Cognitive Radio Networks at WINLAB: Networking and Security Research

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1 Cognitive Radio Networks at WINLAB: Networking and Security WINLAB Rutgers, The State University of New Jersey Contact: Professor Wade Trappe, Associate Director

2 Where Wireless is Heading: Robust, Adaptive and Programmable Multi-Radio Networks The community is researching new architectures, protocols and algorithms for robust/secure networks will allow for a 2 nd generation cognitive radio MANET Collaborative PHY for increased resilience at the radio level Novel MANET architectures and protocols (cross-layer, global control, adaptive) Innovative approaches to security in MANETs Cognitive radio technology to enable spectrum agility and adaptation Protocols for networking of cognitive radios backed up by a comprehensive set of laboratory capabilities for realistic and reproducible evaluations at scale Cognitive radio platforms (GNU/URSP, WiNC2R, WARP) ORBIT radio grid testbed, with upgrade to programmable radios Outdoor vehicular testing Integration with wired network testbeds, PlanetLab & VINI Government will be affected by: Rapidly evolving technologies with high levels of flexibility More universal connectivity Is this really a good thing? New forms of security risks [2] WINLAB

3 WINLAB CogNet projects use unique hardware capabilities and software design Global Control Plane (GCP) Common framework for spectrum allocation, PHY/MAC bootstrap, topology discovery, cross-layer routing and security management Decentralized coordination of protocols across location and layers Data plane Dynamically linked spectrum mgmt, PHY, MAC, Network modules and parameters as specified by control plane protocol Logical separation of control & data for flexible design and low overhead Minimize contention between control & data ( >>50% overhead in networks!) Adaptive Networks of Cognitive Radios Data Plane PHY1/MAC1 to the Internet PHY3/MAC3 Bootstrap Disco very Control Plane Data Path Establish ment Control MAC Control PHY Global Control Plane Control Signalling Naming & Addres sing Data Plane Application Transport Network MAC PHY Radios with Programmable PHY/MAC PHY2/MAC2 WiNC2R platform Protocol Stack with GCP [3] WINLAB

4 Global Control Planes support a Common Spectrum Coordination Channel (CSCC) for cognitive networks CSCC enables mutual observation between heterogeneous nodes to explicitly coordinate spectrum usage Exchange of CSCC messages by an extra narrow-band (low bitrate) radio Periodically broadcast self-states to others Coordinate spectrum usage [4] WINLAB

5 CogRadio Nets: Integrating routing and MAC layer functions is possible via the Global Control Plane Global scheduling of routes and MAC time slots is possible through the Global Control Plane architecture Such scheduling eliminates usual contention that degrades conventional wireless system designs Allocation algorithm works on both frequency (FD) and time (TD) Algorithm checks for compatible time slot and freq at each receiver Allows for more parallel transmissions (fewer exposed nodes ) and eliminates packet contention Significant performance improvement over conventional layered AODV etc. Requires GCP-type capability for distribution of control Comparison of Individual and Aggregate Throughput Global Scheduling Aloha Slot Aloha flow 1 flow 2 flow 3 flow 4 flow 5 Total [5] WINLAB

6 Warp-5: An AI-based Wireless Adaptive Routing Protocol exploits control-plane separation for improvement Overview: Intended for the (CBMANET) CLAN architecture AODV-based Routing: Overload Investigated by Brian Russel and Michael Littman in conjunction with WINLAB AODV (1 radio) Based on machine learning algorithms AODV (Control Plane) Design philosophy: Warp-5 (1 radio) Routing protocols generally make decisions Warp-5 based on (Control Plane) metrics that don t reflect quality of service objectives Shortest route may not always be the fastest or best! Cross-layer factors should be considered: MAC/PHY level data: SNR, RSS, symbol error rate, bit error rate? What about router congestion? WARP-5: 8000 Distance vector, on-demand routing protocol for ad WARP-5 Routing: Automated Balancing hoc networks 6000 Time-based routing metric incorporates router congestion level and environmental noise/interference Routes around heavily-used routers and noisy links even if the route is longer Nodes learn estimated time-to-destination for all neighbors. Protocol benefits 0 present for both single channel and control-channel architectures Simulation Trial Runs Total Packets Delivered [6] WINLAB

7 AUSTIN: An Initiative to Assure Software Radios have Trusted Interactions Goal: to regulate the future radio environment, ensure trustworthy cognitive radio operation (Team: Rutgers, Virginia Tech, UMass) How two complementary mechanisms On-board enforcement restrict any violation attempt from accessing the radio: Each CR runs its own suite of spectrum etiquette protocols Onboard policy checking verifies actions occur according to spectrum laws An external monitoring infrastructure: Distributed Spectrum Authority (DSA) police agent observes the radio environment DSA will punish CRs if violations are detected via authenticated kill commands. [7] WINLAB

8 AUSTIN involves formalizing security languages for CR regulation and a security management plane AUSTIN will use law-governed interaction (LGI), which is more powerful than conventional access control in both expressive power and scalability. LGI employs locality, which supports decentralization of access control, and scalability for stateful regulation LGI can achieve global effects over a community because all members of that community are subject to the same law A broad and expressive regulatory language will be designed XGPL is a starting point, but does not involve policy enforcement AUSTIN-XGPL will use a concrete representation of past behaviors to allow a detailed evaluation for regulation. AUSTIN-XGPL challenges: Make the language support variable degrees of interoperability between federations of CR devices. Make the language powerful, yet simple enough to minimize the risk of a poorly-written/buggy law AUSTIN Credo: Security must be designed into all future CR devices (e.g. an FCC-imposed requirement) All CR devices will have a mandatory trusted computing component that includes a well-architected Security Management Plane (SMP) RF units immediately partition incoming signals to extract SMP communications and relay these to a trusted module on the CR AUSTIN-SMP will be driven by associated Security Management Agents (SMA) Security Message Units (SMUs) will support multiple regulation services via a unified packet format. AUSTIN-SMP provides an exciting approach to more provably secure protocols, as well as improved network manageability LGI-based Interaction AUSTIN-SMP Architecture [8] WINLAB

9 Secure software and hardware methods prevent corruption of CR software, while the AUSTIN-Controller regulates actions Ensuring the security of radio software involves Ensuring that the radio software components come from authorized entities Assuring that the download and installation processes are secure Thwarting the unauthorized modification of the software once it has been installed. Hardware security mechanisms should provide a rootof-trust and thus must be tamper-proof Bitstream encryption prevents the configuration from being revealed outside the chip Unlike ASICS, FPGAs reveal no design information when powered off, forcing the adversary to probe an active die. AUSTIN will investigate the enforcement of basic operational policies using hardware-layer interlocks that cannot be overridden by software layers. Will require: Analyzing the interfaces and dependencies between hardware and software Selecting the policies to be enforced with hardware Formal state analysis of the hardware blocks responsible for policy enforcement A mechanism for securely updating policy enforcement circuits. Sensorary Data Regulatory Policies/ Ontologies Ontology Interface Rule Sets Knowledge Database AUSTIN- Controller Requests & Commands Policy Controller Policy Reasoner General Radio Interface Radio Platform Reasoning Results & Response Policy Monitor The AUSTIN-Controller is a policy engine that receives requests from CR processes, and makes formal decisions on whether to allow requested actions to occur AUSTIN-Controller involves: Ontology Interface Knowledge Database Policy Reasoner Policy Controller Policy Monitor [9] WINLAB

10 Cognitive radios support new forms of security: Secret Key Extraction from a Wireless Channel Use channel reciprocity to build highly correlated data sets Probe the channel in each direction Estimate channel using recd. probe Eve receives only uncorrelated information as she is more than λ/2 away Level crossings are used to generate bits Alice and Bob must exchange msgs over public channel to create identical bits What if channel is not already authenticated? Requires additional sophistry to prevent man-in-the-middle attack. It is possible using the correlated data collected from received probes. PROBE PROBE Positive excursion Get channel estimates PROBE Locations of excursions Negative excursion Locations in agreement [10] Key WINLAB Key

11 Radio Telepathy Prototyping: Establishing a secret key using a 64 Point Channel Impulse Response from a Preamble Tallest Peak in CIR Extracted STA= Bob, AP =Alice Probing of channel: PROBE request and PROBE response New PROBE every 110msec [11] WINLAB