mobility at cern 6/6/2014 mobility at cern2 [email protected] co-author:...
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Mobility at CERN 2
Mobility at CERN
6/6/2014
Co-author: [email protected]
IT/Communication Services
CAPPS meeting
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Agenda• How does wireless work?• Some good practices• CERN mobile network• CERN Wi-Fi network• Future
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How does wireless work?
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RF signals travel in the air
Liberty, Mobility but…
There are rules and drawbacks
Radio wave
Passband Radio PassbandRadio
Radio medium Radio medium
Encoding of the dataModulation of the baseband signalTransmission of the modulated signal
001010111
Reception of the modulated signalDemodulation of the baseband signalDecoding of the symbol
Propagation of the RF signal in the environment
001010111
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The drawback?
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· Contrary to the wire, we cannot overpower the air…– RF propagation– Interference – Medium access and contention
· … Nor the end-user devices
· Spectrum is a limited resource we have to share
· Free bands are not so free– 2.4GHz ISM band is crowded
· Licensed bands definitely not free
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Signal reception and performance
• Received signal level NOT the single factor
• High performance requires· Good signal quality· Clean RF spectrum· Low contention· Stable wireless device SW· Good wireless device HW
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Wireless devices might not perform equally in the same condition!!!
Wireless infrastructure& environment
Your wireless device
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Ask for advice!
• Mobile Apps testing MUST move!!!
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• Buffer the data• Test the various hardware• Think 3G/4G and Wi-Fi
• Secure the App
Wireless encryption = Full security
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The CERN Wireless infrastructure
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The CERN mobile network
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• HSPA+: 3G++ or 3.75G• Where? Underground facilities and Swiss territory• What?
• Infra: 15Mbps DL & & 4 Mbps UL• Single user: 7Mbps DL & 1 Mbps UL• Shared resources and rate adaptation• 900MHz compatible mobile device• Live Video Streaming
• EDGE: 2.75G• Where? French territory• What?
• 384Kbps DL and 800ms latency• Not for real time Apps
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Sunrise Outdoor GSM radio coverage around CERN
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The CERN Wi-Fi network
• 802.11a/b/g/n• 2.4GHz band up to 80Mbps half-duplex shared• 5GHz band up to 240Mbps half-duplex shared• Latency 4ms to 100ms
• Real time Apps? Yes, but not everywhere• No L3 roaming yet
• Coverage map on GIS
https://gis.cern.ch/gisportal/IT_Equipment.htm
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Coming soon
DraftImproving
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In-building Wi-Fi coverage
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Future
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LTE(4G)
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• Pilot in LHCb and sector 1-8 this summer• Up to 90Mbps DL & 14Mbps UL (theoretical)• 3G/4G in surface in 2015
• Even more LTE?• Aggregation of two bands
• A second leaky feeder (2x2 MIMO)
Speed X2
Speed X2
Test this summer
Feasibility study
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802.11ac
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• 5 GHz only• New higher rate modulation • Will be released in 2 “waves”
Wave 1 (End 2014) Wave 2 (2016)Up to 80MHz Up to 160MHzUp to 3 spatial streams Up to 4 spatial streamsSingle-User MIMO Multi-User MIMO Up to 650Mbps Up to 1732Mbps
Speed X5
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Potential advanced services
Mobile campus
Hotspot 2.0
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You are Here
Real time locationReal time video
But where we go?
