LTE-Unlicensed JOSH FORGIE CTS

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

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

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

LTE-U Deployments AT&T Verizon T-Mobile Trials in 2016 5 GHz in 20MHz channels Verizon Trials beginning in 2015-2016 5 GHz and 3.5 GHz T-Mobile 5 GHz in 2016 Uses LTE-U enabled small cells from Alcatel-Lucent NOKIA

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

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

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

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

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

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

Three No LBT Coexistence Mechanisms Channel Section and Flow Chart

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

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

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

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 http://assets.fiercemarkets.net/public/newsletter/fiercewireless/qualcommlteuwhitepaper.pdf

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

LBT Required Coexistence Mechanism Listen Before Talk Framing

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

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 http://assets.fiercemarkets.net/public/newsletter/fiercewireless/qualcommlteuwhitepaper.pdf

LTE-U Verification Prototype and Test LTE-U Physical Layer Performance Assessment Throughput Fairness Assess Interference Discontinuous Transmission Standards Compliance http://www.ni.com/white-paper/53044/en/ Workshops Wi-Fi Alliance Wi-Fi and LTE-U Coexistence Test Workshop – April 2016 http://www.wi-fi.org/wi-fi-alliance-wi-fi-and-lte-u-coexistence-test-workshop-0

References Qualcomm RCR Wireless News Android Headlines https://www.qualcomm.com/documents/progress-laa-and-its-relationship-lte-u-and-multefire https://www.qualcomm.com/invention/technologies/lte/laa https://www.qualcomm.com/news/onq/2015/06/11/introducing-multefire-lte-performance-wi-fi-simplicity https://www.qualcomm.com/media/documents/files/lte-unlicensed-coexistence-whitepaper.pdf RCR Wireless News http://www.rcrwireless.com/20160301/carriers/making-sense-of-lte-u-laa-multifire-and-more-tag17 Android Headlines http://www.androidheadlines.com/2016/02/ah-tech-talk-topics-avoided-by-the-wireless-industry-at-mwc.html http://www.androidheadlines.com/2016/03/att-is-considering-laa-as-an-alternative-to-lte-u.html Radio Electronics http://www.radio-electronics.com/info/cellulartelecomms/lte-long-term-evolution/lte-u-unlicensed-laa-license-assisted-access.php National Instruments http://www.ni.com/white-paper/53044/en/ http://www.ni.com/product-documentation/52533/en/

References Huawei Wi-Fi Alliance Fierce Wireless http://www.huawei.com/ilink/en/download/HW_327803 Wi-Fi Alliance http://www.wi-fi.org/wi-fi-alliance-wi-fi-and-lte-u-coexistence-test-workshop-0 Fierce Wireless http://www.fiercewireless.com/tech/story/att-verizon-t-mobile-throw-support-behind-new-lte-u-laa-coalition/2015-09-28 http://www.fiercewireless.com/tech/story/att-trial-lte-u-early-2016/2015-09-09