XG Dynamic Spectrum Experiments, Findings and Plans Panel

1. DoD Spectrum Summit 2006 XG Dynamic Spectrum Experiments, Findings and PlansPanel Preston Marshall, DARPATodd Martin, STA Mark McHenry, Shared SpectrumPaul Kolodzy, Kolodzy Consulting

2. Panel Structure

3. DARPA XG Program All Spectrum May Be Assigned, But… XG is Developing the Technology and System Concepts for DoD to Dynamically Access All Available Spectrum …Most Spectrum Is Unused! Goal: Demonstrate Factor of 10 Increase in Spectrum Access

4. Static Spectrum Management is Limited in Its Ability to Improve Spectrum Utilization Efficiencies Spectrum Allocation & Utilization Today’s Networks are Heavily Constrained by Lack of Spectrum Heavy Use Heavy Use Less than 6% Occupancy Sparse Use Medium Use • Fixed Spectrum Assignments Lead to Inefficient Spectrum Utilization • Opportunities Exist in Time, Frequency, and Geography • Constrain Network Adaptation • RF Spectrum Allocated by Policy • Allocations, Assignments, and Incumbents Vary by Country • Observations Show Bands of Local Heavy and Sparse Activity • Temporal Usage Characteristics Vary by Band & Service • Potential for Usage Dependent on Incumbent Service & Equipment

5. Sensing Loop Policy Reasoner RF Info Acquisition Develop Options Process Request System Strategy Reasoner Determine Opportunities Select Opportunities Accredited Policy Engine Policy Transceiver XG Operation MessageFlow RF Resource Request Radio Platform RF Transmit Plan Yes/No or Additional Constraints

6. DARPA XG Program Investments Signal Processing Algorithms Sensor Technology Distributed Sensing Algorithms Subnoise Detection Spectrum Measurements Capability and Affordability Increased Awareness Spectrum Awareness Dynamics Optimizing Strategies Tactics Interference Effects Assessment Adaptive NetworkOperation XG Prototype & Demonstration Assessments Non-Interfering Operation Performance Experiments Spectrum Adaptive Networking Engineering Basis Behavior Enforcement Implementation PolicyLanguage Methodology Policy Reasoning Framework &Semantics Policy Description IEEE 1900

7. Progress In Dynamic Spectrum • Successful XG Testing Performed at Fort A. P. Hill in August 2006 • Demonstrated the Three Core Principles of XG Program • Does Not Interfere with Other Spectrum Users • Functions in Setting Up and Maintaining Networks • Creates Capacity Where Spectrum Was Not Available • Focus in this Demo was Demonstrating non-Interference to Legacy Systems • Military Network Radios, Military and Civil Voice • Attendance by DoD (OSD, COCOMs & Services) and Civil Regulatory (FCC and NTIA) Communities

8. NII XG Phase 3bMetric Objectives • No Harm: Causes no Harmful Interference to Non-XG Systems • Abandon Time: Abandon a Frequency ≤ 500 ms • Interference Limitation: Maintain ≤ 3dB of SNR at a Protected Receiver. • XG Works: Forms and Maintains Dynamic Connectivity • Network Formation/Rendezvous Time: Establish XG Network of Six (6) Nodes in ≤ 30 sec. • Net Join Time: Join a Node to an Existing XG Network in ≤ 5 sec. • Channel Re-Establishment Time: Reestablish XG Network of Six (6) Nodes ≤ 500 ms • XG Adds Value: Reduces Spectrum Management Setup Time (Increases Deployment Flexibility) and Increases Spectrum Access (Communications Capacity) • No Pre-assigned Frequencies • ≥ 60% Spectrum Occupancy with XG Network of Six (6) Nodes Metrics Defined by DARPA & OSD/NII as Threshold for Establishing Early Confidence in Viability of Dynamic Spectrum Access Technologies

9. Legacy Radio Operation and Interference Measurement Todd Martin XG Test Director

10. Legacy Radios Legacy DoD Radio (fixed) PRC-117 Microlight XG Radios(mobile) Legacy DoD Radio/Test Equipment • Legacy Radios • PRC-117: Frequency Hopping to Force Dynamics • PSC-5: Narrowband Voice • EPLRS: DoD Networking Radio • Micro-Lite: DoD Networking Radio • ICOM F561: Widely Used in Public Safety PSC-5

11. The XG “Electromagnetic Obstacle Course” EPLRS PRC-117 EPLRS Micro-Lite XG drive path Night Vision Observation Building PSC-5 Jammer ICOM

12. Drive Route Spectrum Density • Demo Environment Created Artificially High Spectrum Density to Stress XG • Some Regions Would Have No Spectrum Available for Multiple XG Nets • Typical Tactical Density Less Than 6% Legacy Node Placement, Terrain, and Propagation Effects Created Dense and Dynamic RF Environment

13. Legacy Radio Performance Telemetry • JSC or JHU APL Personnel Oversaw each Radio Pair • Real Time Telemetry of Each Legacy Radio (except for Unicom PTT Public Safety) • Reported Bit Error Rate or Packet Delivery, Depending on Radio Type • PSC-117 Also Reported Hop Frequency Perfect Interference 4 Legacy Radio Nets Performance

14. XG Demonstration and Quantitative Results Mark McHenry XG Principle Investigator

15. XG Radio System Display showing XG operational state Rockwell Sensor RF Power Amp RF Enclosure GPP with 802.16 modem 225-600 MHz RF Transceiver (located under shelf) GPP with XG algorithms

16. Components • Trusted dynamic policy control architecture • Scheduler (detector to share the RF chain) • Group sensing (use distributed measurements made by individual nodes and fused across a collection of nodes)

17. Test scenario

18. objective • No harm ( avoid interference) • Works (forms and maintains connected nw) • Adds value (spectrum efficiency)

19. No harm • Channel abandonment time <500ms • Time between one of the nodes detect a non-cooperative signal and the time the XG radios ceases transmission • Sends an alert to nw members and renegotiate band • Challenges: • Propagation loss causes some packets to be lost • XG nodes have different observation of spectrum availability • RF chain differences (detection sensitivities, WiMAX receiver sensitivities, power level) • Interference to Noise Ratio • Interference at primary receivers • Metric: whether a XG radio can cease transmission in the presence of (weak) primary signals • Note: there are assumptions on relative locations of PM and XG.

20. XG works • Network join time • Detect the signal signature of the XG system, (sweeping existing bands) • Declare its presence • Handshake and join the existing nw. • NW re-establish time • Time to reestablish a channel after abandoning its existing channel • ? Use rendezvous channels? • Allow existing users to empty queues • No pre-assigned frequencies • No infrastructure, no dedicated control channel for network startup • Link uptime

21. Adds value • White space fill factor • Time factor. • How about spatial factor? • Success in channel use • Limiting factors: • No channel available (too many secondary users) • Cannot find channel (sensing failure) • Link not usuable because of propagation loss

22. Discussions • Various metrics defined in this study --- a set of reasonable expectations at the current stage • Simple schemes designed to achieve the target • Research opportunities: • Other metrics? • Better protocols to achieve a set of targets • how to set a startup protocol with no prior info. on other users’ locations, cell size, frequency, intf., etc. • ESCAPE protocol for channel evacuation • Performance analysis (both protocol-wise and fundamental) • given the required success in channel use, how many users can N channels support? Can a centralized protocol achieve it? How about a (simple) robust distributed one? • INR analysis w.r.t. locations • Given collision probability, the ultimate capacity bound (Senhua’s work) • Tradeoffs among a set of targets • Tradeoff between utilization (fill factor) and QoS (success in channel use) • Aggressive in sensing (sensing threshold) vs. INR (intf. to noise ratio) • Application-aware/context-aware schemes • A VoIP may choose a band that is narrower, but more reliable (e.g., occupancy factor) • A large file download may choose a high-bandwidth high risk channel. • How to quantify such heuristics?

23. Phase 3 Metrics & Results Summary XG Demonstrated Reliable Networking Without Harming Legacy Nodes In Dense Spectrum Environments

24. XG Demo Results Instant Replay Colors Indicate Current Frequency (ex. EPLRS is Orange) Dots Are XG Radio Nets Perfect Interference 4 Legacy Radio Nets Performance Circles Are Legacy Radio Nets PLAY Three XG Radio Nets Performance

25. Phase 3 Metrics & Results Summary XG Demonstrated Reliable Networking Without Harming Legacy Nodes In Dense Spectrum Environments

26. No Harm: XG INR at Non-XG Radios Mean Value < 0.1 dB ! XG Produced Marginal INR at Non-XG Radios in All Cases

27. XG Works: Re-Establish Time XG Re-Established Networks in < 500 msec. in All Cases

28. 4 Node NW 6 Node NW Adds Value: Spectrum Occupancy Phase 2 Simulations Phase 3 Field Data Measured Tactical Occupancy XG Achieved > 60% Spectrum Occupancy for Networks of 6 Nodes: 85% Access Confidence at 83% Occupancy

29. XG Transition Strategies and Regulatory Needs Paul Kolodzy Ex-DARPA PM and FCC Spectrum Policy Task Force

30. XG Program – Transition • Anticipate Incremental Adoption on a Not to Interfere Basis (NIB) • Military on Military (10x Greater Packing of Radios) • Coordinated Sharing (Military with Coordinated Users) • Opportunistic (WidespreadNIB Operation) • Incremental Rollout Enables Near-Term Deployment as Appliqué Into Existing Systems • Add Protocols and Adaptation Software to Digital Networking Radios • Add Spectrum Sensing Algorithms Military on Military Coordinated Sharing Opportunistic Spectrum Not Necessary to Establish New Regulatory Framework, Either Nationally or Internationally

31. Next Steps Preston Marshall XG Program Manager

32. XG Program Next Steps • What’s Done • Demonstrated Ability to Avoid Interference to Other Radios • 225-600 MHz • Developed Waveform for Spectrum Agility using Dynamic PHY and Wideband Sensing Integrated into MAC • Validated Core Components of Spectrum Access Logic and Algorithm Needs • What’s Left to Do • Integrate XG into Network Technology • Enable Variable Network Topologies • Establish Load Balancing to Assure High Confidence • Develop and Demonstrate Scalability • Increased DoD Radio Applications up to 2.5 GHz • Greater XG-XG Network Size, Density, and Interaction • Address Broader Class of Signals • Sub-noise Detection and Wideband Signals • Data Fusion for False Alarm and Detection Confidence • Extend Spectrum Access Logic and Algorithms to Cover the Range and Complexity of DoD Operational Needs • Early Transition • Investigate Operational Benefits in a Jamming Environment • Investigate Immediate Transition into an Existing Military Network Radio Phase 3b Investments Provide Cornerstone for Phase 3c Development of Fieldable Technologies

33. XYZ.COM Enter Search Future Wireless Program is Attacking All Aspects of Networking No Cell Towers Finite Energy Migrating Central Servers No Frequency & Network Planning Unknown Topology Distributing Cache Servers Distributed Index Services No Fiber & Wires

34. WNAN/WANN Adaptive Radio Uses All Network Layers to Resolve Issues Each Technology Can Throw “Tough” Situations to other More Suitable Technologies without Impact on User QOS Topology Planning Re-plan Topology Spectrum Planning Re-plan Across Network Network-Wide MIMO Spectrum Too Tight Dynamic Spectrum Key to Adaptive Networking No Good MIMO Paths Dynamic Spectrum Need More Range Relocate Around Spur Radio Device Unavoidable Strong Signal Move to New Preselector Band Device Spurs, … Beam Forming Nulling Strong Neighbor Signal Link

35. WANN/WNAN Hardware Platform • Single RF Processing Slice Replicated to form 1, 2 and 4 channel MIMO/XG/ Beamforming Capable Radios • Reverse of Standard STO Approach • Build Early H/W and Incrementally Add Network Capability • Have Early Demonstrator of DARPA Philosophy and Technology • Approach: • Develop early Prototypes By Leveraging Available Commercial Chips (TV-Tuners and Others) • Use Cost Pressure to Force Innovation for Lower Cost/Higher Performance • Contribution from MTO New Analog Signal Processing (MEMs Filter Program) Essential Control - Based MANET New Technology New Technology Dynamic MIMO $ 500 per 4 Channel Node, Spectrally Adaptive, MIMO, Beamforming, Member of Four Simultaneous Subnetworks, Ultra Low Latency Spectrum (MnM) (XG) COTS Chip Set

36. WNAN Networks Achieve Reliability through Diverse Paths and Frequencies Mesh or MANET WNAN Color Depicts all radios on the same frequency Color Depicts sub-net frequencies -- MIMO Mode Not Depicted • Unconstrained Scalability • Additional Nodes Create Additional Networks – Enabling More Capacity • Diversity in Frequency Avoids Interference • Multiple Routes Reduce Link Dependency • Dynamic Spectrum Can Use Network to “Make Before Break” • Limited Scalability • Bandwidth Constrained by Mutual Interference – More Nodes do Not Create More Capacity • Low Reliability Due to Single Link Routes • Large Number of Nodes on Single Frequencies