ensuring capabilities via spectrum access: meeting the 21st century mission dr. larry b. stotts...
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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