Information Theory for Mobile Ad-Hoc Networks (ITMANET)

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Information Theory for Mobile Ad-Hoc Networks
(ITMANET) The FLoWS Project
FLoWS Overview and Update Andrea Goldsmith
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DARPAs ITMANET Challenge

• Develop and exploit a more powerful information
  theory for mobile wireless networks.
• Anticipated byproducts include new separation
  theorems to inform wireless network "layering" as
  well as new protocol ideas.

Hypothesis A better understanding of MANET
capacity limits will lead to better network
design and deployment.
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Limitations in theory of MANETs today
B. Hajek and A. Ephremides, Information theory
and communications networks An unconsummated
union, IEEE Trans. Inf. Theory, Oct. 1998.

• Success on narrowly-defined information theory of
  wireless networks.
• Large body of wireless (and wired) network theory
  that is ad-hoc, lacks a basis in fundamentals,
  and lacks an objective success criteria.
• Little cross-disciplinary work spanning these
  fields, except applying optimization techniques
  to existing wireless network designs.

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Our Approach Consummating Unions
Wireless Information Theory
Wireless Network Theory
Optimization Theory

• When capacity is not the only metric, a new
  theory is needed to deal with nonasymptopia (i.e.
  delay, random traffic) and application
  requirements
• Shannon theory generally breaks down when delay,
  error, or user/traffic dynamics must be
  considered
• Fundamental limits are needed outside asymptotic
  regimes
• Optimization provides the missing link to address
  these issues

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FLoWS Program Objectives

• Develop tractable and insightful metrics and
  models for MANET information theory.
• Define fundamental performance limits for MANETs
  in terms of desired objective metrics.
• Obtain upper and lower performance bounds for
  these metrics for a given set of MANET models.
• Define the negotiation between the application
  and network for resource allocation and
  performance optimization of our given metrics
• Bound the cost of using our set of metrics as the
  interface between the network and applications.

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Application Metrics and Network Performance
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Thrust Objectives and Rationale

• Models and Metrics (Leads Effros and Goldsmith)
  
• Objective Develop a set of metrics for dynamic
  networks that capture requirements of current and
  future applications
• Rationale Models for MANETs are needed that are
  tractable yet lead to general design and
  performance insights
• New Paradigms for Upper Bounds (Leads Koetter
  and Medard)
• Objective Obtain bounds on a diversity of
  objectively-defined metrics for complex
  interconnected systems.
• Rationale A comprehensive theory for upper
  bounding the performance limits of MANETs will
  help guide design
• Layerless Dynamic Networks (Lead Zheng)
• Objective Design of networking strategies as a
  single dynamic probabilistic mapping, without
  pre-assigned layered structure
• Rationale Remove layering and statics from MANET
  theory.
• End-to-End Metrics and Performance
  (LeadsOzdaglar and Shah)
• Objective Provide an interface between
  application metrics and network performance
• Rationale A theory of generalized rate
  distortion, separation, and network optimization
  will improve application performance

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Thrust Synergies and New Intellectual Tools
Thrust 1
New Bounding Techniques
Code Construction
Combinatorial Tools
Thrust 2
Dynamic Network IT
Optimization
Structured Coding
Thrust 3
CSI, Feedback, and Robustness
Stochastic Network Analysis
Optimization
Game Theory
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Progress since December

• New breakthroughs in generalized capacity and
  separation, robust source and channel coding,
  equivalence classes, scaling laws, wireless NUM,
  cross-layer optimization, and distributed
  resource allocation.
• New synergies within and between our thrust areas
• New and ongoing collaborations among PIs
• Overview paper for Scientific American
• Co-authors Effros, Goldsmith, Medard
• Paper near completion, will be submitted next
  month
• JSAC Tutorial on MANET Capacity with Cognitive
  Radios
• Co-authors Goldsmith, Jafar, Maric, and
  Srinivasa
• Paper accepted for publication, to appear in
  2009.
• Website updated with Dec. PI meeting slides,
  recent publications, and recent results.

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Thrust 0 Achievements
Models
Boyd, Effros, Goldsmith, Zheng Fading
with/without CSI
GoldsmithFinite State Markov Dynamics
Boyd, Goldsmith, Ozdaglar, Johari General
Network State Distributions
Shah Arbitrary node placement and traffic
Boyd, Effros, Goldsmith, Koetter, Ozdaglar, Shah
General traffic models, including multicast
traffic
Effros, Goldsmith Expectation and Outage in
Capacity and Distortion
Goldsmith Diversity/multiplexing/delay tradeoffs
Coleman, Medard, Koetter, Effros, Goldsmith
Capacity Regions
Boyd, Ozdaglar, Medard, Goldsmith End-to-end
optimization metrics subject to specific
constraints (e.g. delay)
Ozdaglar, Medard Downloading delay
Moulin Error-erasure tradeoffs
Zheng Error exponents
Zheng, Medard Distortion-diversity tradeoffs
Metrics
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Thrust 1 Achievements
Zheng error exponents unequal error protection,
embedded control messages to reduce overhead.
New bounding techniques
Effros, Koetter A characterization of the source
coding region of networks for line networks
Koetter likelihood forwarding
Zheng, Medard New techniques to unify multiple
description and multi-resolution,
distortion-diversity
Code construction Network information theory
Moulin covert channel by timing information
Goldsmith Interference channel with cognitive
user, asymmetric cooperation
Koetter, Effros, Medard Equivalence classes of
networks based on emulation of a channel or a
building block by arbitrary channels, including
multipoint channels
Goldsmith, Effros generalized capacity and
source-channel coding
Goldsmith, Medard, Katabi analog network coding
Ozdaglar, Medard Cross-layer optimization under
different metrics and constraints
Ozdaglar, Medard Network coding for downloading
delay
Ozdaglar, Medard Rate allocation in multiple
access networks
Medard, Koetter network coding capacity via
conflict graphs
Networking and optimization
Combinatorial Tools
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Thrust 2 Achievements
Dynamic Network Information Theory
Goldsmith general relaying, soft combining
Goldsmith Interference forwarding
Goldsmith Degraded FS Broadcast Channels
Coleman Rate Distortion of Poisson Processes
Goldsmith DMT for multi-hop networks
Zheng Euclidean Information Theory
Moulin Information flow via timing
Coleman E-type broadcasting channels
Goldsmith Feedback and Directed Information
Goldsmith Cognitive users and interference
Medard, Zheng Diversity-distortion tradeoff
Moulin Error/erasure tradeoff for compound
channel
Coleman Joint Source/Channel Coding in Networks
Moulin Universal Decoding in MANETs
Effros, Goldsmith Generalized capacity,
distortion, and joint source/channel coding.
Zheng Message embedding in feedback channels
Zheng Embedded Coding and UEP
Goldsmith Broadcasting with layered codes
CSI, feedback, and robustness
Structured coding
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Thrust 3 Achievements
Optimization Theory Distributed efficient
algorithms for resource allocation
Boyd Efficient methods for large scale network
utility maximization
Goldsmith Layered broadcast source-channel coding
Medard, Ozdaglar Cross-Layer optimization for
different application delay metrics and
block-by-block coding schemes
Medard, Shah Distributed functional compression
Boyd, Goldsmith Wireless network utility
maximization (dynamic user metrics, random
environments and adaptive modulation )
Medard, Ozdaglar Efficient resource allocation
in non-fading and fading MAC channels using
optimization methods and rate-splitting
Ozdaglar Distributed optimization algorithms for
general metrics and with quantized information
Goldsmith, Johari Game-theoretic model for
cognitive radio design with incomplete channel
information
Shah Capacity region characterization through
scaling for arbitrary node placement and
arbitrary demand
Johari Local dynamics for topology formation
Shah Low complexity throughput and delay
efficient scheduling
Ozdaglar Competitive scheduling in collision
channels with correlated channel states
Meyn Generalized Max-Weight policies with
performance optim- distributed implementations
Game Theory New resource allocation paradigm that
focuses on hetereogeneity and competition
Stochastic Network Analysis Flow-based models and
queuing dynamics
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Focus Talks and Posters

• Thrust 1
• Koetter A tool oriented approach to network
  capacity (joint with Effros and Medard)
• Thrust 2
• Goldsmith Interference in MANETs Friend or Foe?
  
• Thrust 3
• Shah Capacity region of large wireless networks
  (joint with Neisen and Gupta)
• Posters on all new (green) results

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Progress Criteria Phase 1 (completed)

• Upper and lower bounds characterization of n(n-1)
  capacity region for small networks with simple
  assumptions
• Koetter, Effros, Medard Equivalence classes of
  networks based on ability of a channel or a
  building block to emulate arbitrary channels
• Goldsmith, Medard, Katabi Joint relaying,
  combine symbols in PHY, bits, or network layer
• Scaling and achievability results for large
  networks with fixed traffic
• Shah Optimal capacity scaling for arbitrary node
  placement and arbitrary multi-commodity flows
• Shah multiple access decomposition for
  constructive scaling laws
• Analysis of tractability vs. practicality of
  channel models and robustness to modeling
  assumptions and system uncertainty
• Meyn, Zheng, Medard mismatched receiver, online
  robust algorithm to combat imperfect channel
  info.
• Goldsmith Broadcasting with layered source code,
  graceful degradation for weaker users
• Joint characterization of trade-offs among delay,
  energy and capacity
• Medard, Zheng diversity-distortion tradeoff
• Shah Low complexity throughput and delay
  efficient scheduling
• Goldsmith, Boyd Capacity and delay under
  Wireless NUM

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Progress Criteria Phase 1 (completed)

• Study of optimized node cooperation incorporating
  not only virtual MIMO, cooperation diversity,
  conferencing, and relaying but also network
  coding for networks of 5-10 nodes. Includes
  impact of generalized decode-forward and
  amplify-forward (list decoding, partial
  decoding). Includes impact of delay, energy, and
  outage probability.
• Goldsmith MANET capacity w/ node cooperation
  and cognition
• Koetter Likelihood forwarding
• Study dynamic allocation of rate, power, and the
  spatial degrees of freedom associated with
  multiple antennas, as well as dynamic spectrum
  allocation
• Goldsmith, Johari Game-theoretic model for
  cognitive radio design with incomplete channel
  information
• Medard, Ozdaglar Efficient resource allocation
  in non-fading and fading MAC channels using
  optimization methods and rate-splitting
• Study strengths and vulnerabilities posed by
  addressing jamming with cooperating and
  non-cooperating nodes
• Moulin, Medard On Manet jamming

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Progress Criteria Phase 1 (completed)

• Study fundamental limits of the ability of inside
  attackers to observe and contaminate degrees of
  freedom in a MANET
• Medard, Effros Byzantines attacks
• Study systematic techniques for bounding the
  achievable rate region for distributed source
  coding in complex networks, considering issues of
  robustness to unknown/imperfect source and
  network statistics and application of universal
  coding and decoding techniques to such systems.
• Coleman Joint Source/Channel Coding in Networks
• Effros/Koetter A characterization of the source
  coding region of networks for line networks
• Study network-aware design stability of network
  operation with respect to application-aware
  optimization will be studied.
• Boyd Dynamic and stochastic network utility
  maximization with delivery constraints
• Ozdaglar Distributed optimization algorithms for
  general metrics and with quantized information

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Progress Criteria Phase 2 (next 12 months)

• Evolve results in all thrust areas to examine
  more complex models, robustness/security, more
  challenging dynamics, and larger networks.
• Koetter, Effros, Medard Network equivalence
• Ozdaglar, Medard Rate allocation in multiple
  access networks
• Goldsmith Multihop networks Cooperation,
  Cognition, and Robustness Tradeoffs
• Moulin Error/erasure tradeoff for compound
  channel
• Zheng Message embedding in feedback channels
• Coleman E-type broadcasting channels
• Johari Local dynamics for topology formation
• Meyn Generalized Max-Weight policies with
  performance-optimal distributed implementations
• Shah Capacity scaling laws for arbitrary node
  placement and arbitrary demand
• Demonstrate synergies between thrust areas
  compare and tighten upper bounds and
  achievability results for specific models and
  metrics apply generalized theory of distortion
  and utility based on performance regions
  developed in Thrusts 1-2.
• Ozdaglar, Medard Cross-layer optimization under
  different metrics
• Zheng, Medard Unifying multiple description and
  multi-resolution, distortion-diversity
• Boyd, Goldsmith Wireless NUM with cooperative
  PHY
• Medard, Ozdaglar Cross-Layer optimization for
  different application delay metrics and
  block-by-block coding schemes
• Ozdaglar Competitive scheduling in collision
  channels with correlated channel states

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Progress Criteria Phase 2 (next 12 months)

• Demonstrate that key synergies between
  information theory, network theory, and
  optimization/control lead to at least an order of
  magnitude performance gain for key metrics.
• Ozdaglar, Medard Network coding for downloading
  delay
• Goldsmith Generalized capacity, distortion, and
  separation
• Boyd, Goldsmith Wireless network utility
  maximization
• Pose clearly defined community challenges related
  to evolving our theory that inspires other
  researchers to collectively make breakthrough
  progress.
• Community challenges posed in plenary talks and
  tutorials, as well as invited papers and vision
  papers
• Publish 2 vision papers, one for the community
  (e.g. in the IEEE Wireless Communications
  Magazine) and one for the broader technical
  community (e.g. in Nature or Science)
  illuminating our ideas, results, and their
  potential impact
• Draft paper for Scientific American near
  completion. To be submitted in Oct.
• Outline of community paper will be discussed in
  Friday team meeting

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Project Impact To Date

• Plenary Talks and Panels
• Boyd Dysco07, S. Stevun Lecture08, CNLS08,
  ETH08
• Effros ISIT07
• Goldsmith ACC07, Gomachtech08, ISWPC08,
  Infocom08, LTE Wshp09
• Medard Gretsi07, CISS07, NRC07, IT Winter
  School08
• Koetter ITW07, WiOPT08
• Meyn Erlang Centennial09
• Recent Tutorials
• Boyd MOCCS08, WOSP08
• Ozdaglar Networks' challenge Where game theory
  meets network optimization (ISIT08)
• Medard/Koetter Intro. to Network Coding
  (PIMRC08)
• Maric/Dabora Cooperation in Wireless Networks
  (PIMRC08)
• Conference Session/Program Chair
• ISIT07 Technical Program (Chairs Medard and
  Goldsmith)
• CTW08 session (Chairs Andrews and Goldsmith)
• Invited journal papers
• Breaking spectrum gridlock through cognitive
  radios an information-theoretic approach, IEEE
  Proc09 (w/ Jafar, Maric, and Srinivasa)

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Publications to date

• 10 accepted journal papers, 10 more submitted
• 80 conference papers (published or to appear)
• Publications website
• http//www.stanford.edu/adlakha/ITMANET/flows_pub
  lications.htm

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Summary

• Significant progress on all thrust areas
• Significant progress on synergies between thrust
  areas
• Ongoing and fruitful collaborations between PIs
• Roadmap towards meeting Phase 2 goals underway
• Significant impact of FLoWS research on the
  broader research community (IT, communications,
  networking, and control/optimization)