jamming mitigation in multiradio wireless networks

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jamming mitigation in multi-radio wireless
networks

• sherif khattab
• skhattab_at_cs.pitt.edu
• cs research competition
• 2008

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outline

• jamming in multi-radio networks
• jamming defense approaches
• multi-radio channel hopping
• reactive or proactive (simulation)
• radio allocation (model-based)
• conclusions

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multi-radio
quad-radio Wi-Fi Access Point
radio boards
mother board
www.atific.fi
www.hopling.nl
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multi-radio usage

• mainly to increase throughput
• parallelism
• interference avoidance
• e.g., mesh networks
• to improve reliability

orthogonal channels
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jamming

• blocking communication by radio interference
• denying access to medium at sender
• signal corruption at receiver

jammer
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physical-layer protection

• frequency hopping
• limited in bandwidth
• too fancy for cheap sensors
• direct sequence
• hardware controlled
• jamming possible using the same hardware

www.hometoys.com
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channel hopping

• software controlled
• Hop between orthogonal channels

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proactive channel hopping

• proactive (periodic)
• sub-packet wood et al secon 07
• rapid navda et al infocom 07
• slow gummadi et al sigcomm 07
• reactive xu et al ipsn 07
• complex detection xu et al mobihoc 05

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multi-radio channel hopping

• reactive or proactive
• radio allocation problem
• jamming defense
• throughput enhancement

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outline

• jamming in multi-radio networks
• jamming defense approaches
• multi-radio channel hopping
• reactive or proactive (simulation)
• radio allocation (model-based)
• conclusions

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reactive or proactive? it depends

• overall goal
• communication availability
• energy efficiency
• attack strategy
• system parameters
• channels
• jamming detection delay
• hopping overhead
• traffic rate

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jamming games

• simple max-min games
• two-player defense vs jammer
• nash equilibrium

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defense and attack strategies

• defense
• proactive
• reactive
• attack
• sweeping (periodic)
• fast
• slow
• scanning

channels
jammer
channels
jammer
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reactive is better in availability game
better
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reactive is better or same in efficiency game
better
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outline

• jamming in multi-radio networks
• jamming defense approaches
• multi-radio channel hopping
• reactive or proactive (simulation)
• radio allocation (model-based)
• conclusions

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(n,m) coding

• e.g., IDA rabin 89

goodput throughput x
data
redundancy
n4
m2
data
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best coding depends on attackers
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adaptive hopping
system parameters
model
attack strategy
attackers
defense strategy
coding parameters
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theoretical analysis

• markov chain
• state is blocked radios
• ideal detection
• zero hopping delay

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summary

• first to address channel hopping in multi-radio
  networks
• defined jamming games with different payoffs
• reactive is better in multi-radio
• radio allocation problem
• model-based adaptive hopping (ongoing)

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acknowledgements

• joint work with my advisors
• rami melhem and daniel mossé

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questions?