Information Theory for Mobile Ad-Hoc Networks (ITMANET):
The FLoWS Project
FLoWS Progress and Next Steps
Andrea Goldsmith
Phase 3 Kickoff
Sept. 14-15, 2009
FLoWS Challenge, Progress, and Goals
• Develop and exploit a more powerful information
theory for mobile wireless networks.
• The development of this theory has progressed
along three main thrust areas, with breakthrough
progress and new theory in each area.
• Synergies between thrust areas have emerged,
which are blurring the lines between thrusts.
• In Phases 3-4 our goal is to identify and attack
the largest outstanding ITMANET challenges
MANET Metrics
New Paradigms
for Upper
Bounds
Constraints
Capacity and Fundamental Limits
Capacity
Upper
Bound
Layerless
Dynamic
Networks
Delay
Lower
Bound
Degrees of
Freedom
Power
Application
Metrics and
Network
Performance
Models and
Dynamics
Application and
Network Optimization
Capacity
(C*,D*,E*)
Delay
Utility=U(C,D,E)
Power
Metrics
Models
Fundamental Limits
of Wireless Systems
New MANET Theory
Application Metrics
Thrust Objectives and Rationale
• Models and Metrics (Leads: Effros,Goldsmith,Medard):
– 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: Effros,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, Coleman)
– 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 (Leads: Ozdaglar,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
Two New PIs Added to FLoWS
• Cover and El Gamal have been added for the last two
phases to complement the existing team
• Cover’s work will focus on
– Coordinated capacity: How much dependence can be set up
with a given set of communication constraints
– Applications include distributed game theory, task assignment
and rate distortion theory.
• El Gamal’s work will focus on
– Network information theory to develop new coding schemes
for the canonical channel models with many users
– Computing/decision making over a network with distributed
sources: lossy distributed averaging
Project Thrusts and Organization
Metrics and Models
Lead: Goldsmith and Effros
All PIs Contribute
New Paradigms
for Upper Bounds
Layerless
Dynamic Networks
App. Metrics and
Network Performance
Co-Leads:
Effros and Medard
Co-Leads:
Zheng and Coleman
Co-Leads:
Ozdaglar and Shah
— Cover
— El Gamal
— Koetter
— Goldsmith
— Cover
— Effros
— El Gamal
— Goldsmith
— Koetter
— Medard
— Moulin
— Shah
— Coleman
— Effros
— Goldsmith
— Johari
— Medard
Thrust Synergies and New Intellectual Tools
Thrust 1
Equivalence
Classes
Combinatorial
Tools
Code Construction
Thrust 2
Optimization
Dynamic
Network IT
Thrust 3
Optimization
Stochastic
Network
Analysis
Game Theory
CSI, Feedback,
and Robustness
Structured
Coding
Open Questions circa 2006
• Capacity of time-varying links (with/without feedback)
Yi-1
Tx
Xi
p(yi,si|xi,si-1)
Si-1
D
Yi
Rx
Si
• Capacity of basic network building blocks
• Capacity of large dynamic networks
Progress on these questions
• Capacity of time-varying
links (with/without feedback)
Y
i-1
Tx
Xi
p(yi,zi,si|xi,si-1)
Si-1
•
•
•
•
D
Yi
Rx
Si
Capacity of finite-state Markov channels with feedback
Converses under unequal error protection
Multiplexing-diversity-delay-distortion tradeoffs in MIMO
Generalized capacity and separation
• Capacity of basic network building blocks
• Capacity region/bounds for Z channel and interference channels
• Capacity bounds for cognitive interference/MIMO channels
• Upper bounds and converses for interference channels with a
relay (via interference and message forwarding)
• Capacity of dynamic networks
•
•
•
•
•
•
•
•
•
•
Network equivalence
Scaling laws for arbitrary node placement and demand
Multicast capacity
Effect of feedback and side information
Dynamic/multiperiod network utility maximization
Generalized Max-Weight policies
Game-theoretic approaches
Mobility for interference mitigation
Delay or energy minimization
Distributed optimization
New Theory
• Thrust 1
– Equivalence classes
• Thrust 2
– Layered and structured codes
– Control principles for feedback channels
– Generalized capacity and separation
• Thrust 3
– Stochastic Multi-period Network Utility Maximization
– Relaxation and distributed techniques for network optimization
– Stochastic games
• Interthrust
–
–
–
–
Relaying, cooperation and cognition
Network coding
Capacity regions for more than 3 users
Coordination capacity
Thrust 0 Recent Achievements
Models
Coleman, Effros, Goldsmith, Medard, Zheng:
Channels and Networks with Feedback
Effros: networks with side information
Cover: Coordinated Networks
Moulin: Mobility
El Gamal: More than 3 users
Goldsmith: Cognitive Nodes
Medard, Zheng: Distortion-Outage tradeoff
Effros, Goldsmith: Expectation and
Outage in Capacity and Distortion
Zheng: UEP
Goldsmith: Diversity/multiplexing/delay tradeoffs
Medard: delay/energy minimization
Shah: multicast capacity
Metrics
Medard: Stability Regions
Thrust 1 Recent Achievements
Goldsmith: multi-way relay channel
Goldsmith: multicasting with a relay
Medard: effect of coding versus routing
El Gamal: more than 3 users
Effros: continuity of network coding regions
New bounding techniques
Code construction
Network information theory
Goldsmith: joint source-channel coding with limited feedback
Goldsmith: capacity and interference rates for the interference channel
Effros: linear code construction
Cover : Capacity of coordinated actions
Zheng, Medard : distortion-outage tradeoff
Metrics
Koetter, Medard: On the stability region of networks with instantaneous decoding
Combinatorial Tools
Networking
and optimization
Thrust 2 Recent Achievements
Dynamic Network Information Theory
El Gamal: BC with 3+ receivers
Goldsmith: Multicast with
Moulin: exploiting mobility
relay; BC with cognitive relay
of relay networks
Effros: distributed network coding
with coded side information
Cover: coordination capacity
Effros: linear representation of network coding
Coleman: Control principle for feedback channels
Medard, Zheng: Diversity-distortion tradeoff
Goldsmith: Joint source channel coding / outage
Zheng: tilted matching for feedback channels
CSI, feedback, and robustness
Effros: two stage polar codes
Structured coding
Thrust 3 Recent Achievements
Optimization
Distributed and dynamic
algorithms for resource allocation
Boyd, Goldsmith: Wireless network utility
maximization as a stochastic optimal control
problem
Ozdaglar: Distributed second order methods for
network optimization
El Gamal: Overhead in distributed algorithms
Shah: Distributed MAC using queue
based feedback
Medard: Decoding and network
scheduling for increased capacity
Ozdaglar: Noncooperative power control using
potential games
Johari: Large network games
Ozdaglar: Near potential games for network
analysis
Meyn: Q-learning for network optimization
Johari: Supermodular games
Effros: Noncooperative network coding
Stochastic Network Analysis
Flow-based models and
queuing dynamics
Game Theory
New resource allocation
paradigm that focuses on
hetereogeneity and competition
FLoWS progress since March
• New breakthroughs in upper bounds, feedback and CSI,
cognitive techniques, interference forwarding, multicast
traffic, and dynamic/distributed network optimization,
• New synergies within and between our thrust areas
• New/ongoing collaborations among PIs within FLoWS and
with Nequit PIs; integration of new PIs Cover and El Gamal
• Overview paper for Scientific American to appear
– Co-authors: Effros, Goldsmith, Medard
• Comm. Magazine paper with overview of FLoWS
– Submitted and reviewed; likely to be accepted after revision
• Discussion of Phase 3 and 4 progress criteria
– Identification of main challenges
• Website updated with March PI meeting slides, recent
publications, and recent results.
Focus Talks and Posters
• Thrusts 1 and 2:
– El-Gamal: More than Three Users
– Cover: Coordination Capacity
• Thrust 2:
– Zheng: Tilted Matching for Feedback Channels
• Thrust 3:
– Ozdaglar: Near-Optimal Power Control in Wireless
Networks: A Potential Game Approach
• Posters on all recent achievements
Progress Criteria: Phase 3
1. Revolutionize upper bounding techniques through new and different
approaches that go beyond the classical MIN-CUT bounds and Fano's
inequality that have dominated capacity bounds for the last several
decades.
2. Determine the optimal channel/network “coding” that achieves these
capacity upper bounds when possible, and characterize for which classes
of networks gaps still exist between achievability & upper bounds, & why.
3. Develop a generalized theory of rate distortion and network utilization as
an optimal and adaptive interface between networks and applications that
results in maximum performance regions
4. Demonstrate the consummated union between information theory,
networks, and control; and why all three are necessary ingredients in this
union
•
Progress towards meeting each criteria (more details in Thrust talks)
•
Identifying “grand challenges” remaining to develop an IT for MANETS
•
•
•
First pass will be presented in the thrust talks
Will focus on these challenges during Phases 3 and 4
Team meeting Tuesday dedicated to this topic
Project Impact To Date
• Recent Plenary Talks
– Boyd: Stevun Lec.’08, CNLS’08, ETH’08, ISACCP’09, ISMP’09, ICOCA’09, CCCSP’09
– Goldsmith: Gomachtech’08, ISWPC’08, Infocom’08, RAWC’09, WCNC’09, ICCCN’09
– Medard: IT Winter School’08, UIUC Student Conference’08, Wireless Network
Coding’08, ITC.09, ITW’09
– Meyn: Erlang Centennial’09, Yale Workshop’09, Diaconis Symp.’09
– Ozdaglar: ACC 2009, NecSys'09 , ASMD’08
– Johari: World Congress of the Game Theory Society’08
– El-Gamal: Allerton’09, Padovani Lecture’09, Brice Lecture’09
– Shah: Net Coop’09, Winedale’09
• Conference Session/Program Chairs/Panels
– CTW’09, ITW’09, ISMP’09, INFORMS’09, ITW’10, CTW’10
• Recent Tutorials
– Meyn: Mathematics of OR’09,
– Shah: CDC’09,
• Invited/award winning journal papers
– “Breaking spectrum gridlock through cognitive radios: an information-theoretic
approach”, Goldsmith, Jafar, Maric, Srinivasa, IEEE Proc’09.
– “A Random Linear Network Coding Approach to Multicast”, Ho , Medard , Koetter,
Karger, Effros, Shi, and Leong, Joint IT/Comsoc Paper Award 2009.
– "XORs in the Air: Practical Wireless Network Coding“, Katti, Rahul, Hu, Katabi,
Medard, and Crowcroft. Bennett Prize in Communications Networking 2009.
Publications to date
• 22 accepted journal papers, 16 more submitted
• 127 conference papers (published or to appear)
• SciAM paper to appear
• Comm. Magazine paper submitted and reviewed
• Book on FLoWS vision and results under development
– Alternative to NoW Foundations and Trends article
• Publications website:
– http://www.stanford.edu/~adlakha/ITMANET/flows_publications.htm
Summary
• Significant progress in and across all thrust areas
• Ongoing and fruitful collaborations between PIs
• Powerful new theory has been developed that goes
beyond traditional Information Theory and Networking
• Addition of El Gamal and Cover adds new perspective
and experience to our team
• Significant impact of FLoWS research on the broader
research community (IT, communications, networking,
and control/optimization)
• Want to maximize research impact in the final two
phases of the project by identifying key challenges within
and beyond the progress criteria