Shivendra S. Panwar - US grants

The next decade will see increasing levels of integration of all kinds of communication needs in a common network. There has been a marked interest in packet-switched networks as a means to attain that goal. While the performance of data traffic is measured in terms of delay, real-time traffic such as voice and video is measured in terms of packet losses. Besides giving real-time traffic priority over data traffic, little work has been done in determining scheduling policies which minimize packet losses. This research models nodes in the network as queues with customers (packets), each of which has a deadline for service which, if exceeded, leads to a packet loss. A scheduling policy, called the shortest time to extinction (STE) policy, is shown to be optimal for a class of queues. These results are extended to a larger class of queueing systems, including multi-server and multi-class queues. To aid the analysis and design of queues with such scheduling policies, methods of computing losses for such queues are developed.

The principal investigator (PI) will explore buffer management policies for ATM (Asynchronous Transfer Mode) networks. Traffic concentrators and switch buffers will be modeled as queues with impatient customers, possibly belonging to different priority classes. The impatient customers correspond to cells or packets from time-constrained traffic such as voice or video. The focus here is the development of optimal scheduling policies which, for example, maximize the number of customers served before their respective deadlines. The techniques used will be based on sample path comparisons, stochastic dominance, and stochastic dynamic programming.

This project will support five graduate research traineeships over a five year period in the School of Electrical Engineering and Computer Science at the Center for Advanced Technology in Telecommunications (CATT) of the Polytechnic University. The specific areas to be addressed are as follows; high speed networks, signal processing, and software producibility. The traineeships will be used to attract more women and underrepresented minorities into doctoral studies in this field.

9413803 Chao Three research projects are supported by this research infrastructure award: (1) ``A Multicast Output Buffered ATM Switch'', (2) ``Priority Queue Management for ATM Switches'', and (3) ``An Experimental ATM LAN Testbed''. These projects involve VLSI chip design, switch fabric and congestion control device prototyping, theoretical analysis, computer simulations, and experiments on a high-speed ATM (Asynchronous Transfer Mode) network testbed. In the first project, we plan to prototype a 32x32 ATM switch fabric based on our proposed MOBAS (Multicast Output Buffered ATM Switch) architecture in order to demonstrate the capability of growing the prototyped switch to a large switch (e.g., with several hundred input and output ports). We will design and fabricate two application specific integrated circuit (ASIC) chips using the advanced CMOS 0.8-micron technology (available from the NSF funded MOSIS). In the second project, we will first investigate the performance and implementation complexity of several different queue management control schemes that combine the priority cell discarding and the priority cell departing schemes. We will then implement one of the queue management schemes and integrate with the ATM switch. In the third project, we plan to deploy an experimental ATM local area network (LAN) in Polytechnic University. The ATM LAN will be connected to a wide-area network, called NYNET, through a SONET OC-3 optical link (155.52 Mbit/s), for conducting various experiments such as B-ISDN service applications, distributed processing, system performance measurement, congestion/flow control, and network management. ***

97-30028 Wang, Yao Guleryuz, Onur G. Polytechnic University CISE Research Instrumentation: Integrated Video Encoding and Networking This research instrumentation grant contributes to enable the following research projects: - Multiple Description Coding and Multiple Path Transport for Video Communication over Unreliable Networks, - Video Packet Transmissions with Renegotiated Service Parameters, - Traffic Control and Admission Control for Video Networks, - Dense Motion Field Estimation and Representation for Video Compression, and - Stereo Sequence Compression. The next generation Internet must support many applications with widely varying performance requirements. Among these, the transmission of delay-sensitive compressed video traffic poses a unique challenge. The main objective of this project is to show that the efficiency of a video network can be improved by increasing the integration of video coding and video networking. Solutions with practical impact can only be achieved if the concepts are shown to be practically feasible in an actual testbed. The requested instrumentation will be used to set up a Video Networking (VINE) testbed. This testbed will enable collaborative research in robust video encoding and transport, video-aware resource reservations, and traffic control and admission control of video services. The requested video equipment will also facilitate other video coding research.

The need to improve congestion control techniques for the Internet has grown recently. Non real-time data traffic, which is currently transported on a "best effort" basis, will increasingly have more stringent delay and throughput requirements to meet critical scientific, corporate and e-commerce applications. In order to meet this enhanced quality of service requirement, the existing feedback congestion control scheme incorporated in the Transmission Control Protocol (TCP) needs to be understood. For this purpose, the PIs intend to:

1) Build an analytical model that can incorporate key features of TCP Reno and TCP enhancements under consideration by the IETF. The model the PIs present here is interesting in that it can accommodate multiple TCP flows and possibly multiple network nodes.

2) Place TCP in a control-theoretic framework so that its stability and transient behavior is well understood. The use of non-linear control techniques proposed here is novel, and should make available a new set of mathematical tools to study this problem.

3) The synthesis of these two activities will in turn suggest methods that ensure that any proposed TCP successor is stable, as well as improving throughput and fairness. A more limited goal but with perhaps more immediate impact is a better understanding of the stability and performance of TCP Reno.

All of this work will be performed within the complementary congestion control efforts underway such as traffic engineering using the Multiprotocol Label Switching (MPLS) protocol, traffic shaping and policing, service scheduling and buffer management.

In addition to a survey of the state of the art, the PIs present some preliminary results and ideas for future research. The PIs demonstrate an analytical model of TCP Reno for the single node case, and some of the insights that even such a simple model provides. The PIs also present a way of extending recent control theoretic work in flow control to a more realistic and general context, where boundary effects and unknown, time-varying propagation delays appear in networks. Lyapunov theory, the theory of functional (retarded) differential equations and constructive design methods in modern nonlinear control will play a key role in the synthesis of new feedback congestion control schemes for the Internet.

The broader impacts of this research include the development of closer interaction between the control theory and networks research communities, curriculum enhancement at the graduate and undergraduate levels, applying some of the practical implications of this work through ongoing industry interactions, and inputs to IETF groups.

Ad-hoc networks are a new networking paradigm, in which the network nodes create a network "on demand." There is a number of characteristic attributes associated with the ad-hoc networking approach: highly dynamic network architecture (nodes join and leave the network often and without warning), totally distributed architecture, and multi-hop routing.
Due to the high reconfiguration rate of the ad-hoc network architectures, many, if not most of the conventional routing protocols do not perform well in this type of environment. Consequently, a number of novel routing protocols, specifically suited for the ad-hoc networks, were proposed. A new Internet Engineering Task Force working group, the MANET Working Group, has been established to address the issues of routing in ad-hoc networks.
One topic that has not been adequately covered in the context of routing in ad-hoc networks is the issue of QoS-routing for multimedia applications, in general, and the issue of routing for real-time traffic, in particular. More specifically, an ad-hoc network may undergo frequent and unpredictable changes in the network topology, which results in relatively short lifetime of the network paths. Thus, paths become frequently invalid, and, what is more of a problem, there may be little warning of a path going down. Although this might not be a substantial problem for non real-time applications, such frequent path invalidation will most often lead to severe degradation of real-time communication. Thus, a mechanism is needed that will compensate for this behavior of ad-hoc networks.
A number of approaches have been previously proposed in the technical literature. For instance, maintaining a secondary route, so that when the primary route fails, the system can fall back onto the secondary route as soon as the failure is detected, has proven a good strategy. However, the secondary route mechanism is insufficient in many cases, as the state of paths in the network is usually highly correlated. Thus, failure of the primary path usually means that the secondary path may not be available as well. Also, the change-over time may last too long , so as to cause a perceptible degradation of the signal quality during this period.
One characteristic of the ad-hoc networks is that there are many paths between a source and a destination. Thus, a mechanism that takes advantage of these multitude of paths is bound to perform better (i.e., in supporting QoS for real-time traffic) than the above two-path approach. Moreover, rather than selecting a single path at any time to use for a specific connection, a better scheme would be to always distribute the information among multiple paths, possibly with some correlation between the information on the various paths, so as to protect against failure of some subset of the paths. The proposed mechanism thus consists of four steps: i) discovery of multiple paths between the source and the destination nodes and evaluation of the correlation in the paths' availability; ii) selection of a subset of the paths into an Active Path Set (APS), based on some "goodness'' measures (such as the expected availability of the path, the capacity of the path, the delay and jitter of the path, etc), and a scheme that allows to evaluate these measures for the network paths; iii) a method of coding and spreading the information among the paths
(including matching the paths with the specific requirements of a traffic type); iv) a scheme to monitor the APS paths, estimate their QoS parameters, and update the APS based on the state of the paths and their correlation.
The above approach is general and can be applied to a variety of real-time traffic types. However, to make the study more realistic, the researchers chose video communication as the real-time test application. Thus, the researchers intend to propose a specific set of algorithms/protocols that addresses the four steps as outlined above, in the context of video communication. For instance, they will determine what are the parameters relevant to transmission of compressed video traffic over unstable paths and propose schemes to code video source into multiple correlated descriptions that can be spread over multiple paths.
The researchers intend to integrate the above multi-path transport scheme for video traffic into a comprehensive simulation of the ad-hoc networking environment, that will include a radio propagation model, nodal mobility model, MAC protocol, and a routing algorithm (to discover the network paths). The researchers will gather performance measures from the simulation that will allow them to determine the quality of video at the application level depending on the parameters of the models used. The researchers expect to be able to answer questions, ranging from the very basic issue of viability of supporting real-time traffic in an ad-hoc networking environment to what type of routing protocol is most suitable for real-time traffic.
The research will be performed through both analytical and simulation tools. In particular, for the simulation, the researchers will use advanced models for prediction of the radio propagation environment, the user mobility model, and the traffic generation model.

This proposal is to plan for a new multi-university I/UCRC that aims to promote a research program of interest to both industry and universities on technologies for wireless internet. This new multi-university center will be able to have a broad impact on the industry through having its existing resources enhanced by the addition of the partner that is also being recommended to receive a planning grant. The two partners are this University and Columbia University.

The proposed Center's goal is to work on two overlapping categories:

- Information delivery focussing on software development, addressing security and robustness, and
- Data transmission related to management of radio resources and the management of competition and cooperation between different technologies

The proposal deals with an area of significant need and by assembling the two institutions into one research team, the breadth and depth is enhanced

Existing video streaming networks (VSN) rely on a few dedicated servers to store and distribute videos. Such architecture is very costly, both in terms of server cost and Internet-connection cost. Failures of a single server can also cause the collapse of the entire system. This research project investigates a peer-to-peer based VSN that has the promise to provide low-cost and yet high quality video on-demand service. The system encodes each video into multiple equally important sub-streams (called descriptions) and places each sub-stream on a different peer. When a client wants to see a video, multiple peers act as servers, each sending a different sub-stream of the video to the client. When a serving peer disconnects in the middle of a streaming session, the system looks for a replacement peer that stores the same video sub-stream and has sufficient surplus uplink bandwidth. The video coder is designed such that there is only a modest degradation in video quality in the period before a replacement peer is located. The system design has five interacting components: 1) multiple description video coding; 2) sub-stream placement; 3) admission control; 4) sub-stream server selection; and 5) sub-stream delivery. Both analytical studies and experimentations are conducted to examine the system performance and its gain over infrastructure-based systems. Successful development of the system will enable people to, at very low cost, search and view on-demand enormous libraries of digital video content for the purpose of education, healthcare, entertainment, etc., thus benefiting the society as a whole.

This collaborative Industry/University Cooperative Research Center will perform research in three critical, overlapping areas. Cooperative Communications and Networking research will examine wireless networks build out of nodes that cooperate at the physical and network layers. Cooperative networks offer enhanced capacity, reliability and efficiency relative to infrastructure and ad hoc networks. The second area of research focuses on extending the battery life of portable terminals thereby removing a major enhancing the convenience and value of wireless terminals and sensors. The third research area is Wireless Applications and associated Information Delivery mechanisms. Wireless Applications under investigation include content distribution, applications that leverage the ubiquity of wireless infrastructure with location awareness, and applications that adapt to the capacity limitations of the wireless vis-a'-vis the wired network. Each project focuses on a specific mode of wireless connectivity of the Internet to portable mobile information devices. In addition to developing and evaluating protocols and applications, Information Delivery research addresses security and robustness.

National Science Foundation
NETS - Research in Network Technologies and Systems
CISE/CNS


ABSTRACT

Proposal Number: 0435303
Principal Investigator: Panwar, Shivendra S.
Institution: Polytechnic University of New York
Proposal Title: High-Performance Stable Packet Switches



While switching capacity follows Moore's Law and doubles every 18 months, op-tical fiber line bandwidths double every 12 months. Consequently, packet switching technology continues to be one of the bottlenecks in the development of broadband networks. In this project, the research team has devised a new class of low complexity matching algorithms, i.e. Exhaustive Service Match with Hamiltonian Walk, which achieves stability and low packet delay, as opposed to cell delay, which was the focus of most previous research. Specifically, the fol-lowing two important issues are studied: (i) determination of the optimal packet delay for a matching algorithm, and (ii) options for the packet delay to increase sub-linearly with switch size under a general traffic pattern. This project will also address the class of switches that resolve the output contention by using the load balancing, where no scheduler is used, and re-sequencing is needed at the output. The total packet delay being investigated consists of the queuing delay and the re-sequencing delay. Another goal is to re-examine switch archi-tectures and their performance under more realistic long range dependent (LRD) traffic, and suggest improved architectures tuned to LRD traffic based on the insights thus derived.

Dr. Admela Jukan
Program Director, CISE/CNS
Aug 5, 2004.

This project investigates the concept of cooperation between nodes in a wireless network to increase its traffic capacity and reduce radio interference. Currently, transmissions between two nodes overheard by a third node are discarded. It has been shown that this overheard information can be used by the third "helper", through additional transmissions, to increase the capacity of the network. Alternatively, the cooperating nodes can also reduce the power needed to transmit the same amount of information as a network without cooperation. The notion of cooperation will be investigated both for the actual bits being transmitted, as well as in the medium access and routing protocols that facilitate and exploit it. The research will consider ad hoc networks in addition to infrastructure-based networks.

This work shows how to increase the capacity of wireless networks, and allow for a better spatial reuse of a limited amount of bandwidth by reducing the interference to other nodes in the vicinity. Analysis, simulations and proof of concept implementations are used in this research. Broader impacts, besides the research itself, include the positive outcomes of joint work with industry partners, and involving a wide group of students in research through the implementation-related projects.

Proposal #: CNS 07-08989
PI(s): Erkip, Elza
Bertoni, Henry L.; Panwar, Shivendra S.; Wang, Yao
Institution: Polytechnic University of New York
Brooklyn, NY 11201-3840
Title: IAD: Cooperative Networking Testbed Amount Rec: $ 300,000

Project Proposed:

This project, building two complementary testbeds for cooperative networking, responds to the fading and multipath distortion, as well as interference caused by multiple users operating over a limited bandwidth, often suffered by wireless communication systems. Respectively, each testbeds will
. Use open source drivers for backward compatibility with the current WiFi technology based on the IEEE 802.11 standard. This approach uses a standard, non-cooperative physical layer since it is not possible to access the physical layer in commercial products.
. Be based on software defined radio, allowing maximum flexibility in the implementation of a cooperative physical layer, a cooperative medium access control (MAC) layer as well as cross-layer design.
Cooperative networking, where two or more active users in the network share their resources to jointly transmit their messages, provides resistance to fading, high throughput/low delay and reduced interference/low transmitted power. This infrastructure, leveraged in part by the WARP platform at Rice U, the ORBIT testbed at Rutgers U, and the CRAWDAD database at Dartmouth U, provides an open-access platform that will be used to build experimental deployable and scalable cooperative wireless networks, enabling current techniques to be moved beyond the current theoretical and simulation studies.
The testbeds validate the feasibility of cooperative networking, enable platforms where new algorithms can be tested, and lead to new theory founded on more realistic assumptions.

Broader Impacts: This first effort in implementing a fully cooperative network is expected to accelerate commercial developments in the field and impact current wireless standards. It facilitates a closer relationship with industry. Moreover, the infrastructure contributes to train students and service new courses.

Proposal #: CNS 07-22868
PI(s): Erkip, Elza
Panwar, Shivendra S.; Wang, Yao
Institution: Polytechnic University of New York
Brooklyn, NY 11201-3840
Title: MRI/Acq.: Experimental Platform for Wireless Multimedia Networking

Project Proposed:
This project, acquiring an experimental platform to support integrated research and educational activities on wireless multimedia networking, examines problems of limited bandwidth of the wireless channel, of
interference caused from multiple users operating in the same band, of rapid variations due to signal fading, of limited battery life of wireless devices, and of speed and reliability of wireless networking. The instrumentation consists of multiple radios based on software defined radio platforms, wireless nodes and open source drivers based on the IEEE 802.11 Wireless Local Area Network (WLAN) standard, DSP platforms enabling real time video encoding and wireless transmission, dynamic power scaling, and power measurement, and test equipment. The instrument supports research on:
. Cooperative wireless networking, Wireless video transmission, Energy efficient networking, and
. Integration of research and education through the Wireless Information Systems Lab.
The platform contributes to advance the state-of-the-art in multimedia wireless communications, not only enabling testing of new and existing algorithms, but also leading new theory founded on more realistic assumptions.
Broader Impacts: The instrument impacts new wireless technologies, serves to integrate research and education through the Wireless Information Systems Lab (WISL), enables the training of undergraduate and graduate students in wireless communication, and development of new courses for the curriculum. It contributes to the first efforts of implementing a fully cooperative network, whose benefits have been well established through theory and simulations. The experimental platform is expected to accelerate commercial developments in the field and impact current wireless standards. The impact on industry will be facilitated by the close relationship of the institution with Wireless Internet Center for Advanced Technology (WICAT) member companies.

Cooperative networking exploits the broadcast nature of the wireless channel by effectively pooling the overheard information, which is traditionally treated as harmful interference. While there is a mature suite of tools at the physical (PHY) layer to harvest cooperative gains, it is still unclear how these tools can be employed to deliver significant network capacity gains. The goal of this project is to design and implement cross-layer mechanisms for cooperative networking. By integrating PHY layer cooperation with Medium Access Control (MAC) and application layers, the project will provide higher network capacity and improved multimedia quality.

The project has two interrelated components investigating basic architectures for next generation cooperative networks: (i) Cooperative data transmission, which focuses on a robust cooperative MAC-PHY incorporating multiple relays under mobility and loose requirements on synchronization and network topology. (ii) Cooperative video transmission, which exploits the synergy between cooperation and layered compression in providing unequal error protection, as well as differential quality in multicast.

Apart from potential impacts on the theory and practice of new wireless technologies, this project will train undergraduate and graduate students in all aspects of wireless communications. The impact on industry will be facilitated by the close relationship of NYU-Poly with WICAT member companies.


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

This proposal seeks funding for the Center for Wireless Internet Center for Advanced Technology (WICAT) studies conducted by the Polytechnic Institute of New York site (lead), the University of Virginia site and the site at Auburn University. Funding Requests for Fundamental Research are authorized by an NSF approved solicitation, NSF 10-507. The solicitation invites I/UCRCs to submit proposals for support of industry-defined fundamental research.

This proposal is a comprehensive research project for significantly improving the capacity of wireless networks. In past decades, there has been an exponential growth of wireless devices and wireless networks. While wireless networks have brought us the convenience of mobility and new applications, they are limited by bandwidth bottlenecks. The industry and spectrum regulators are trying to allocate more bandwidth, but they still fall behind the bandwidth increases in wireless networks. Thus it is critically important to use spectrum resources more efficiently. The proposed work aims to decrease interference, including cooperative and cognitive networking. This research will not only make significant contributions to the research community, but also be very valuable for the wireless industry and spectrum regulators.

This proposal aims to eliminate wireless system bottlenecks using cooperative and cognitive technologies, with the potential of enabling a broad spectrum of new wireless applications. The PIs will exploit existing programs, such as NSF REUs and the collaboration with Tuskegee and Northern New Mexico College, which focus on including students from underrepresented groups in the research. The student body at NYU-Poly is quite diverse. Most of the requested funding is going toward student support. The Pisa lo intend to incorporate this work into the new graduate course at NYU-Poly and the new ABET-accredited program at Auburn. Dissemination is clearly outlined: reports to NSF, reports to their IAB, journal and conference papers and making the resulting software packages open source.

Wireless Internet Center for Advanced Technology (WICAT)
Proposal #1127960

This proposal seeks funding for the Wireless Internet Center for Advanced Technology (WICAT) sites at the Polytechnic Institute of NYU (lead), Auburn University, the University of Virginia, and the Virginia Polytechnic Institute and State University. Funding Requests for Fundamental Research are authorized by an NSF approved solicitation, NSF 10-601. The solicitation invites I/UCRCs to submit proposals for support of industry-defined fundamental research.

Increasing demand for video services on handheld and other wireless devices has made efficient exchange of video data using wireless devices a necessity. However the continual changes in user demand, network traffic and hardware of the wireless environment pose significant research challenges to achieving this goal. The proposed research seeks to address these challenges via a three pronged effort to explore wireless technologies able to adapt to changing communication system states. A test bed environment for the conduct of the proposed work that will provide system surveillance and cloud computing infrastructure will be provided by Cisco Systems.

Efficient and seamless use of video on wireless platforms in the emerging cloud computing environment will have major economic impact in virtually all economic sectors. Ubiquitous implementation and widespread adoption of these services will also create societal impact through the degree of communication it will enable. The proposed work has the potential to inform and define approaches to achieving this video content integration. The work has the potential to strengthen collaborative ties and link resources among the four participating center sites to further both research and education in this critical area.

Efficient use of limited spectrum is emerging as a major issue in wireless systems. The proposed work focuses on technologies that provide better understanding of wireless networks and greatly enhance spectrum efficiency. with three coupled thrusts: (i) wireless network modeling; (ii) mechanisms for efficient spectrum sharing; and (iii) exploiting enhanced spectrum efficiency for wireless video communications. The project also includes an experimental research component in which the developed approaches will be implemented and tested on the cognitive radio testbed hosted at Virginia Tech and the cooperative networking testbed hosted at NYU-Poly.

The proposed research plans to systematically investigate several of the unique technical challenges and open problems in enhancing radio spectrum efficiency, and supporting emerging video services. This fundamental research will support the development of technologies that achieve new levels of efficiency and quality in wireless broadband services, and will help alleviate the wireless bandwidth limits now being experienced. The work is supported by the Industry Advisory Board as well as individual industry members of the center and has the potential to extend the centers portfolio. The PIs plan to disseminate the work to their industry members and the broader industry and academic community via open-source software as wel as introduce the content within their degree and outreach programs.