Ensuring Capabilities Via Spectrum Access: Meeting the 21st Century Mission

Dr. Larry B. StottsDeputy Director, Strategic Technology Office

Defense Advanced Research Projects Agency

Ensuring Capabilities Via Spectrum Access: Meeting the 21st Century Mission

Dr. Larry B. StottsDeputy Director, Strategic Technology Office

Defense Advanced Research Projects Agency

The views, opinions, and/or findings contained in this article/presentation are those of the author/presenter and should not be interpreted as representing the official views or policies, either

expressed or implied, of the Defense Advanced Research Projects Agency or the Department of Defense Approved for Public Release, Distribution Unlimited

DoD Spectrum Symposium

14-15 October 2009

2

Network Centric Wireless OperationsTechnical Challenges

2

JTRS GMR

Apple iPhone

How do we enable networks to scale to a large number of users

and adapt to users’ mobility?

How do we provide reliable spectrum access and

coexistence for thousands of RF-based systems?

How do we reliably deliver information and sustain

networks despite frequent network disruptions?

How do we enable reliable communications in urban areas where signals are scattered by

buildings and terrain?

How do we provide interoperability and reliable networking among the

hundreds of US Military, Coalition, & Public Safety radio types?

How do we provide content to soldiers at an affordable cost?

COTS

Military

• MIL-STD

• 2 channels

• High Cost, Low Volume

• Voice & Data

• Commercial Stds

• Multi-channel

• Low Cost

• Rich User Content

PRC 117

Coalition

EPLRS

PublicSafety

Cellular

SATCOM

The Network May Overcome Radio Limitations

RADIO LIMITATIONS

● Link Outages

● LOS Routing

● Bandwidth

● Quality of Service (QoS)

● Radio Command and Control

● Dissemination to Disparate Groups

NETWORK COMPENSATION

● Disruption Tolerance

● LOS / NLOS Routing / Rerouting

● Spectral Re-Use and Routing

● Prioritization / Retransmission

● Control Plane

● Multicast / Unicast

Why are These Challenges?

XG Wideband Sensor

4

Next Generation (XG) Technologies and System Concepts for Dynamic Spectrum Access

Static Spectrum Management is Limited in Its Ability to Improve

Spectrum Utilization Efficiencies – Currently ~ 6%

Utilization

Static Spectrum Management is Limited in Its Ability to Improve

Spectrum Utilization Efficiencies – Currently ~ 6%

Utilization

OBJECTIVE: Dynamically allocating spectrum in frequency, space, and time

Fre

qu

ency

(M

Hz)

Time of Day (Sec)

Unused Spectrum

Changes in Time and

Space

90-95% not being used!

Goals

• Demonstrate Factor of 10 Increase in Spectrum Access

• Demonstrate Enhanced Robustness by Interference Avoidance (Radios, Radar, Jammers, etc.)

• Mechanism for “Bandwidth on Demand” thru Dynamic Provisioning

TODAY: Spectrum statically allocated

XG can operate across currently partitioned spectrum allocations

PRC-152 Falcon-III

PRC-148 JEM

Capability to Integrate Software with Existing Legacy Radios

XG Wideband Prototype

XG/DSA Proven Potential

PRC-152

PRC-148

XG Wideband Prototype

WNaN

Capabilities Proof

Operational Exercise

Capabilities Enhancement

Final Eval & Demo

Field Upgrade

Networking

WNaN

Aug06 Mar07 Mar08 Apr08 June08

• Demonstrated Core DSA Operations

• Works, No Harm, Adds Value

• Demonstrated High-Power Non-Interference DSA Capabilities in Trident Warrior ‘07

• Adaptive-Power Non-Interference DSA Capabilities

• Policy-Based Spectrum Rule Enforcement

• DSA-Enabled PRC-148 & PRC-152

• CREW Coexistence• Scalable DSA Networks

Ready for Software Upgrade to Existing Inventory• PRC-148 & -152

Handover to Services

Transition to Programs of Record• JTRS, WNW,

FCS…

Low-Cost Edge Communications• JTRS, WNW,

FCS…

XG/DSA Demonstrated Ability to be Implemented in Current and Future Network Systems

Mobile Networked MIMO (MNM)

6

Exploiting the surrounding landscape to provide more robust, higher data rate links that work well in complex urban environments

Metrics Goals Results

8 Node Network Throughput

10 Mbps

16 Mbps

Spectral Occupancy

10 MHz 7.8 MHz

LPD/AJ Processing

20 dB 21dB

Latency 90% < 2 sec

96-99%

Packet Delivery 80% 90-96%

8 Node Network Initialization Time

< 10 min

< 1 min

Node Entry Time < 2 min < 3 seconds

Detect Node Exit Time

< 30 sec

< 3 seconds

Field Test Results Exceeded All Program Goals

Disruption Tolerant Networking

Reliable Communications Across Intermittent and Disrupted Tactical Networks

DTN is developing network protocols and interfaces to provide high reliability communications over intermittent and disrupted links

Better reliability in service scenarios

Reliable On-The-Move edge-to-edge

Delivery in Disrupted Networks

DTN delivers 100% after

nominal latency

IP delivers immediately or

never

End-to-End IP Only

DTN with IP

IP doesn’t and can’t deliver from

disconnected nodes

Aggregate Delivery: DTN

vice E2E IPin a permanently

partitioned network

Per-Node Delivery: DTN

vice E2E IPin a permanently

partitioned network

Fort AP Hill Nov. 2007

- from Report on “Coalition Operations in Operation Iraqi Freedom”, 27 Aug. 2007

“Communications is the lifeblood of command / of a special forces team / of intelligence/ of what we do...”“Communications is the lifeblood of command / of a special forces team / of intelligence/ of what we do...”

Networking without Infrastructure

3.5x Increase in EPLRS capacity

3x bandwidth reduction for C2PC using stateful compression

DARPA Interference Multiple Access (DIMA)

● Current State of Networking Technology– Current communication networks use the interference

avoidance paradigm, which fundamentally limits overall network performance, i.e. network capacity and user throughput.

– Interference avoidance relies on spectrum allocation methods that limits users to partial use of the spectrum and require a controlling entity to manage channel access.

88

Po

wer

Time

Frequen

cy

TDMA/FDMA

Po

we

r

Time

Frequen

cy

CSMA/CA

Po

we

r

Time

Frequen

cy

CSMA/CA

Po

we

r

Time

Frequen

cy

Demonstrate a mobile ad hoc spread spectrum communications network that requires no infrastructure and has 3X the aggregate capacity of 802.11 or IS-95

DIMA Technology Advancement– Exploit multi-access interference through Multiuser

Detection (MUD) allowing multiple users to simultaneously occupy the same channel.

– Enables high capacity mobile ad-hoc spread spectrum communications without infrastructure or power control

802.11 Media Access Control (MAC) Protocol

DIMA

signal 4

signal 1

signal 2

signal 3

0 dB*

-3 dB*

-6 dB*

-9 dB*

Current method:

conventional

Multi-user based

algorithm

Digital Receivers

signal 1

signal 2

signal 3

signal 4

signal 1

signal 2

signal 3

signal 4