LTE and WiFi on the LE
Sami Susiaho – Head of Edge Technologies, Sky Business, Sky
UK
Star Wars: The Empire Strikes Back
Cambridge wireless in London 17th September 2015
Overall picture of technologies
LTE-U
LAA-LTE
• Wild west LTE
on 5 GHz
• In the US,
China, India
and Korea
• Ready, but
requires
hardware
update
• Potentially
polite LTE on 5
GHz
• Global when
the standards
are ready
• Details yet to
be defined
• In the works,
ready in 2016
LWA
• LTE using WiFi to boost
capacity
• Requires
device and
core software
update only
2
Carrier Wi-Fi
• What Wi-Fi
operators like
The Cloud do
now
• Best practice
in Wi-Fi offload
• Ready, but
improving
LTE-U - the Wild West standard of LTE on Wi-Fi spectrum
• Integration with Licensed LTE: supplemental
downlink (CA with uplink not needed)
• Coexistence with Wi-Fi: dynamic channel
selection and CSAT( based on LTE duty
cycle)
• No support for Listen Before Talk (LBT)
• Based on 3GPP release 10-12
• Not for EU but available in other markets,
such as China, Korea, India and the US
• Fewer changes from licensed LTE
• Earlier commercialization
3
LAA-LTE –the yet-to-be stamped future standard of LTE on LE
• Licensed Assisted Access – LTE
• Devices use licensed anchor band when
using Wi-Fi
• Wi-Fi like Coexistence with Wi-Fi: dynamic
channel selection and Listen Before Talk
• Based on 3GPP Release 13
• Compliant with regulatory requirements of
most countries
• Later commercialization
4
LWA - LTE and Wi-Fi aggregation or LTE with “Wi-Fi boost”
• Using both LTE and Wi-Fi to achieve the highest
possible capacity for mobile devices
• Proposed technology to be introduced in 3GPP
Release 13
• Uses the same 5 GHz spectrum as LTE-U or
LAA would and additionally, the 2.4 GHz band
• Crucially, LWA would not require any changes
for current Wi-Fi handsets or infrastructure, it
would be a software update
• Uses Wi-Fi only for downlink, LTE carrying all
uplink traffic and potentially, helping with the
downlink
• Both technologies played against their strenghts
5
Carrier Wi-Fi
• Carrier grade Wi-Fi has been the hot topic of many conferences and is getting a definition
• It is essentially, a Wi-Fi technology ideally suited for offloading data during peak times
• The Cloud estate is considered one of the most sophisticated Wi-Fi hotspot networks and
as such, often used as an example of a “Carrier grade Wi-Fi” network deployment
• Professionally deployed estate in high demand locations
• Technically advanced with scalable core, dual band Access points with smart antennas,
Passpoint ready, EAP-SIM ready, with central controller and sophisticated user
experience management
6
LTE has better spectral efficiency and coverage
• Dynamic link adaptation gives LTE a
slight advantage over Wi-Fi
• Furthermore, comparing IEEE
802.11ac and LTE Rel.12 at 256QAM
gives LTE an 11% advantage, with
WiFi at 6.67bits/symbol and LTE at
7.43bits/ symbol, respectively
• Time to market and market adoption,
scale of deployments and availability
of services being perhaps more
relevant measures
7
Co-existence work
• 3GPP work for co-existence with Wi-Fi has just started
• Concerns raised from IEEE/802.11 and WFA how the co-existence use cases are set up
and what scenarios are included
– Co-existence behavior with multiple overlapping deployments should be considered
– Test the networks with multiple clients, wide channels and
– LBT (Listen Before Talk) should be included with exponential back-off, in DL and UL.
– LBT timing rules and thresholds for energy detect that meld with Wi-Fi
– Preamble detection and/or reservation signaling
– KPIs other than just throughput and latency, such as Jitter, Packet loss, Frame retransmission rate,
beacon loss and deferral and power save signaling loss and deferral should be included
8
Relevance of 11% in the real world
• Difference between a good AP and a good AP can easily be
50% in performance and the range of minimum quality of
service
• Different configurations in LE deployments can quite easily
gain or lose much more than that
• Having said that, 11% addition to speed or range would be
welcome, but what about cost?
9
“Cost” of LTE on LE is unknown
And extremely hard to quantify
10
The real world of seamless user experience is a three dimensional
problem, not all of which are always considered
Wi-Fi
Other
Wi-Fi
LTE
11
Final thoughts
Wi-Fi is ready to deploy now
LTE on LE is still in the works
• Excellent coverage and capacity
• Deployments will likely introduce a hardware
change – further prolonging the adoption
timelines
• Low cost to deploy
• Excellent co-existence mechanisms with other
LE users
• Higher cost to design and deploy
• Risk of harming other LE use cases
• Admission control, band steering, airtime
fairness and fast transition/roaming features
• Smallcell deployments are Wi-Fi like
• 802.11ax, 802.11k&r, Passpoint and multiband
• Does not rule out the LTE deployments, or even
the LAA deployments
• Wi-Fi calling
• Perfect neutral host with 100% handset
adoption
12
Thank you
Star Wars: Return of the Jedi