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DoD Spectrum Symposium 14-15 October 2009 Ensuring Capabilities Via Spectrum Access: Meeting the 21st Century Mission Dr. Larry B. Stotts Deputy 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 Network Centric Wireless Operations Technical Challenges 2 How do we enable networks to scale to a large number of users and adapt to users’ mobility? How do we reliably deliver information and sustain networks despite frequent network disruptions? How do we provide reliable spectrum access and coexistence for thousands of RFbased systems? How do we provide interoperability and reliable networking among the hundreds of US Military, Coalition, & Public Safety radio types? PRC 117 SATCOM Cellular How do we enable reliable communications in urban areas where signals are scattered by buildings and terrain? How do we provide content to soldiers at an affordable cost? Military • MIL-STD • 2 channels • High Cost, Low Volume • Voice & Data COTS Coalition EPLRS Public Safety • • • • JTRS GMR Apple iPhone Commercial Stds Multi-channel Low Cost Rich User Content 2 Why are These Challenges? RADIO LIMITATIONS NETWORK COMPENSATION ● Link Outages ● Disruption Tolerance ● LOS Routing ● LOS / NLOS Routing / Rerouting ● Bandwidth ● Spectral Re-Use and Routing ● Quality of Service (QoS) ● Prioritization / Retransmission ● Radio Command and Control ● Control Plane ● Dissemination to Disparate Groups ● Multicast / Unicast The Network May Overcome Radio Limitations Next Generation (XG) Technologies and System Concepts for Dynamic Spectrum Access Goals • Demonstrate Factor of 10 Increase in Spectrum Access • Demonstrate Enhanced Robustness by Static Spectrum Management is Limited in Its Ability to Improve Spectrum Utilization Efficiencies – Currently ~ 6% Utilization Interference Avoidance (Radios, Radar, Jammers, etc.) TODAY: Spectrum statically allocated • Mechanism for “Bandwidth on Demand” thru Dynamic Provisioning XG Wideband Prototype XG can operate across currently partitioned spectrum allocations XG Wideband Sensor Capability to Integrate Software with Existing Legacy Radios PRC-148 PRC-152 JEM Falcon-III Frequency (MHz) OBJECTIVE: Dynamically allocating spectrum in frequency, space, and time Unused Spectrum Changes in Time and Space Time of Day (Sec) 90-95% not being used! 4 XG/DSA Proven Potential Field Upgrade Capabilities Enhancement Capabilities Proof • Demonstrated Core DSA Operations • Works, No Harm, Adds Value • Adaptive-Power NonInterference DSA Capabilities • Policy-Based Spectrum Rule Enforcement Ready for Software Upgrade to Existing Inventory • PRC-148 & -152 Handover to Services PRC-152 PRC-148 Networking Aug06 Mar07 Mar08 Operational Exercise • Demonstrated HighPower Non-Interference DSA Capabilities in Trident Warrior ‘07 Apr08 June08 Final Eval & Demo • DSA-Enabled PRC-148 & PRC-152 • CREW Coexistence • Scalable DSA Networks Transition to Programs of Record • JTRS, WNW, FCS… WNaN Low-Cost Edge Communications • JTRS, WNW, FCS… XG Wideband Prototype WNaN XG/DSA Demonstrated Ability to be Implemented in Current and Future Network Systems Mobile Networked MIMO (MNM) Field Test Results Exceeded All Program Goals 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 Exploiting the surrounding landscape to provide more robust, higher data rate links that work well in complex urban environments 6 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 Networking without Infrastructure Reliable On-The-Move edge-to-edge 3.5x Increase in EPLRS capacity Delivery in Disrupted Networks 3x bandwidth reduction for C2PC using stateful compression “Communications is the lifeblood of command / of a special forces team / of intelligence/ of what we do...” - from Report on “Coalition Operations in Operation Iraqi Freedom”, 27 Aug. 2007 Aggregate Delivery: DTN vice E2E IP End-to-End IP Only in a permanently partitioned network DTN delivers 100% after nominal latency IP delivers immediately or never DTN with IP Per-Node Delivery: DTN vice E2E IP in a permanently partitioned network Fort AP Hill Nov. 2007 IP doesn’t and can’t deliver from disconnected nodes – 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. TDMA/FDMA DIMA Technology Advancement 0 dB* -3 dB* Current method: conventional -6 dB* signal 1 Digital Receivers -9 dB* signal 2 signal 3 signal 4 u eq cy en Fr CSMA/CA DIMA Time signal 1 signal 2 signal 3 signal 4 Multi-user based algorithm Time Power – 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 Time 802.11 Media Access Control (MAC) Protocol Power ● Current State of Networking Technology Power DARPA Interference Multiple Access (DIMA) signal 1 signal 2 signal 3 signal 4 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 8 8