Plum Consulting, London | +44 (0)20 7047 1919 | www.plumconsulting.co.uk
Wi-Fi and its role in an
evolving mobile ecosystem
John Burns, Plum Consulting
7th Future of Wireless International Conference
24th June 2015
Overview
1. Wi-Fi / Cellular Evolution and Spectrum
2. Wi-Fi as a mobile data enabler
3. Wi-Fi / Cellular interworking
4. Meeting future spectrum demand
5. What is the future for Wi-Fi and data offload?
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Wi-Fi / Cellular Evolution
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EDGE
UMTS
HSPA
HSPA+
LTE
LTE-A
5G
802.11
802.11b
802.11a
802.11n
802.11ac
802.11ad
802.11ay
Cellular Spectrum around the World
Based on current 3GPP standards as of August 2014. Band designations may change in the future and may vary in individual countries. No liability is accepted for any errors or omissions.
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Wi-Fi Bands around the World
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2.4 GHz Global2400 MHz 2483.5 2500
Japan*
5 GHz Global5150 5350 5470 MHz 5725 5850
Global US
3.7 GHz US3650 MHz 3700
60 GHz
57 GHz 66
Europe
57 GHz 64
North America, Korea
59 GHz 66
North America, Korea
China
59 GHz 64
Australia
59.4 GHz 62.9
Global
* 802.11b only
Wi-Fi has been a key enabler of mobile data growth…
Up to 80% of data traffic carried by Wi-Fi
・Mainly in homes and offices but increasingly via public hotspots
and WMANs
Virtually all mobile devices now have Wi-Fi
・2.4 GHz and 5 GHz bands ensure global connectivity regardless
of model
Automatic authentication increasingly prevalent
Offload benefits both users and networks
・Relieves capacity pressure on mobile network (hence lower
costs)
・Conserves data allowance for end users (hence lower costs)
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Wi-Fi / Cellular interworking initiatives
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PasspointTM / Hotspot 2.0
・Developed by Wi-Fi Alliance to enable seamless connections
between hotspot networks and mobile devices
Automatic Network Discovery and Selection Function (ANDSF)
・Developed by 3GPP to manage Inter-System Mobility and Routing
・Provides mobile devices with information about available networks
and policies for selecting and using networks
LTE / Wi-Fi Link Aggregation
・Simultaneous data streams over LTE and Wi-Fi, split and re-
combined at PDCP layer (under MNO control)
Wi-Fi complements rather than substitutes cellular…Wi-Fi ideal for localised data hotspots or leveraging fixed access points
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Capacity Enhancement: WMANs and hotspots provide significant extra headroom
at busy locations
Coverage Enhancement: Initiative such as FON provide rural wireless broadband
beyond reach of 3G / 4G networks
Cellular ideal for wide area coverage and mobility
20 cellular sites = 400+ Wi-Fi sites
Meeting future spectrum demand Actions underway to find more spectrum for both Wi-Fi and Cellular
・ Several bands already identified below 5 GHz for cellular
・Wi-Fi focus on consolidating existing bands and possible use of TV white spaces
・ But like 5G mobile, will have to look higher to support long term growth
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400 500 MHz 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700
3400 3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 4600 4700 4800 4900 5000 5100 5200 5300 5400 5500 5600 5700 5800 5900 6000
Cellular (available now)Cellular (planned or under consideration)Wi-Fi (available now)Wi-Fi (under consideration)
590 MHz
740 MHz
538 MHz
270 MHz
} 1,330 MHz
} 808 MHz
5 GHz has a lot of capacity, but usage is growing rapidly
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5 GHz
2.4 GHz
5 GHz
2.4 GHz
Feb 2013 Apr 2015
Detected Wi-Fi channel frequencies in a 60 minute walk around Central London (source: Plum Consulting)
Fragmentation and sharing constraints are also an issue…
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• Studies suggest further 80 – 160 MHz needed to meet growing data demand (mainly
residential in urban centres)
• Obvious solution is to expand the existing band – but how to protect incumbent satellite and
aeronautical users?
• Alternative is to exploit higher frequency bands…
LTE also has eyes on 5 GHz…
LTE-U – based on existing (Rel 12) standard but duty cycling deployed to facilitate
Wi-Fi co-existence
・Limited to US non-DFS bands – does not meet ETSI co-existence requirements
・FCC enquiry underway in response to Wi-Fi industry concerns
LTE-LAA (Licence Assisted Access) – will incorporate Wi-Fi like “politeness
protocols” to comply with ETSI requirements
・Expected to be in Rel 13 next year – needs ETSI approval in Europe
・Simulations suggest impact on Wi-Fi no greater than other Wi-Fi systems
Will provide supplementary capacity on opportunistic basis to primary licensed
carrier
・No plans for “stand-alone” operation
LTE-U / LTE-LAA plan to extend cellular technology into licence exempt band, sharing with Wi-Fi services
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So what is the future for Wi-Fi offload?
Ubiquity of Wi-Fi enabled devices
Globally harmonised spectrum allocations
Improved interoperability with cellular
Low barriers to market entry
Facilitates fixed / mobile substitution
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• Several factors suggest a continued and growing long term role:
• So ensuring adequate spectrum will be a key consideration
How does Wi-Fi fit with 5G?
Key consideration is spectrum
・5G dependent on access to higher bands (above 6 GHz)
・WRC-19 agenda item proposed to identify suitable bands
・Recent Ofcom report suggests five potential options
・But Wi-Fi already has a global allocation – ideal for very short range high speed applications
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40 50 60 70 80 90 GHz
Suggested 5G bands (source: Quotient Associates / Ofcom)
Existing Wi-Gig band (Europe)
Atmospheric absorption dB/km
The Wi-Gig initiative – 5G Wi-Fi?
Originally a stand-alone initiative, now formally part of the Wi-Fi
ecosystem, maintained and certified by the Wi-Fi Alliance
Intended to deliver multi-gigabit speeds, low latency, and security-
protected connectivity between nearby devices using 60 GHz
Delivers up to 4.6 Gbps in single antenna mode
Potential for up to 32 x 32 MIMO array with theoretical speed over 100
Gbps
Material absorption is a big problem – effectively limits to line of sight
Device chipsets available now (802.11ad) – but no routers yet!
Work on “next generation” 60 GHz now underway (802.11ay)
Should yield valuable lessons for 5G technology development
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Summary
Wi-Fi has been a key enabler of mobile data traffic growth
Up to 80% of mobile data traffic carried over Wi-Fi
Wi-Fi complements rather than substitutes cellular
technology
LTE making inroads to Wi-Fi bands but ubiquity of Wi-Fi
devices and improved interoperability means likely to
remain dominant
Existing Wi-Fi spectrum and technology in mm-wave
bands suggests continuing strong role in 5G ecosystem
The future looks bright for Wi-Fi!
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