Sensor

System

Enhanced Ver. & Con.

Optimize VHM Software Investigation

Process Spec. Analysis Process/Design Synergy

Seamless 

Ground &

Avionics

Connectivity

Two Shuttle Control

CLCS Launch Capable

Investigate Architecture Proto Development Selection

Highly Reliable Computer Network

Intelligent Data Analysis Expert Control System

Next Generation

Health Man.

Hi Fidelity Training Sim

Near Term Goals Mid-Term Goals Far Term Goals

Hardware Systems

Reliability Simulation

System Checkout Sim

Simulation Technologies

Expert Control System

Expert Control System

Diagnostic

and Control

System

Goals Specific 

to Focus Area

Decrease 

Variable 

Costs:

Baseline=

$25M/Yr

-Near term 

Reduction

-Mid Term

$2.5M/Yr

contrib.

-Far Term

$250k/Yr

contrib.

Decrease 

Fixed Costs:

Baseline=

$175M/Yr

-Near term 

Reduction

-Mid Term

$20M/Yr

contrib.

-Far Term

$2M/Yr

contrib.

Gen 2/3 RLV

Requirements

Small Businesses

& Universities

Requirements Technology

Thrust Areas/

Capabilities

States

KSC Technology Roadmaps

Figure 1-1 ARTWG/ASTWG National Development Strategy 

16

Process: Team Integration/Interaction

Telemetry Comm.

Architecture Weather Tracking & Surveillance

Decision 

Making

Coordination 

of Assets Commanding

Sub Groups

Chair & Co-Chair

Membership

Chair & Co-Chair

Membership

Chair & Co-Chair

Membership

Chair & Co-Chair

Membership

Chair & Co-Chair

Membership

Chair & Co-Chair

Membership

Chair & Co-Chair

Membership

Chair: Phil Weber, NASA KSC

Membership:

•ARTWG Chair & Co-Chair

• Each Sub Group Chair & Co-chair

•ARTWG Vision Team

Project

Program

Senior Agency

ARTWG Executive 

Steering Committee

Senior Executive 

Steering Committee

Chairs: NASA KSC, Director, SE&T & TBD Equiv. USAF AFSPC

Membership:

•Chair & Co Chair Technology Integration Steering Committee

• ARTWG Chair & Co-Chair

• TBD Membership

Chairs: NASA Code M Rep & Equivalent AFSPC 

Membership:

•Chair & Co Chair ARTWG Executive Steering Committee

• Others: NASA Codes, Center Directors, etc & Equivalent AFSPC

•TBD

Notional

Final Roadmaps approved by: Under Secretary USAF 

NASA/Office of Space Flight (Code M), Associate Administrator

COMSTAC, AFSPC Ind. GRP

ARTWG Vision

Team

Technology Integration 

Steering Committee

Integration /Architecture

ARTWG:

NASA Chair

AF Chair

UCF Consultant

Industry Advisors 

Examples: 

CSA’s Extended Range Concept Definition Study –

Booz/Allen/Hamilton 

KSC’s Space Based Range Distributed Systems Working Group –

RISM Project

RISM

Figure 1-2 ARTWG Integration/Interaction Process 

 3
ECT - Phase 3 

* Controlled Range Volume opens and closes for launch operations

Range Environment Mission

• Enable transport of humans and cargo to and from space

• Ensure public safety during operations

• Satisfy customer requirements

Figure 1-3 Spaceport and Range Environments 

ARTWG and ASTWG complement the ECT activities and provide an avenue to interact 

with other government, industry, and academia personnel on new developments 

applicable to Ranges and Spaceport of the future. National conferences are held once or 

twice a year. During FY-03, ECT personnel attended the joint ARTWG / ASTWG 

conference in Washington DC between May 24 and May 26. 

 4
ECT - Phase 3 

2.0 FREE SPACE OPTICS

2.1 BACKGROUND 

Free Space Optics (FSO) was one of the original three First Mile/Last Mile broadband 

wireless access systems identified in the RISM Phase I report1. An auto-track system by 

AirFiber was purchased, tested and reported during the ECT Phase 2 activities2

. For 

ECT Phase 3, a fixed-alignment and multiple beams system by fSONA was procured and 

tested. 

Optical communication systems provide the highest available carrier frequencies and thus 

the fastest data rates possible today. FSO is designed to be a lower cost alternative to 

conventional fiber-optic cable-based communication links3. FSO is especially attractive 

within a metropolitan environment where the costs for trenching, cable installation, and 

street repairs can run from $200K to easily over $1M per mile, depending on the urban 

location. 

FSO is a maturing technology that offers significant enhancements over most wireless 

technologies, including higher data rate, and the complete avoidance of any spectrum 

licensure costs. Its primary competition today is from existing fixed fiber installations. 

Today, a significant percentage of FSO sales are international. This has occurred due to 

the extensive USA fiber infrastructure that was installed in the 1990’s slowing its 

expansion within the USA. 

Although FSO offers the potential of maximum wireless performance, the limited 

opportunities within the US and an international recession have combined to reshuffle the 

FSO industry. Table 2-1 lists and compares key international FSO players. AirFiber, the 

industry leaders 2 years ago but presently out of business4, is listed for comparison. 

FSO links are based on infrared lasers and optical detectors. Over short distances, they 

are capable of providing very high data rates. Standard rates of OC-3 (155 Mb/s), OC-12 

(622 Mb/s), and OC-48 (2.5 Gb/s) are all available off the shelf today. 

The primary limitations on using FSO involve weather over distance. Thick fog can 

attenuate the laser signals and restrict the usefulness of a FSO link. Distance is not 

normally a concern when FSO is used as a “First Mile” technology; however, distance 

does magnify weather effects. 

 

1

 Range Information Systems Management (RISM) Phase I Report, NASA/TM-2004-211523, September 

2002 

2

 Emerging Communication Technologies (ECT) Phase 2 Report, Volume 1, Main Report, NASA/TM2004-211522, September 2003 

3

 http://www.airfiber.com/products/index.htm 

4

 http://www.airfiber.com is operation and was updated in 2004 

 5
ECT - Phase 3 

Table 2-1 FSO Industry Comparisons 

 

Company Tx Auto 

Track

Wave 

Length

Comments 

AirFiber 1 Y 785 Out of business 

Alcatel SA - - - Uses fSONA equipment 

Cablefree Solutions 3 N 780 UK 

Canon Inc. 1 Y 785 USA 

Communication By 

Light GmbH (CBL) 

4 N 870 Germany 

Corning Cable Sys 4 Y 850 USA 

Dominion Lasercom 1 Y 850 USA 

fSona Com 4 N 1550 Canada 

Infrared Com 

Systems (ICS) 

1 N 780 & 

980 

USA 

Infrared technologies 

America, LLC 

- - - Uses LaserBit equipment 

iRLan Ltd. 1 N unk Israel 

LaserBit Com 8 N unk USA. 

LightPointe 

Communications 

4 Y 850 USA. 

LSA Photonics 1 N 785 USA 

Maxima Corp unk unk 10,000 Long wave length infrared; USA 

Mostcom Ltd - - - Same as Sceptre 

MRV (TeraScope) 4 N 850 USA 

Omnilux Inc. 3 unk unk Mesh design, USA 

PAV Data Systems 3 N 830 UK 

Plaintree Systems 4 N unk Canada 

Sceptre Comm. Ltd. 2 N 850 UK & Russia 

Terabeam Corp. 1 Y 1550 USA 

FSO testing under the ECT project was conducted around the fSONA SONABEAM 622-

M transceiver units. The fSONA system was selected after an evaluation of multi-beam 

FSO COTS equipment and manufacturers. The fSONA system was selected based on the 

following: 

• Cost 

• Engineering & Factory Support 

• Market Share 

• Technical and Performance Features 

• Training 

 6
ECT - Phase 3 

2.2 BASIC FSO THEORY 

Free Space Optical (FSO) communication was discussed at length in the previous Phase I 

RISM report and the ECT Phase 2 report. A brief summary is repeated here for 

continuity, and to serve as an introduction to the technology for those unfamiliar with the 

technology. 

FSO dates to pre-history. Extensive FSO networks were established in the 19th Century 

throughout France and North Africa, based around semaphore systems. Later, during the 

latter part of the 19th century, FSO telephone communication was developed. 

The modern FSO age commenced with the invention of the laser slightly more than 40 

years ago. Coherent light provided the ability to select specific wavelengths to achieve 

FSO systems that enable lessening atmospheric attenuation, providing operation through 

rain, and achieving eye-safety through the selection of appropriate wavelengths for the 

laser light selected. 

Fundamentally, modern FSO systems typically employ NRZ (non-Return to Zero) 

modulation of laser light. Digital data is encoded as either a high intensity beam or as a 

low intensity beam, depending on the extinction ratio present in the ON to OFF states 

engendered by the modulating device. 

Within the receiver, a photodetector provides the optical to electrical (OE) conversion. 

Depending on the range over which communication is desired, both Positive-IntrinsicNegative (PIN) diodes and APDs (Avalanche Photodetector Diodes) are used. PIN 

diodes provide less sensitivity, but require only minimal voltage bias to make them 

operational. APDs provide the maximum in sensitivity, but require voltages often 

exceeding 100 Volts dc to achieve their maximum sensitivity. This, in turn, increases the 

need for properly coating circuit cards for FSO apparatus intended for use outdoors, 

through conformal coating the cards, in order to avoid accidentally shorting out the high 

dc bias during high humidity conditions. 

At the output of the photodetector is a Trans-Impedance Amplifier (TIA). Its purpose is 

to provide the necessary gain by which to generate a voltage from the current produced 

by the photodetector diode when exposed to light. Beyond this lie the framing and other 

packetizing electronics, needed to provide the proper data interfaces for the subsequent 

parts of the communication system. For fiber optic extensions, it is necessary to have 

clock and data recovery circuitry, by which clocks are derived from incident light pulses 

coming into the FSO system via fiber optic cable, to provide proper timing interfaces. 

For the fSONA system tested on this project, a Smartbits OC-12 fiber optic interface 

operating at 622 Mb/s served as the physical data interface in and out of the two units. 

2.3 TEST DESCRIPTION 

 7
ECT - Phase 3 

Phase 3 FSO testing was to evaluate a fixed alignment, multi-beam FSO system. The 

SONAbeam 622-M system was selected. Initial tests were to become familiar with the 

system and to evaluate its performance at short distances. Later tests were to evaluate 

performance at increasing link distances. Weather testing was not accomplished due to 

the combination of lack of adequate weather condition opportunities, safety concerns of 

lightning-free rainy weather, and storm closures during Hurricanes Charlie and Frances 

which closed KSC for a total of 7 days during the last two months of the project during 

multiple weeks. 

2.4 TEST OBJECTIVES 

The FSO test objectives were as follows: 

 Evaluate COTS FSO equipment for possible future use at KSC 

 Identify any fundamental shortcomings that must be filled in commercial FSO 

communication technologies prior to integrating this technology into future range 

architectures. 

 Evaluate a fixed alignment / multiple beam system against the previously tested 

auto-tracking single beam system. 

2.5 TEST SETUP 

Various test setups were utilized in evaluating the FSO equipment. The basic setup was 

to place the two Optical Transfer Units (OTUs) a fixed distance apart and to establish a 

link. Initial alignment was usually accomplished using the factory-provided 9X power 

rifle scope with eye-safe internal filtering at the 1310 nm wavelength transmitted by the 

transmitting lasers. 

 

Once an initial link was established, the link was refined and optimized using the factory 

provided software on a laptop computer. This provided a display of micro-watts at the 

OTU receiver. Fine adjustment was accomplished using jacking screws on both azimuth 

and elevation lever arms. Once the alignment was complete, the azimuth and elevation 

axis were clamped and not changed until the OTU were repositioned. 

A SmartBits Bit Error Rate test device was used to determine throughput and packet loss 

for various packet sizes. A typical setup is shown in Figure 2-1. A SmartBits sent a 

variable length data stream to the input of OTU #1. The laser transmitters at OTU #1 

transferred the data packets to OTU #2. The output from OTU #2 was connected to its 

input. OTU #2 then used its laser transmitter to return the data to OTU #1. The output 

from OTU #1 was returned to the SmartBits where a comparison was made to determine 

any throughput or data packet losses. 

 8
ECT - Phase 3 

The primary independent variable for all tests was link distance. A summary of test 

locations and distances is included in Table 2-2. Specific details about each test location 

are included in the following sections. The FSO units, test equipment and software are 

described in later sections. 

OTU #1 OTU #2 

 

 Fiber 

 loop back 

 SmartBits 

 Laptop Laptop 

Figure 2-1 Typical Test Setup Using SmartBits with Loop at OTU #2 

Table 2-2 FSO Test Locations 

No. Location One Way Distance Loop Back 

1 EDL ANDL5 28 ft Y/N 

3 EDL East Parking Lot 113 ft Y 

4 EDL to SSPF Parking Lots 1066 ft Y 

5 Schwartz Road 1.0 mile Y 

6 Schwartz Road 1.5 mile Y 

7 Schwartz Road 1.75 mile Y 

8 Schwartz Road 2.0 mile Y 

9 Schwartz Road 2.5 mile Y 

 

5

 EDL Advanced Network Development Lab, Rm 124 

 9
ECT - Phase 3 

2.5.1 EDL ANDL Setup 

Initial testing and checkout were performed in the Advanced Network Development Lab 

(ANDL), Room 124 in the Engineering Development Lab (EDL). A pair of short pipe 

stands was fabricated to enable installation of the fSONA 622M units within the ANDL. 

Universal electrical boxes were modified to house the power supplies which converted 

115 VAC to 48 VDC. 

OTU #1 was placed on top of an existing workbench (Figure 2-2) while OTU #2 was 

place 30 feet away on top of a cabinet (Figure 2-3). The two locations were selected to 

avoid laser beam interruption during normal lab operations. 

The SONAbean 622-M is a fixed alignment, multi-beam design. Initial alignment is 

normally achieved using an eye-safe filtered rifle scope. Due to the close confines of the 

ANDL, it was impossible to use the rifle scope. Initial alignment was accomplished in 

the ANDL using a machined adapter and a laser pointer. Fine alignment was still 

accomplished using the fSONA Terminal Controller Software. For most ANDL tests, 

only a single transmitter was used. A fiberglass screen mesh, shown in Figure 2-2, was 

used over the receiver to attenuate the signal at the close distances. 

. 

Figure 2-2 OTU #1 in the ANDL on the North Bench 

 10
ECT - Phase 3 

Figure 2-3 OTU #2 in the ANDL by the South Wall 

The Advanced Network Development Lab was chosen for initial checkout and testing 

since it was a secure area and contained a rack-mounted SmartBits test unit that could be 

used as a source of optical data packets. The SmartBits unit was configured as shown in 

Figure 2-1 for some tests and configured for a single optical pass in other tests. In these 

latter tests, the fiber loop-back at OTU #2 was replaced with a direct fiber link back to 

the SmartBits. Multi-mode fiber (MMF) was used for all cables to and from the 

SmartBits and for the loop back. A 10 dB optical attenuator was required on the fiber 

output to OTU #1 in order for the SmartBits to work properly. This remained in place for 

all tests outside the ANDL. 

Testing was accomplished by measurements the receiver power using a laptop running 

the fSONA Terminal Controller Software. A typical setup is shown in Figure 2-4. 

 11
ECT - Phase 3 

Figure 2-4 OTU #1 with Laptop Measuring Receiver Performance 

2.5.2 EDL East Parking Lot Test Setup 

The second series of FSO tests were performed on the East parking lot of the EDL. To 

facilitate moving, spacing and positioning the units, each FSO units was mounted on a 

trailer. A pair of existing antenna trailers (Figure 2-5), remaining from another project, 

were modified to support FSO testing. New tri-pod mounts were fabricated and bolted to 

the trailer structure to provide a quick mount (Figure 2-6). The antennas shown stored 

horizontally across the top of the trailers were not used in these tests. 

 12
ECT - Phase 3 

Figure 2-5 OTU #1 Mounted on an Existing Antenna Trailer 

Figure 2-6 OTU Mounted On Fabricated Support Stand 

 13
ECT - Phase 3 

The testing configuration was per Figure 2-1. OTU #1 and OTU #2 were located 154 

feet apart (Figure 2-7). This distance was selected based on available parking space. 

Power was provided by a pair of small generators (Figure 2-8). 

Figure 2-7 Trailer Mounted OTUs in East EDL Parking Lot (113-Ft Range) 

Figure 2-8 Portable Generator Used for Power During Remote Testing 

 14
ECT - Phase 3 

2.5.3 EDL to SSPF Parking Lots Test Setup

The third series of FSO tests were between the Engineering Development Laboratory 

(EDL) and the Space Station Processing Facility (SSPF) parking lots (Figure 2-9). The 

trailer with OTU #2 was parked on the North side of the EDL (Figure 2-10). The second 

trailer with OTU #1 was parked in the SE corner of the SSPF East parking lot (Figure 2-

11). Figure 2-12 is a view from the OTU #2 toward the OTU #1. The test configuration 

was again per Figure 2-1. This setup provided a one-way distance of 950 feet with a 

round-trip distance of 1900 feet. 

 SSPF 

 OTU #1 

 950’ 

 OTU #2 

 

 EDL 

Figure 2-9 EDL to SSPF Parking Lots Test Setup 

Figure 2-10 OTU #2 in the EDL North Parking Lot 

 15
ECT - Phase 3 

Figure 2-11 OTU #1 in the SSPF Parking Lot 

Figure 2-12 View from OTU #2 to OTU #1 

 16
ECT - Phase 3 

2.5.4 Schwartz Road Test Setup

Schwartz Road is a remote East-West road at KSC that runs relatively straight for 2.7 

miles. Extensive long-distance testing was performed at this location. Trailers were 

positioned off to the side of the road at various distances. Initial testing was performed at 

1.0 mile. This was followed with tests at 1.5, 2.0, 2.5, 2.0, 1.75, and 1.5 miles 

respectively. The West trailer (OTU #2, Figure 2-13) remained relatively fixed for all 

tests. The East trailer with OTU #1 (Figure 2-14) was repositioned as needed to set the 

desired link testing distance. The test configuration was again per Figure 2-1 with the 

SmartBits and Laptop positioned on the trailer (Figure 2-15). The longer distances 

tested on Schwartz Rd. often made it difficult to even see the mating trailer. Figure 2-16 

shows the view from the one mile range. Tests at 2.5 mile were even more demanding 

during initial alignment. 

Figure 2-13 OTU #2 Parked on West End of Schwartz Rd. 

Schwartz Road testing was interrupted twice due to hurricanes. Hurricane Charley 

required that the trailers be moved to nearby fixed objects where they could be tied down. 

A few weeks later saw the arrival of Hurricane Frances. 

 17
ECT - Phase 3 

Figure 2-14 OTU #1 Parked on East End of Schwartz Rd. 

Figure 2-15 OTU #1 with SmartBits and Laptop Connected 

 18
ECT - Phase 3 

Figure 2-16 View from OTU #1 toward OTU #2 at 1.0 Mile Range 

2.6 TEST EQUIPMENT AND SOFTWARE 

Key FSO test hardware included the following: 

• SONAbeam 622-M - Optical Transceiver Unit (OTU) 

• Laptop – Laptop computer for interfacing with the OTU 

• SmartBits – Data packet source for measuring Throughput and Packet Loss 

In addition to the above hardware, two software packages were instrumental in testing 

and data acquisition. These software packages were: 

• SONAbeam Terminal Control Software 

• SmartApplications 

 19
ECT - Phase 3 

2.6.1 SONAbeam 622-M

The SONAbeam 622-M OTU shown in Figure 2-17 was the primary component under 

test. Specifications for the units are summarized in Table 2-3. A pair of 622-M units 

was purchased around 3/1/04 under the ECT task order (#00087). The purchase price 

included the following: 

• (2) 622-M OTUs 

• (2) connection boxes 

• (2) Power supplies 

• (2) Tri-pods 

• Associated equipment 

• Terminal controller Software 

• Factory training for 2 

Figure 2-17 Front of SONAbeam 622-M OTU 

 20
ECT - Phase 3 

Table 2-3 SONAbeam 622-M Specifications 

Manufacturer fSONA Communication Corp 

140-11120 Horseshoe Way 

Richmond, B.C. Canada 

Model SONAbeam 622-M 

Cost $40,522.69/pair w/training 

Purchase Date 3/15/04 

Data rate OC-12 (622 Mbps) 

Distance Min 30 ft 

 Max 1.6 miles; 1.5 miles successfully tested 

Transmitters No. 4 

Tx Wave length 1550 nm 

Receiver Dia 8-inch 

Interfaces Types Fiber Single mode or Multi-mode 

Interfaces Connector SC 

Management RJ-45 or DB9 

Voltage -48 vdc 

BER 10-12

Environment Max Operating Temp 140 F 

 Max Operating wind 100 mph 

Warranty 3 years 

Laser Safety Class 1M 

Serial Numbers #1 1130050858 

 #2 1130030756 

Factory training was included with the purchase of the 622-M. Training took place in 

Vancouver B.C. on 2/18/04. ASRC employees Dr. Gary Bastin and Bill Harris attended. 

The units came with a factory-supplied junction box. The inside of the box is shown in 

Figure 2-18. Payload fiber, management Ethernet, and power connections are made 

within this box. The two orange fibers running up to the right are the multimode fibers 

connecting the SmartBits to OTU #1. Also visible on the lower fiber is the 10 dB 

attenuator inserted in the output line to enable the OTU and SmartBits to communicate. 

Figure 2-19 shows the junction box mounted on the support pole just below the OTU. 

The smaller utility box in this figure is the in-house fabricated power supply housing. It 

contained the 110 VAC to -48 VDC power supply. 

 21
ECT - Phase 3 

Figure 2-18 SONAbeam Junction Box Open 

Figure 2-19 Pole Mount with OTU, Connection Box & Power Supply Box 

 22
ECT - Phase 3 

Each OTU was shipped with a factory assigned address (Table 2-4). These were later 

field changed as shown in Table 2-5. 

Table 2-4 FSO Factory IP Addresses 

OTU #1 #2 

IP Address 0.0.0.1 0.0.0.1 

Subset Mask 255.255.255.0 255.255.255.0 

Gateway 192.168.1.254 192.168.1.254 

Table 2-5 FSO Reset IP Addresses 

OTU #1 #2 

IP Address 128.217.108.178 128.217.108.179 

Subset Mask 255.255.255.0 255.255.255.0 

Gateway 128.217.108.10 128.217.108.10 

2.6.2 Laptop

A pair of Gateway laptop computers, as shown in the following figure, were used to 

support the ECT testing. Each computer was loaded with fSONA’s Terminal Controller 

Software. This software enabled each OTU to be initialized, controlled, and monitored. 

The software is discussed in a later section. 

Figure 2-20 Gateway 450 XL Laptop Computer 

 23
ECT - Phase 3 

Specifications for the Laptops are shown in the following table. 

Table 2-6 Laptop Computer Specifications 

Manufacturer Gateway 

Model DS 450 XL 

Processor Intel Pentium 4 

Speed 2.0 GHz 

Hard Drive 40 GB 

RAM 512 MB 

Connectors USB, RJ-45, Phone 

Wi-Fi Standard 802.11b (Internal) 

Operating System Windows XP V.2002 

Table 2-7 Laptop Computer Installation Parameters 

Name BH GB 

IP Address 128.217.107.119 128.217.107.175 

MAC 00-02-2D-6E-A2-F4 00-02-2D-6E-5B-7E 

2.6.3 SmartBits

An existing SmartBits test unit, the lower unit shown in Figure 2-21, was used to test the 

OTUs. The SmartBits created varying size data packets that were sent through the FSO 

communication link at OC-12 data rates. The SmartBits compared the data sent with the 

data received and produced a report on Throughput and Packet Loss. 

The SmartBits are populated with test drivers that produce data streams of different 

protocols. For ECT testing, Cards 17 and 19 shown in Figure 2-21 were used. These 

cards are for ATM at OC-12. Card 19 was usually the transmitter and Card 17 was the 

receiver. The jumper in Figure 2-21 was used from the receive port in Card 19 to the 

transmit port of Card 17. 

The SmartBits was initially rack mounted in the ANDL. During lab testing, a duplex 

multimode fiber was routed from the input and output ports of the OTUs. For testing in 

the parking lots and on Schwartz Rd., the SmartBits was removed from the rack (Figure 

2-22) and powered by the portable generator. 

 24
ECT - Phase 3 

Figure 2-21 SmartBits Test Unit 

Figure 2-22 Field Testing with the SmartBits & a Laptop 

 25
ECT - Phase 3 

2.6.4 SONAbeam Terminal Controller Software

The main Operating System for the fSONA 622-M is the Terminal Controller Software. 

This was loaded on the laptops. This software allows for initialization and monitoring of 

the OTUs. An Ethernet connection is made from the laptop’s COM1 port to an RJ-45 

port within the connection box. A DB-9 to RJ-45 adapter is used on the back of the 

laptop. An alternate DB-9 port is also available within the connection box. Various 

screens of the controller software are shown in the following figures. 

Figure 2-23 Initialization Page for fSONA Terminal Controller Software 

Figure 2-24 Comm 1 Status Showing No FSO Connection or Input 

 26
ECT - Phase 3 

Figure 2-25 Comm 1 Tx Configuration With System Power At Level 1 

Figure 2-26 Comm 1 Rx Power Level 

 27
ECT - Phase 3 

Figure 2-27 Comm 1 Diagnostics with No FSO Lock or Input 

Figure 2-28 Comm 1 Settings 

 28
ECT - Phase 3 

2.6.5 SmartApplications

SmartApplications is the operating system software for the SmartBits. This software 

enables the user to setup the communication links (Cards 17 to 19 for these tests) and to 

control the specifics of each tests. The software User Manual6 and hardware-operating 

manual7

 are normally available within the ANDL. 

Figure 2-29 Smart Applications Main Page with Card 17 to Card 19 Test Setup 

Figure 2-29 shows a test setup for Card 17 to input data to the OTU with Card 19 

receiving the return data. For most tests, data was sent in the other direction (from Card 

19 to 17). The three types of tests available, Throughput, Latency, and Packet Loss, are 

also shown in this figure. Only Throughput and Packet Loss tests were run on the FSO 

equipment. The Latency tests are not applicable to FSO laser hardware testing. 

 

6

 Smart applications for Ethernet, Token Ring, ATM; User Guide; Net Com systems; 3/21/98 

7

 SmartBits – Advanced Multiport Performance Tester / Simulator / Analyzer; SMB-2000; Getting Started 

 29
ECT - Phase 3 

2.7 TEST RESULTS 

FSO testing consisted of testing at four test locations with two types of tests at each 

location. The four locations and the general test objectives at each are summarized in the 

following table. 

Table 2-8 Summary of Test Locations & Objectives 

Location Test Objectives 

EDL ANDL Setup, Initialization, Checkout, Familiarization, 

Baseline 

EDL East Parking Lot Remote location initialization, checkout, & 

performance 

EDL to SSPF Parking Lots Intermediate distance initialization & performance 

Schwartz Road Long distance testing 

Testing involved four activities at each location as summarized in the following table. 

Table 2-9 Summary of Test Types and Data Measurements 

# Test Type Data Measurements 

1 Establish an FSO link8 Transmit & Receive Signal strengths at each 

OTU 

2 Set Tx Power Transmit & Receive Signal strengths 

3 SmartBits Throughput 

4 SmartBits Packet Loss 

2.7.1 Results Summary

 

FSO testing was conducted from March 2004 through August 2004. Additional testing 

was interrupted by Hurricanes Charley and Frances. During the test period, the fSONA 

622-M units worked without any noticeable problems. The most difficult part of 

operating the OTUs was establishing the initial FSO link. 

Successful links were established out to 1.5 miles. A temporary link was established at 

2.5 miles, but this link quickly degraded and the link was lost. Links could not be reestablished at the 2.5, 2.0 or 1.75 distance. Due to the impact of preparing for, and 

securing, the hardware trailers repeatedly for hurricanes, the cumulative impact of time 

lost did not permit continued in-depth investigations at the 1.5 mile range. 

In establishing links, maximum and minimum receiver power became obvious. 

Established values are as follows: 

 

8

 Indicated by Green System Status light on Status page of Controller SW 

 30
ECT - Phase 3 

Table 2-10 Recommended Receiver Power Levels 

Item Value (uW) 

Minimun 5.0 

Maximum 260 

Values less than 2 microwatts usually would not establish a link. Values greater than 260 

often oversaturated the receiver and caused similar problems. The over-power level was 

only a problem at short distances. During lab testing, a fiberglass screen was used over 

the receiver lens to attenuate the signal. In addition, all but one transmitter was turned 

off. 

During testing in the EDL parking lot, the screens were not used, but the OTUs were 

purposely misaligned to lower receiver power levels into acceptable dynamic operational 

ranges. 

Whenever links were established, the systems appeared to have significant reserve 

power. Links out to 1.5 miles were established with the transmitters set at system level 4. 

System levels go from 1 to 28. System level 1 is one transmitter set to level 1. System 

level 2 is two transmitters set to level 1. System level 4 is four transmitters set to level 1. 

System values that are multiples of 4 equate to all four transmitters being on at level 1 to 

7. System level 28 (max) is all transmitters on at maximum level 7. At the larger 

distances, System values below 4 were not investigated. 

The fSONA 622M also has an Automatic Power Control (APC) feature. This nonfeedback control attempts to control transmitter powers based on the incoming receiver 

power. Various runs were made in the APC mode and these are reported in the data. The 

APC feature may turn this ON or OFF. It was OFF for most tests. 

All testing was done in typically good weather. Due to testing at remote locations, 

lightning hazards, and the potential for damage to expensive test equipment as well as 

injuries to ECT personnel, no testing in the rain or during unsafe hurricane wind 

conditions was attempted. Fog opportunities did not occur. 

Figure 2-30 summarizes the minimum receiver power as a function of distance. All 

values were measured at Receiver #1 with Transmitter #2 set at System Level 4 or lower. 

Figures 2-31 and 2-32 show typical receiver power levels at various opposite transmitter 

system levels for 1.0 and 1.5 miles respectively. 

 31
ECT - Phase 3 

Min Receive Power Vs Distance

0

20

40

60

80

100

120

140

160

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Distance (Mi)

Recever Power (uW)

Figure 2-30 Minimum Receive Power versus Distance 

Rcv1 Vs Tx2 @ 1.0 Mile

0

10

20

30

40

50

60

70

80

90

0 5 10 15 20

System Transmit Level

Receiver Power (uW)

Figure 2-31 Receive Power versus Transmitter Setting @ 1.0 Mile 

 32
ECT - Phase 3 

Rcv1 Vs Tx2 @ 1.5 Mile

0

5

10

15

20

25

30

35

40

0 5 10 15 20

System Transmit Level

Receiver Power (uW)

Figure 2-32 Receive Power versus Transmitter Setting @ 1.5 Mile 

A summary of FSO testing is presented in the following table. 

Table 2-11 Summary Of fSONA 622-M Testing 

 Unit #1 Unit #2 

 Receive Tx Rx Tx 

Date Loc 

Dist 

(ft/mi) uW 

Attn 

dB 

Sys 

Lvl 

Lsr 

On uW 

Sys 

Lvl 

Lsr 

On Comments 

 

 

8/18/04 Schwartz 1.5 1.7 10 28 All 0.5 28 All 

Trl #1 repositioned to 1.5 miles, 

System status=red 

8/18/04 Schwartz 1.75 1.1 10 28 All 0.4 28 All System status=red 

8/18/04 Schwartz 1.75 1.2 10 28 All 0.4 28 All 

Optimum meter alighment for #1, 

scope #1 down & ?, trl not in 

view, scope #2 down& left, 

System status=red 

8/18/04 Schwartz 1.75 0.5 10 28 All - 28 All Optimum scope alighment for #1 

8/18/04 Schwartz 1.75 0.0 10 28 All 0.5 28 All 

Sys Status=red, same position as 

yesterday 

 

8/17/04 Schwartz 1.75 1.0 10 28 All 0.5 28 All 

Scope #1 up & left, Rx2 went to 

0.0 with no traffic 

 

8/12/04 Schwartz 2.0 1.0 10 28 All 0.1 28 All 

Scope #2 high & far right, scope 

#1 down & left, Sys Status=red 

8/12/04 Schwartz 2.0 0.6 10 28 All - 0 0 Rx1=0.6 with #2 off 

 

8/12/04 Schwartz Secured trailers, Hur. Charley 

 33
ECT - Phase 3 

 

8/10/04 Schwartz 2.5 0.1 10 28 All - 28 All Sys Status=red 

 

8/9/04 Schwartz 2.5 0.3 10 28 All 0.3 28 All 

Rx1 decreased from 130 to 0.3, 

Rx2: 78 to 0.3 

8/9/04 Schwartz 2.5 130 10 28 All 75 28 All Link established 

8/9/04 Schwartz 2.5 - 10 28 All 75 28 All Moved to 2.5 miles 

8/9/04 Schwartz 2.0 0.9 10 28 All 0 28 All Sys Status=red 

 

8/5/04 Schwartz 2.0 1.7 10 28 All 1.2 28 All Sys Status=red 

8/5/04 Schwartz 2.0 1.8 10 28 All 1.2 20 All Sys Status=red 

8/5/04 Schwartz 2.0 0.7 10 20 All - 20 All Sys Status=red 

8/5/04 Schwartz 2.0 0.9 10 16 All 1.8 20 All Sys Status=red 

8/5/04 Schwartz 2.0 - 10 16 All 1.9 16 All Sys Status=red 

8/5/04 Schwartz 2.0 0.7 10 16 All 0.7 0 0 Rx1=0.7 with #2 off 

 

8/3/04 Schwartz 2.0 East trailer moved 

 

8/2/04 Schwartz 1.5 5 10 2 1&7 1.7 2 1&7 Some loss, trigger lgts blink red 

8/2/04 Schwartz 1.5 5 10 2 1&7 1.7 2 1&7 

Some < 100%, trigger lgts blink 

red 

8/2/04 Schwartz 1.5 7 10 4 All 5 4 All Zero loss 

8/2/04 Schwartz 1.5 7 10 4 All 5 4 All All 100% 

8/2/04 Schwartz 1.5 10 10 8 All 6 8 All Zero loss 

8/2/04 Schwartz 1.5 10 10 8 All 6 8 All All 100% 

8/2/04 Schwartz 1.5 34 10 16 All 15 16 All Baseline, zero loss 

8/2/04 Schwartz 1.5 34 10 16 All 15 16 All Baseline, all 100%, overcast, 89F 

 

7/29/04 Schwartz 1.0 15 10 2 1&7 6.5 2 1&7 Zero loss 

7/29/04 Schwartz 1.0 15 10 2 1&7 6.5 2 1&7 All 100% 

7/29/04 Schwartz 1.0 27 10 4 All 6.5 4 All Zero loss 

7/29/04 Schwartz 1.0 27 10 4 All 6.5 4 All All 100% 

7/29/04 Schwartz 1.0 40 10 8 All 10 8 All Zero loss 

7/29/04 Schwartz 1.0 40 10 8 All 10 8 All All 100% 

7/29/04 Schwartz 1.0 85 10 16 All 25 16 All Baseline, zero loss 

7/29/04 Schwartz 1.0 85 10 16 All 25 16 All 

Baseline, all 100%, partly cloudy, 

90F 

 

7/28/04 Schwartz 1.0 75 10 16 All 25 16 All Over ride APC 

7/28/04 Schwartz 1.0 75 10 16 All 25 16 All Over ride APC 

7/28/04 Schwartz 1.0 280 10 15 All 20 APC All Over ride APC, set distance 

7/28/04 Schwartz 1.0 295 10 20 All - APC All 

Test failed & hung up SB 

operating SW 

7/28/04 Schwartz 1.0 275 10 APC 1&7 2.2 APC All 

APC causing problems, trigger 

lights flash randomly 

7/28/04 Schwartz 1.0 275 10 APC 1&7 2.2 APC All 

APC causing problems, trigger 

lights flash randomly 

7/28/04 Schwartz 1.0 275 10 APC All 12 APC All 

 

7/27/04 Schwartz 1.0 275 10 28 All 160 28 All Setup at Schwartz Rd 

 

 34
ECT - Phase 3 

7/26/04 Schwartz 1.0 trailers moved to Schwartz Rd 

 

7/19/04 SSPF 950 45.2 10 APC All 50.2 4 All 

System status red, FSO lock = 

red, FSO input lock = red, 

SmartBits not connected due to 

rain 

7/19/04 SSPF 950 45.2 10 APC All - 4 All Changed focus, Trigger lights off 

7/19/04 SSPF 950 69.0 10 APC All - 4 All 

Changed focus until trigger light 

comes on 

7/19/04 SSPF 950 12.2 10 APC All - 4 All 

APC #2 off, APC #1 on, light 

rain 

7/19/04 SSPF 950 12.5 10 APC All - 4 All 

APC #2 off, APC #1 on, light 

rain 

7/19/04 SSPF 950 - 10 APC - 1.7 4 All 

APC #2 off, APC #1 on, Rx2=1.7 

max, status=green, light rain 

7/19/04 SSPF 950 

111.

2 10 APC - 11.3 APC All 

Tx1 APC on, System status red @ 

#2, light rain 

7/19/04 SSPF 950 

111.

2 10 APC - - APC All 

Tx1 APC on, RxLOS red light 

still on, light rain; Did not receive 

learning frame; recycled 

SmartBits 

7/19/04 SSPF 950 

111.

2 10 APC 1&7 - APC All 

Tx1 APC on, RxLOS red light 

still on, light rain; Did not receive 

learning frame 

7/19/04 SSPF 950 

580.

4 10 APC 1&7 - APC All 

Tx1 APC on, RxLOS red light 

still on, light rain; Did not receive 

learning frame 

7/19/04 SSPF 950 

550.

0 10 APC All - APC All 

Tx1 APC on, trigger red lights 

still on, light rain 

7/19/04 SSPF 950 15.0 10 APC All - APC All 

Tx1 APC on, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 56.2 10 APC All - APC All 

Tx1 APC on, RxLOS red light 

still on, light rain; Did not receive 

learning frame 

7/19/04 SSPF 950 55.9 10 16 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.6 10 15 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.6 10 14 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.6 10 13 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.6 10 12 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.6 10 11 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.6 10 10 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.0 10 9 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.0 10 8 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.0 10 7 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.0 10 6 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.0 10 5 All - APC All 

Increase Tx1, RxLOS red light 

still on, light rain 

7/19/04 SSPF 950 55.0 10 4 All 13.1 APC All 

Recycled SmartBits, RxLOS light 

on, De-focused to Rx1=55 

 35
ECT - Phase 3 

7/19/04 SSPF 950 

365.

7 10 4 All 13.1 APC All Sys green; 

7/19/04 SSPF 950 - 10 4 All 13.1 APC All 

APC #2 on; 1 & 5 @ lvl 5, 5 7 11 

@ lvl 4; light rain 

7/19/04 SSPF 950 - 10 4 All 3.6 16 All 

Reset Tx2 to sys lvl 16 (4 @ lvl 

4) 

7/19/04 SSPF 950 54.6 10 4 All 2.5 4 All Test OK 

7/19/04 SSPF 950 54.6 10 4 All 2.5 4 All Test OK 

7/19/04 SSPF 950 45.0 10 4 All - 4 All 

Min Rx1 value to keep trigger 

lights off 

7/19/04 SSPF 950 70.0 10 4 All - 4 All 

Max Rx1 value to keep trigger 

lights off 

7/19/04 SSPF 950 64.3 10 4 All - 4 All Adjusted el @ #1 (East end) 

7/19/04 SSPF 950 27.3 10 4 All - 4 All 

Recycled SmartBits with no 

change 

 

7/14/04 SSPF 950 54.3 10 4 All 2.2 4 All 

Could not adjust #2 higher than 

2.2 

7/14/04 SSPF 950 54.3 10 4 All 2.2 4 All Test OK 

7/14/04 SSPF 950 55.1 10 4 All 2.2 4 All Test OK 

7/14/04 SSPF 950 55.1 10 4 All 2.2 4 All Test OK 

 

7/14/04 SSPF 950 71.5 10 4 All - 4 All Test OK 

7/14/04 SSPF 950 71.5 10 4 All - 4 All Test OK 

7/14/04 SSPF 950 69.6 10 4 All - 4 All 

Lower Tx1 to sys lvl 4 (4 @ lvl 

1) 

7/14/04 SSPF 950 71.0 10 8 All - 4 All 

Lower Tx1 to sys lvl 8 (4 @ lvl 

2) 

7/14/04 SSPF 950 72.1 10 12 All - 4 All 

Lower Tx1 to sys lvl 12 (4 @ lvl 

3) 

7/14/04 SSPF 950 73.0 10 16 All - 4 All 

Increase Tx1 to sys lvl 16 (4 @ 

lvl 4) 

7/14/04 SSPF 950 

622.

0 10 16 All - 4 All 

Increase Tx1 to sys lvl 16 (4 @ 

lvl 4) 

7/14/04 SSPF 950 

622.

0 10 12 All - 4 All Re-focus 

7/14/04 SSPF 950 

180.

0 10 12 All - 4 All 

Increase Tx1 to sys lvl 12 (4 @ 

lvl 3) 

7/14/04 SSPF 950 

180.

0 10 8 All - 4 All 

Increase Tx1 to sys lvl 8 (4 @ lvl 

2) 

7/14/04 SSPF 950 

176.

0 10 4 All 33 4 All 

Focus; #2 lasers are hot or #1 

receiver is sensitive 

7/14/04 SSPF 950 

177.

5 10 4 All 33 4 All 

Focus; #2 lasers are hot or #1 

receiver is sensitive 

7/14/04 SSPF 950 46.0 10 4 All 19.4 4 All De-focus 

7/14/04 SSPF 950 90.0 10 4 All 19.4 4 All De-focus 

7/14/04 SSPF 950 

250.

5 10 4 All 19.4 4 All De-focus 

7/14/04 SSPF 950 

702.

0 10 4 All 19.4 4 All 

Peaked arount 700 @ m#1, too 

hot to use; had to de-focus 

7/14/04 SSPF 950 

107.

2 10 4 All 19.4 4 All 

Adjusted to up Rx2 from 0.5 to 

19.4 

 

7/12/04 EDL PL 154 

137.

6 10 4 All 3.4 4 All 

7/12/04 EDL PL 154 

137.

6 10 4 All 3.4 4 All Recycled SmartBits power 

7/12/04 EDL PL 154 

139.

1 10 4 All 3.4 4 All 

Defocused unit #1 to lower 

receive pwr 

7/12/04 EDL PL 154 252. 10 4 All 3.4 4 All Defocused unit #1 to lower 

 36
ECT - Phase 3 

3 receive pwr 

7/12/04 EDL PL 154 

711.

3 10 4 All 

646.

0 4 All 

System pwr increased to 4 (4 @ 

lvl 1) 

7/12/04 EDL PL 154 

711.

3 10 3 1,5,7 4 All 

System pwr increased to 3 (3 @ 

lvl 1) 

7/12/04 EDL PL 154 

711.

3 10 2 1,7 4 All 

System pwr increased to 2 (2 @ 

lvl 1) 

7/12/04 EDL PL 154 711 10 4 All 4 All 

System pwr increased to 2 (2 @ 

lvl 1) 

7/12/04 EDL PL 154 711 10 4 All 

646.

0 4 All 

Change both power levels to Sys 

4 (4 @ lvl 1) 

7/12/04 EDL PL 154 711 10 8 All 

725.

0 8 All 

Refocus Unit #2 (South end of 

parking lot) 

7/12/04 EDL PL 154 40.6 10 8 All 47.3 8 All 

Change both power levels to Sys 

8 (4 @ lvl 2) 

7/12/04 EDL PL 154 57.3 10 12 All 65.9 12 All 

Change both power levels to Sys 

12 (4 @ lvl 3) 

7/12/04 EDL PL 154 92.9 10 16 All 104 16 All 

7/12/04 EDL PL 154 92.9 10 16 All 104 16 All 

Change both power levels to Sys 

16 (4 @ lvl 4) 

7/12/04 EDL PL 154 220 10 24 All 

266.

0 24 All Baseline 

 

7/9/04 EDL PL 154 125 10 24 All 209 24 All 

7/9/04 EDL PL 154 130 10 24 All 209 24 All 

7/9/04 EDL PL 154 141 10 24 All 

201.

0 24 All 

7/9/04 EDL PL 154 141 10 24 All 

201.

0 24 All 

7/9/04 EDL PL 154 141 10 24 All 

201.

0 24 All 

7/9/04 EDL PL 154 141 10 24 All 

201.

0 24 All 

Change both power levels to Sys 

24 (4 @ lvl 6) 

 

7/9/04 EDL PL 154 25.8 10 28 All 

306.

0 24 All 

Focus #2, stopped at 306 to avoid 

saturation 

7/9/04 EDL PL 154 25.8 10 28 All 18.4 24 All Focus #1 

7/9/04 EDL PL 154 5.7 10 28 All 4.0 24 All 

7/9/04 EDL PL 154 5.7 10 0 0 4.0 24 All 

Reflective energy off #1 or 

background 

 

7/8/04 EDL PL 154 0.2 10 28 All 50.0 0 0 

Reflective energy off #2 or 

background 

7/8/04 EDL PL 154 9.6 10 28 All 50.0 24 All Increased #2 to Sys 28 (4 @ lvl 7) 

7/8/04 EDL PL 154 9.1 10 24 All 50.0 24 All Smart Bits connected 

7/8/04 EDL PL 154 2.1 10 4 All 9.6 8 All No Smart Bits 

7/8/04 EDL PL 154 2.1 10 4 All 6.5 4 All No Smart Bits 

7/8/04 EDL PL 154 2 10 4 All 0.6 4 All No Smart Bits 

 

 

7/7/04 EDL PL 154 1.5 10 4 All 0.5 4 All No Smart Bits 

7/7/04 EDL PL 154 2.2 10 spec 5 0.6 2 1,7 No Smart Bits 

 

6/17/04 Units mounted on trailers 

Attenuation 

screens 

used for 

most tests 

that follow 

 37
ECT - Phase 3 

6/16/04 Lab 178 10 spec 5 

240.

0 spec 1 Same as previous test, w/screens 

6/16/04 Lab 90.8 10 spec 5 

249.

3 spec 1 Same as previous test 

 

6/10/04 Lab 90.8 10 spec 5 

249.

3 spec 1 Same as previous test 

6/10/04 Lab 90.8 10 spec 5 

249.

3 spec 1 Same as previous test 

 

6/2/04 Lab 91 10 spec 5 

250.

0 spec 1 Same as previous test 

6/2/04 Lab 91 10 spec 5 25.0 spec 1 Same as previous test 

 

5/18/04 Lab 55.8 10 spec 5 

259.

0 spec 1 

Same as previous test; 

Recommend Max Rx = 260

5/18/04 Lab 55.8 10 spec 5 

259.

0 spec 1 Same as previous test 

 

5/7/04 Lab 55.8 10 spec 5 

252.

6 spec 1 Same as previous test 

5/7/04 Lab 55.8 10 spec 5 

253.

0 spec 1 

In good data zone; Decreased 

power at #2 by tilting #1 down 

5/7/04 Lab 55.8 10 spec 5 

267.

6 spec 1 

Transition point; Same as 

previous test 

5/7/04 Lab 55.8 10 spec 5 

267.

0 spec 1 

Transition point; Decreased 

power at #2 by tilting #1 down 

5/7/04 Lab 55.8 10 spec 5 

290.

0 spec 1 

Decreased power at #2 by tilting 

#1 down 

5/7/04 Lab 55.8 10 spec 5 

324.

0 spec 1 Inc power at #2 by tilting #1 up 

5/7/04 Lab 55.8 10 spec 5 

260.

0 spec 1 Same as previous test 

5/7/04 Lab 55.8 10 spec 5 

260.

8 spec 1 Inc power at #2 by tilting #1 up 

5/7/04 Lab 55.8 10 spec 5 

197.

5 spec 1 Same as previous test 

5/7/04 Lab 55.8 10 spec 5 

198.

2 spec 1 Inc power at #2 by tilting #1 up 

5/7/04 Lab 55.8 10 spec 5 

118.

2 spec 1 Same as previous test 

5/7/04 Lab 55.8 10 spec 5 

118.

2 spec 1 Inc power at #2 by tilting #1 up 

5/7/04 Lab 55.8 10 spec 5 81.9 spec 1 Baseline: 

5/7/04 Lab 55.8 10 spec 5 81.7 spec 1 Baseline: 

5/7/04 Lab 55.8 

10/1

0 spec 5 81.2 spec 1 

Add 2nd 10 dB attenuator; w/ 10 

dB on #1 input & output fibers 

5/7/04 Lab 55.8 10 spec 5 80.4 spec 1 Baseline: 

5/7/04 Lab 55.8 10 spec 5 80.4 spec 1 

Baseline: w/ 10 dB on #1 output 

fiber, screen on each receiver 

 

5/4/04 Lab 55.8 10 spec 5 94.7 spec 1 w/ 10 dB on #1 output fiber 

5/4/04 Lab 55.8 10 spec 5 94.5 spec 1 Reinstall 10dB on #1 output fiber 

5/4/04 Lab 55.8 0 spec 5 92.0 spec 1 Remove 10dB 

5/4/04 Lab 55.8 10 spec 5 92.0 spec 1 Baseline w/10dB, 2 screens 

5/4/04 Lab 55.8 10 spec 5 92.0 spec 1 Baseline w/10dB, 2 screens 

 

5/3/04 Lab 50.5 10 spec 5 90.6 spec 1 Same as last, no pkt loss 

 38
ECT - Phase 3 

5/3/04 Lab 50.5 10 spec 5 90.6 spec 1 

Refocused #1 down to get weaker 

signal at #2, 10 dB still in 

5/3/04 Lab 

128.

0 10 spec 5 347 spec 1 

Refocused #1 up, rx pwr 

increased at #2 

5/3/04 Lab 147 10 spec 5 

274.

0 spec 1 

Add screen to #1, 10 dB, screen 

on #2, 

5/3/04 Lab 147 10 spec 5 272 spec 1 

Add screen to #1, 10 dB, screen 

on #2, 

5/3/04 Lab 239 10 spec 5 276 spec 1 Baseline, 10 dB, screen on #2, 

5/3/04 Lab 239 10 spec 5 276 spec 1 Baseline, 10 dB, screen on #2, 

 

4/30/04 Lab 239 10 spec 5 

279.

0 spec 1 

Baseline with 10 dB & screen on 

#2 

4/30/04 Lab 239 10 spec 5 

279.

0 spec 1 

Baseline with 10 dB & screen on 

#2 

 

4/29/04 Lab 242 10 spec 5 

278.

0 spec 1 

Lowered pwr lvl for each end, 

poor performance in Packet l;oss 

test 

4/29/04 Lab 310 10 spec 5 

373.

0 spec 1 

Higher pwr lvl for each end, no 

data transferred in Packet loss test 

4/29/04 Lab 310 10 spec 5 

373.

0 spec 1 

Upped pwr lvl for each end, no 

data transferred in Throughput 

test 

4/29/04 Lab 235 10 spec 5 

275.

0 spec 1 

Packet loss test; screen on #2 

rcvr, all sys lgts green; Installed 

10 dB attenuator in exit of #1 

4/29/04 Lab 235 10 spec 5 

275.

0 spec 1 

Throughput test; screen on #2 

rcvr, all sys lgts green; 10 dB 

attenuator in exit of #1 

4/29/04 Lab 235 15 spec 5 

275.

0 spec 1 

Throughput test; screen on #2 

rcvr, all sys lgts green; Installed 

15 dB attenuator in exit of #1 

4/29/04 Lab 235 0 spec 5 

275.

0 spec 1 

Throughput test; screen on #2 

rcvr, all sys lgts green; Removed 

10 dB attenuator in exit of #1 

4/29/04 Lab 235 10 spec 5 

275.

0 spec 1 

Packet loss test; screen on #2 

rcvr, all sys lgts green; 10 dB 

attenuator in exit of #1 

4/29/04 Lab 236 10 spec 5 

276.

0 spec 1 

Throughput test; screen on #2 

rcvr, all sys lgts green; 10 dB 

attenuator in exit of #1 

4/29/04 Lab 239 10 spec 5 441 spec 1 

Rx light flickering without 

Smartbits transmitting. 10 dB 

attenuator in exit of #1 

 spec 

4/26/04 Lab 204 0 spec 5 484 spec 1 

Removed 10 dB attenuator in; 

SmartBits Rx for Card 17 is out 

4/26/04 Lab 204 10 spec 5 484 spec 1 

Turned down power to min for of 

each Tx; 10 dB attenuator in; 

flickering green receive at 

SmartBits 

4/26/04 Lab 267 10 spec 5 498 spec 1 

Turned down power of each Tx; 

10 dB attenuator in; flickering 

green receive at SmartBits 

4/26/04 Lab 513 10 spec 5 650 spec 1 

Reinstalled 10 dB attenuator at 

ouput of #1, test unsuccessful; 

nothing being received at 

SmartBits 

4/26/04 Lab 513 0 spec 5 650 spec 1 Reset SmartBits; test failed 

4/26/04 Lab 513 0 spec 5 643 spec 1 All FSO indicators green 

 

 39
ECT - Phase 3 

4/22/04 Lab 491 0 spec 5 641 spec 1 

Turned down #1 laser to Lvl 2, 

Rx pwr at #2, Sys lgt Green, no 

attenuation in fiber 

4/22/04 Lab 491 0 spec 5 725 spec 1 

Turned down #1 laser to Lvl 4, no 

drop in Rx pwr at #2, Sys lgt red 

4/22/04 Lab 491 0 spec 5 725 spec 1 

Turned down #2 laser to Lvl 4, 

Sys lgt red 

4/22/04 Lab 711 0 0 0 65.8 spec 1 

Self-Reflected energy from #2, 

Sys lgt red 

4/22/04 Lab 711 0 spec 5 725 spec 1 Realigning, Sys lgt red 

4/22/04 Lab 711 0 spec 5 725 spec 1 Realigning, Sys lgt red 

4/22/04 Lab 711 0 spec 

5 & 

7 725 spec 1 Realigning, Sys lgt red 

4/22/04 Lab 711 0 spec 7 64 spec 1 

Units had been moved, Sys light 

red 

 

4/15/04 Lab 74.3 0 spec 7 105 spec 1 

Repeat previous successful 

config; both Optical head lights 

green, Throughput Test 

4/15/04 Lab 74.8 0 spec 7 104 spec 1 

Repeat previous test after 

resetting SmartBits; Sonet not 

established 

4/15/04 Lab 74.8 0 spec 7 104 spec 1 

Repeat previous test for Packet 

loss 

4/15/04 Lab 74.8 0 spec 7 104 spec 1 

Jumper at #1, send at #2; still card 

19 to Card 17, Throughput test; 

part of data missing; all Optical 

heads lights green 

4/15/04 Lab 74.9 0 spec 7 103 spec 1 

Packet Loss test, both Optical 

units have all green lights 

4/15/04 Lab 74.9 0 spec 7 103 spec 1 

wiggled 17 Rx fiber & got green 

LED ; ThroughPut test, both 

Optical units have all green lights 

4/15/04 Lab 75.5 0 spec 7 103 spec 1 wiggled fibers 

4/15/04 Lab 75.5 0 spec 7 103 spec 1 

Back to previous successful 

config, did not work; #2 Fiber 

in=red, sys=red; #1 fiber in = 

green, sys=red 

4/15/04 Lab 74.5 0 spec 7 103 spec 1 

Repeat last test with Smartbit 

jumper; #2 Fiber in=green, 

System=red; #1 Fiber in & Sys = 

red 

4/15/04 Lab 74.6 0 spec 7 103 spec 1 

Replaced fiber pair to #2, Tx 17 

(#2) to 19 (#1); Fiber input #2 = 

green; System Stat = red; Both 

red @ #1 

4/15/04 Lab 75.6 0 spec 7 102 spec 1 

Repeat last test, 17 (#2) to 19 

(#1); reversed back fibers to unit 

#2; Fiber input #2 = red; System 

Stat = red; Both red @ #1; Sonet 

not established 

4/15/04 Lab 75.6 0 spec 7 102 spec 1 

Repeat last test, 17 (#2) to 19 

(#1); reversed fibers to unit #2; 

Fiber input #2 = red; System Stat 

= red; Both red @ #1; Sonet not 

established 

4/15/04 Lab 75.6 0 spec 7 102 spec 1 

Repeat last test, 17 (#2) to 19 

(#1); loop at smart bits for unused 

fibers; Fiber input to #2 is red; 

some data processed 

4/15/04 Lab 75.6 0 spec 7 102 spec 1 

Repeat last test, switching fiber 

pairs for same unit; ltr to blank 

4/15/04 Lab 75.6 0 spec 7 102 spec 1 

Reverse direction send 17 (#2) to 

19 (#1) 

 40
ECT - Phase 3 

4/15/04 Lab 75.6 0 spec 7 102 spec 1 

Rerun prev test for Packet Loss, 

sys state red both units, fiber 

input red #2 

4/15/04 Lab 75.6 0 spec 7 102 spec 1 

Reset SmartBits, set acceptable 

thruput loss at 5% from 0%, sys 

state red both units, fiber input 

red #2 

4/15/04 Lab 74.3 0 spec 7 102 spec 1 

Reset SmartBits, set acceptable 

thruput loss at 5% from 0% 

4/15/04 Lab 74.3 0 spec 7 102 spec 1 

Card 19 to 17 (#1 to #2), 1 to 1, 

ThruPut not successful 

 

4/14/04 Lab 76.3 0 spec 7 106 spec 1 

SmartBits set to Tx #1 (card 19) 

& Rx #2 (card 17), loop from Tx 

card 17 to Rx card 19; all tests 

failed but some data appears to be 

passed. Tx=6959835, Rx 

6952150 

4/14/04 Lab 76.3 0 spec 7 106 spec 1 

Card 19 to 17 (#1 to #2); jiggle 

cables helped at SmartBits; 

switched cables around at 

SmartBits, passing data but failed 

test 

4/14/04 Lab 76.2 0 spec 7 106 spec 1 Increase #1 pwr lvl to 7 (max) 

4/14/04 Lab 76.2 0 spec 7 45.7 spec 1 Increase #2 pwr lvl to 7 (max) 

4/14/04 Lab 38.8 0 spec 7 43.7 spec 1 Restart 

4/13/04 Lab 38.8 0 spec 7 41.1 spec 1 

Turn off APC at #2 and set Tx 1 

O'clock to Custom, Lvl 5 

4/13/04 Lab 77.8 0 spec 7 41.1 12 all 

Restart with 2nd laptop at #2 

position, APC on @ #2 

4/12/04 Lab 77.0 0 spec 7 41.1 12 all 

Inscrease pwr level of #1 to Level 

5; APC on @ #2 

4/12/04 Lab 77.0 0 spec 7 13.2 spec 1 

Reconnect SmartBits to #2, 

changed APC to enable, system 

lights still all green. All 4 Tx 

turned on 

4/12/04 Lab 17.4 0 spec 7 13.5 spec 1 

Reconnect SmartBits to #1, 

system lights still all green 

4/12/04 Lab 17.4 0 spec 7 13.5 spec 1 

Media converter input at #1, loop 

at #2. Input recognized. All 

system lights green at #1 

4/12/04 Lab 17.4 0 spec 7 13.5 spec 1 

Tried media converter input at #1. 

Input recognized. Input at #2 

from SmartBits not recognized 

 

4/9/04 Lab 16.2 0 spec 7 13.5 spec 1 

Used night vision goggles to try 

& see laser orientation. Did not 

work 

4/9/04 Lab 16.2 0 spec 7 13.5 spec 1 

Zeroed received power both 

machines 

4/9/04 Lab 8.7 0 2 

1 & 

7 3.4 2 

1 & 

7 

Configured SmartBits software; 

no change. Diagonostic says no 

FSO lock & no Fiber Input Lock, 

Fiber input detect=Red; System 

status=red 

4/9/04 Lab 8.7 0 2 

1 & 

7 3.4 2 

1 & 

7 

Removed jumper & connected 

SmartBits 19 to unit #1, 17 to unit 

#2 

4/9/04 Lab 8.7 0 2 

1 & 

7 3.4 2 

1 & 

7 

Adjusted elev on #2; no link 

established, fiber jumper at #1 

4/9/04 Lab 1.9 0 2 

1 & 

7 3.4 2 

1 & 

7 

No link established, fiber jumper 

at #1 

 41
ECT - Phase 3 

4/9/04 Lab 1.4 0 2 

1 & 

7 3.4 2 

1 & 

7 

No link established, fiber jumper 

at #1 

4/8/04 Lab 1.3 0 2 

1 & 

7 3.4 2 

1 & 

7 

Used video camera to try and see 

laser orientation. Did not work 

4/8/04 Lab 1.3 0 2 

1 & 

7 3.4 2 

1 & 

7 

Realigned both; #2 was reflecting 

off #1 and receiving its own 

signal 

 

4/7/04 Lab 0 0 4 all 0 4 all Align units 

 

4/6/04 Lab 0 0 4 all 0 4 all Align units 

 

4/2/04 Lab 0 0 4 all 0 4 all 

IP's set, SmartBits cable 

connected 

 

3/29/04 Lab 0 0 4 all 0 4 all 

#1 & #2 Powered up & 

initialized, IP set 

 

2.7.2 SmartBits

2.7.3 SmartBits Testing

SmartBits testing was performed at all locations. Test profiles included Throughput and 

Packet loss. Throughput tests included the following frame sizes and packet rates. 

Table 2-12 SmartBits Throughput Test Parameters 

Frame Size Pks/Sec 

64 706415 

128 470943 

256 235471 

512 128439 

768 83107 

1024 64219 

1518 44150 

Packet loss tests used the same frame sizes and usually resulted in zero packet losses. 

Typical Throughput test results are shown in the following tables. These were the third 

tests on 8/2/04. The first is throughput results and the second is Packet loss. 

 42
ECT - Phase 3 

Table 2-13 Typical SmartBits Through-Put Test 

T-080204-T3 

Frame % Pks/Sec 

64 100 706415 

192 100 282566 

320 100 201832 

448 100 141283 

576 100 108679 

704 100 94188 

832 100 78490 

960 100 67277 

1088 100 61427 

1216 100 54339 

1344 100 48718 

1472 100 45575 

Table 2-14 Typical SmartBits Packet Loss Test 

T-080204-P3 

Frame % % 

64 100 0.000 

192 100 0.000 

320 100 0.000 

448 100 0.000 

576 100 0.000 

704 100 0.000 

832 100 0.000 

960 100 0.000 

1088 100 0.000 

1216 100 0.000 

1344 100 0.000 

1472 100 0.000 

2.8 FSO SECURITY CONCERNS 

Security for FSO links is usually achieved by controlling physical access. The FSO 

beam is relatively large at a distance of one mile; diverging at approximately a 2 milliradian angle for the beam results in a divergence of 0.002 miles at one mile, or 

equivalently a diameter of 10.56 feet for the beam diameter at one mile. Any covert 

attempt to intercept the signal would require a relatively large receiver physically placed 

in an obvious location within the beam or very near the transmitter. Any interception 

attempt would be obvious. In addition, transmitters and receivers are usually physically 

mounted high. This would likewise make it difficult to intercept a signal covertly 

without detection. Any attempts to redirect the beam would normally be immediately 

obvious due to the loss of signal and the breaking of the communication link. Security of 

the connecting fibers is likewise assured by either access control or existing fiber security 

methods. 

 43
ECT - Phase 3 

2.9 COMPARISON OF MULTI-BEAM AND SINGLE BEAM 

SYSTEMS 

The fSONA multi-beam 622-M tested in ECT Phase 3 and the AirFiber 5800 single beam 

tested in ECT Phase 2 are very different systems to install and operate. The biggest 

difference is not the number of beams, but the auto-track feature that the AirFiber system 

incorporates. Both systems involved a significant learning curve plus the factory training 

included with each was extremely valuable in shortening the operational learning curves. 

The fSONA 622-M units performed well during testing out to a distance of 1.5 miles. 

This agrees well with the factory spec of 1.6 miles. The major difficulty with the 622-M 

was in the initial alignment and obtaining a system lock between the two OTU. The 

AirFiber units were easier to align initially due to the auto-track feature; however, the 

long distances of the fSONA tests were never attempted with the AirFiber units. 

Acquiring a signal at one mile using AirFibers built-in cameras without optical zoom 

would have been extremely difficult. 

Both systems worked well without any observed difficulties once a link was established. 

The AirFiber system was tested in light to moderate rain while the fSONA units were 

only tested in good weather. 

It is not obvious that either system has a clear technical advantage over the other. From a 

reliability standpoint, the simpler wide-beam, non-tracking fSONA has a theoretical 

advantage. Likewise, the simpler, lower-cost fSONA unit likely has a price advantage 

when procured in large quantities. It would appear that the optimum system for future 

use within the unique KSC environment would include features from both the narrowbeam, auto-tracking technology of the AirFiber design, as well as feature from the 

simpler, more reliable fSONA unit. This hypothetical future FSO system for use at KSC 

would likely include the following characteristics: 

• Multiple transmitters (fSONA), thereby providing redundancy in the event of a 

single laser failure 

• Gross Auto-tracking (AirFiber had fine auto-tracking) 

• Closed-loop feedback from one unit to another (AirFiber) 

• Telescope for initial alignment (fSONA) 

• Internal camera for real-time view (AirFiber) 

• Optical zoom on internal camera (new) 

 

 44
ECT - Phase 3 

2.10 FSO SUMMARY AND RECOMMENDATIONS 

The precept of ECT during Phases 2 and 3 was to investigate newly-introduced FSO 

products while they were still in their infancy, and thereby influence the development of 

these developing products as early as possible, before we needed operational FSO 

systems on the Range at KSC. We are now much closer to fielding practical FSO systems 

at KSC, and we have clearly gained an in-depth understanding of the limits of this 

technology within the unique KSC environment. As in any industry, the state of the art 

continues to improve. And we have found that there are critical unique aspects of the 

KSC environment that force a shift from the priorities that commonly exist for FSO 

systems intended for urban areas. 

For example, in Phase 2, we found that the large birds native to the Merritt Island 

National Wildlife Refuge are quite capable of blocking the narrow laser beams of autotracking FSO systems, thereby introducing data link interruptions. The mitigation, 

investigated during Phase 3, was to switch to non-tracking, widebeam FSO systems. 

These systems utilize multiple laser beams that diverge to more than a meter in diameter 

at reasonable communication distances. The small 1⁄4-meter diameter laser beams that are 

used in the auto-tracking FSO systems investigated during Phase 2 are easily blocked by 

large birds. The larger non-tracking multiple beam systems investigated this year, in 

Phase 3, are largely immune to these bird-blocking outages, despite being more difficult 

to install a link with relative to the auto-tracking systems.. For the KSC environment, 

though, the reduced vulnerability to bird-blockages is an important advantage. 

Hybrid multi-beam systems with auto-track are now on the market. They provide the 

best of both worlds, with an increased ease in establishing a link, while having the 

advantages of being largely immune to bird blockages. Different wave lengths are also 

being marketed by new entrants, and for maintaining communication during planned 

burning of overgrown brush and grasses, this could be an advantage. More importantly, 

the impacts of networking multiple FSO systems needs to be investigated, prior to 

fielding multiple systems, to understand better the limits for networking multiple FSO 

systems at KSC. ECT follow-on activities should investigate these architectural 

developments over the next year, prior to fielding operational FSO systems. 

Another practical application that should be investigated is an FSO system with a GPS or 

other tracking technology to enable high-speed initial automatic acquisition of high datarate communication with mobile objects. Initial applications could be a slow moving 

object such as a Shuttle recovery convoy or a rocket roll-out, where high-speed data 

connectivity is desired without dragging long cables that often break, which is the 

practice currently used for Atlas launch-vehicle processing. 

We are clearly much closer to our goal of fielding high data-rate FSO systems within the 

KSC environment, gaining the flexibility of not having to bury fiber optic cables or 

 45
ECT - Phase 3 

dragging such cables alongside rail-mounted convoys, while still achieving higher data 

rates over longer distances than is possible with Wireless Ethernet. 

 46
ECT - Phase 3 

3.0 ULTRA WIDE BAND

3.1 INTRODUCTION 

Emerging Ultra Wideband (UWB) Orthogonal Frequency Division Multiplexing 

(OFDM) systems hold the promise of delivering wireless data at high speeds, exceeding 

hundreds of megabits per second over typical distances of 10 meters or less. The result of 

this year’s UWB research was an investigation of the timing accuracies required of the 

timing error which can adversely affect the positional accuracies and Bit Error Rates of 

UWB systems. The impact is greater on BER performance than on positional accuracy 

performance, hence the focus in this paper is placed primarily on BER effects of timing 

uncertainty rather than on positional uncertainty. If communication is not achieved at all, 

positional awareness, were communication to exist, is of little importance. 

Specifically, the effect of these timing errors can impact the achievement of Bit Error 

Rates on the order of magnitude of 10-12 or better. The dual purpose of investigating 

timing accuracies is therefore to assess the positional awareness as well as the Bit Error 

Rate performance of UWB systems needed for addressing future NASA communication 

needs. By understanding the practical limits of performance due to implementation 

problems, it thereby becomes possible to avoid overloading the correction of irreducible 

errors due to misaligned timing errors to a small absolute number of bits in error in realtime relative to a data rate of hundreds of megabits per second. Then, once 

communication is possible at low BER, positional awareness performance can be 

achieved. 

The research approach involved managing positional awareness errors and bit error rates 

through identifying the effects of maximum timing synchronization error parameters. 

The effect of these parametric errors determine the timing accuracies required to avoid 

operation of communication systems within the asymptotic region of BER flaring at low 

BERs in the resultant BER curves. The proposed solution to these errors is to push 

physical layer bit error rates to below 10-12 before using forward error correction (FEC) 

codes. This way, the maximum reserve is maintained for the FEC hardware to correct for 

burst as well as recurring bit errors due to corrupt bits caused by other than timing 

synchronization errors. The effect on location accuracy is likewise minimized. 

 47
ECT - Phase 3 

Table 3-1 List Of UWB-Related Abbreviations 

Bit Error Rates (BER) 

Binary Phase Shift Keying (BPSK) 

Bandwidth (BW) 

Clock and data recovery (CDR) 

Energy per bit (Eb) 

Federal Communications Commission (FCC) 

Forward error correction (FEC) 

Hertz (Hz) 

Inverse Fast Fourier Transform (IFFT) 

Multi-Band OFDM Alliance (MBOA) 

Mega Bits per second (Mbps) 

Multiplexer (Mux) 

Effective noise (Neff) 

Orthogonal Frequency Division 

Multiplexing (OFDM) 

On/Off Keying (OOK) 

Pulse Amplitude Modulation (PAM) 

Performance Analysis Tool (PAT) 

Probability density function (pdf) 

Physical (PHY) 

Pulse Position Modulation (PPM) 

Radio frequency (RF) 

Unit Interval (UI) 

Ultra Wideband (UWB) 

Wireless personal area networking (WPAN) 

 48
ECT - Phase 3 

3.2 BACKGROUND 

In the near future, wireless broadband communications systems will require data rates 

exceeding hundreds of mega bits per second (Mbps). To address these approaching 

demands, emerging Ultra Wideband (UWB) Orthogonal Frequency Division 

Multiplexing (OFDM) offers an ideal physical (PHY) layer solution to address wireless 

personal area networking (WPAN) needs over short ranges. As UWB modulation 

becomes better understood and data rates increase to near their high data rate potentials, 

the control of timing synchronization errors will become ever more critical in measuring 

UWB’s system performance parameters. The ECT Phase 3 research explored the timing 

accuracies required to support the operation of UWB OFDM systems in such a future 

communication landscape. 

3.3 OFDM OVERVIEW 

Instead of using the traditional Pulse Position Modulation (PPM), Pulse Amplitude 

Modulation (PAM), Binary Phase Shift Keying (BPSK), and On/Off Keying (OOK) 

modulations investigated in the prior two years research, an alternate approach for 

modulating Ultra Wideband (UWB) Pulses is investigated in this year’s research, 

consistent with changing trends monitored in the trade press for implementing UWB 

communication techniques. This newer modulation technique is achieved through 

OFDM (Orthogonal Frequency Division Multiplexing). OFDM is a modulation 

technique suitable for high data rate systems for networked applications, and is more 

suited to future congested communications arenas than the simpler PPM, PAM, BPSK, 

and OOK methods of modulation. 

The prominent emerging UWB OFDM system has been developed by the Multi-Band 

OFDM Alliance (MBOA http://www.mboaalliance.com ) and uses the OFDM technique 

to occupy the statutory wide bandwidths permitted for UWB systems. The basic idea of 

OFDM involves splitting a high-rate data stream XN into a number of lower rate streams 

that are transmitted simultaneously at different frequencies over a number of sub-carriers 

(X0, X1,...XN-1) (See Figure 3-1). 

Figure 3-1 De-Multiplexed High Data Rate Of DM Data Stream 

 49
ECT - Phase 3 

In OFDM the sub-carrier pulse used for transmission is a rectangular pulse. With this 

rectangular pulse, the task of pulse forming and modulation can be simply implemented 

with an Inverse Fast Fourier Transform (IFFT). According to the Fourier Transform 

Theorem, the rectangular pulse shaped sub-banded pulses in OFDM will lead to the 

[sin(x)/x] spectrum at the receiver, when the signal is Muxed back together, seen in 

Figure 3-2. To obtain high spectral efficiency, the frequency response of the sub-banded 

are overlapped and orthogonal, which means that where the signal is evaluated (at the 

maximum peak), the value of all other signals are zero. 

Figure 3-2 Overlapping Orthogonal Sub-Carriers In OFDM Symbol 

Major benefits of the OFDM technique include higher spectral efficiency, resiliency to 

radio frequency (RF) interference, and lower multi-path distortion [4]. On the other hand, 

OFDM shortcomings evolve through its high sensitivity to frequency and time 

synchronization error compared to single carrier system [4]. Frequency synchronization 

error results from misalignment in sub-carrier frequencies due to fluctuations in radio 

frequency oscillators or channel’s Doppler frequency introducing inter carrier 

interference (ICI). Timing synchronization errors refer to the incorrect timing of the 

OFDM symbols at the demodulator introducing inter symbol interference (ISI). [3]. Both 

ICI and ISI cause bit errors in a UWB-OFDM system. The focus of this research was to 

analyze how accurate timing synchronization errors must be to obtain a bit error rate of 

10-12, or better, assuming perfect frequency synchronization. A closer examination of this 

phenomenon will be shown in Section 2. 

 

Although currently there are two major UWB proposals, consisting of single band and 

multi-band impulse-centered approaches, both with their own advocates fighting for their 

approach to become the accepted IEEE and FCC standard, in this paper we focus on the 

multi-banded OFDM approach and its concepts and limitations. This focus is chosen 

since the multi-band approach currently has achieved more favor among the candidate 

approach to become the universal UWB standard. 

 50
ECT - Phase 3 

3.4 RESEARCH ORGANIZATION 

The importance of controlling timing synchronization errors was established earlier. 

Discussions regarding timing synchronization errors in UWB-OFDM systems are 

discussed starting the next section. Then starting in Section 3.10, new methodologies are 

presented for analytical solutions for bit synchronization effects on BER (Bit Error Rate). 

Starting in Section 3-20, results from analytical and experimental analyses are presented 

along with a hypothesis of the timing error effects. Finally, in Section 3-27 the research 

concludes by restating the research objectives, documenting why timing synchronization 

is important, and summarizing the effect on BER and positional accuracy performance if 

the timing accuracies are not maintained in a UWB-OFDM data link. 

3.5 TIMING JITTER IN UWB-OFDM COMMUNICATION SYSTEMS 

Measured performance of a digital data transmission system usually is obtained through 

analyzing the probability of error at a given bit error rate and signal-to-noise ratio. As 

the UWB systems evolve into their expected achievable high data rate values, controlling 

timing synchronization errors becomes essential since timing errors cause bit errors that 

degrade UWB-OFDM system performance. To present the concept of “How timing 

errors affect UWB-OFDM system performance”, this section is divided into three parts. 

First the OFDM symbol structure is described. Then, how timing errors in the OFDM 

symbols affect the system’s performance is discussed; and third is an analysis of the 

impact of timing jitter in digital communication systems. This section concludes with a 

Tikhonov approximation approach for estimating the timing error. 

3.6 OFDM TECHNIQUE 

Orthogonal Frequency Division Multiplexing (OFDM) is a flexible technique that 

increases bandwidth efficiency, resiliency to radio frequency (RF) interference, and 

lower multi-path distortion. For example, if interference with an existing narrowband 

system occurs, UWB -OFDM permits simply not using one or more particular sub-bands. 

This technique can be thought of as analogous to a combination of multi-carrier 

modulation (MCM) and frequency shift keying (FSK). MCM divides a data stream into 

several bit streams and modulates each bit stream onto sub-carriers [16]. FSK transmits 

data onto one carrier from multiple orthogonal carriers. Orthogonality between the subbands among an UWB-OFDM modulation format is accomplished by separating the 

bands by an integer multiple of the inverse of symbol duration of the parallel bit streams 

[4] Orthogonality in the symbol is crucial because it helps to eliminate inter-symbol 

interference (ISI) and inter-carrier interference (ICI). This is best done by adding a guard 

time insertion or a cyclic prefix to the beginning of the OFDM symbol. Cyclic prefix 

(CP) involves attaching a copy of the last part of the OFDM symbol to the beginning of 

the symbol as shown in Figure 3-3. 

 51
ECT - Phase 3 

Figure 3-3 OFDM Symbol 

In the transmitter, after the parallel data of N sub-channels are modulated onto N subcarriers (d0,d1,...dN-1), where each dN represents a complex number, they are fed into an 

Inverse Fast Fourier Transform (IFFT). The transmitted data is given by [5]: 

where Ts is the symbol duration of the OFDM pulse and fi (i=0.1,....N-1) is the frequency 

of the ith sub-carrier given by [5]: 

Here, f(t) is the pulse waveform of each of the symbols and it is defined as 

After the IFFT process, the signal s(t) goes through a guard time insertion circuit where 

the cyclic period is added so inter-symbol interference can be avoided as much as 

possible. 

One requirement of adding a cyclic prefix to the symbol is that it should be longer than 

the impulse response of the channel. When the cyclic prefix to the symbol is longer than 

the impulse response of the channel, it acts as a guard space between the sub-carriers. 

The guard time is chosen larger than the expected delay spread, such that multi-path 

components from one symbol cannot interfere with the next symbol [15]. This eliminates 

ISI and ICI almost completely. However, some residual ICI may still exist. This happens 

when the multi-path delay becomes larger than the guard time. At this point, the system 

may manifest timing errors due to the cumulative effects of multi-path delay variations. 

 52
ECT - Phase 3 

At the output of the guard time insertion circuit, the OFDM symbol is given by: 

[5] 

where the modified pulse waveform of each symbol is defined as 

 [5] 

3.7 TIMING ERROR EFFECTS ON SYSTEM PERFORMANCE 

Timing signals play several of different roles in communication systems. One example 

evolves in digital systems, where clock signals are used to transfer logic signals in and 

out of registers at times when their values are valid. The maximum clock frequency is 

usually limited by the propagation delay of the logic circuits between registers. In high 

bandwidth digital input/output systems, however, the date transfer rate can be limited by 

uncertainty in the clocks used to transfer the data [21]. Fixed offsets between transmit 

and receive clocks or timing errors due to noise comprise this uncertainty. 

Timing errors in UWB-OFDM are simply a short variation of the OFDM sub-band’s bit 

timing from its ideal time slot location. A bit’s timing is simply the composite effect of 

multiple monocycles acting in concert due to various multi-path delays acting in addition 

to the composite effect of digital circuitry timing errors. Effects of errors in the time base 

of the signal, due to timing errors can also limit performance parameters such as 

achievable bit rates of the system. When this happens the system is said to have a 

degraded performance due to timing errors. 

3.8 TIMING JITTER AND PHASE NOISE RELATIONSHIP 

Oscillator or clock uncertainties in synchronous digital systems can degrade a system’s 

performance, resulting from in bit errors. Phase noise and timing jitter result from 

uncertainties in the clock’s oscillator output. Phase noise defines the frequency output of 

the oscillator. For example, when the output to a noisy phase oscillator is given by: 

[17] 

 53
ECT - Phase 3 

then 

is the phase noise also referred to as the spectral density of phase fluctuation. The random 

fluctuations of phase, that are responsible for phase noise, can also be observed in the 

time domain as timing jitter. Given that timing jitter is a measure of variation in the time 

domain, it ultimately describes how far a bit period wanders from its ideal location. In 

OFDM systems, controlling timing jitter in the sub-carriers calls for precise 

synchronization at the OFDM demodulator. This control involves determination of the 

starting sample of the ith OFDM symbol such that the cyclic prefix (CP) can be 

disregarded and the OFDM symbol can be properly realigned [3]. For example, consider 

the OFDM block diagram shown in Figure 3-4. Before the OFDM symbol can be 

multiplexed back together and the orthogonality of the symbol at the receiver is 

preserved, timing errors must be controlled or even corrected to some degree. Otherwise, 

the system will experience inter-carrier interference (ICI). ICI is crosstalk between 

different sub-carriers, which means that the sub-carriers are no longer orthogonal in 

signal space [15]. The orthogonality of the sub-carriers can be maintained and individual 

sub-carriers can be separated by using an FFT (Fast Fourier Transform) circuit when 

there is no inter-symbol interference (ISI) and inter-carrier interference introduced by 

transmission channel distortion [1]. In reality, these conditions cannot be obtained. To 

manage distortion caused by the transmission channel, in the next section we introduce a 

method for estimating the timing accuracy required for achieving a given bit error rate 

performance for a high data rate UWB-OFDM digital link. 

Figure 3-4 OFDM Block Diagram 

3.9 TIKHONOV APPROXIMATION OF TIMING ERROR 

In OFDM bit symbols there will always be some fluctuation in the bit symbol’s ideal 

timing. This fluctuation can be estimated around the ideal timing’s mean value. Since the 

timing errors are random values, to estimate fluctuation in timing, we characterize the 

actual timing with a probability density function (pdf). The pdf shows how the actual bit 

timing estimate can be before or after the ideal value. 

 54
ECT - Phase 3 

In the literature [3,18,19.20], it is found that timing errors are usually characterized with 

a Gaussian or a Tikhonov pdf. However, the choice of a Tikhonov pdf is selected in this 

research so that we can obtain a more representative characterization of the bit 

synchronizer statistical properties in agreement with observed properties. The next 

section displays the use of the Tikhonov approximation of timing errors. 

3.10 BIT SYNCRONIZATION 

This section introduces and presents methods and procedures for estimating the timing 

accuracy required for achieving a given bit error rate performance for a high data rate 

UWB-OFDM digital link. Through this analysis, equations can be developed to 

determine and identify maximum timing synchronization errors of high data rate links 

incorporating Manchester (Bi-Phase), Miller, RZ, or NRZ coded data. 

Most high speed communication systems have a low tolerance for bit errors; the 

allowable uncorrected bit error rate (BER) for such systems operating in the hundreds of 

mega bits per second typically must fall between 10-9 and 10-12 to prevent introducing 

error correction overload within the error correction hardware. This means that the BER 

impacts of synchronization and timing errors must be analyzed to estimate the timing 

accuracies required to avoid overloading the correction of irreducible errors due to 

misaligned timing errors. 

In previous studies [3,18], timing error analyses have been investigated performance in 

bit error regions ranging from 10-3 to 10-6. Such a lower-performance BER is entirely 

appropriate for low speed communication systems operating at data rates only in the tens 

of mega bits per second. Unfortunately, these previously investigated regions are not 

sufficient for proposed high speed UWB systems having data rates in the hundreds of 

mega bits per second. For example, consider a system running at 500 Mbps, with a target 

bit error rate of 10-6. Such an error rate would produce 500 bit errors per second, in such 

a high-speed system, and a 10-6 level of bit error rate would cause severe system 

performance degradation. 

Instead of battling with the high bit error rates mentioned above, the recommended 

approach involves reducing bit error rates to lower rates through first identifying the 

performance requirements associated with, and then managing, the maximum range of 

timing synchronization errors. Thus, it became a research goal to determine how 

accurate the timing errors must be among the multitude of OFDM data streams, to avoid 

operation in the asymptotic region where BER flaring occurs at low BERs in the resultant 

BER curves. Otherwise, it becomes impossible to achieve high positional awareness 

accuracies and low Bit Error Rates. The approach chosen is push bit errors to below 

10-12 before taking advantage of forward error correction (FEC) codes. This way, the 

maximum reserve is maintained for the FEC hardware to correct for bit errors caused by 

other than timing synchronization errors. 

 55
ECT - Phase 3 

For the purpose of presentation, this section is divided into two sections: analytical 

solutions for bit synchronization errors and experimental test cases with PulsON 200 

evaluation kit hardware manufactured by Time Domain Corporation of Huntsville, AL. 

3.11 ANALYTICAL SOLUTIONS FOR BER PERFORMANCE 

At the beginning of the analytical solutions research, the focus was placed on estimating 

a maximum achievable bit rate, conditioned on timing synchronization bit errors. 

Through this analysis, timing error effects on bit error rate performance of a high data 

rate link could be identified. 

The chosen methodology closely follows the derivations and methods of Lindsey and 

Simon [2]. The difference between the methods in this paper and the methods discussed 

in [2] are that we characterize the synchronization error λ to be a normalized timing error 

resulting from a delay locked loop. Additionally, we examine bit synchronization for a 

high data rate stream instead of for symbol synchronization for narrowband applications. 

Also, we expand the average error probability Pe to below 10-12, since one must target 

this region of interest for applicability to high data rate links. Finally, the standard 

deviation σλ and variance σλ

2

 of the normalized timing error represent ratios of a 

normalized Unit Interval (UI) of a data bit time period in a data link. Through utilizing a 

Unit Interval approach, in place of an absolute timing approach, the results of this 

research can easily be applied to ever-increasing data rates for future, yet unimagined 

OFDM-UWB data links, thereby increasing the value of the research documented in this 

paper. 

In the following section, the methodology for the analytical solutions that estimated a 

maximum achievable bit rate, conditioned on bit timing synchronization errors are 

discussed. The analysis begins with obtaining conditional error probability values of the 

correlation detector conditioned on a timing error. Next, an explanation of how to 

average the obtained conditional error probabilities over a Tikhonov pdf (probability 

density function) to arrive at estimations of probability of bit error at the receiver is 

presented. 

3.12 CONDITIONAL ERROR PROBABILITIES 

Given that the optimum detector for a known signal is a cross-correlator, the first step in 

performing the analysis is to obtain derivations for the error probability of the correlation 

detector conditioned on a bit synchronization error for Manchester, NRZ, RZ and Miller 

coded data. 

Below are the equations, taken from prior literature, that is used in this analysis to obtain 

the conditional error probabilities for Manchester, NRZ, RZ, and Miller coded UWBOFDM data. (See [2] for derivations.) 

 56
ECT - Phase 3 

3.13 MANCHESTER CODED DATA 

For a Manchester coded bit stream, the conditional error probability can be realized 

through the following equation (see Table 3-2 for variable definitions): 

 (3-1) 

(Where the maximum random value for timing error λ is defined to be 

4

1 for Manchester 

coded UWB-OFDM data.) 

3.14 NRZ CODED DATA 

Furthermore, when the bit stream is coded by NRZ data, then the following equation can 

be used to achieve conditional error probability values: 

 (3-2) 

(Where the maximum random value for timing error λ is defined to be 

2

1 for NRZ data. 

3.15 RZ CODED DATA 

Next, when the bit stream incorporates RZ coded data, the conditional error probabilities 

can be obtained with equation (3-3). 

 57
ECT - Phase 3 

 (3-3) 

(Where the maximum random value for timing error is defined to be 4

1 for RZ coded 

data.) 

3.16 MILLER CODED DATA 

Finally, in the event that Miller coded data is used in the bit stream, equation (3-4) 

represents an equation that obtains its conditional probability error values. 

 

 

 (3-4) 

where 

 

(And where the maximum random value for timing error λ is defined to be 

4

1 for Miller 

coded data.) 

 58
ECT - Phase 3 

3.17 ESTABLISHING AVG. ERROR PROB. AT THE RECEIVER 

Next in the analysis, after obtaining the stated conditional error probabilities in equations 

(3-1), (3-2), (3-3), and (3-4) , they are averaged over the probability density function 

(pdf) p(λ) of the bit synchronization errors, to obtain the average error probability Pe at 

the receiver. Average error probabilities at the receiver can be determined by equation (3-

5). This equation states that the average error probability at the receiver Pe is equal to the 

conditional error probability Pe(λ) averaged over the pdf p(λ)of the normalized timing 

synchronization error λ. 

 (3-5) 

Hence, λmax reflect the maximum value of which is defined for in the corresponding Pe(λ) 

equations in (3-1), (3-2), (3-3), (3-4), depending on the data format chosen, and p(λ) 

represents a probability distribution of the normalized timing synchronization error. 

Although in [5], timing synchronization error postulate a Gaussian approximation, we 

assume a Tikhonov pdf p(λ) since, as stated earlier, this is a more typical characterization 

of timing errors observed in practical bit synchronizers. [18] Completely characterized in 

terms of its variance σλ

2

 of the normalized timing error, the Tikhonov pdf for the various 

data formats are stated in equations (3-6) and (3-7). 

For NRZ data formats, p(λ) can be characterized by 

 (3-6) 

when a Tikhonov pdf is assumed. 

Likewise, when employing Manchester, Miller or RZ coding, all of which are base-band 

techniques that utilize transitions in the middle of the symbol interval, p(λ) can be 

characterized by the Tikhonov pdf in equation (3.7) 

 (3-7) 

 59
ECT - Phase 3 

Table 3-2 Analytical Equation Definitions 

 60
ECT - Phase 3 

 By substituting (3-6) or (3-7) into (3-5) along with the Pe(λ) of the reflecting equations 

of the different data formats, equation (3-5) is used to generate MathCad plots, 

developed in Figures 3-9 through 3-12. These graphs display average probability of error 

versus the ratio of the energy per bit (Eb) versus the spectral noise density (No) (EbNo) 

for the selected UI parameters of normalized timing errors. 

With the process described above, it becomes possible to obtain the attainable bit rate for 

a data link conditioned on normalized timing synchronization errors in Manchester, NRZ, 

RZ, and Miller coded data. The MathCad graphed results, in Figures 3-9, 3-10, 3-11, and 

3-12, demonstrate how accurate Unit Interval (UI) normalized timing error variances 

must be to avoid entering the asymptotic region where BER flaring occurs. At the 

instance where the curves begin to flare, we identify the maximum timing 

synchronization bit errors that can be permitted to exist in the physical implementation of 

the hardware for the data link before the use of forward error correction coding. 

Since this research proposed pushing bit errors to below 10-12 before using forward error 

correction (FEC) codes, as summarized through the average error probability graphs, and 

established with equation (3-5), one can determine how accurate timing error instances 

must be to achieve a bit error rate of 10-12. 

Later in the analysis, the average probability of error results conditioned on timing 

synchronization errors is used to make empirical comparisons with PulsON 200 

experimental results. But first, in the following section, the research methodology is 

continued by comparing PulsON 200 statistical data with its theoretical performance 

curve. 

3.18 TEST CASE WITH THE PULSON200 RADIOS 

Performance Analysis Tool (PAT) software was used in conjunction with two PulsON 

UWB Evaluation Kit (EVK) transceivers, to gather statistical information about wireless 

data passed between the two radios. With the receipt this year of two PAT software 

upgrades, with the latest version including for the first time Eb/No estimates as well as 

Bit Error Rate, it became possible for the first time to assess the implementation loss 

associated with the PulsON radio implementations, unlike in last year’s research. This 

PAT software is provided with the EVK transceivers to permit easily assessing link 

performance. With PAT, the following radio data link statistical parameters were 

measured: 

 61
ECT - Phase 3 

Receiver Statistics: 

• Bit error rate (BER) 

• Number of bit errors 

• Number of bits received 

• Number of packets received 

• Number of packets dropped 

• Effective data rate 

• Time (in seconds) that the radio has been running 

• Percentage of packets received 

• Temperature of the PulsON 200 radio development Module 

• Energy per bit (Eb) 

• Effective noise (Neff), Energy per bit to effective noise strength (Eb/Neff) 

Transmitter Statistics: 

• Number of transmitted bits 

• Number of transmitted packets 

• Time (in seconds) that radio has been running 

• Temperature of PulsON 200 radio development Module 

3.19 TEST PROCEDURES 

ECT Phase 3 testing investigated Range vs. Data Rate, which tested the throughput BER 

over various distances of the UWB transceivers. After configuring the radios for 

establishing a simple link as outlined in [5], we proceeded with the following steps: 

Step 1: Double click on the PAT icon displayed on the laptop or PC monitor 

Step 2: When the GUI, similar to Fig.3-1, appears on the monitor, select appropriate 

Radio IP address from the pull down menu and then click the connect button. 

Step 3: Once a message appear in the message area that says, “Connected to Radio,” 

select radio mode, select link rate, and the Eb/Neff mode box from the tabbed form field. 

Repeat Steps 1-3 for both radios 

Step 4: After a connection has been established for both radios, use measuring tape to 

separate radios to the desired distance. 

Step 5: Next, after performing calibration tests as specified in [5], click start radio on the 

transmitter radio followed by clicking start on the receiving radio. 

Step 6: Analyze statistical data in the statistics frame area, paying close attention to the 

receiver percentage rate. 

 62
ECT - Phase 3 

Step 7: Vary the gain in the Tabbed Form field area until the receiver percentage rate is 

98% or higher. (When radios are far apart, the VGA and the threshold constant, located 

in the Acquisition Tab, may need to be varied to obtain receiver percentage rate of 98% 

or higher) 

Step 8: Once receiver rate reaches 98% or higher, let the radios run and collect real time 

statistical data for five to thirty minutes. (Let radio run longer when BER still displays 0) 

Step 9: Click Stop radio button on the receiver radio and record radio distance and 

statistical information from the Statistics Frame 

Repeating Steps 1-9 for various separations of the transceivers resulted in the data 

collected in Table 3-3. 

 Tabbed form fields

 

 Radio operations command area

 

 

 Message Area Statistics frame

Figure 3-5 Performance Analysis Interface For PulsON 200 Receiver 

 63
ECT - Phase 3 

 To validate the PulsON 200 statistical data, the theoretical BER curve for a binary 

antipodal modulation scheme was calculated and graphed, using the default bi-polar flip 

modulation while operating the PulsON 200 link (See Figure 3-6). 

The theoretical data of Figure (3-6) were graphed from the following equations: 

 (3-8) 

where 

and where Eb/Neff ranged from 0 to 14, in unit steps. 

Development of this curve became necessary to validate the accuracy of the PulsON 200 

statistical data. 

Figure 3-6 Theoretical BER vs Eb/No For PulsON 200 Flip Modulation 

 64
ECT - Phase 3 

In a following section, Figure 3-15 displays the theoretical curve plotted in Figure 3-6 in 

conjunction with Eb/No vs. BER data points collected from the PulsON 200 test cases 

collected in Table 3-3. These comparisons confirm that the received data statistics 

gathered with the PulsON 200 PAT agree well with its theoretical BER curve displayed 

above, and therefore validates the collected data from the PulsON 200 transceiver for the 

performance down to where flaring in the BER rate curve occurs. 

After validation that the PulsON 200 collected statistical data closely followed the 

theoretical curve, the measure of the residual BER of the single-banded PulsON 200 link 

was begun. By measuring the residual BER of the single-banded PulsON 200 link, it was 

possible to make measurements of a single sub-banded data stream. Then by 

extrapolation the equivalent timing uncertainties inherited in a single data stream for 

estimating the total timing uncertainty in a set of data stream were determined. By 

measuring the residual BER of a single band link, the irreducible timing errors due to a 

single path were determined. The summary result is that timing errors introduce an effect 

that limits the probability of bit error such that increasing Eb/No (through increasing 

transmitter power) does not improve BER below a certain error rate. 

3.20 RESULTS OVERVIEW 

As was stated previously, the purpose of this UWB research is to determine how accurate 

timing instances must be to avoid entering the asymptotic region of BER flaring at low 

BERs in the resultant BER curves. To review, this study examined and predicted the 

flaring in the bit error curves that occur for the different values of normalized timing 

jitter variances. To validate the study, empirical comparisons were made using 

experimental results gathered with a pair of PulsON 200 UWB Evaluation Kit 

Transceivers and Performance Analysis Tool (PAT). Following are the results from the 

statistical analysis and the experimental analysis. For the purpose of presentation, this 

section has been divided into four parts. The first part shows the BER effects due to 

timing synchronization errors. The second part displays results from the PulsON 200 

UWB Radio test cases. In the third part, a relationship is shown with analytical and 

experimental results. Finally, the fourth part concludes the section with a detailed 

discussion of how the research results of this paper can be applied to designing systems 

at all data rates and discusses future research for applying this basic theoretical technique 

to multi-carrier UWB-OFDM systems. 

3.21 BER EFFECTS DUE TO TIMING ERRORS 

Bit synchronization information traveling from the transmitter to the receiver must be 

recovered accurately in digital communication systems. Because in practical digital 

communication systems we typically transmit only the bit stream and regenerate the bit 

clock through clock and data recovery (CDR) as required for enabling the taking of the 

bit samples required for making soft (initial) bit decisions), we introduce bit errors. 

These bit errors are caused by distortions and noise in the received bit stream along with 

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ECT - Phase 3 

imperfections in bit clock regeneration (see Figures 3-7 and 3-8). Since the research 

approach involved reducing bit error rates to as low as possible in UWB systems through 

identifying maximum timing synchronization errors, we evaluated BER effects due solely 

to timing jitter, while recognizing that additional effects are often observed in practical 

hardware implementations. 

Figure 3-7 Representation Of Timing Errors In A Digital Signal 

Figure 3-8 Representation Of Distortions In A Signal 

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ECT - Phase 3 

In the statistical analysis we considered effects of timing jitter on a system’s BER 

performance. The first step in this process was to obtain equations that would derive the 

error probability of the correlation detector conditioned on a bit synchronization error. 

Then we took this conditional error probability and averaged it over the probability 

density function (pdf) of the synchronization error, yielding the average error probability 

at the receiver [2]. As a result, we graphically displayed the process mentioned above 

through Equations (3-1), (3-2), (3-3), (3-4) from the previous section. We plotted these 

results with MathCAD; the generated plots are shown in Figures 3-9, 3-10, 3-11 and 3-

12, respectively. 

Figure 3-9 BERs For Timing Jitter (Manchester Data) 

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ECT - Phase 3 

Figure 3-10 BER For Timing Jitter (RZ Data)

Figure 3-11 BERs For Timing Jitter (MILLER Data) 

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ECT - Phase 3 

Figure 3-12 BERs For Timing Jitter (NRZ Data) 

Analysis of the data from Figures 3-9 through 3-12 determined how accurate normalized 

timing error variances must be to avoid entering the asymptotic region of BER flaring. 

Given that the flaring shows the minimum irreducible BER a system with timing errors 

can achieve at any arbitrarily high transmitter power level, before incorporating forward 

error correction codes, we estimate how far the bit errors can be pushed down, before the 

probability of error stops improving (Thereby identifying the flaring points of the UI 

curves). The Manchester coded graph showed the amount of timing uncertainty that can 

be budgeted for a transmitter de-multiplexer and the receiver clock and data recovery 

multiplexing operation. Likewise, NRZ, Miller, and RZ graphs showed the same effect as 

the Manchester graph, except they may be used for designing systems which incorporate 

NRZ, Miller, or RZ data in their digital communication system schemes. 

To apply the statistical analysis, in the next section we describe a test case that we 

developed and performed, to approximate or bound the actual timing uncertainty that 

exists in PulsON 200 radios. As this technique utilizes an easy to implement statistical 

data collection technique to determine an otherwise difficult-to-determine stochastic jitter 

performance, it has particular merit whenever making measurements at faster data rates 

where test equipment performance has not yet caught up to the performance level 

necessary for directly assessing jitter performance. 

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ECT - Phase 3 

3.22 PULSON200 TEST CASE 

Following the analyses shown earlier, we performed test cases to correlate a statistical 

analysis with actual hardware analysis. The experimental analysis was achieved with 

PulsON 200 UWB transceivers and Performance Analysis Tool (PAT) software. PulsON 

200 radio technology uses a true UWB pulse, as defined by the FCC, and analysis 

statistical information about the data sent from transmitter to receiver, is analyzed in real 

time with PAT. Data passed between the PulsON 200 radios allow an evaluator to 

configure command and receive performance of UWB data. (See [5] for specific PAT 

user operations) 

For simplicity, the test cases used the default bi-polar FLIP modulation (see Figure 3-13) 

as the choice of modulation. To conduct the analysis, we selected the data rate to be 9.6 

Mbps. Although next-generation UWB systems will deliver data rates in the hundreds of 

mega bits per second, this experiment confirms that the analysis performed in this paper, 

showing flaring due to timing errors, is demonstrated in practice by the PulsON 200 

radios. 

In the following section we outline the equipment list and test setup used to conduct the 

experiment. 

Figure 3-13 Flip Modulation9

 

 

9

 Picture from K. K. Lee UWB presentation of Flip Modulation 

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ECT - Phase 3 

3.23 REQUIRED EQUIPMENT AND TEST SETUP 

To adequately test the UWB radios the following equipment was used: 

(2) Time Domain PulsON 200 UWB transceivers 

(2) Laptop Computers with PAT software version 3.0 configured and installed 

(2) Category 5 Ethernet crossover cables to connect laptops to UWB radios 

(1) RS-232 cables to change radio IP address or view calibration test in hyper terminal 

under Microsoft Windows XP 

(1) Measuring tape 

Figure 3-14 PulsON 200 Evaluation Kit Setup10 

Using the test setup in Figure 3-14, the objective became to acquire an appropriate 

amount of statistical data to track a theoretical FLIP modulation BER curve and 

determine indirectly the timing jitter achieved, consistent with the BER flaring 

performance actually achieved. Results from these test cases are shown in the following 

section. 

3.24 TEST CASE RESULTS 

As described previously, statistical analyses about the data transmitted and received from 

the PulsON 200 transceivers were obtained with the PulsON 200 PAT. To obtain 

efficient data, we continuously passed data between the two transceivers for time periods 

ranging from approximately 40 to 1600 second per distance, per test case, as shown in 

Table 4-1. 

 

10 Picture from [6] 

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ECT - Phase 3 

Then, to confirm the experiment result, we examine how close the results were to the 

well-known theoretical formula for binary antipodal modulation: 

Notice in Table 3-3 the collected values for BER and Eb/No. Plotting these values, in 

conjunction with the theoretical curves, shows a close similarity between the curves. This 

indicates that the collected date confirms the theory. However, a gradually asymptotic 

BER flare evolves around 10-4. This flaring in the BER curve leads to a discussion, 

presented later, that allows one to estimate the approximate timing uncertainty inherent 

with the PulsON 200 transceivers. 

 Table 3-3 PulsON 200 Collection Of Data Rate Vs Range Test Cases 

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ECT - Phase 3 

Figure 3-15 Flip Modulation Theoretical Curve vs PulsON 200 Data (9.6 

Mbps) 

3.25 ASSESSMENT OF TIMING UNCERTAINTIES 

For the purpose of comparing Manchester coded data with experimental data collected in 

Figure 3-15, this section plots the Manchester graph in Figure 4-3 against the 

experimental data points from Figure 3-15, to assess the approximate residual timing 

uncertainty inherent within the UWB radio link. 

As mentioned previously, the summary result is that timing errors introduce an effect that 

limits the probability of bit error such that increasing Eb/No does not improve BER 

below a certain error rate. With the experimental data in Figure 3-15, we found that the 

probability of error stopped improving in approximately the 10-4 region. After collecting 

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ECT - Phase 3 

enough data to identify where the BER stopped improving, we then extrapolated these 

data points and inserted them into the Manchester theoretical graph as seen in Figure 3-

16. Since the Manchester graph shows probability of error conditioned on normalized 

timing synchronization error, we were able to identify the normalized unit interval value 

of timing error in the PulsON 200 radio. We identified this region on the Manchester 

curve, and expanded timing sync values in the region of 10-3 to 10-5. 

Graphed in Figure 3-16., the black solid curve represents theoretical values, while the 

other curves range from normalized variances of 0.055 UI to 0.030 UI. The extrapolated 

data points from the PulsON 200 experiment is also represented on the graph by the 

diamond-shaped points. As seen in Figure 3-16., experimental values surrounded the 

curve that represents 0.04 UI. From this analysis, one can identify the normalized unit 

interval value of timing error in the PulsON 200 radio. The hypothesis concerning timing 

uncertainty budgeted for the PulsON 200 radios is identified to be 0.04 UI, since this UI 

jitter curve best fits the experimental data points. 

Figure 3-16 Manchester Data With Extrapolated PulsON 200 Data 

In conclusion, this research estimated the normalized timing uncertainty for the PulsON 

200 radio, due to timing jitter, through an easily measured indirect technique, instead of a 

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ECT - Phase 3 

difficult-to-make direct technique. One is able to use this same concept to predict how 

much timing uncertainty should be budgeted for designing future high data rate 

(hundreds of Mbps) UWB systems. This analysis technique allows one to budget how 

much timing uncertainty can be allowed while still achieving acceptable margins for the 

transmitter de-multiplexer and the receiver clock and data recovery multiplexing 

operations, which leads to the discussions in the next section. 

3.26 ANALYSIS OF EFFECTS ON UWB-OFDM SYSTEM WITH HIGH 

DATA RATES 

Predicting how much timing uncertainty that should be used in designing future high data 

rate systems in the multiple hundreds of mega bits per second can be estimated with the 

previously identified unit interval (UI) matching approach. A UI is defined as one 

nominal bit period for a given signaling speed. Therefore, rather than using an absolute 

timing approach, the UI approach method of analysis can be used in budgeting timing 

uncertainties for UWB-OFDM systems operating at higher data rates. 

Likewise, normalized (with respect to a bit time) timing error UI’s are represented as the 

timing synchronization errors analyzed throughout this paper. These values are small 

percentages of a unit interval, which define the standard deviation of a normalized timing 

error in terms of UI random timing jitter. A 0.02 UI random timing error measurement 

informs that the standard deviation statistic of a bit period deviation is 2% around the 

ideal bit period time, through utilizing a Unit Interval approach, in place of an absolute 

timing approach, the results of this paper can easily be applied to ever-increasing data 

rates of future UWB-OFDM data links considered for meeting NASA’s communication 

needs. 

The results in this paper pertain to a reference UWB-OFDM system. In practice, 

approaching UWB- OFDM systems will likely use a multi-band approach where a cyclic 

prefix is appended to the beginning of the OFDM symbol. Once the bit timing 

synchronizations are corrected using the approach discussed in this paper, further 

research can be applied to analyze the timing symbol synchronization errors in the multiband UWB-OFDM. In the same way as for the reference UWB OFDM system affected 

by bit timing errors, the average probability of error may be obtained for the symbol 

timing errors in the practical UWB-OFDM system. Assessment of timing uncertainty of 

realistic symbol timing in the practical multi-band UWB-OFDM may be realized through 

the same approach used to assess the bit time synchronization timing uncertainties in the 

reference UWB-OFDM system. Qualitatively, the main results from this paper remain 

valid for the practical multi-band UWB-OFDM systems. 

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ECT - Phase 3 

3.27 SUMMARY OF RESULTS 

This paper has developed theoretical equations for estimating BER effects due to timing 

uncertainties among multiple OFDM channels. Having been considered are UWBOFDM systems which are coded by Manchester, Miller, RZ, and NRZ data. The focus is 

on reducing BER to as low as possible through identifying maximum timing 

synchronization errors for each data format. Since pushing bit errors to below 10-12

before using forward error correction codes is advocated, the maximum reserve can be 

maintained for the FEC hardware to correct for errors caused by instances other than 

timing errors. Specifically, this paper identifies how accurate timing error instance must 

be to avoid introducing the asymptotic region of BER flaring at probability of errors of 

10-12 or below. According to the presented analysis for Manchester data formats, to 

obtain a Pe of 10-12 or below, timing accurate instances should be budgeted at a 0.02UI 

maximum. NRZ coded data timing accuracy should be budgeted at a maximum of 

0.04UI. RZ data formats should be budgeted at a maximum of 0.015UI. Miller Coded 

data was not able to achieve a probability of error of 10-12 for reasonable values of Eb/No. 

Therefore, it was found that this data format should not be used. These budgetary values 

provide an estimate of the timing accuracies required for a given BER performance to 

MUX a set of parallel transmitted, De-Muxed data streams sent in parallel over multiple 

OFDM data streams, utilizing multiple OFDM symbols transmitted within multiple subbands. 

The PulsON 200 “EVK” was used to make measurements of a single sub-banded data 

stream, to determine the equivalent timing uncertainties inherited in a single data stream 

for estimating the total timing uncertainty in a set of OFDM data streams. With the test 

cases performed using PulsON 200 we were able to use the analytical solutions to 

determine the approximate amount of timing uncertainty budgeted for the radios. This 

test case demonstrated that the analytical and experimental solutions agree well. As a 

result, we are able to assess how much timing uncertainty that can be budgeted for UWB 

systems and all other high data rate systems through the unit interval approach. 

3.28 RECOMMENDATIONS FOR FUTURE RESEARCH 

Recommendations for continuing this research include determining the probability of 

error effects due to second order degradations other than timing errors. These second 

order degradations may include probability of error effects due to phase noise, multi-path 

propagation effects, noise figure. 

In addition, looking at timing error effect along with the second order degradations 

mentions above should be examined for multi-banded UWB-OFDM. Instead of 

examining the bit synchronization of the data stream as examined in this paper, the idea 

can be expanded to examine the symbol synchronization effects. This would involve not 

only timing error effect, but also frequency error effects of the multiple OFDM symbols 

and the requirement to multiplex the symbols back together in ways that minimize inter-

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ECT - Phase 3 

symbol interference and inter-carrier interference, while lowering bit error rates down 

below 10-12. 

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ECT - Phase 3 

4.0 ECT SUMMARY RECOMMENDATIONS FOR CONTINUED 

RESEARCH 

The following major task areas are recommended for continued research in the next fiscal 

year for emerging communication technology development: 

• Networked FSO 

• RFID 

• Expanded Range Wi-Fi 

• UWB 

1.) Survey: Conduct an industry survey on networking hardware for 

implementing a small networked optical FSO system, and procure a fixed, 

non-tracking, wide-beam optical FSO system set of components with 

redundant optical beams to investigate the limits of networking multiple FSO 

systems. 

2.) FSO Testing: 

a. Update previously generated test procedures, adapting and expanding 

these procedures to account for the multiple FSO OTUs, to permit 

testing the FSO system exemplars for Bit Error Rate, and throughput 

rates versus weather-induced degradations (e.g., fog, rain, etc.) when 

operating in a networked configuration. 

b. Test the performance limits of this FSO hardware within the unique 

environment of KSC, with data path links over both water and over 

land, comparing the applicability of this technology to KSC’s needs 

versus the single FSO link tested previously 

3.) UWB Analysis: 

a. Analyze new, OFDM multi-band UWB hardware for applicability on 

the Range, with particular emphasis on piconet sub-division capability 

within LANs, recurring costs of hardware, and life-cycle operational 

costs. 

b. Analyze position-aware capabilities of UWB communication 

technology, with particular emphasis on determining positional 

accuracy limitations (e.g., accuracy in centimeters, ability to provide 

relative and absolute positional information.) 

4.) UWB Testing: 

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ECT - Phase 3 

a. Update previously generated test procedures, adapting and expanding 

these procedures for testing the UWB evaluation kit for position aware 

functionality. 

b. Test position-aware capabilities of UWB communication technology 

using the UWB evaluation kit (EVK) procured during FY03, 

following the position aware enhanced test procedures developed from 

previously generated test procedures. 

c. Review current UWB and FSO products and theoretical developments 

through attending two major optical communication conferences and 

one joint NASA-USAF Advanced Range and Spaceport Technology 

Conference. 

These activities are needed to achieve the 24/7, always-on, highly-mobile vision of an 

interconnected communication for use on the Range employing First Mile / Last Mile 

extensions to the existing Range communication infrastructure. 

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ECT - Phase 3 

APPENDIX A: 

UWB EVK Performance Analysis Tool (PAT) Software 

A.1 PAT Statistics Frame Area

The Statistics Frame Area shown on the right side of the Performance Analysis Tool 

(PAT) shows key PulsON 200 radio performance measurements (See Figure A-1) While 

observing performance parameters of the connected radio, one is able to analyze: BER, 

Bit errors, Receiver Total Bits, Receiver Data Rate, Receiver Packets, Dropped Packets, 

Transmitter Total Bits, Transmitter Data Rate, Transmitter Packets, Run Time, Receiver 

percentage Rate, Radio Temperature, Energy Per Bit/ Effective Noise (dB), Energy Per 

Bit, Effective Noise, and Number of Samples Over which Eb is computed. 

Figure A-1: PAT Statistics Frame Area 

The above statistical parameters were defined and computed automatically with the PAT 

by the following (As outlined in [5]): 

Bit Error Rate (BER)- The ration between the number of bits in error and the total bits 

received, computed as: BER= Bit Errors/ Rx Total Bits (BER) 

Bit Errors-Total number of bit errors detected by comparing the received bit pattern 

with the known transmitted bit pattern. 

RX Total Bits- Total number of payload bits received. This number does not include the 

overhead of the acquisition preamble or the packet header. 

RX Data Rate- Rate at which data is being received: 

Rx Data Rate = Rx Total Bits/ Run Time (Effective data rate) 

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ECT - Phase 3 

RX Packets- Total number of packets received 

Dropped Pkts- Total number of packets whose number is not sequential to the packet 

last received, computed as: 

Dropped Packets= Dropped Packets + (current packet number – last packet number-1) 

TX Total Bits- Rate at which data is being transmitted, computed as: 

Total number of payload bits transmitted. 

TX Data Rate- Rate at which data is being transmitted, computed as: 

(# of packets received/# of packets sent) x 100 

Temp- temperature of the temperature sensor on the PulsON 200 Development Module 

Eb-Energy per bit, computed as: 

where 

N= 1 for Flip modulation, 2 for QFTM, 4 for QFTM4 

r= raw positive ramp value with calibrated DC offset applied 

R= number for ramp 

Neff- Effective noise computed as: 

R= number for ramp 

r =raw positive ramp value with calibrated DC offset applied (when running a normal 

link) 

OR 

 =raw positive or negative ramp with calibrated DC offset applied (when capturing 

Ambient RF) 

Eb/Neff- Energy per bit/ Effective Noise, computed as: 

Eb – Neff (dB) 

Eb Samples- This value is the number of samples over which Eb is computed. The 

default number of samples is 512 and must follow the rule: 2<= Eb Samples <= 4095. 

 81
ECT - Phase 3 

A.2 PAT Range vs. Data Rate Test Cases

The Range vs. Data Rate Test used in this research tested throughput rates over various 

distances between the UWB transceivers. Test Cases performed during the testing 

proceedings are shown below through screen shoots taken from the Performance 

Analysis Tool (PAT). 

Figure A-2: PAT Test Case @ 330 feet distance 

Figure A-3: PAT Test Case @ 330 feet distance 

 82
ECT - Phase 3 

Figure A-4: PAT Test Case @ 345 feet distance 

Figure A-5: PAT Test Case @ 300 feet distance and VGA 31 

By extracting the Eb/Neff value and its corresponding BER from each test case above, 

we were able to plot and analyze the data and make hypotheses throughout this paper. 

 

 83
ECT - Phase 3 

Figure A-6: PAT Test Case @ 16.40 feet or 5 meters distance 

Figure A-7: PAT Test Case @ 300 feet distance 

 84
ECT - Phase 3 

Figure A-8: PAT Test Case @ 300 feet distance 

Figure A-9: PAT Test Case @ 200 feet distance 

 85
ECT - Phase 3 

Figure A-10: PAT Test Case @ 200 feet distance 

Figure A-11: PAT Test Case @ 100 feet distance 

 86
ECT - Phase 3 

Figure A-12: PAT Test Case @ 10 feet distance 

Figure A-13: PAT Test Case @ 5 feet distance 

 87
ECT - Phase 3 

Figure A-14: PAT Test Case @ 26.24 feet or 8 meter distance 

Figure A-15: PAT Test Case @ 26.24 feet or 8 meter distance 

Figure A-16: PAT Test Case @ 26.24 feet or 8 meter distance 

 88
ECT - Phase 3 

Figure A-17: PAT Test Case @ 26.24 feet or 8 meter distance 

 89
ECT - Phase 3 

APPENDIX B: 

Digital Signaling Formats Applicable T0 FSO And UWB Communication Signaling 

Figure B-1:Binary Line Coding 

Binary 1’s and 0’s may be represented by various binary line codes. Some of the more 

popular formats are shown in Figure B-1 and are defined as follows. 

Unipolar NonReturn to Zero (NRZ) Signaling is a positive logic unipolar signaling where 

the binary 1 is represented by a high level and a binary 0 by a zero level. This type of 

signaling is also called on-off keying and is of the NRZ type since the high level does not 

return to zero during the binary 1 signaling intervals. 

Unipolar Return to Zero (RZ) is a unipolar waveform in which a binary 1 is represented 

by a high level over half of a bit period and then returns-to-zero. The binary 0 is 

represented by a zero level. 

Polar NRZ is binary 1’s and 0’s that are represented by equal positive and negative 

levels. This type of waveform is also said to be of the NRZ type. 

Manchester coding is where each binary 1 is represented by a positive half-bit period 

pulse followed by a negative half-bit period pulse followed by a positive half-bit period 

pulse. This is called split-phase encoding. 

Miller line code is where a binary 1 is represented by a transition at the mid-bit position, 

and a binary 0 is represented by no transition at the mid-bit position. If a 0 is followed by 

 90
ECT - Phase 3 

another 0, however, the signal transition also occurs at the end of the bit interval, that is, 

between the two 0s. 

 91
ECT - Phase 3 

APPENDIX C: 

Q-Function, ERF, AND ERFC, Applicable To Bit Error Rate Theoretical Analysis 

Of FSO AND UWB Communication Systems 

Q-function is described as the tail integral of a unit Gaussian probability density function 

(pdf). Represented mathematically: 

Other functions that are closely related to Q(x) include error function erf and 

complimentary error function erfc. 

[23] 

and 

[23] 

Relationships between Q(x), erf, and erfc can be shown by the following: 

In scientific literature there are a few variations of erfc which differ by definition. For 

example in literature reference by Harry Van Trees, erfc is defined differently than the 

classical mathematical definition in material referenced by Abramowitz and Stegun. The 

choice made in this paper is to use the classical definition, which is more commonly used 

in the published literature 

 92
ECT - Phase 3 

 93
ECT - Phase 3 

REFERENCES 

1. Harada, Hiroshi, Prasad, Ramjee, Simulation and Software Radio for Mobile 

Communications, Artech House, 2002. 

2. Lindsey, W. C. and Simon, M. K., Telecommunication Systems Engineering, 

Prentice-Hall, Inc., 1973. 

3. Athaudage, Chandranath, “BER Sensitivity of OFDM Systems to Time 

Synchronization Error,” Proceedings of the IEEE, vol.1 (2002): 42-46. 

4. Heiskala, Juha and Terry, John PhD, OFDM Wireless LANs: A theoretical and 

Practical Guide, SAMS Publishing, 2002. 

5. “PulsON 200 Evaluation Kit Users’ Manual,” Time Domain Corporation, 2001-

2002. 

6. Bastin, Gary L.; Harris, William G.; Chiodini, Robert; Nelson, Richard A; Huang, 

Po Tien; and Kruhm, David A., “Emerging Communication Technologies Phase 2 

Report,” NASA/TM-2004-211522, vol. 3, September 2003. 

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Macmillan, Inc., 1987. 

8. Ziemer and Tranter, Principal of Communication, Fifth Edition, John Wiley and 

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9. Aiello, G. Roberto and Roberson, Gerald D., “Ultra-Wideband Wireless 

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10. Win, Moe Z., Scholtz, Robert A, “Impulse Radio: How It Works,” Proceedings of 

the IEEE, vol.2 (1998): 36-38. 

11. Retrieved July 28, 2004 from, 

http://www.fcc/gov/Bureaus/Engineering_Technology/Orders/2002/fcc02048.pdf. 

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Impulse Radio Modulation”, Proceedings of IEEE, RAWCON Conference, August 

(1998), pgs: 67-70. 

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http://www.intel.com/technology/ultrawideband/downloads/UltraWideband_Technology.pdf. 

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http://www.win.tue.nl/~hmei/Personal/MSc_thesis_HailiangMei.pdf

15. Van Nee, Richard and Prasad, Ramjee, OFDM for Wireless Multimedia 

Communications, Artech House Publisher, 2000. 

16. Bingham, John A. C., “Multicarrier Modulation for Data Transmission: An Idea 

Whose Time Has Come,” Proceedings of the IEEE, vol.28 (1990): 5-14. 

17. Chandler, David, “Phase Jitter Phase noise and Voltage Controlled Crystal 

Oscillators,” Corning Corporations retrieved from, 

http://www.corningfrequency.com/library/phase_jitter_note.pdf. 

18. Simon, Marvin K, “A Simple Evaluation of DPSK Error Probability Performance 

in the Presence of Bit Timing Error,” Proceedings of the IEEE, vol. 42 (1994) 263-267. 

19. Lo, C.M. and Lam, W. H., “Error Probability of binary Phase Shift Keying in 

Nakagami-m Fading Channel with Phase Noise,” Proceedings of the IEEE, vol. 36 

(2002) 1773-1774. 

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ECT - Phase 3 

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20. Piechocki, R.J., Kasparis, C., Nix, A. R., Fletcher P. N., and McGeehan, J. P., 

“Bootstrap Frequency Equalization for MIMO Wireless Systems,” Proceedings of IEEE, 

vol.7 (2003) 4175-4179. 

21. Lee, T., and Donnelly, K., “A 2.5V CMOS Delay Locked Loop for an 18 MBIT 

500 Megabyte DRAM,” Proceedings of IEEE, vol. 29 (1994) 1491-1496. 

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http://www.wirelessapplications.com/wireless/services/lostFound/images/Eb_No_and_S_

N_Final.pdf

23. Retrieved August 15, 2004 from, http://jove.prohosting.com/~skripty/
 

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3. REPORT TYPE AND DATES COVERED 

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4. TITLE AND SUBTITLE 

Emerging Communication Technologies (ECT) Phase 3 Report 

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13. ABSTRACT (Maximum 200 words) 

The Emerging Communication Technology (ECT) project investigated three First Mile communication technologies in 

support of NASA’s Second Generation Reusable Launch Vehicle (2nd Gen RLV), Orbital Space Plane, Advanced Range 

Technology Working Group (ARTWG) and the Advanced Spaceport Technology Working Group (ASTWG). These First 

Mile technologies have the purpose of interconnecting mobile users with existing Range Communication infrastructures. 

ECT was a continuation of the Range Information System Management (RISM) task started in 2002. RISM identified the 

three advance communication technologies investigated under ECT. These were Wireless Ethernet (Wi-Fi), Free Space 

Optics (FSO), and Ultra Wideband (UWB). Due to the report’s size, it has been broken into three volumes: 1) Main Report 

2) Appendices 3) UWB 

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104 

14. SUBJECT TERMS 

Range Information Systems, Emerging Communication Technologies, Advanced 

Communication, FSO, UWB, Ranges, Spaceports 16. PRICE CODE 

 

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