XG Dynamic Spectrum Experiments, Findings and Plans Panel

XG Dynamic Spectrum XG Dynamic Spectrum Experiments, Findings Experiments, Findings

and Plansand PlansPanelPanel

DoD Spectrum Summit 2006DoD Spectrum Summit 2006

Preston Marshall, DARPAPreston Marshall, DARPATodd Martin, STA Todd Martin, STA

Mark McHenry, Shared SpectrumMark McHenry, Shared SpectrumPaul Kolodzy, Kolodzy Consulting Paul Kolodzy, Kolodzy Consulting

2Distribution Statement A – Approved for Public Release – Distribution Unlimited

Panel Structure

Quick Introduction to DARPA XG

Preston Marshall

Legacy Radio Operation and Interference Measurement

Todd Martin

Demonstration Scenario and Results

Mark McHenry

Incremental Transition Paul Kolodzy

Next Steps

Questions and Discussion

Preston Marshall

All


All Spectrum May Be Assigned, But…

…Most Spectrum Is Unused!

XG is Developing the Technology and System Concepts for DoD to Dynamically Access All Available

Spectrum

React

Formulate Best Course of Action

ReactReact

Formulate Best Formulate Best Course of ActionCourse of Action

Adapt

Transition network to new emission plan

AdaptAdapt

Transition Transition network to new network to new emission plan emission plan

Characterize

Rapid waveform determination

CharacterizeCharacterize

Rapid waveform Rapid waveform determinationdetermination

Sense

Real time, Low-power, wideband

monitoring

SenseSense

Real time, LowReal time, Low--power, wideband power, wideband

monitoringmonitoring

AutonomousAutonomousDynamic Dynamic SpectrumSpectrumUtilizationUtilization

DARPA XG Program

Goal: Demonstrate Factor of 10 Increase in Spectrum Access

Maximum Amplitudes

Frequency (MHz)

Am

pli

du

e (

dB

m)

Heavy UseHeavy Use

Sparse UseSparse Use

Heavy UseHeavy Use

Medium UseMedium Use


Maximum Amplitudes

Frequency (MHz)

Am

pli

du

e (d

Bm

)

Spectrum Allocation & Utilization

Static Spectrum Management is Limited in Its Ability to Improve Spectrum Utilization Efficiencies

Static Spectrum Management is Limited in Its Ability to Improve Spectrum Utilization Efficiencies

• Fixed Spectrum Assignments Lead to Inefficient Spectrum Utilization• Opportunities Exist in Time, Opportunities Exist in Time,

Frequency, and GeographyFrequency, and Geography• Constrain Network AdaptationConstrain Network Adaptation• RF Spectrum Allocated by PolicyRF Spectrum Allocated by Policy

– Allocations, Assignments, Allocations, Assignments, and Incumbents Vary by and Incumbents Vary by CountryCountry

Heavy Use

Sparse Use

•Observations Show Bands of Local Heavy and Sparse Activity Temporal Usage Characteristics

Vary by Band & Service Potential for Usage Dependent on

Incumbent Service & Equipment

Heavy Use

Medium Use

Less than 6% OccupancyLess than 6% Occupancy

Today’s Networks are Heavily Constrained by Lack of Spectrum

Today’s Networks are Heavily Constrained by Lack of Spectrum


Transceiver

SystemStrategy

Reasoner

XG Operation

Select

Opportunities

PolicyReasoner

DevelopOptions Process

Request

Determine

Opportunities

Yes/No or Additional

Constraints

AccreditedPolicy

RF Info Acquisition

Sensing Loop

Policy Engine

RadioPlatform

Me

ss

age

Flo

w

RF ResourceRequest

RF Transmit Plan


DARPA XG Program Investments

XG PrototypeXG Prototype& Demonstration& Demonstration

Spectrum AwarenessSpectrum Awareness

InterferenceInterferenceEffectsEffectsAssessmentAssessment

BehaviorBehavior

AdaptiveAdaptiveNetworkNetworkOperationOperation

Spectrum Measurements

Sensor Technology Signal Processing Algorithms

Distributed SensingAlgorithms

IEEE 1900IEEE 1900PolicyDescription

Spectrum AdaptiveNetworking

OptimizingStrategies

PolicyReasoning

Capabilityand Affordability

Dynamics

SubnoiseDetection

IncreasedAwarenes

s

PerformanceExperiments

Methodology

Framework &Semantics

EngineeringBasis

Non-InterferingOperation

Tactics

PolicyLanguage

EnforcementImplementation

Assessments


Progress In Dynamic Spectrum

• Successful XG Testing Performed at Fort A. P. Hill in August 2006

• Demonstrated the Three Core Principles of XG Program

1. Does Not Interfere with Other Spectrum Users2. Functions in Setting Up and Maintaining Networks3. 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


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

Metrics Defined by DARPA & OSD/NII as Threshold for Establishing Early Confidence in Viability of Dynamic Spectrum Access Technologies


Legacy Radio Operation and Interference

Measurement

Todd MartinXG Test Director


Legacy Radios

Legacy DoD Radio/Test Equipment

PSC-5

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

XG Radios(mobile)

Legacy DoD Radio (fixed)

MicrolightPRC-117


The XG “Electromagnetic Obstacle Course”

EPLRS

EPLRS Micro-Lite

PRC-117

PSC-5

Night Vision Observation Building

Jammer ICOM

XG drive path


Drive Route Spectrum Density

Legacy Node Placement, Terrain, and Propagation Effects Created Dense and Dynamic RF Environment

Legacy Node Placement, Terrain, and Propagation Effects Created Dense and Dynamic RF Environment

• 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 Radio Performance Telemetry

4 Legacy Radio 4 Legacy Radio Nets PerformanceNets Performance

PerfectPerfect

InterferenceInterference

• JSC or JHU APL Personnel Oversaw each Radio PairJSC or JHU APL Personnel Oversaw each Radio Pair• Real Time Telemetry of Each Legacy Radio (except for Real Time Telemetry of Each Legacy Radio (except for

Unicom PTT Public Safety)Unicom PTT Public Safety)• Reported Bit Error Rate or Packet Delivery, Depending on Reported Bit Error Rate or Packet Delivery, Depending on

Radio TypeRadio Type• PSC-117 Also Reported Hop FrequencyPSC-117 Also Reported Hop Frequency


XG Demonstration and Quantitative Results

Mark McHenryXG Principle Investigator


XG Radio System

GPP with 802.16 modem

GPP with XG algorithms

RF Enclosure

Display showing XG operational stateRockwell Sensor RF Power Amp

225-600 MHz RF Transceiver (located under shelf)


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)


Test scenario


objective

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


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.


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


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


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?


Phase 3 Metrics & Results Summary

Metric Threshold ResultsXG Causes No Harm

Abandon Time 500 msec 100% in 465 msec

Interference Limit 3 dB Mean: 0.16dB, Max: 0.49dB

XG WorksNet Formation 30 sec w/ 6 Nodes 90%: 3.6s; 100%: 8.68s

Net Join 5 sec 90%: 2.07s; 100%: 4.36s

Net Re-Establish 500 msec 100%: 165msec

XG Adds ValueSpectrum Occupancy 60% w/ 6 Nodes 85% Occupancy at 83%

Confidence

XG Demonstrated Reliable Networking Without Harming Legacy Nodes In Dense Spectrum Environments



XG Demo Results Instant Replay

4 Legacy Radio 4 Legacy Radio Nets PerformanceNets Performance

Three XG Radio Nets PerformanceThree XG Radio Nets Performance

PerfectPerfect

InterferenceInterference

Circles Are

Legacy Radio Nets

Dots Are XG Radio Nets

Colors Indicate Current Frequency (ex. EPLRS is Orange)

PLAY


Phase 3 Metrics & Results Summary

Metric Threshold ResultsXG Causes No Harm

Abandon Time 500 msec 100% in 465 msec

Interference Limit 3 dB Mean: 0.16dB, Max: 0.49dB

XG WorksNet Formation 30 sec w/ 6 Nodes 90%: 3.6s; 100%: 8.68s

Net Join 5 sec 90%: 2.07s; 100%: 4.36s

Net Re-Establish 500 msec 100%: 165msec

XG Adds ValueSpectrum Occupancy 60% w/ 6 Nodes 85% Occupancy at 83%

Confidence




No Harm: XG INR at Non-XG Radios

XG Produced Marginal INR at Non-XG Radios in All CasesXG Produced Marginal INR at Non-XG Radios in All Cases

INR Histogram and CDF

0%

2%

4%

6%

8%

10%

12%

14%

-0.1

6-0

.12

-0.0

9-0

.06

-0.0

30.

010.

040.

070.

100.

140.

170.

200.

230.

270.

300.

330.

360.

400.

430.

460.

49

Measured INR

Occ

urr

ence

Pro

bab

ility

(%

)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Cu

mu

lati

ve P

rob

abili

ty (

%)

Measured Data

Cumulative Probability

Mean Value < 0.1 dB !


Channel Re-Establishment Time

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 20 40 60 80 100 120 140 160 180

Channel Re-Establishment Time (ms)

Cu

mu

lati

ve P

rob

abili

ty (

%)

2 of 6 Nodes

3 of 6 Nodes

4 of 6 Nodes

5 of 6 Nodes

6 of 6 Nodes

XG Works: Re-Establish Time

XG Re-Established Networks in < 500 msec. in All CasesXG Re-Established Networks in < 500 msec. in All Cases


XG Spectrum Access vs. Network Connectivity- Phase 2 Predicted and Phase 3 Demonstrated -

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 20% 40% 60% 80% 100%

% XG Bandwidth Utilization

% X

G C

on

necti

vit

y

Adds Value: Spectrum Occupancy

XG Achieved > 60% Spectrum Occupancy for Networks of 6 Nodes: 85% Access Confidence at 83% Occupancy

XG Achieved > 60% Spectrum Occupancy for Networks of 6 Nodes: 85% Access Confidence at 83% Occupancy

Phase 2 Simulations

Phase 3 Field Data

4 Node NW

6 Node NW 0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0% 20% 40% 60% 80% 100%

25-500 kHz Mix

50 kHz - 1 MHz Mix

100 kHz - 2 MHz Mix

150 kHz - 3 MHz Mix

200 kHz - 4 MHz Mix

300 kHz - 6 MHz Mix

Measured Tactical Occupancy


XG Transition Strategies and Regulatory Needs

Paul KolodzyEx-DARPA PM and FCC Spectrum

Policy Task Force


• 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 (Widespread

NIB 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

XG Program – Transition

Not Necessary to Establish New RegulatoryNot Necessary to Establish New RegulatoryFramework, Either Nationally or InternationallyFramework, Either Nationally or Internationally


Next Steps

Preston MarshallXG Program Manager


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

Phase 3b Investments Provide Cornerstone for Phase 3c Development of Fieldable Technologies


XYZ.COM

Future Wireless Program is Attacking All Aspects of Networking

MigratingMigratingCentralCentralServersServers

DistributingCache

Servers

UnknownTopology

No Frequency No Frequency & Network & Network PlanningPlanning

Enter SearchDistributed Distributed

Index Index ServicesServices

No Fiber &Wires

No Cell Towers FiniteFinite

EnergyEnergy


WNAN/WANN Adaptive Radio Uses All Network Layers to Resolve Issues

MIMOMIMO

BeamBeamFormingForming NullingNulling

TopologyTopologyPlanningPlanning

SpectrumSpectrumPlanningPlanning

DeviceDeviceSpurs, …Spurs, …

RelocateAround

Spur

SpectrumToo Tight

Re-planAcross

Network

Re-planTopology

UnavoidableStrongSignal

NeedMore Range

Each Technology Can Throw “Tough” Situations to other More Suitable Technologies without Impact on User QOS

No Good MIMO Paths

Network-Wide

Radio Device

Link

Move to New Preselector

BandStrongStrong

NeighborNeighborSignalSignal

DynamicDynamicSpectrumSpectrum

Dynamic Spectrum Key to Adaptive

Networking


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

Frequency 900 MHz to 6 GHz

Power 36 dBm

SFDR 60 dB

IP3 What it is!

Peak 10 Mbps

Control- Based MANET

NewTechnology

NewTechnology

DynamicSpectrum

(XG)

MIMO(MnM)

COTS Chip Set

$ 500 per 4 Channel Node, Spectrally Adaptive, MIMO, Beamforming, Member of Four Simultaneous Subnetworks, Ultra Low Latency


WNAN Networks Achieve Reliability through Diverse Paths and Frequencies

Mesh or MANET WNAN

• 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

• 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”

Color Depicts all radios on the same frequency Color Depicts sub-net

frequencies -- MIMO Mode Not Depicted

XG Dynamic Spectrum Experiments, Findings and Plans Panel

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