Wade Trappe, Ph.D. - US grants

This collaborative research proposal is focused on the creation of a large-scale wireless network testbed which will facilitate a broad range of experimental research on next-generation protocols and application concepts. It is recognized that powerful technology and market trends towards portable computing and communication imply an increasingly important role for wireless access in the next-generation Internet. At the same time, new sensor and pervasive computing applications are expected to drive large-scale deployments of embedded computing devices interconnected via new types of short-range wireless networks. The speed of technology innovation in the wireless networking field can be significantly increased with the development of a flexible, open-access wireless network testbed that can be shared by experimental researchers across the networking community.

The proposed ORBIT (Open Access Research Testbed for Next-Generation Wireless Networks) system is a two-tier laboratory emulator/field trial network testbed designed to achieve reproducibility of experimentation, while also supporting evaluation of protocols and applications in real-world settings. In particular, the laboratory-based wireless network emulator will be constructed using a novel approach involving a large two-dimensional grid of static and mobile 802.11x radio nodes which can be dynamically interconnected into specified topologies with reproducible wireless channel models. All radio devices in the system provide open API's that permit end-users to download radio link, MAC and network layer protocols to construct a specific networking scenario. Once the basic protocol or application concepts have been validated on the lab emulator platform, users can migrate their experiments to the field test network which provides a configurable mix of both high-speed cellular (3G) and 802.11x wireless access in a real-world setting. Extensive measurement tools will be provided to support research evaluation, including both network traffic and radio link/spectrum usage aspects.

In addition to the development of the ORBIT wireless testbed infrastructure, this project includes a comprehensive set of "experimental work packages" intended to generate design requirements and serve as end-user application drivers for the system being developed. Specific research topics to be covered during the course of this project are:

1. Ad hoc networking in 802.11x WLAN scenarios [Raychaudhuri, Seskar; Rutgers & Acharya; IBM]
2. Message-based multimedia delivery [Schulzrinne, Columbia; Yates, Rutgers]
3. XML-based content multicasting for mobile information services [Ott, Raychaudhuri; Rutgers]
4. Location-based mobile network services [Schulzrinne; Columbia]
5. Pervasive computing software models for sensor networks [Parashar, Zhang; Rutgers]
6. Security protocols for next-generation wireless networks [Kobayashi; Princeton & Trappe; Rutgers]
7. Intelligent network middleware (INM) for mobile services [Paul; Lucent Bell Labs]
8. Peer-to-peer infrastructure for VoIP and IM [Acharya, Saha; IBM Research]
9. Power/bandwidth efficient media delivery to portable platforms [Ramaswamy, Wang; Thomson R&D]

The project will be conducted as a collaborative effort between several university research groups in the NY/NJ region: Rutgers, Columbia, and Princeton, along with industrial partners Lucent Bell Labs, IBM Research and Thomson. The wireless network testbed will be developed and operated by Rutgers WINLAB, using facilities located at the Rutgers New Brunswick campus and at partner sites in the area. The testbed will be available for remote or on-site access by other research groups nationally, subject to NSF guidelines for use. Additional partners will be sought during the course of the program both for testbed infrastructure development and for research collaboration.

The scientific/technical merits of the proposed project are: advancing the state-of-the-art in design and
implementation of flexible and scalable wireless network testbeds, and experimental investigation of novel
architectures, protocols and service concepts for next-generation wireless networks. Broader impacts are in
acceleration of the R & D cycle for wireless networking by providing the research community with a shared-use experimental platform, and in fostering increased use of experimental methods in both research and teaching.

Abstract:

Providing privacy for sensor networks is an important problem that is complicated by the fact that it is easy for adversaries to observe communications between sensor nodes. A first line of defense for protecting sensor communications is cryptography. However, these methods cannot address the complete spectrum of privacy issues in sensor systems. Specifically, security solutions are inadequate for protecting the privacy of contextual information surrounding a sensor application, such as the source's location, or the time at which a measurement was made, or even the size of sensor data packets.

This project investigates the development of a framework for providing three critical types of contextual privacy to sensor communications: source location privacy, temporal privacy, and traffic privacy. The project takes the viewpoint that the existing network stack can be modified to protect privacy while maintaining desirable levels of resource-efficiency. This investigation will enhance the privacy levels achieved through the development of new routing protocols involving the use of directed random walk techniques to obfuscate the data source, the modification of the structure of sensor messages to prevent traffic analysis attacks, the introduction of delay in the delivery of messages to reduce temporal correlation attacks, and the introduction of modifications to physical layer communications and the sensor topology to prevent the localization of a communication source. Through dissemination of the research results in both archival publications and new curricula, this project will advance the development of sensor applications by addressing critical privacy issues before sensor systems become a communal asset.

The securing of wireless systems has traditionally employed cryptographic protocols that are modifications of conventional wired security mechanisms. However, the wireless environment enables new forms of intrusion that render such techniques inadequate. At the same time, the properties of the wireless medium comprise a unique source of domain-specific information.

This project exploits that information to complement and enhance traditional security mechanisms. The project utilizes the unique space, time and frequency characteristics of the physical (PHY) layer, in combination with traditional higher layer techniques, to significantly enhance authentication and confidentiality. This cross-layer research is investigating fundamentally new approaches that utilize the statistical correlation properties associated with multipath propagation in designing new protocols. The project work relies on an integration of analysis, simulation and experiment by an interdisciplinary team whose expertise includes RF propagation, PHY-layer communications, statistical analysis, and wireless security and cryptographic protocols.

The growing use of wireless communications by consumers, businesses, and governments can be undermined by security attacks that exploit the medium itself. Strengthening the responses to this threat serves all of society. The goals of this project are to uncover how authentication and confidentiality can be achieved using the PHY-layer, under what situations these objectives are achievable, and how much benefit it can add to conventional security mechanisms. This interdisciplinary research and education effort will include wide dissemination of its results in academic and industrial forums spanning both wireless communications and security.

Most commercial wireless devices do not make lower-layer properties (e.g., raw waveform-level samples from an analog-to-digital converter) accessible to users. Recently, however, the research community has directed its attention towards the development of cognitive radios that will expose the lower-layers of the protocol stack to researchers and developers. Although the promise of such a flexible platform is great, there are also some serious potential security drawbacks. It is easily conceivable that cognitive radios could become an ideal platform for abuse since the lowest layers of the protocol stack will be accessible to programmers in an open-source manner. The proposed project addresses these concerns by focusing on two important building blocks needed in constructing a holistic solution to ensuring the trustworthy operation of software radios: first, the investigating team plans to develop tools to quantify the degree to which spectrum etiquette policies are abused in a network of cognitive radios and, second, the team plans to investigate methods for identifying such spectrum abuse, which is necessary in order to drive anomaly detection and response mechanisms. Overall, the broader impact of the effort is centered around the fact that cognitive radios represent an emerging technology that requires security mechanisms to be developed before these highly-programmable radios reach the public market.

The ORBIT Radio Grid as a Flexible Large-Scale Community Testbed for Next-Generation Wireless Network Research

The 400-node ORBIT radio grid facility at Rutgers was developed under the NSF NRT program (2003-07) with the objective of enabling realistic and reproducible wireless network experiments at scale. The ORBIT radio grid was first made available to research users on an informal basis in Oct 2005, and since then, has rapidly become a de-facto community resource for evaluation of emerging wireless network architectures and protocols. ORBIT is also being used as a proof-of-concept platform for validating wireless aspects of NSF?s GENI future Internet infrastructure.

This project is aimed at supporting community release of the ORBIT radio grid testbed on a more formal basis. This involves several key technical upgrades necessary to support emerging experimental needs, as well as enhancements to service software and operations staffing necessary for a 24/7 shared testbed facility. Specific work items to be carried out in this project include:
? Feature upgrades including support for software-defined radios, improved topology and mobility control, and wired + wireless network emulation.
? Virtualization of the radio grid to support multiple simultaneous experiments.
? Improved ORBIT user portal, along with enhanced software and operations support services.
? ?ORBIT kit? development and establishment of an open-source software repository.
Major deliverables of the project include community release of the ORBIT radio grid testbed with enhanced technical and service support features in year 2, followed by an upgrade with GNU/URSP2 software radios in year 3.

TC:Large: Collaborative Research: AUSTIN?An Initiative to Assure Software Radios have Trusted Interactions (CNS-0910557)

Software and cognitive radios will greatly improve the capabilities of wireless devices to adapt their protocols and improve communication. Unfortunately, the benefits that such technology will bring are coupled with the ability to easily reprogram the protocol stack. Thus it is possible to bypass protections that have generally been locked within firmware. If security mechanisms are not developed to prevent the abuse of software radios, adversaries may exploit these programmable radios at the expense of the greater good.
Regulating software radios requires a holistic approach, as addressing threats separately will be ineffective against adversaries that can acquire, and reprogram these devices. The AUSTIN project involves a multidisciplinary team from the Wireless Information Network Laboratory (WINLAB) at Rutgers University, the Wireless@Virginia Tech University group, and the University of Massachusetts. AUSTIN will identify the threats facing software radios, and will address these threats across the various interacting elements related to cognitive radio networks. Specifically, AUSTIN will examine: (1) the theoretical underpinnings related to distributed system regulation for software radios; (2) the development of an architecture that includes trusted components and a security management plane for enhanced regulation; (3) onboard defense mechanisms that involve hardware and software-based security; and (4) a algorithms that conduct policy regulation, anomaly detection/punishment, and secure accounting of resources.
Developing solutions that ensure the trustworthy operation of software radios is critical to supporting the next generation of wireless technology. AUSTIN will provide a holistic system view that will result in a deeper understanding of security for highly-programmable wireless devices.

This project is aimed at the design and experimental validation of a comprehensive clean-slate future Internet architecture. The proposed MobilityFirst architecture is motivated by the ongoing paradigm shift of Internet usage from today?s fixed PC/host (client)?server model to emerging mobile data services and pervasive computing applications. The major design goals of the architecture are: mobility as the norm with dynamic host and network mobility at scale; robustness with respect to intrinsic properties of the wireless medium; trustworthiness in the form of enhanced security and privacy; usability features such as support for context-aware services, evolvability, manageability and economic viability. The key components of the MobilityFirst network design are: (1) separation of naming and addressing, implemented via a fast global dynamic name resolution service; (2) self-certifying public key network addresses to support strong authentication and security; (3) generalized delay-tolerant routing with in-network storage for packets in transit; (4) flat-label internetwork routing with public key addresses; (5) hop-by-hop transport protocols operating over segments rather than an end-to-end path; (6) a separate network management plane that provides enhanced visibility; (7) optional privacy features for user and location data; and (8) an integrated computing and storage layer to support programmability. The project?s scope includes architectural design, validation of key protocol components, testbed prototyping of the MobilityFirst architecture as a whole, and real-world protocol deployment on the GENI experimental infrastructure. The results of this project will provide architectural guidance for cellular-Internet convergence, and are expected to influence future technical standards in the networking industry.

Improving the usage of communication spectrum resources is critical to future wireless systems. The OSTARA project focuses on the development of RF photonic techniques that support the ability to simultaneously transmit and receive in wireless devices. The effort involves a mix of theoretical development (specifically investigating potential improvements in capacity), as well as systems validation efforts involving building an opto-cancellation circuit capable of cancelling out co-site interference associated with simultaneous transmission and reception. . Specifically, the theoretical component of the effort will involve using ray-tracing to understand the role of cancelation of multipath components on communication rate, as well as an investigation into the impact of idealized cancellation on network capacity using graph coloring. The systems component of the effort will involve developing photonic circuits that subtract off the transmitted signal from the receiver chain, as well as potential multipath images of the transmitted signal. Validation will involve field testing the opto-canceller by setting up test scenarios on the ORBIT testbed at WINLAB.

Broader Impact: The proposed research will improve the spectrum utilization of future wireless systems, an issue of critical national importance. Additionally, the project will educate students and post-doctoral fellows in the inter-disciplinary area of RF-photonics as applied to advanced radio systems.

Objective:
The objective of the proposed project is to explore the problem of scanning large amounts of spectrum in order to detect anomalous usage of that spectrum. The project will examine spectrum scanning using a single spectrum sensor and using multiple spectrum sensors. The approach will involve using game theoretic formulations that allow for the determination of scanning strategies that give an optimal likelihood of detecting an adversarial or accidental misuse of spectrum in terms of the bandwidth that can be scanned in a single scan and the bandwidth that an anomalous activity might involve. The optimization of strategies are complemented by techniques that increase the amount of spectrum that can be scanned in a single scan, and spectrum mapping algorithms that estimate the received power levels at arbitrary spatial locations.

Intellectual merit:
The intellectual merit of the proposed effort stems from the pulling together of a mixture of technologies from different fields, including game theory, signal processing, security, wireless communications, and RF photonics to address the challenging problem of detecting and preventing anomalous spectrum activity across a wide swath of bandwidth.

Broader impacts:
The broader impacts of the proposed effort will include the cross-pollination between different disciplines, such as game theory, security, photonics and signal processing. Additionally, the project will guide the development of graduate and undergraduate students at both participating institutions, giving the students new tools with which to contribute to wireless and optical communications. Finally, new interdisciplinary curricula will be developed as part of the effort.

The development of radio technologies that support efficient and reliable spectrum sharing is an enabler for utilizing the spectrum being made available through the National Broadband Plan. Software defined radios represent a promising technology that supports spectrum sharing as evidenced by the large amount of algorithms and protocols that allow for cognitive radio networks (CRNs) to be deployed. Unfortunately, the economic promise of dynamic spectrum access is easily undermined if cognitive radio users act dishonestly or maliciously, thereby subverting protocols that are founded on the cooperation of users. It is therefore important that mechanisms are developed that ensure the trustworthy operation of CRNs in the presence of potentially malicious or malfunctioning wireless nodes. The objective behind the project's research activities is to develop technological solutions that ensure that cognitive radios operate in trustworthy manner in spite of potential security threats. As a result of this research effort, it is possible for radio spectrum to be more reliably utilized, thereby ensuring that the economic opportunities associated with the radio spectrum are fairly utilized by everyone. The educational impact of the work comes from its multi-disciplinary foundation, broadening student views of wireless system design, and guiding the next generation of wireless engineer to include security and reliability in the design process.

Wireless technologies are an enabler for economic growth in the United States, and cognitive radio networks are an emerging form of wireless system that make spectrum access more available to the broader population. Unfortunately, cognitive radio systems are susceptible to threats that undermine the correct operation of their algorithms and protocols, and thus solutions that support the secure operation of cognitive radio networks are needed. This project ensures the trustworthy operation of cognitive radio networks by: 1) developing algorithms that ensure the correct operation of spectrum sensing procedures upon which spectrum access protocols rely; 2) developing traffic monitoring tools that identify improper communication activity by cognitive radio devices; and 3) developing new forms of interference-resistant communications that ensure that cognitive radio communication continues reliably in the face of interference. The research effort is inter-disciplinary, pulling from statistical tools to network traffic analysis to communications theory to support the secure operation of cognitive radio networks. The algorithms and protocols developed in this project are complemented by a systems prototyping and experimentation effort aimed at guaranteeing that the technologies developed are suitable for deployment in real wireless systems.

The Next-Phase MobilityFirst (MF) project aims to have a major impact on the architecture of the future Internet by re-architecting it to address the needs of emerging mobile platforms and applications. Adoption of technologies arising from this project may be expected to provide improved efficiency, security and robustness that would benefit both network operators and end-users of the Internet. This project, originally funded as a collaborative research effort under the NSF Future Internet Architecture (FIA) program (2010-13) in which the MF architecture was designed over the past 3 years, is centered on a new name-based service layer which serves as the narrow-waist of the protocol; this name-based services layer makes it possible to build advanced mobility-centric services in a flexible manner while also improving security and privacy properties. The architecture incorporates novel storage-aware routing techniques which provide significant improvements in mobile network capacity and functionality. The next phase of the MobilityFirst project is aimed at making the transition from early-stage architecture and prototyping to advanced real-world services and trial network deployments. The research and experimental trials agenda is aimed at validating and refining the core name service, routing, security and management components of the MF architecture, while also responding to emerging trends in network technology and services such as the cellular mobile data explosion, the growth of content, the emergence of cloud computing, and software-defined network (SDN) technology.

Intellectual Merit: This project includes several research thrusts aimed at transitioning the MobilityFirst architecture to advanced services and field deployable technology. These include: (1) advanced name-based network services and development of enhanced global name service (GNS) technology; (2) network security and privacy designs and enhancements; (3) design of advanced content services; (4) application of MobilityFirst protocols to next-generation mobile cloud computing; (5) design of advanced context-aware services; (6) technical and economic study of cellular-Internet convergence; (7) software-defined network (SDN) ready protocol design; and (8) technology platforms, router implementation and deployment strategies. These research thrusts will be informed by three distinct real-world network environment trials: a "mobile data services" trial with a wireless ISP (5Nines) in Madison; WI; a "content production and delivery network" trial involving several public broadcasting stations in Pennsylvania connected by a greenfield optical network called PennREN; and a "context-aware public service" weather emergency notification system (CASA) with end-users in the Dallas/Fort Worth area. These network environment trials are the centerpiece of the proposed project, and are expected to provide a firm basis for validation of the MobilityFirst protocol stack and its usefulness for developing advanced mobile, content, context and cloud applications, while also advancing the technology to the field-deployment stage. Expected outcomes from the project include research results on security, privacy, content/context/cloud services and SDN; MobilityFirst protocol stack software revisions; router technology implementations; multiple real-world trial deployments of the technology; and experimentally supported evaluations of the architecture. This project is a collaborative effort involving Rutgers, UMass, MIT, Duke, U Michigan, U Wisconsin, and U Nebraska with the participation of several industrial research and network environment trial partners.

Broader Impacts: The MobilityFirst project will have impact as a new approach to a future Internet that by design addresses mobility and mobile platforms, and as an enabler of new mobile Internet applications of social value such as context-aware emergency notification services. The release of open source protocol software may be expected to help to stimulate further experimental research on future Internet architectures across the networking community. The project also contributes to education and training in the key areas of Internet and mobile network technology.

This project is aimed at a third-generation equipment upgrade for the ORBIT (Open Access Testbed for Next Generation Wireless Networking) testbed which has been operated by Rutgers University as a community resource since 2005. The ORBIT testbed, which researchers access remotely over the Internet, provides a flexible, scalable and reproducible platform for conducting wireless network experiments. ORBIT lowers the barrier for experimentation in the area of radio and wireless technology and thus improves education and research productivity in the field. The goal of this project is to extend the testbed to incorporate two key new capabilities: (1) LTE (Long Term Evolution) radio access, to support realistic evaluation of future mobile data services, and (2) "cloud radio" processing to enable experimental studies of emerging "5G" radio access technologies. The proposed testbed enhancements will help accelerate the pace of wireless/mobile technology development by facilitating evaluation of emerging radio technologies and network architectures such as dynamic spectrum access, cooperative MIMO (multiple input multiple output) and heterogeneous cellular networks. More specifically, the LTE and radio cloud capabilities to be added in this project will enable the study of techniques for enhancing wireless system capacity, helping to address the important societal problem of spectrum scarcity as mobile data usage continues to grow exponentially.

The ORBIT upgrade proposed here involves two major enhancements to the testbed. First, both the radio grid emulator and the outdoor ORBIT campus network will be upgraded to incorporate LTE in addition to the existing WiMax capability. LTE is rapidly being deployed in 4G cellular systems worldwide, and it is important to enable the research community to use this access technology for realistic mobile network experiments. LTE capability will be added to the outdoor ORBIT network by retrofitting a commercial base station to be controllable through the ORBIT management framework (OMF), while LTE on indoor nodes will be implemented in software running on available SDR platforms. Second, the radio grid's backend will be upgraded with a unique combination of FPGA and CPU based "software radio cloud" that will increase processing speeds by two orders-of-magnitude. The proposed radio cloud is designed as a hierarchically organized high-performance system which includes fast CPU-based servers, FPGA co-processors and "thin-client" software-defined radio nodes all connected together by a fast and programmable switching backplane. The system will include nearly 16 compute server blades (each with rated computing capacity of 700 GIPS), a large FPGA-based centralized co-processor array, a total of about 48 software defined radio (SDR) client nodes and about 128 x 10Gbps OpenFlow switch ports for connectivity. Examples of experiments that will be enabled include LTE-WiFi interworking, LTE-based mobile cloud services, wideband spectrum sensing and dynamic spectrum access algorithms, massive MIMO (multiple input multiple output) and cooperative PHY, cellular cloud RAN (radio access network) and virtual wireless networks. LTE capabilities will be released during year 1 of the project, and a first version of the radio cloud will be released in year 2, followed by an updated version in year 3.

The availability of wireless channel maps can greatly improve the performance and reliability of wireless networks. In addition to traditional applications which depend on channel information, channel maps can be valuable in emerging applications such as communication-aware motion and path planning, network routing, connectivity maintenance and dynamic coverage, which will support improved wireless performance. In a realistic setting, the statistics of the wireless medium change dynamically in time and space. This research develops theory and algorithms for building wireless channel maps over a geographical area based on channel measurements obtained by the network nodes.

The descriptive statistics of the channel, referred to here as the channel state, are modeled as discrete time stochastic processes, evolving in time or space according to a fully or partially known statistical model. The channel state encompasses the path-loss exponent, the shadowing power and the correlation distance, and is hidden from the network nodes; the nodes can only observe their respective channel realizations. This project develops a novel framework for dynamic spatiotemporal estimation / tracking / prediction of both the channel state and the channel magnitude, in complex, nonlinearly evolving, time varying and possibly nonstationary environments. The estimation problem is approached through the rich theory of nonlinear filtering and stochastic control. Several issues are studied, including (1) Decentralized channel tracking & spatiotemporal channel prediction, (2) Event triggered sampling for efficient channel sampling, (3) Structured stochastic models for nonstationary channels. The project has an experimental component, which informs the analytical models and is also used to test/evaluate the developed methods. The project engages graduate and undergraduate students in a range of theoretical subjects and also measurements performed on WINLAB?s communications testbed.

Evolving communication systems rely on using increasingly higher frequencies for larger channel bandwidths. The increased channel capacities enabled by higher carrier frequencies provide high speed communication for commercial and active users, however, these benefits do not extend to passive users, such as radio astronomy. The focus of the proposed effort is to create a framework for spectrum coexistence that is beneficial for both active and passive users. Instead of simply switching to higher and undeveloped frequencies - which passive users cannot - the proposed research uses high frequency, optical signal carriers for interference separation, enabling the coexistence of active and passive users at the same time and in the same physical location. The proposed coexistence solution will enable continuous availability of wideband spectrum for passive users, an important requirement for detecting unknown signals, since the bandwidth and the time window for unknown astronomical, atmospheric and geospace signals cannot be manipulated. The proposal involves collaboration between one private and two state universities in New Jersey, and will support education at various levels: for pre-college students, the PIs will develop games and instructive presentations that integrate the explanation of science fundamentals. Undergraduate students will access the evolution of communication technologies through Rowan University’s 8-semester research-based Engineering Clinic program. Commercial applications will be explored through industrial partners within local area of the PI campuses.

Since there is a projected increase in interference at both high and low RF frequencies, which will impair the success of both commercial and scientific use of spectrum, it is necessary to develop technologies that will mitigate the interference observed by all users of the radio spectrum, ultimately allowing better coexistence between the wide range of applications dependent on radio spectrum. The proposed system is implemented by redesigning the hardware and exploring communication protocols at multiple layers. In the physical layer, the photonic system separates a mixed received signal in the congested radio spectrum by upconverting the signal carriers to optical frequencies, providing over 100GHz of bandwidth in a single channel. In the network level, communication protocols are redesigned to enable passive users to continuously access to wideband spectrum and coexist with active users. The network layer protocol will optimize the deployment of the hardware system to minimize the cost of new infrastructures, better share spectrum, and improve communication throughput. The intellectual merit stems from the completely orthogonal approach proposed to address the challenges of radio spectrum, and the seamless integration of hardware innovation with communication protocols. By harnessing the unique properties of optical carriers, the photonic system processes analog signals before digitization, which eliminates both the current bandwidth limit and the resolution limit. The hardware innovation creates unprecedented resources for communication applications. The photonic system functions as a platform that provides new resources for both the existing and emerging spectrum sharing methods, specifically, dynamic spectrum allocation, interference alignment, etc. With a multi-layer design, the proposed system will advance the understanding of spectrum usage by enabling conexistence of systems with diverse power levels and large bandwidths.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.