1. LTE-Unlicensed JOSH FORGIE CTS

2. Flavors LTE-U / LAA LWA WiFi MultiFireTM LTE-U Forum New deployments
Link Aggregation - Expands operator deployments into existing WiFi
WiFi
New deployments - 802: .11ac/.11ad/.11ax/.11ay
MultiFireTM
‘Stand-Alone’ without anchor carrier – neutral host suitable
Association to develop global technical standards and certifications
Expansion of LTE into new deployments
LTE-U Forum
Created by Verizon, Alcatel-Lucent, Ericsson, LG, Qualcomm and Samsung

3. LTE-U Continually Changing
Industry defined coexistence with 3GPP Release 12 – primarily USA
Already incorporates 3GPP 10 and 11
Built on carrier aggregation of LTE-Advanced
No license required to use spectrum
Radios must comply with existing FCC Part 15 regulations
Non-exclusive spectrum use
Spectrum subject to interference
Consistency, Accessibility and Reliability
Disrupts existing WiFi
Quality of Service
Discontinuous Transmission
Capacity over Coverage
No new deployments in locations without existing licensed coverage
Significant performance gains over WiFi

4. LTE-U Frequencies Power Frequency and use specific Typical:
200 mW indoor
1 W outdoor

5. LTE-U Deployments AT&T Verizon T-Mobile Trials in 2016
5 GHz in 20MHz channels
Verizon
Trials beginning in
5 GHz and 3.5 GHz
T-Mobile
5 GHz in 2016
Uses LTE-U enabled small cells from Alcatel-Lucent NOKIA

6. LAA License-Assisted Access
Intended to allow WiFi and LTE-U to coexist
Clear Channel Assessment / Listen before Talk – eNodeB Fairness
Instantaneous access not guaranteed
Opportunistic use of spectrum
Increases capacity
Part of 3GPP Release 13
Deployed in Europe and Japan/Asia
Supports Gigabit Class LTE - 5 Gbps near future
Combines LTE in unlicensed 5GHz downlink with licensed LTE
Carrier Aggregation
Targeted for new small cell deployments
Issue: Hotspot 2.0 / Passpoint

7. LAA AT&T reported as saying LAA is a better option than LTE-U
Cost of spectrum
Listen before Talk is seen as a good technique to reduce interference
Certified by 3GPP
LAA ‘restricts’ usage to LAA
Intended rollouts
AT&T – LTE-U in test; Upgradable to LAA
Verizon – some this year
T-Mobile - some this year
Handsets
Available in 2016

8. Coexistence and Fairness
Control and scheduling controlled by carrier
Coexistence can be divided into two regimes:
No regulations specifying what is “fair”
Listen Before Talk is required by regulation

9. Architectures
Enabling unlicensed secondary carriers and be seamlessly controlled by the network

10. Markets without LBT Requirements
Mainly US, China and South Korea (2014)
Proprietary coexistence mechanisms
Comply with 3GPP LTE Releases 10-13
Generally software based
Fast prototyping
Support for new frequencies and changing features

11. Three No LBT Coexistence Mechanisms
Channel Section
Simplicity
Small cell chooses ‘cleanest’ channel based on WiFi and LTE measurements
Falls through to CSAT (#2)
Channel interference is determined by energy detection
Independent of interference type
Independent of interference source
Sensitivity improvement by:
Technology specific measurements
WiFi preambles estimate and detect neighbor Access Points
Detect neighboring LTE-U’s PSS, SSS, and PBCH channel
Device assistance
802.11k and UE measurements – hidden node effect

12. Three No LBT Coexistence Mechanisms
Channel Section and Flow Chart

13. Three No LBT Coexistence Mechanisms
Carrier-Sensing Adaptive Transmission – CSAT
CSAT amounts to channel sharing using Time Division Multiplexing

14. Three No LBT Coexistence Mechanisms
Carrier-Sensing Adaptive Transmission
Useful is dense environments where a ‘clean’ channel is difficult to find
Containing many WiFi and Small Cells
CSAT
LTE MAC control elements control the activation of LTE-U and determine timing as per 3GPP Release 10-12
When the channel is off, the channel is available to other WiFi users
The eNodeB measures WiFi utilization during the off period to determine LTE-U duty cycle requirements
100’s of millisecond time scale

15. Three No LBT Coexistence Mechanisms
Opportunistic SDL - Supplemental Downlink
Anchor carrier in licensed band is always available
SDL is available as needed
SDL is used when traffic crosses a threshold and users in an area are present
SDL provides above threshold offload
SDL can also reduce or eliminate interference caused by continuous Reference Signal transmissions from LTE-U in and around a given channel

16. Three No LBT Coexistence Mechanisms Aggregate Qualcomm Simulation Results
LTE-U Median User Downlink Data Rate Gain: 3.1 over WiFi alone Carrier WiFi improves too: 10%. Simulation results and simulation conditions are specific. Read the whitepaper for details. Take Away: Performance Improvement

17. Markets with LBT Requirements
Mainly Europe, Japan and India (2014)
Regulations require periodically checking for the presence of signals before initiating a transmission
Frame based
Checks occur on a millisecond time scale
Check window duration is called Clear Channel Assessment – CCA (yellow)
Channel Occupancy is defined as being between 1 and 10 ms (green)
If the channel is empty during CCA, one Channel Occupancy period may be used
Longer transmissions require additional CCA checks

18. LBT Required Coexistence Mechanism
Listen Before Talk Framing

19. LBT Required Coexistence Mechanism
Requires design modifications to LTE PHY and MAC layers to implement LBT
Actively being discussed by 3GPP (Release 13+)

20. Regulated LTE-U Qualcomm Simulation Results
LTE-U Median User Downlink Data Rate Gain: 2.8 over WiFi alone Simulation results and simulation conditions are specific. Read the whitepaper for details. Take Away: Performance Improvement

21. LTE-U Verification Prototype and Test LTE-U
Physical Layer
Performance Assessment
Throughput
Fairness
Assess Interference
Discontinuous Transmission
Standards Compliance
Workshops
Wi-Fi Alliance Wi-Fi and LTE-U Coexistence Test Workshop – April 2016

22. References Qualcomm RCR Wireless News Android Headlines
RCR Wireless News
Android Headlines
Radio Electronics
National Instruments

23. References Huawei Wi-Fi Alliance Fierce Wireless
Wi-Fi Alliance
Fierce Wireless