Behnaam Aazhang - US grants

This project will investigate the problem of multiple-access communications through non-Gaussian channels via spread-spectrum modulation. It is motivated in large part by the fact that modern urban radio networks must operate in complex and variable noise environments that are often dominated by impulsive, non- Gaussian man-made and natural noise sources. Non-Gaussian disturbances are now known to be present in many situations, and they can greatly reduce the performance of conventional digital communication systems. The overall purpose of this research is to develop new design methods suitable for multiuser systems operating in such non-Gaussian channels. The study can be divided into two principal tasks to be considered. There are the development of time and phase synchronizers; and the design of "optimum" nonlinear, coherent, spread-spectrum receivers in non-Gaussian noise. In many applications, in the presence of non-Gaussian noise sources, the impulsive and transient characterisitics of noise suggest that a nonlinearity in the receiver structure can significantly reduce the effective noise power by reducing the large voltage deviation caused by noise impulses. Thus it is proposed to design and analyze the performance of optimum memoryless nonlinearities for synchronization and correlation reception. Possibilities of introducing memory in the structure of receivers will also be explored. It is anticipated that the results of this study will find widespread application in urban and military mobile radio networking and low frequency communications.

ABSTRACT: NCR-9506681, William Marsh Rice University, Algorithms and Architectures for Channel Estimation and Multiuser Detection in CDMA Communication System, PI-Behnaam Aazhang and Joseph R. Cavallaro: There are three major problems in using multiuser detection for the next generation cellular CDMA networks: estimation of the signal and channel parameters, real-time hardware implementation of multiuser estimation and detection algorithms, and system adaption to changes in the network. This project addresses the development and concurrent implementation of algorithms for channel estimation and data detection in a multiuser environment. The objective is to find computationally efficient algorithms that are near-far resistant, are capable of tracking slowly varying channels, and can be extended to systems with antenna arrays. An integral part of the project is the implementation of these algorithms. The mapping of the algorithms onto parallel architectures, particularly using standard DSP processors in combination with custom VLSI co-processors will be studied. The project combines developments in multiuser communications with developments in DSP and VLSI to provide practical solutions for problems in CDMA communications. ***************************************************************************** Aubrey M. Bush
Program Director, Acting Deputy Divison Director
Division of Networking and Communications Research and Infrastructure
National Science Foundation

Adve, Sarita V. Aazhang, Behnaam Rice University CISE Research Instrumentation: Design and Evaluation of Architectures, Programming Environments, and Applications for Shared-Memory Systems This research instrumentation grant facilitates acquiring a shared-memory multiprocessor to support the following research projects: -Design and Evaluation of ILP-Based Shared-Memory Multiprocessors -Parallelizing Compilers for Shared-Memory Systems- Interactive and Adaptive Techniques for Tuning the Performance of Shared-Memory Parallel Programs -Parallel Algorithms for Communications Systems -Signal and Image Processing. The following research is thus enabled:- Architectural techniques to exploit instruction-level-parallelism in shared-memory multiprocessors: Fast simulation methods are the key enabling technology for this research. The proposed multiprocessor enables the development and use of high-performance parallel simulators. - Compilation techniques for High Performance Fortran (HPF): The proposed multiprocessor is a cost-effective platform for HPF compiler development and an important target for evaluating the compiler-generated parallel code. - Runtime techniques to identify and remedy performance bottlenecks in shared-memory programs: The multiprocessor is the desired platform to develop and evaluate the techniques. - Algorithms for wireless and network communication systems: Most such algorithms must meet stringent real-time constraints. The multiprocessor enables the development of parallel algorithms to meet these constraints.- Algorithms for signal and image processing for applications including geophysics, radar, and medical imaging diagnostics: The multiprocessor is needed to test and develop parallel and resource-intensive sequential algorithms on real data sets. Overall, the proposed system enables the above research in three critical ways: enables parallelization of applications that cannot be run sequentially, provides a testbed for compiler and tools research, and provides cost-effective resources for sequential but resource-intensive tasks.

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.

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.
.

This project, developing a Distributed National University Wireless Testbed in cooperation with multi-disciplinary multi-university teams from UCLA, U Mass, and Ohio State, promotes the sharing of resources and expertise among various universities. The work leads towards a national experimentation infrastructure that can serve the wireless communication research and engineering community. The infrastructure enhances the existing local wireless testbed at Rice, contributing to the development of a distributed wireless testbed, and enabling researchers to access a wireless testbed in different remote university sites through web interfaces. The platform, intended to serve as a flexible, programmable, and publicly available testbed, provides a seamless integration of experiments with theory, supporting the following research activities:
Reconfigurable Wireless Architectures,
High Data Rate Communication, and
QoS Scheduling and Modeling for Dense Wireless Networks.
The web-enabled testbed allows researchers to test, validate, and design RF, baseband, VLSI, and networking components of future systems. At Rice, the research platform will be composed of programmable and configurable multiple antenna wireless communication transceivers based in high speed baseband processors, RF transmitters and receivers, channel emulators, and a programmable RF switching matrix.

Providing students a more well rounded education, this experimental communication research offers a
distinct advantage over a more traditional academic/theoretical research environment. The distributed research and educational platform will also be utilized for outreach activities, both on campus and via the web interface.

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.

High Data Rate Wireless Networks: A Power Efficiency Perspective

B. Aazhang and A. Sabharwal

Department of Electrical and Computer Engineering, Rice University


In the last five years, there has been a cultural shift from wired landlocked connectivity to pervasive wireless information access. Most emerging mobile devices are now equipped with some form of embedded wireless radio. The expectations of high data rates and increased battery longevity have put tremendous pressure on all aspects of wireless system design. To meet the challenges of next generation wireless systems, there is a need for fundamentally new understanding in cross-layer design as well as new methods which exploit all available dimensions for optimizations. The following agenda outlines the key elements of the research framework we are pursuing to
achieve increased power efficiency while simultaneously increasing system wide throughput.

1. Fairness, delay and power efficiency: Traditionally network protocols address throughput fairness
among users and delay requirement of applications while communication algorithms address location dependent reliability, transceiver power, and channel access. This project develops a framework to systematically analyze and design power efficient access and scheduling protocols. Using short time scale channel variations along with source burstiness, the minimal power opportunistic scheduler will meet delay requirements while maintaining a system wide statistical fairness.

2. Scalable space-time codes: To achieve the gains from packet and flow scheduling, it is critical that the physical layer coding be able to serve the scheduled data rates. At the same time to achieve high levels of spectral and power efficiency, it is important that the coding methods exploit as much information available regarding the channel at the transmitter. Thus, the design space targeted by this research project covers a wide range of mobile speeds and channel conditions. In particular, space-time codes are designed that have either imprecise or no channel information at the receiver with no information at the transmitter, covering high to medium mobile speed communications. And for low speed mobiles, the project addresses the fundamental issues in the design of efficient feedback channels for space-time coding methods.

3. Integration into wireless research platform: The strong theoretical innovations for low power
design are tested on the rapid prototyping platform for multiple antenna systems at Rice University. The end-to-end system design and development is stress tested, and the power and spectral
efficiency of the overall system is quantified.
The ongoing research paves the way to understand the fundamental relationships among spectral efficiency, algorithm complexity, and power consumption to increase the utility of wireless capable mobile devices and to directly impact their emerging market. The broader impact of the project on education is ensured by engaging a large number of undergraduate and graduate students in projects in our laboratory.

The proposal requests partial support for young researchers and students to participate in 2006 IEEE Communication Theory Workshop in Dorado, Puerto Rico. The NSF support will provide opportunities for 20 young participants to interact with established researchers in a small workshop setting. The focus of the workshop is on the interplay between communication theory and networks.

The broader impact of the proposal is fostering an environment of technical discussions and debates among two different communities of communication theory and networking. In addition the workshop is set out to encourage participation by young scientists and researchers.

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 operational spectral efficiency of wireless networks is typically far lower than the spectral efficiency of underlying physical layers. This reduced spectral efficiency is primarily due to protocol overhead,
which consists of transmissions that do not depend on information bits, in both physical and network layers. However, none of our analytical models allow a coherent and complete accounting for protocol overheads in the system. Using the viewpoint that network protocols manage time-varying unknowns, this research is
developing fundamentally new methods to account for all resource consumption in wireless networks.

The key innovation is the use of a two-way channel formulation to account for all resource usage, whether it is for feedback, state estimation or transmission of data. In the two-way formulation, each node has data for other nodes in the system, and hence all nodes are both receivers and transmitters. With the two-way structure at every node, data-independent transmissions are jointly coded with the data-dependent transmissions to allow a coding-theoretic analysis of finite, noisy side-information transmission. The investigators study both fading channels and bursty sources, and derive new performance bounds and protocol classes.
The new protocols classes can then be used to derive practical protocols which dramatically reduce overhead in real wireless systems.

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 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}).

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.

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.

This Integrative Graduate Education and Research Traineeship (IGERT) award provides Ph.D. students at Rice University with innovative training in neuroengineering, spanning the disciplines of neuroscience, electrical engineering, mechanical engineering, and bioengineering. In collaboration with Baylor College of Medicine and seven other universities and participating organizations, Rice University trainees are developing the tools to understand, interface with, model, and manipulate the nervous system.

Intellectual Merit: Due to improved technologies that enable neuroscientists to interact with brain cells, and due to the increasing types of neuroscientific data collected through electrical and optical methods, the neuroengineers who create and work with these complex data sets require highly specialized training. This program trains students in three specific areas: (1) cellular systems neuroengineering, which studies the nervous system?s signaling processes at the molecular and cellular levels; (2) engineering multi-neuron circuits, which involves collecting and analyzing data from groups of brain cells and devising methods to induce them to produce new functional responses; and (3) translational neuroengineering, which develops systematic approaches to improve clinical devices such as prosthetics and deep brain stimulators. Trainees in this program are learning to be technologically innovative; to be aware of social, cultural, and ethical aspects of neuroengineering; to communicate their work effectively to a wide variety of audiences; and to understand the pathways to commercialize their discoveries.

Broader Impacts: As this program trains neuroengineers to develop advanced solutions to functional and structural problems in the brain, a new problem-based learning curriculum will result and will be shared with the public through open education resources. By cultivating relationships with biomedical device companies, international researchers, and collaborators within two minority-serving institutions in Texas, students in this program are expanding the applications of their training and increasing participation in their research.

IGERT is an NSF-wide program intended to meet the challenges of educating U.S. Ph.D. scientists and engineers with the interdisciplinary background, deep knowledge in a chosen discipline, and the technical, professional, and leadership skills needed for the career demands of the future. The program is intended to establish new models for graduate education and training in a fertile environment for collaborative research that transcends traditional disciplinary boundaries, and to engage students in understanding the processes by which research is translated into innovations that benefit society.

The classical approach to wireless communication is to isolate communication links by maximizing signal strength and minimizing interference between users. This simple philosophy is supported by a rich theoretical foundation which has inspired powerful coding techniques and protocols that lie at the heart of modern wireless systems. However, these systems have recently become victims of their own success as the rising density and data requirements of wireless devices have led to a surge in interference. Fortunately, an emerging body of work indicates that the phenomenon of interference may in fact represent an untapped opportunity for increasing the spectral and energy efficiency of next-generation wireless systems. Although many interference-aware communication strategies have been proposed in the literature, the promised gains have been mostly limited to the theoretical realm.

The objective of this project is to create practical interference-aware wireless protocols that can operate near the performance predicted by theoretical bounds in terms of throughput, energy efficiency, and reliability. The project is organized into three complementary thrusts that encompass theory, algorithms, and practice. The first thrust investigates lattice-based constellations and low-complexity codes for the compute-and-forward strategy, which enables receivers to decode linear combinations of transmitted codewords. Compute-and-forward can in turn be used as a building block for realizing interference-aware protocols such as physical-layer network coding and multiple-user MIMO (multi-input-uulti-output) systems. The second thrust aims to implement these protocols on a three-node WARP (Wireless Open-Access Research Platform) testbed. A series of carefully designed experiments will be used to compare the performance of interference-aware strategies while accounting for overhead costs. The third thrust leverages the data collected from these experiments to revise channel models to capture key features that impact the performance of interference-aware strategies such as asynchronism and channel fluctuations. These models will be used to revisit the theoretical foundations of interference-aware strategies and tailor them to the channels encountered in practice. This project features several outreach efforts including undergraduate research experiences connected to the WARP testbed and a public repository of training modules and videos.

Understanding the relationship between brain activity and human behavior is not only one of the most important scientific challenges of our generation but also one of the most important challenges in medicine and public health. This project develops new technology that can address the minute size of the neurons, and the vast amount of data generated by neural activity. This project leverages the collaborative environment between Rice and Texas Medical Center to develop novel electrical stimulation approaches to modulate the seizure network, adaptively and selectively. If successful, the end result would be a reparative therapy that leverages inherent brain plasticity mechanisms and may one day be independent of chronically implanted electronics.

This project develops algorithms that capture the dynamic, frequency dependent connectivity of the brain from real-time monitoring of the brain using ECoG (Electrocorticography) and then identifying the "optimal" parameters of the LFS (low-frequency electrical stimulation) to modulate the connectivity of the epilepsy network with temporal and spatial precision. The complexity of modeling such connectivity in real-time is managed by first segmenting neural activity into different epochs and spectral bands and then deriving the sparse connectivity in each of the segments. Effective connectivity in each spectral-temporal segment is estimated using Granger causality. LFS is applied after detecting interictal epileptiform discharges (IEDs) at spatial locations identified from the model. These critical steps lead to the development of a prototype system of real-time stimulation with a natural trade-off of complexity versus accuracy prompting a compromise between battery life and efficacy. The efficacy of spatially-optimized, activity-triggered LFS is evaluated by measuring the irritability of the seizure network and comparing the rate of IEDs detected during pre- and post-treatment periods. These experiments would point the way to treatment of pharmacologically refractory epilepsy without surgical resection of brain tissue and lead to reparative therapies leveraging inherent brain plasticity. The proposed methodology presents the first of its kind reparative, real-time, and selective network modulation to treat a debilitating disease.

With the rapid growth of demand for ever-increasing data rate, spectrum resources have become more and more scarce. As a promising technique to increase the efficiency of the spectrum utilization, cognitive radio (CR) technique has the great potential to meet such a requirement by allowing unlicensed users to coexist in licensed bands. In conventional CR systems, the spectrum sensing is performed at the beginning of each time slot before the data transmission. This unfortunately results in two major problems: 1) transmission time reduction due to sensing, and 2) sensing accuracy impairment due to data transmission. To tackle these problems, a new design for future CR is proposed by exploring the full-duplex (FD) techniques to achieve the simultaneous spectrum sensing and data transmission. The aim of this proposal is to transform the promising conceptual framework into the practical wireless network design by addressing a diverse set of transformative challenges such as protocol design and theoretical analysis. The educational plan will provide interdisciplinary training for graduate and undergraduate students. Active student involvement is ensured via mentoring, research involvement, and participation in testbed development. Outreach events targeting high school students, particularly women and minority, will be organized. Broad dissemination is guaranteed via publications, tutorials, workshops, and online tools.

The proposed research aims at laying the foundations of FD CR networks via an interdisciplinary framework that synergistically marries concepts from signal processing, wireless communications, networking, and RF hardware design to yield several innovations: 1. With multiple input and multiple output (MIMO) FD radios, secondary users can simultaneously sense and access the vacant spectrum, and thus, significantly improve sensing performances and meanwhile increase data transmission efficiency. The research issue is using MIMO to jointly considering primary user receivers and FD self-interference. 2. Classic CR networks using listen-before-talk, while FD enable listen-and-talk, which can significantly improve the network performances. The research issues are to investigate the tradeoffs. 3. The classical multiple random access protocol is based on carrier sensing multiple access/collision avoidance (CSMA/CA), while FD enables collision detection (CSMA/CD). The research issue is to analyze the performances under self interference. 4. The proposed FD network protocols will be tested using WARP boards equipped with MIMO technology.

Humans produce language, which is a defining characteristic of our species and our civilization. We can select words precisely out of a large lexicon with remarkably low error rates. It is perhaps not surprising that this complex speech production system is easily affected by disease. Brain damage induced language disorders affect millions of Americans, and there is little hope of remediation. Research on the anatomical, physiological, and computational bases of speech production has made important strides in recent years but this has been limited by a glaring lack of information on the dynamics of the process. This limitation results from the low spatio-temporal resolution of the available tools to collect data and the effectiveness of the current tools for analysis. Our driving vision in this project is to develop an unparalleled understanding of cortical connectivity in the human language system at small spatio-temporal scales. We possess much expertise in signal decoding of the processes of cued word production with intracranial recording techniques, as well as using cortical stimulation to modulate the system. FDA-approved arrays will be used to perform closed-loop decoding of sensorimotor processes during speech production and transient neuromodulation of the language system in patients with epilepsy undergoing intracranial electrode placement for the localization of seizures. Ultimately though, the fine-grained understanding and representation of sensorimotor loops in the language system necessitates the development of ultra-small energy efficient detectors that will enable the knowledge gained in this exploratory project to be eventually applied in patients who have sustained neurological injuries that have resulted in pervasive language impairments. This integrative project brings innovative microelectronics technologies together with state of the art large data analysis techniques to begin to develop a first of its kind system to remediate language disorders.

The engineering objective is to develop biocompatible microchips to vastly enhance our insight into language and other cognitive processes and learning. Miniaturized microchips in silicon technology will be developed that can record neural signals, digitize them, and transmit the signals to an in vitro receiver wirelessly. The three-fold thrust of the project will be integrated when the PIs develop closed-loop real time decoding and transient neuromodulation system based on a population of miniaturized detectors and neuromodulators. The system has the potential to provide an unprecedented detailed understanding of the human language system and provide the framework and hardware for neural prosthetics in patients with aphasia and other language disorders. The project embodies multiple high-risk goals that have the potential to shift neuroengineering paradigm from recording and modulating in only a few regions of the brain to deploying a population of ultra-small and energy efficient detectors-modulators.

This project will begin by questioning the basic design paradigms of wireless networks, where there are limited spectral resources for a large population of users needing a diverse set of services. The ultimate goal of the project is to expand the application base of wireless networks from wireless Internet, to include scalable mobile healthcare, first-responders, security applications, transportation, factory automation and robotics. The main strength of the project will be to bring theoretical foundations, as well as system level designs and algorithms to develop a realizable network. The PIs plan to work closely with their industrial partners to ensure that project outcomes impact next-generation wireless networks.

This research presents a fundamentally novel approach to address spectrum efficiency that reflects the shifting nature of networking philosophy as networks migrate from the classical paradigm of well-defined users and operators to the notion that networking is a tool for the provision of services. Then the primary objective of future service centric networks is to distribute content and to provide fresh information about on-going processes. Over the last few years, the rise in the number of different wireless services has put unprecedented pressure on providers' networks, to the point that current architectures cannot scale to meet the exponential growth of users' demands and the dissimilarities in the services. To confront the crisis, this research meets the required paradigm shift away from a static view of users' needs and in accord with a vertically integrated architecture to harness features of the services. The driving vision in this project is to architect a wireless network with a prevailing service centric philosophy. The concept of network-wide cognition is introduced in this endeavor to explore attributes and disparities of these services as well as heterogeneity of network nodes. Exercising 'true cognition' at the physical layer, nodes in the network will be assumed to operate with flexible radios and that the network is agnostic to the radio access technology; however, the network will be designed to exploit this flexibility. Therefore, the concept of network- wide cognition substantiates across several layers of wireless network design and revisits core network foundations in two coupled thrusts one on scheduling for service centric networking and the other on network provision for delay sensitive services.

Cardiovascular disease is the number one cause of death worldwide. For example, heart failure is a significant source of mortality within the U.S; it is responsible for 1% of all emergency room presentations and contributes to one in every nine deaths. A significant proportion of heart failure patients have concurrent conduction system disease, which will lead to their eventual death. Cardiac resynchronization has proven to be a useful therapy for improving cardiac function as well as reducing mortality in some patients. However, a significant number of patients fail to respond to resynchronization therapy, often due to inadequate pacemaker lead placement. There currently exists no pacemaker system that provides the 'potential' benefits of multisite temporally and spatially precise pacing for resynchronization. To reach the audacious goal of eliminating cardiovascular diseases, new technologies must be developed that will monitor the diseased heart with unprecedented temporal and spatial precision and will manage the pacing of the heart to restore a healthy function of the heart. This project will process data recorded from multiple sites and will generate a pacing therapy specific to the patient in real-time.

The award revisits the core foundation of pacemakers to develop temporally and spatially precise pacing at multiple sites for resynchronization. The researchers will develop a robust, well-annotated database of intra-cardiac electrograms (IEGM) from multiple cardiac sites. The focus will be on identifying challenging cases that are clinically difficult to differentiate and, thus, stand to reap the greatest benefit of being able to direct overall algorithm development. This information will be added to the associated metadata file. Data will be collected from a minimum of 150 patients with at least 50 patients from each identified pathophysiology. Pathology of each patient based on data from multiple intra-cardiac recording sites will be identified. The proposed machine-learning pipeline explores the representation of time series using wavelets and then learns transformations of multiple time series using the Lie group framework. This pipeline clusters time-series data to identify the right pathology for the specific patient. In addition, the project explores implementation as an application specific integrated circuit (ASIC) that will be implanted subcutaneously to continuously process intracardiac multi-site recordings as well as to generate temporally and spatially precise pacing patterns. The overall approach is to holistically develop a methodology that can address an extremely low-power implementation of machine learning and signal processing algorithms, by not only combining, but jointly optimizing, algorithmic-, circuit- and architecture-level innovations.

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.

PROJECT SUMMARY/ABSTRACT Social interactions, a ubiquitous aspect of our everyday life, are critical to the health and survival of the species, but little is known about their underlying neural computations. The major limitation preventing our understanding of the neural underpinnings of social cognition is the lack of a suitable framework to allow us to study how it emerges in real time from interactions among brain networks. Indeed, examining the neural bases of complex social interactions has been traditionally performed by studying the brain of nonhuman primates in a laboratory environment in which the head and body are restrained while synthetic stimuli are presented on a computer monitor. However, it has become increasingly understood that studying the brain in spatially confined, artificial laboratory rigs poses severe limits on our capacity to understand the function of brain circuits. To overcome these limitations, we propose a novel approach to understand the neural underpinnings of social cognition. We will use a high-yield wireless system to study the cortical dynamics and plasticity of social interactions by recording population activity in multiple visual, temporal, and prefrontal cortical areas while nonhuman primates are interacting freely with their environment and with other animals. This new approach will enable us to uncover the dynamics of neuronal network activity that drives social interactions in an ethologically relevant behavioral task that involves sensory integration, memory, and complex decision-making. Our integrative project brings together innovative brain recording technologies and microelectronics together with large data sets analysis techniques. Our proposed research will constitute a paradigm shift by moving social neuroscience ? from simply observing animal behavior and recording the responses of single cells ? to a quantitative understanding of the distributed neuronal network encoding during social behavior in freely moving nonhuman primates performing rich naturalistic tasks. We anticipate that the large quantity of neural data recorded using our approach will be of great interest to clinicians and computational neuroscientists studying general properties of normal and dysfunctional neural networks, possibly leading to medical insights into the mechanisms of autism and attention deficit disorders that impair social interactions.