Edward W. Knightly - US grants

ATM and next generation IP networks will provide the fundamental building blocks for integrated services networks: the ability to reserve network resources on behalf of bursty real-time applications. However, provisioning network resources accurately is quite challenging in the real-world environment characterized by heterogeneous and highly bursty traffic streams which exhibit rate variations over multiple time scales. The goal of this research is to design accurate and robust admission control and resource management algorithms that scale to large internetworks. In particular, we plan to study the following three problems. First, in a shared public network, applications cannot be trusted to adhere to their specified traffic parameters and therefore must be policed. However, deterministic policing must not preclude statistical resource sharing, which is essential for efficient resource utilization. We are designing an accurate envelope-based resource allocation algorithm that enables the network to statistically multiplex traffic streams while simultaneously enforcing applications' specified traffic parameters. Second, many applications will be unable to specify their traffic parameters in advance so that the network must somehow reserve resources even for applications with unknown resource requirements. We are developing a measurement-based service that adaptively measures the envelope of the aggregate traffic flow to predict future resource requirements and performance parameters for such ill-characterized applications. Finally, internetworks are characterized by a large number of heterogeneous components so that a resource management scheme must scale to such realistic environments. We are devising end-to-end resource management techniques that exploit coarse-grained representation and allocation of network resources.

ABSTRACT NCR-9730105 Hui Zhang Carnegie Mellon University Rick Wilder and Chuck Song MCI Joint with NCR-9730104 Edward W. Knightly Rice University Joint with NCR-9730103 Jorg Liebeherr Polytechnic University Integrated Resource Management for the Integrated Services Internet The IETF has defined several key components for enabling an integrated services Internet: (1) service classes, which define the service models for supporting end-to-end per-flow QoS, (2) a link sharing model, which defines how different organizational entities (agencies) can share the same physical resources, and (3) a resource reservation protocol, which provides the signaling mechanisms to support these services. While these capabilities are indeed revolutionary as compared to the current Internet, serious impediments remain to achieving the vision of a ubiquitous multi-service Internet. In particular, efficient resource management algorithms must be available that actually deliver these services to the applications. Packet scheduling algorithms must be devised that can meet the service requirements of heterogeneous applications and different agencies while, at the same time, exploiting statistical multiplexing; admission control algorithms must be designed to allocate the minimum amount of network resources without violating any of the service requirements. At present, no set of resource management algorithms is available that can provide multi-service capabilities while considering the complex dynamics among connections, services, and agencies. This project will provide the first truly integrated resource management infrastructure for multi-service networks. Taking a new and comprehensive approach at resource management algorithms within the framework of the integrated services Internet, we propose to develop: (1) A novel hierarchical link sharing service model and algorithm that simultaneously supports all of the services proposed by the IETF without sacrificing efficient utilization of network resources, (2) Traffic control and scheduling algorithms that are amenable to efficient implementation in high speed and scalable switching systems, (3) Admission control algorithms for an enforceable controlled-load service with statistical quality of service guarantees, (4) Robust admission control algorithms for measurement-based controlled-load services, and (5) Traffic control algorithms that provide graceful quality-of-service adaptation in the presence of transient fluctuations of the network load. This project will develop the theoretical underpinnings of integrated resource management algorithms for multi-service networks. Moreover, in a collaboration that involves an integrated services network provider (MCI Telecommunications), a network equipment vendor (Ascend), and academic researchers (CMU, Rice, Polytechnic), the PIs will build a complete prototype implementation of the proposed algorithms on the vBNS national network infrastructure. This reference implementation will provide a first-of-its-kind platform for experimental research on the integrated services Internet that will yield critical input to both practitioners in the field and standards bodies on the effectiveness of current and newly proposed resource management algorithms.

In the past decade, the number of subscribers to mobile and wireless communication services has grown at an exponential rate. Concurrently, emerging wireless devices have enabled new modes of communication beyond traditional cellular voice. However, to remain continually "connected," users face the frustrating task of manually coordinating a vast disarray of services, devices, and wireless technologies.

The goal of this project is to develop a platform for truly seamless communication throughout environments as fundamentally different as high-speed indoor wireless and conventional cellular systems. The investigators propose to design, build, and evaluate RENE (Rice Everywhere NEtwork), a multi-tier system that provides network- and application-level services using a single network interface card. The key innovations of the RENE project are as follows:

1. The design of an mNIC (multi-tier Network Interface Card), a novel network interface card that is reprogrammable on-the-fly to different physical- and network-layer standards. The mNIC will support soft handoffs, both horizontally within a tier and vertically among tiers, including transitions from a prototype 100 Mbps indoor wireless LAN protocol to commercial CDMA cellular standards.

2. The building of a proxy file system that enables seamless and consistent access to a user's home working environment, independent of the user's location or available network resources. The system will respond to changes in available capacity using transcoders, allow consistent reading and writing of files (even when transcoded), and facilitate network-awareness in unmodified applications.

3. The investigators will perform an extensive measurement and modeling study of proxy traffic using multi-fractal models. Using these results, policies will be devised which enable the proxy to make intelligent decisions on when and to what extent to transcode or store user data to best meet user performance objectives.

4. The development of a new coarse-grained approach to resource reservation and admission control that enables users to obtain predictable performance in multi-tier environments. The key technique is to abstract system resources into networks of virtual bottleneck cells such that by provisioning resources in the virtual cells, quality of service objectives can be satisfied in the actual system.

This research will be conducted in collaboration with Nokia and Texas Instruments in order to build a complete prototype implementation of the RENE system and demonstrate its capabilities.

The emergence of new applications has fostered a number of attempts to add functionalities to the minimalist Internet core. However, the adoption of enhancements to the Internet has either been slow, failed entirely, or limited to special-purpose private networks. The key reasons for this failure are extensibility and scalability: First, IP networks were not designed to be extensible at the internetworking level. Second, proposals for new network layer services often require that vast amounts of state information be managed in the core network infrastructure, thus, introducing scalability bottlenecks which exacerbate the existing scalability problem of the growing Internet.
Today, the development and deployment of advanced services on the Internet has reached a crossroads: efforts to add new services have quickly encountered scalability problems, yet new services are in critical demand and must be rapidly and widely deployed.
The research goal is to develop truly scalable services for each of the three fundamental components of the Internet's infrastructure: information communication, replication, and storage. Taking a new and unified approach to the seemingly conflicting requirements for scalability and sophisticated network services, the researchers propose to develop:
1. Scalable Performance-Predictable Communication: a new foundation for quality-of-service communication via a scalable edge-based architecture.
2. Scalable Multicast for Efficient Data Dissemination: a self-organizing multicast infrastructure scalable to many spontaneously-formed groups.
3. Scalable Storage for Next Generation Information Services: an infrastructure which brings information
closer to users and enables scalable third-party information storage services.
4. Design Principles of Scalable Services: a multi-faceted approach for the development and deployment
of scalable services in the global Internet, under consideration of economic models, industrial structure,
theories and algorithms, engineering, and deployment.
Thus, this project proposes to develop architectures and methodologies for deploying scalable services in the global Internet. The impact of this project will be to provide the theoretical underpinnings, basic architecture, and a prototype implementation for the information communication of the global Internet of the 21st century. An integral part of this project is the dissemination of results and the infiltration of standard organizations with the concepts developed within this project, and innovative approaches to educate the next generation of engineers for the future Internet.

EIA - 0224458
Cavallaro, Joseph R.
Aazhang, Behnaam
Frantz, Jeremy P.
Knightly, Edward W.
Sabharwal, Ashutosh

Rice Universiy

Title: CISE RR: A Comprehensive Multi-tier Wireless Network Development Platform

This proposal, developing an infrastructure within the Center for Multimedia Communication (CMC)
to enable repeatable fields' experiments in the laboratory, aims to develop integration techniques beyond simulations and other modeling. Using actual field measurement in its emulation, the infrastructure fills a gap to experimentally validate theoretical results under real-world conditions promising seamless wireless content delivery (without any service disruptions). The equipment, mainly consisting of two channel emulators, a logic analyzer, and a spectrum analyzer, benefits three major projects.
Reconfigurable Wireless Architectures,
High Data Rate Multiple Antenna Communication, and
Opportunistic Multi-Tier Wireless Scheduling.
The first project involves the design of new communication architectures that reconfigure based on the network availability, channel conditions, and data requirements of a handset. The infrastructure will enable a complete suite of efficient prototypes, which will simultaneously connect to next generation wireless LANs, third generation wireless cellular, and Bluetooth personal area networks (PANs), bringing closer the ideal ability of a single device to seamlessly maintain its link to the network using whatever connectivity is available. The second project develops new communications coding and feedback methods for high data rate wireless access by prototyping new algorithms with multiple transmit and receive antennae on reconfigurable baseband platform and stress tested in different wireless configurations for their robustness, performance limits, and power efficiency. The last project involves the design of optimal methods for scheduling data using all the resources available by a multi-tier network, including other mobile nodes connecting the backbone infrastructure. The packet schedulers are being prototyped on a mobile network processor platform and will use the multi-tier network interface (mNIC) prototype developed within CMC in its field trials.
On the educational side, students will continue their research on these projects, and new developments captured for new courses. Rice University is quite active with under-represented groups.
.

The PIs driving vision is to provide a high-performance, scalable and widely deployed wireless Internet that facilitates services ranging from radically new and unforeseen applications to true wireless "broadband" to residences and public spaces at rates of 10s of Mb/sec. Unfortunately, today's wireless networks such as cellular and WiFi hot-spots cannot achieve this vision due to problems encountered on multiple fronts: (1) excessive costs of the wired backhaul network, (2) poor performance scaling, and (3) excessive costs of spectral license fees. We will design an architecture that is based on Transit Access Points (TAPs), devices that form a wireless backbone mesh via high-performance directional-antenna wireless links operating in the unlicensed band.

This multihop wireless mesh interconnects wireless TAPs with limited wired Internet entry points and with wireless multihopping mobile users. To achieve the objectives with this architecture, the PIs will use a combination of theory, algorithm and protocol design, simulation, and implementation and testbed experimentation to address the following fundamental research issues: (1) development of scalable distributed opportunistic scheduling and media access protocols, (2) development of coordinated multi-hop resource management algorithms, (3) analysis of system capacity that incorporates the critical effects of protocol overhead, and (4) deployment of a first-of-its-kind neighborhood testbed.

A national glass fiber network to serve 100 million households with two-way
symmetric data communications service at 100 Mb/sec per household will
inevitably be constructed during the next few years. The barriers to the
creation of such a network are not simply questions of deployment issues or
the cost of the network. Rather, fundamental innovations will be required in
the way networks are organized and managed.


The project uses a three pronged approach to investigate the possibilities and
technical consequences of this once-in-a-century event.: (1) a holistic
network architecture designed from first principles, (2) interdisciplinary
fundamental research that addresses the design of an economical, robust,
secure and scalable 100x100 network, and (3) proof-of-concept network
implementations to demonstrate how the network of the future can be built.

The results from the project will take several forms. First, the blueprint
for the 100x100 network will offer a coherent intellectual framework on how
the next generation network could be built. The resulting architecture and
design can serve as a compass to guide investment in network development, and
will be disseminated to government and industry through presentations and
partnerships. Second, in preparing the 100x100 blueprint, fundamental
research advances will be made in security, economics, protocol design, switch
architecture, and network management. These will be disseminated through the
research community. Third, the physical testbeds created through the project
can be used as a platform for further studies, for example, the development of
applications demanding high bandwidth or social science research on the impact
of connectivity in the home. Forth, the software and tools used to design and
validate the 100x100 network, particularly the emulation systems, will be used
to create new curricula for network education for two- and four-year colleges.

Abstract

Program: NSF 04-588 CISE Computing Research Infrastructure
Title: CRI: Wireless Open-Access Research Platform (WARP) - A Scalable and Extensible Testbed for High Performance Wireless Systems
Proposal: CNS 0551692
PI: Sabharwal, Ashutosh
Institution: Rice University

The principal investigators at Rice University will develop the Wireless Open-Access Research Platform (WARP) that promotes a holistic and rapid approach to wireless network design. WARP will be a scalable and extensible platform with three component layers: custom hardware with scalable processing and extensible I/O, platform support packages that provide seamless integration across different hardware components, and an application design environment. They will develop an open-access repository with WWW access that allows WARP users to construct wireless networks, share experiments over the Internet, and implement their networks on their own WARP hardware kits; lastly the investigators will develop a wireless development kit and make it available to other researchers and educators, conduct workshops on use of the WARP system, and host a student exchange program.

This project, developing a platform to overcome the barriers to high performance wireless testbeds, addresses a critical challenge in the shared quest to achieve pervasive high-speed wireless. The work explores how to evaluate and deploy innovative architectures, algorithms and protocols in a real-world environment, without incurring the high costs of conventional custom design cycles. The Wireless Open-Access Research Platform for Networks (WARPnet), built from the ground up, enables researchers, equipment vendors, and network operators to experiment with a vast array of network architectures using a shared set of tools. Key features to be found in WARPnet follow.

-Clean-Slate Programmability in Deployed Networks: WARPnet enables programming of completely clean-slate designs at any layer, while providing access to a rich set of both research and standardized algorithms and protocols at every layer. Furthermore, the WARPnet nodes can be programmed remotely even after deployment, which is crucial to validate, refine, and research new concepts in at-scale networks.
-In-Depth Observability of AT-Scale Networks: WARPnet provides the ability to observe, record, and collect accurate state information at each node in the network at all network layers. The ability to collect fine-grain measurements is crucial to derive accurate network models, understand the impact of new protocols on network efficiency, and gain fundamental understanding of operational networks to facilitate on-line network management.
-Open-Access Collaborative Development: The WARPnet open access repository provides a uniform environment for development of shared, inter-operable components. With both a common hardware and software platform, researchers can reproduce, compare and enhance network instantiations in their local deployments.

The proposal request partial support for young researchers and students to participate in 2007 MobiSys Conference in San Juan, Puerto Rico. The NSF support will provide opportunities for 16 young participants to interact with established researchers. The focus of the conference is on the design, implementation, usage, and evaluation of mobile computing and wireless systems, applications, and services.

The broader impact of the proposal is fostering an environment of technical discussions and debates among the communities of mobile computing and wireless systems. In addition the conference is set out to encourage participation by young scientists and researchers. The intellectual merit of the 2007 MobiSys Conference will be advancing knowledge of mobile system design, implementation, and evaluation.

This project's driving vision is to provide under-resourced urban communities with cost-effective wireless mesh networks, mobile access, and transformational applications including health sensing. This vision will be realized and test-driven via a deployed experimental wireless mesh network in an under-resourced Houston community with experimental mobile devices distributed to community residents. Residents of the community will be engaged with ethnographically-driven qualitative inquiry and analysis to better understand their needs, usage, and user-perceived performance of the wireless infrastructure. This project presents an unprecedented opportunity to holistically study all components of a wireless system, from the end user to the mesh backhaul.

With a multi-disciplinary approach spanning wireless networking, mobile computing, and ethnographic techniques, this project will make fundamental contributions in (i) theory and development of predictable and resilient mesh network services, (ii) design and deployment of usable and energy-efficient mobile access, and (iii) ethnographic evaluation of user impact in under-resourced urban communities.

This project will produce new technologies for optimizing wireless mobile computing and understanding the technological needs of under-resourced urban communities. The experimental deployment in an under-resourced and primarily Hispanic Houston community will provide low-cost access to IT for its residents. Its success will demonstrate the possibility to achieve affordable, economically-sustainable, wireless broadband access for all. The project will offer opportunities for minority students in the universities and the served neighborhoods. Our extensive collaboration with community leaders, equipment manufacturers, and health-care providers will help transfer technologies and lessons for future IT deployments.

This project studies a paradigm in which nodes cooperate by pooling power and bandwidth resources and where flows interact opportunistically to avoid interference and increase network utilization. The PIs will leverage their existing expertise in cooperative and opportunistic communications to analyze the implications for broader networks of communication nodes. In particular, they will instantiate their design philosophy in three ways:


Node Information Management: While previous network analyses considered only isolated aspects of a node (e.g., channel gain), the project studies a comprehensive network state information, which captures not only physical-layer conditions but also higher-layer information such as queue state, processing power, and availability of forwarding routes.


Novel Network Representations: Instead of regarding the network as a simple connectivity graph, the PIs will introduce and develop a network representation which incorporates both temporal and spatial relationships between nodes. The PIs refer to this as the trellis representation of the network, and it will enable us to describe cooperative and opportunistic communication in a wide area network. The trellis will provide a structure in which to identify opportunities for physical layer cooperation, determine the impact of cooperation on neighboring nodes and flows, and opportunistically schedule and route competing flows at fine grained time scales.

Distributed Cooperative Discovery: Traditional discovery protocols for determining network connectivity are unable to identify cooperative links. New techniques will be developed that leverage existing discovery protocols to efficiently locate potential cooperative topologies, which are a key to opportunistic communication. These discovery protocols will recover network state information and enable the use of the trellis representation to identify the optimal cooperative route through the network.

With these tools, the PIs will develop and analyze protocols for coordinating cooperative and opportunistic communications in heterogeneous networks. The new protocols will expand access in underserved areas while increasing throughput in existing networks.


This research will have a broad impact on education by engaging undergraduate and graduate students in the Rice Center for Multimedia Communication (CMC) laboratory. Cooperative communication will be integrated into several courses at Rice in the wireless communication and networking areas. Software and firmware modules as well as publications will be distributed through the WARP open-access repository
(\href{http://warp.rice.edu/trac}{http://warp.rice.edu/trac}).

The collaborative project focuses on the deployment of a complete, scalable, multi-tiered and integrated wireless mobile infrastructure at urban scale that addresses: 1. at-scale design and evaluation of network protocols; and 2. the compilation and analysis of medical health data collected via the integration of medical health sensors into the wireless network. This collaborative project team will develop, deploy, and operate an information technology infrastructure that serves as a platform for research and societal change. The key innovations of this project and platform are:
1. A multi-tier wireless access network with fully programmable and observable nodes that serves 4,000 users over 4 km2 (an at-scale density surpassing existing deployments),
2. A fully instrumented and deployed mobile computing platform that enables joint assessment of user behavior and end system performance, providing energy-efficient and user-friendly access to the network, and
3. A deployed wireless health-sensing platform that monitors and processes physiological data and seamlessly interconnects it with the mobile-computing and wireless network platforms to enable radically new low-cost treatments for chronic diseases.

The research infrastructure will be deployed in an under-resourced area, Pecan Park, a community in the heart of Southeast Houston with 4,760 residents per km2, a density that is unprecedented for research and has not been reached even by commercial mesh deployments. This scale provides a replicable and sustainable template of what is possible in similar communities world-wide. The infrastructure serves as both a platform for societal change and a platform for research innovation and proof-of-concept system design.

The intent of this research is to develop a wireless mobile computing paradigm consisting of cost-effective wireless broadband network, mobile phones, and relevant applications for underserved urban communities. To date, 3G cellular networks, the proposed deployment of urban-scale mesh networks, and penetration of data-ready mobile phones, provide an initial thrust towards this vision. However, this paradigm invites drastically different user experiences and usage patterns from both traditional personal computers based computing and cellular telephony. Consequently, fundamental research questions arise regarding the design of wireless mobile computing to support users from the targeted communities.

This project addresses these questions systematically, leveraging a CRI supported deployment of a large-scale open-access wireless broadband network in Pecan Park, an underserved Latino community in Houston, Texas and the distribution of experimental Wi-Fi capable mobile phones to establish a wireless mobile infrastructure there. The longitudinal study of this community's adoption and use of this network infrastructure will be performed using remote data collection and ethnographic fieldwork. The results will drive an iterative, value-centered optimization of the technology ranging from user-centered mobile computing design to community-driven network management. This approach utilizes multidisciplinary techniques including mobile computing, networking, human-computer interaction, and cultural anthropology to develop new research methods relevant to this emerging research domain.

Broader Impact. The experimental deployment in Pecan Park will provide low-cost access to information and communication technologies for its residents. Its success will demonstrate the potential of wireless mobile computing to address the digital divide for our nation's urban poor. It will produce lessons and insights for future deployments of wireless mobile infrastructures in other underserved urban communities, both nationally and internationally. The project will provide research opportunities for undergraduate and graduate students, primarily from underrepresented groups.

Proposal #: CNS 09-23479
PI(s): Sabharwal, Ashutosh; Aazhang, Behnaam; Cavallaro, Joseph R.;
Knightly, Edward W.; Zhong, Lin
Institution: Rice University
Collaborative with
Proposal #: CNS 09-23484
PI(s): Dacso, Clifford
Institution: Methodist Hospital Rsrch Inst.

Title: MRI/Dev.: Mobile WARP: Platform for Next Generation Wireless Networks & Mobile Applications

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

Project Proposed:
This collaborative project, developing a mobile, open, and all-layers programmable platform for wireless communication systems research, supports the design, development, and dissemination of a community platform instrument, for collaborative architecting next-generation wireless networks and mobile applications, including medical applications. Wireless Open-Access Research Platform (mobileWARP), targets fundamental new research for next generation mobile network clients.
The work involves the following thrusts:
- Programmable and Context-Aware Mobile Platform,
- True Cross-Layer Design Flows, and
- Open-Access for Research and Education.
Mobile WARP will be completely reprogrammable at all 7 layers of the networking stack and will support a touch-based user interface to develop state-of-the-art applications. With battery-operated
portable form factor, it will integrate context measurements from a variety of sensors (location, motion, power consumption, and health) and enable fundamentally new ideas in context-aware networking and applications. Two new design flows will be developed in support of the new hardware, one for the design of energy-efficient networking components on mobile handsets and the other for the design of mobile applications. Each design flow will be architected such that researchers at each layer do not have to learn any programming languages that they traditionally do not use. Lastly, to realize community-powered development, every part of mobileWARP will be open source: hardware designs, sensor subsystems, and all layers of the networking stack. Semester-long courses, laboratory exercises, operational reference designs, and hands-on mobileWARP workshops will also be developed. Reprogrammability at all layers ensures that clean state designs can be verified in a realistic design and testing environment. The platform opens an opportunity to explore merging application domains that could revolutionize the use of wireless. An important category of mobile healthcare for chronic illnesses will serve as a concrete example. Emphasis will be placed on always-available, ultra-low power designs for sensor, processing, and wireless subsystems.

Broader Impacts: Embodying a bold convergence concept, and with a potential for transformative change in wireless networking and mobile applications, the project directly impacts diverse research communities, cross-cutting multiple areas and application domains, including mobile healthcare for chronic illnesses. Furthermore, courses developed, as well as laboratory exercises, allow students to explore all layers of wireless radio communication.

This travel grant provides partial support for young researchers and students to participate in MobiHoc 2009 Symposium in New Orleans, Louisiana, USA and partial support for a workshop entitled, ?The First Wireless of the Students, by the Students, for the Students Workshop? to be held in conjunction with ACM Mobihoc 2009 created by the students, for the students. The intellectual merit of the student workshop is to pursue a unique format that will develop leadership, early-career development and encourage participation in the research community. The student panels will be an early experience with bold, visionary thinking. Moreover, ACM MobiHoc is the premier international symposium dedicated to addressing challenges emerging from wireless ad hoc networking and computing. The broader impact is fostering an environment of technical discussions and debates among the communities of mobile computing and wireless systems. In addition, the event targets to encourage participation by young scientists and researchers and features a ?Networking Networking Women? meeting.

Intellectual Merit. This project will develop the world?s first urban polymorphic wireless access network, a network that can radically transform its basic properties on-the-fly. A key step is deployment of infrastructure and client nodes that can access diverse spectral ranges spanning from MHz to GHz. This unique capability in spectrum access enables revisiting the foundations of network assessment, design, and access. This experimental approach capitalizes on an unprecedented opportunity in an urban community within Houston: In Pecan Park, an underserved community, the project team will serve as researchers, the wireless network service provider, the network equipment and protocol designers, and community-technology educators and advocates. In a coordinated effort using this urban testbed, the project addresses the following three inter-related research thrusts:

CACTUS: cross sectional assessment of community and technology usage: development of a first-of-its-kind network assessment tool that integrates three new methods with existing network trace collection capabilities: (i) sociological assessment of community-technology wireless access objectives from perspectives of both usage and contribution to a collective good; (ii) in-situ user experience assessment via end-user reporting; and (iii) concurrent in-situ client performance tests instantiated remotely by the network operator.

PAWN: polymorphic architecture for wireless networks: employing an urban deployment of nodes that can access spectrum spanning an order of magnitude from 5 GHz to 500 MHz in the Digital TV white spaces range, the project will (i) develop foundations and tools for dynamic network architecture based on assessment of community objectives and usage; (ii) develop foundations and tools for ?green wireless,? energy-efficient architectures which power down low-usage nodes but retain coverage through spectrum adaptation; and (iii) develop foundations and tools for spectrum-driven mobility management, in which highly mobile clients exploit nodes with large spatial footprints (enabled by low spectral ranges) to obtain a performance-velocity profile that was previously impossible.

CODA: context-driven network access: exploiting CACTUS and context awareness, the project will (i) develop context-driven quality estimation of current and future association choices to a polymorphic wireless network and devise client-directed policies for a client to optimize efficiency, performance, and mobility of association; and (ii) design and realize a polymorphic aggregate network interface that dynamically aggregates packets from multiple network interfaces of multiple spectral bands. Using this mechanism and context-awareness, we will study interface selection and traffic allocation for a client to obtain its required performance with unprecedented efficiency.

Broader Impact. With a strong interdisciplinary nature, this project will develop new research methods and yield foundational findings for areas spanning wireless networking to social sciences. The deployment in a low-income community provides access to information technologies for its residents. It will produce lessons and insights for future deployments of wireless infrastructures in other urban communities, including underserved ones, both nationally and internationally. The unique use of DTV white spaces can guide future FCC policy decisions. The project will provide research opportunities for undergraduate and graduate students from a variety of disciplines. It will also produce educational content that can significantly enrich our curricula in multiple disciplines. The project will continue to produce publicly available data sets that have already been utilized by researchers world-wide. The data sets are unique in that they provide unprecedented access to all system components from the end-user to the network.

Current wireless network architectures are based on interference avoidance, which advocates eliminating simultaneous transmissions to avoid collisions at the receivers. However, this design principle is largely an artifact of design simplification. In contrast, if neighboring nodes pool their resources, and cooperate in their signal transmissions, the network could turn interference to its advantage for potentially many-fold increase in network capacity. This cooperative viewpoint necessitates revisiting networking research?s foundations, which are being addressed with a two-part strategy:

1. Network-centric Cooperative Signal Design: Cooperative signaling injects "network" into signal design, thereby breaking conventional boundaries. Nodes have to understand how their transmissions will be perceived, decoded, suppressed, cancelled, enhanced or forwarded by other nodes. This fundamental shift in signal design (from conventional point-to-point PHYsical layer) is being addressed by developing capacity bounds, distributed codes and messaging protocols for scalable cooperation.

2. Signal-centric Cooperative Network Design: The converse to network-inspired signal design is ?signal-centric? network design. Network resource allocation and control have to be cognizant of signal-level interactions between groups of cooperating nodes,? breaking conventional design boundaries in network protocol design. This foundational change is leading to completely new problem formulations in scheduling, routing and protocol design to harness cooperative signal-scale gains.

The project goals are nothing short of rewriting networking fundamentals. By questioning the basic design paradigms, we expect the project will impact research in multiple communities. Our experiment codes and measurements will be open-sourced as community asset. We will also establish a unique inter-university education program including joint advising and collaborative experiments.

PI(s): Knightly, Edward; Reed, William S; Sabharwal, Ashutosh; Zhong, Lin;
Institution: William Marsh Rice University
Title: MRI: Development and Deployment of an Operational and Programmable
Diverse-Spectrum Access Network
Project Proposed:
This project, SPAN, a system for Spectrum-Programmable Access for Next-generation Deployments, proposes a novel instrument and testbed environment with wireless access in diverse spectral ranges, which is open, disruptive and unconstrained by any standard. This project will yield three key developments, including the SPANnode, SPANscope, and SPANnet, which include the wireless node, unique network scale monitoring systems, and a wireless networks, respectively. SPANnode is a programmable wide-band node, with a unique level of high performance, spanning 100 times more spectrum and aggregate multiple bands to yield 4 times greater transmission bandwidth than any currently available open-source platform. SPANnode will yield the world?s first full-duplex transit node and first multi-user beam-forming gateway. SPANscope is a unique network-scale monitoring tool across vast spectral, spatial, and temporal scales. Finally, SPANnet is a wireless network comprising SPANnodes, SPANscope monitors, SPANscope-compliant smartphones, and community-owned legacy 802.11 clients.
SPAN enables research in
- Spectrum Aggregation: The project will develop and experimentally evaluate an algorithmic toolkit that enables network operators to aggregate diverse spectral bands to best meet their service objectives.
- Networked Multi-antenna Services: The project will exploit a novel multi-antenna features to develop new communication modes including multi-user beam-forming backhaul, full-duplex transit nodes, and enhanced security via a managed spatial footprint.
- Network-Scale Energy Optimization: The project will study energy efficiency performance tradeoffs brought by dynamic spectrum access and multi-antenna transceivers to reduce the operational cost of high-performance wireless network infrastructure and improve the battery lifetime.
Broader Impacts:
This project, unique in its goals and expected results, carries potential for large broader impacts in the areas of spectrum policy, standards, industry, and the research community. The measured data sets collected by in the project will be shared with the broader research community. The researcher is potentially transformational. SPANnet will serve primarily Hispanic community, and the project includes outreach to high schools in the underserved community. The project team actively engages multiple Hispanic and under-represented Ph.D. students. All code will be open-source and proposed are the community events that will promote wide usability of the SPANnodes which will be made available to the research community.

This project will develop foundational principles for hierarchical wireless network design by leveraging full-duplex transmissions in both access and wireless backhaul. Full-duplex is most promising at shorter ranges, and hence is fortuitously aligned with the predicted dominant access range in future networks. Furthermore, larger full-duplex ranges are feasible in infrastructure-to-infrastructure links, and hence are well suited for backhaul links. While full-duplex is well-aligned with the key elements of hierarchical networks, our current design principles are largely developed for half-duplex transmissions which is the basis for all current networks. With that in mind, this project will address both theory and protocols for hierarchical full-duplex networks by looking at: (1) data-driven signal models for self-interference caused by the node's own transmission to its own receiver, (2) theoretical foundations for scheduling and routing that leverage both self-interference and multi-hop interference cancellation; and (3) protocols and prototypes for network scale full-duplex resource management.

Full-duplex breaks one of the basic design constraints in current wireless networks, all of which are either half-duplex in time or frequency; it will therefore rewrite wireless networking fundamentals. Further, with emphasis on realizable networks using extensive Rice University's programmable testbeds, the project will impact the next-generation of wireless networks via its corporate partners. Finally, the project team will establish a unique inter-university education and research program, which will include joint advising and collaborative advising and leverage the team's complementary expertise.

Astounding spectral efficiencies exceeding 40 bits per second per Hertz have already been achieved in multi-user MIMO systems. Unfortunately, the coordination needed to facilitate transmissions in space, frequency, and time can severely limit efficiency. Moreover, many spectral bands are today deemed unavailable even if no active receiver is nearby and hence resources cannot be used at all.

This project fuses three integrated thrusts towards achieving high spectral-spatial efficiency (bits per second per Hertz per square meter) with high spectrum availability (permission to transmit in a particular band at a particular location). First, this project enables a new mode of spectrum availability by exploiting smart primary receivers. The key idea is that a typical primary spectrum transmitter such as a TV broadcaster does not have active receivers in all locations. This thrust realizes an architecture and algorithms for smart primary receivers to inform a controller of their usage, creating vast new dynamically available spatial-spectral resources. Second, this project overcomes fundamental limits in the coordination that is today required for spectrum access. This thrust considers channel sounding and user-state coordination to be a foundational resource of system design that must itself be allocated. An integrated suite of new methods for coordination limited MU-MIMO protocols is developed. The final thrust provides an implementation and measurement study. This thrust yields the first demonstration of spectrum access enhanced by smart primary users and the first multi-user MIMO diverse spectrum system enhanced by coordination limited protocol mechanisms. The platform targets "at scale" experiments via use of maximally amplified signals and real-word scenarios spanning from tower-to-user to indoor WLAN.

Mobile data usage is skyrocketing thanks to the popularity of smartphones and tablets. Wireless network carriers are scrambling to increase their capacity by acquiring spectrum and deploying more base stations. Multiple input, multiple output (MIMO) technologies have been widely recognized for their potential to significantly improve the spectral efficiency of wireless communication. In theory, the capacity of MIMO grows with the number of antennas. Because mobile devices are form factor-constrained, the majority of research has focused on placing many antennas on base stations, with aggressive proposals calling for hundreds of them. Such effort has created three pressing needs in wireless research platforms. First, there is a need for base stations with many antennas so that there is flexibility in how antennas are used, both for communication and experimental measurement. Second, there is a need for a network research platform in which emerging ideas that deal with inter-cell interference can be experimentally studied. Finally, there is a need for a network research platform with adequate and distributed computing resources to address the computational requirement and systems challenges of implementing advanced MIMO technologies. This project will develop ArgosNet, a reconfigurable multi-cell research platform that will meet the above three needs. ArgosNet will not only allow cutting-edge ideas for using MIMO to be experimentally tested under realistic settings, but also enable the teaching of them with a real-world experimental deployment.

ArgosNet has three completely programmable key components: (i) a configurable number of base stations each of which can have up to several hundreds of antennas, (ii) battery-powered mobile terminals, (iii) a server cluster that are connected with the base stations with high-throughout, precisely synchronized backhaul. Real-time, wideband communication between base station and terminal will be supported for UHF and 2.4/5 GHz. Base stations will be precisely synchronized via the backhaul and will cooperate to fully support network functions such as handoff and localization. ArgosNet will be digitally and mechanically reconfigurable with a default configuration of three outdoor base stations each with 108 antennas. It can be easily reconfigured to have fewer base stations each with more antennas or more base stations each with fewer antennas. The research platform will be a new infrastructure deployed on the campus of Rice University. The project will develop an open-access repository with the complete hardware and software design for ArgosNet?s many-antenna base station, as well as examples and a toolkit for rapid prototyping with ArgosNet so that other researchers can build similar research platforms at their own organizations.

To meet the exponentially growing demand in mobile data, opening up more spectrum for data services is not enough. The wireless industry and research community are desperately searching for technologies that can use spectrum more efficiently. The trend in wireless networks is reducing cell sizes combined with increasing number of antennas per device and especially, per base station. In theory, the efficiency of spectrum use increases proportionally to the number of base-station antennas; a large number of antennas promises not only a large gain in spectral efficiency but also a much simplified system. However, it remains an open question how these theoretical promises can translate into spectral efficiency gains in practice. Indeed, simply increasing the number of base-station antennas will break today's network system designs at many places, across several layers. The goal of this project is to provide the much needed practical foundations for networking with many-antenna base stations. The project will not only explore novel approaches toward scaling up the number of base-station antennas to 10s and even 100s; but also rethink the entire network architecture exploiting the emergent properties as the number of base-station antennas grows large. With emphasis on realizable network designs using the NSF CRI-funded ArgosNet testbed, the project team will work closely with our corporate partners to ensure that project outcomes impact the next-generation of wireless networks. The project will establish a unique inter-university education and research program, that will involve both undergraduate students and underrepresented populations.

Toward providing the practical foundations for many-antenna MIMO networks, the project goal will be innovations in three related thrusts. (i) Scalable Control and Coordination: the project will develop scalable designs of control and coordination functions for multi-user multi-input, multi-output (MU-MIMO) networks. In particular, it will design a suite of protocols for network-wide CSI collection that significantly reduce its overhead. (ii) Scalable Resource Allocation. The project will develop novel resource allocation solutions for many- antenna MIMO networks in order to support both high data rates and low-latency requirements. It will contribute a novel scalable scheduling framework that use slow-time-scale information or statistical channel information and design scheduling policies based on MIMO rateless codes. (iii) Empirical Foundations from Measurements. The project will perform previously impossible real-time measurements of MU-MIMO channels in order to understand channel correlation, variation and reciprocity and their relationships with spectrum band, mobility, and hardware impairment. In particular, the project will derive novel models, reciprocity calibration methods, and novel channel state representations that will power research in network designs.

The driving vision of this project is to develop the foundations to scale line-of-sight (LOS) Wireless Local Area Networks (WLANs) to Terabit/second (Tbps) throughput and to exploit Tbps LOS interconnections to form distributed arrays in lower frequency bands. Namely, this project first targets to scale millimeter-wave networks with wide aperture LOS spatial multiplexing, thereby overcoming a fundamental limit of the lack of rich multi-path channels at high frequency. The second target is to overcome the inability of high frequencies to penetrate objects and the inability of lower frequency devices to have large arrays on a single client due to physical device constraints. Surmounting these obstacles enables formation of all-wireless distributed arrays with unprecedented properties. The proposed research agenda will enable new dimensions for scaling WLAN throughput and range.This project targets to impact spectrum policy via demonstration of novel usage cases of emerging and diverse spectral bands. This project will show how a design based on wide aperture enables high frequency bands to scale to achieve previously impossible capacity gains. This project will impact standards bodies as it will show how enhancements to existing standards and fusion of diverse bands can yield vast performance gains. This project will impact industry through demonstration of results coupled with the investigators' extensive collaborative industry network. Finally, the project includes an inter-disciplinary education plan and the team includes multiple Ph.D. students from under-represented groups. This project will provide two integrated fundamental advances towards realizing a vision of scaling WLAN throughput and range. The first project thrust is development and fabrication of a wide aperture millimeter wave interconnect with pico-second scale synchronization. The key technique is combining widely-spaced radiating elements into a synchronized and coherent line-of-sight spatially multiplexed transmission. Second, the project exploits the diverse properties of spectrum spanning two orders of magnitude (100 times or 100x). By coupling the aforementioned millimeter wave interconnect (operating at 30 GHz to 300 GHz) with legacy bands (500 MHz to 5 GHz), the 100x architecture will enable long-range spatially multiplexed object-penetrating links. The design will enable a device with a single legacy-band antenna to spoof legacy-band MIMO infrastructure into performing full-rank transmission and reception. A key project outcome will be experimental proof-of-concept demonstrations of all scaling principles and the first experimental realization of distributed legacy-band spatial multiplexing for single legacy-band antenna devices, a mode enabled by tightly synchronized distributed antennas with 100x spectrum diversity.

Gigabit-per-second scale wireless transmission is now feasible: Driven by the wide spectrum availability at 60 GHz, multi-Gb/sec systems are already standardized in protocols such as IEEE 802.11ad and wireless HDMI and are available in commercial products and chipsets, including tri-band chips that support 60 GHz as well as legacy bands at 2.4 and 5 GHz. Moreover, the broad range of millimeter wave spectrum (30 GHz to 300 GHz) is considered a leading candidate by industry, regulators and the research community for the next generation of wireless systems. The project's objective is to realize the next order of magnitude in rate, directionality, and range, targeting both direct line-of-sight (LOS) paths and non-line-of-sight (NLOS) paths that must penetrate objects. The project's goal is to both explore the underlying foundations and to design and implement proof-of-concept systems to (i) realize a WLAN architecture that scales to Tbps via networked mm-wave antennas that form a large effective aperture and (ii) fuse diverse spectral bands spanning two orders of magnitude in order to scale client array size, and subsequently capacity, beyond the physical constraints of the device.

The driving vision of this project is to break the Terabit/sec networking barrier through fundamental research, prototype designs, and proof-of-concept field trials. This project will realize the first Tb/sec transmission from a tower to four aggregated clients, each at 300 Gb/sec and 300 meters. The project will simultaneously realize the most diverse spectrum access tower ever deployed, spanning from 500 MHz to 100 GHz. The tower is located in an economically disadvantaged area of Houston, Texas, and will serve the local community. Through Technology For All, the project team has a history of engaging the local community spanning from broadband access to technology training. The project outcomes will provide a template for other communities in the US and globally. This project targets to inform and impact spectrum policy and the FCC via demonstration of novel usage cases of emerging and diverse spectral bands. This project will impact future standards by demonstrating what is feasible in new and diverse bands. This project will impact industry through demonstration of results coupled with the team's extensive collaborative industry network. Finally, the project includes an inter-disciplinary education plan and the team includes multiple Ph.D. students from under-represented groups.

The project's objective is to fundamentally advance today's Gb/sec-scale systems and realize terabit-per-second wireless networks for both fixed backhaul and mobile access. Breaking the Tb/sec barrier requires a 100x increase in rate even beyond expected gains realized from 5G advances such as massive MIMO and full duplex. To realize this vision, the project team proposes the following integrated research thrusts. The first project thrust is development and fabrication of a 10,000 element transmit and receive array at 100 GHz. The key technique is a modular digital-to-impulse on chip radiating design that provides unprecedented directivity. Second, the project targets Tb/sec aggregate access to mobile clients by (1) exploiting the properties of spectrum spanning over two orders of magnitude for high-directivity sender-receiver beam alignment and (2) incrementally aggregating polarized clients to enable simultaneous transmission to multiple clients while controlling inter-stream interference. The final project thrust realizes deployment of all system components on a 20 meter urban tower along with multiple client sites. A key outcome will be an extensive measurement campaign of throughput and its underlying determinants in both operational and controlled testing scenarios.

The driving vision of this project is to detect Volatile Organic Compounds (VOCs) through ASTRO, a platform for autonomous 3-D data-driven mobile sensing via networked drones equipped with gas sensors. VOCs are hazardous to human health and the environment; they are released by explosions, gas leaks, and industrial accidents prevalent in low-income and under-resourced urban neighborhoods in close proximity to industrial processing plants, chemical refineries, and other sources of airborne pollutants. The project is located in an economically disadvantaged area of Houston, Texas. With Technology For All (TFA), the project team has a history of engaging the local community via broadband access, technology training, and connected health. The TFA wireless network already serves 1000's of community members in several square kilometers in Houston's East End via a mix of commercial Wi-Fi and software defined radios. The project targets realizing a high-resolution ground truth of environmental conditions in low-income urban areas which can impact emergency response procedures and environmental justice via policy and law. The project will develop a mobile app that alerts community residents of hazardous VOC concentrations near their current location. This project will impact urban areas with a demonstration of fusing next generation environmental sensing with next generation wireless access via networked drones.

The project's objective is to realize an unprecedented resolution in VOC sensing by development and demonstration of ASTRO, a system for networked drone sensing missions without ground control. ASTRO will realize the unique capability to dynamically move sensors in 3-D according to real-time measurements. Consequently, networks of drones with on-board sensors can find and track VOC plumes, solely by coordinating among themselves, and without requiring a centralized ground controller. Two inter-related thrusts will realize this vision. The first is target detection, tracking, and modeling high VOC concentration clusters, targeting health and environmental safety. The second is development of the underlying principles and methodologies for data-driven mobile missions via drone networks. The project's outcomes will include lightweight machine learning methods that provide foundations for real-time distributed autonomous sensing with environmental and health objectives. These data sets will yield development of atmospheric models of VOCs at a finer resolution than is possible today. Moreover, the outcomes will also include methods for adaptive communication among the networked drones via software defined radios that can adapt their network topology and spectrum usage to realize mission objectives.

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.

The objective of this project is to design the next generation of Wireless Local Area Networks (WLANs) that will meet the ever-growing demands for more spectrum, higher densities, and higher degrees of robustness, moving closer towards the vision of multi-Gigabit-per-second (Gbps) connectivity everywhere. Via a combination of physical (PHY) and link layer innovations, the project will design the first S-T (Sixty Gigahertz to Terahertz) WLAN offering multi-Gbps and Terabit-per-second (Tbps) data rates, supporting both downlink and uplink multi-user multi-stream communication, and providing robust always-on connectivity. The project outcomes are relevant to a very broad segment of the population who use Wi-Fi in their daily lives. The project aims to inform spectrum policy via demonstration of novel use cases of emerging and diverse spectral bands. It will impact future standards and industry through demonstration of results in new and diverse bands coupled with the team's extensive collaborative industry network. Finally, the project includes an inter-disciplinary education plan and the team includes multiple graduate students from under-represented groups.

The project will fundamentally advance today's single user, millimeter wave Gbps WLANs by scaling them in spectrum, user density, and robustness via three integrated research thrusts. The first thrust will develop new PHY layer techniques that maximize the utilization of the multi-Gigahertz (GHz) wide channels available in S-T communication systems. In the downlink, novel bandwidth hierarchical modulations are proposed as a way to enable simultaneous transmissions from users within the same transmit antenna beam. In the uplink, novel multi-beam codebooks will be designed to increase the path diversity and enable simultaneous directional transmission from users within the same area towards a common access point (AP). The second thrust will first explore the empirical limits of multi-user multi-stream communication in S-T bands. It will then design and evaluate low-overhead user and beam selection protocols for enabling downlink and uplink multi-user multi-stream communication in S-T WLANs, leveraging the hierarchical modulation schemes and multi-beam codebooks from the first thrust. The third thrust will design the first PHY-assisted link adaptation framework to realize robust S-T WLANs. The thrust will develop algorithms that leverage unique PHY layer metrics to diagnose the cause of link degradation and perform fine-grained mobility and blockage classification. These algorithms will be leveraged to determine when to trigger adaptation and select the right adaptation strategies in different scenarios. All the proposed solutions will be experimentally evaluated on a one-of-its-kind testbed spanning three different segments of S-T spectrum - 60 GHz, 300 GHz, and 1 THz.

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.

The project's objective is to develop the foundations for realizing denial of service (DoS)-resilience, secrecy, and high throughput in next-generation wireless networks in which base stations or access points (APs) scale their antenna and computing resources to massive multiple-input/multiple-output (massive MIMO). This project considers a practical yet strong adversary that launches both active attacks, attempting to collapse network throughput by polluting AP measurement of Channel State Information (CSI), as well as passive attacks, that attempt to intercept communication via potentially distributed and nomadic eavesdroppers. The first project thrust targets to detect and defend against pilot contamination attacks with zero startup cost, i.e., without requiring prior measurements of conditions without an attack. The second project thrust experimentally explores passive eavesdropping under realworld factors such as a large but finite number of antennas and a discrete and limited set of modulation and coding schemes (MCS). With a discovery of MCS saturation vulnerability, the project will study power control designed to overcome this vulnerability and thwart the adversary. On the uplink, the third project thrust develops antenna index coding as means to target reception on a subset of the massive MIMO array. A key outcome will be both derivation of the secrecy rate as well as experimental evaluation of this new mechanism. All three project thrusts will include an extensive experimental study using the Rice massive MIMO platform and over-the-air measurements. As computing and communication resources must be devoted to realizing the aforementioned counter mechanisms, this project will yield empirical understanding of the tradeoffs in realizing both high spectral efficiency and security.

The proposed research agenda will enable new wireless security defenses and will provide an in-depth understanding of securing next generation communication systems such as massive MIMO. This project will yield new understanding of the design space that spans from traditional throughput optimization to jointly realizing security features and providing security by design. This project will yield new understanding of the security capabilities and limits of designs based on CSI as a shared secret. This project will impact standards bodies as it will expose fundamental limits of existing security mechanisms and will show how enhancements to standards can yield dramatically improved security capabilities. This project will impact industry through demonstration of results coupled with the researchers' extensive collaborative industry network. Finally, the project includes an inter-disciplinary methodology and the team includes multiple Ph.D. students from under-represented groups.

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.

Since the days of Marconi, critics complained that wireless transmission lacked security and was so slow that a boy on a pony would be a faster way to transmit a message, as Lord Byron famously quipped in 1898. Over a century later, terabit-per-second links in terahertz (THz) scale spectrum are around the corner and highly directional beams have been decreed secure by design. However, even THz links can become "too slow" if they suffer from outages while repeatedly re-aligning beams for mobile clients. Likewise, while 60 gigahertz (GHz) bands have been lauded for their improved security, unfortunately, even pencil-beam THz-scale links can be vulnerable to agile eavesdroppers. Consequently, this project targets to design, implement, and experimentally explore proof-of-concept systems to realize a Wireless Local Area Network (WLAN) architecture with efficient and secure access to spectrum from 100 GHz up to 1 THz and WLAN-scale range up to 120 meters. This project will build on fundamental new transmission capabilities enabled by THz-scale devices and spectrum.


The first project thrust will realize Leaky X-Agon, a first-of-its-kind multi-face leaky waveguide WLAN architecture. This architecture couples frequency and steering angle to provide frequency-selective adaptive beam steering enabling unprecedented spatial density of links. Moreover, a new foundation for beam steering and frequency selection is realized via transmission of a wideband "THz rainbow" on each face: by emitting different frequencies at different angles, the receiver can identify all propagation paths and their steering angles simultaneously, as opposed to time-consuming and inefficient trial-and-error testing that is commonly employed today. The second project thrust addresses security and provides experimental analysis and counter-measures for securing spectrum access from 100 GHz to 1 THz. Under a strong adversary threat model, this project thrust will develop methods using THz backscatter and THz rainbow distortion to detect and avoid objects that an eavesdropper may be using to aid interception of a transmission. Moreover, a novel absorption tuning method is proposed to tune the transmission range so that interception beyond the location of the intended receiver is not viable. Using accurate empirical models, the method will tune the carrier frequency to be close to that of a water vapor absorption resonance, yielding exquisite control of the atmospheric propagation loss, and therefore of the transmission range. All project components feature an extensive implementation and experimental plan for over-the-air experiments and validation.

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.

The use of frequencies above 100 GHz for wireless communication is rapidly emerging as a key enabler for future (beyond 5G) wireless systems. These high-frequency systems, which are referred to as terahertz (THz) links, offer numerous exciting possibilities, such as ultra-high-speed data transmission and enhanced resilience against malicious attacks such as eavesdropping. Yet, so far, little research has been devoted to the question of how to implement a network that can provide high bandwidth links for multiple mobile users, while still maintaining security against eavesdroppers. The objective of this proposal is to develop the hardware and protocols necessary to implement a secure network for mobile users which efficiently exploits these high frequencies. The research team will develop a set of methodologies to enable a base station to rapidly locate multiple users in a broadcast region (even if they are moving), to establish high-speed wireless links with each of them, and to detect and mitigate eavesdropping attacks. In addition, the project includes a coordinated plan for broadening participation of traditionally<br/>under-represented groups, and includes a one-week summer course on THz research for high-school students.<br/><br/>The overarching goal of this project is to develop a radically new node architecture which can intrinsically support multiple access for mobile clients in a broadband THz network, while also maintaining a high degree of security. One thrust of this project involves the exploration of novel antenna designs which exploit strong angular dispersion. We propose a new method to enable active fast electrical tuning of such devices which will be exploited for detection of an eavesdropping attack, as well as for localization of legitimate users and mobility detection. A second project thrust aims to develop spatio-temporal modulated array architectures for scrambling the information contained in side-lobes of the broadcast, via spectral aliasing. Combined with agile sensing functionalities, the proposed interface will selectively create secure zones for communication. In a third thrust, we will leverage the power of this new node architecture to ensure that the quality of service for multiple mobile users is maintained, even while guaranteeing that eavesdroppers are unable to access, not only the primary communication channels, but also control plane functions required to establish and maintain mobile links. The result will provide the optimal performance for a spectrally efficient and secure THz network, even in the presence of a sophisticated attack by colluding eavesdroppers.<br/><br/>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.