LTE in the Unlicensed Spectrum - But before we start More Traffic, Faster, Everywhere! LTE in the...

LTE in the Unlicensed Spectrum

Andjela Savoia

Application Engineer

Page

The path beyond 1Gbps

2

E7515A UXM Wireless Test Set

Future-ready capabilities

• 1.6Gbps IP data throughput with LTE-A

4CC CA and 4x4 DL MIMO (with

simulated uplink)

• World’s first benchtop solution capable to

support 5CC

A validated solution

• Industry Leadership: Joint validation and

commercialization

• Mobile Industry Milestone: 1Gbps IP Data

Throughput

• 4x4 MIMO with Carrier Aggregation &

256QAM Downlink

1Gbps!

LTE in the

Unlicensed

Spectrum

PageAgenda

– The unlicensed spectrum opportunity

– It’s happening in multiple ways:

• WLAN inter-working

• LTE in the Unlicensed Spectrum

– Summary

Page

But before we start…

LTE in the

Unlicensed

Spectrum 4

Page

But before we start…More Traffic, Faster, Everywhere!

LTE in the

Unlicensed

Spectrum 5

Mobile data traffic grew another 75% in 2015

o From 2.1EB/month in 2014 to 3.7EB/month in 2015 (1 EB = 1 million TB)

o Expect to reach 30EB/month by 2020

The FCC closed a $45 billion wireless spectrum auction in 2015

o Auction for the so called AWS-3 mainly used to deploy 4G

Mobile video will increase 11-fold between 2015 and 2020

Source: Cisco Mobile Data Traffic Forecast Update, 2015-2020

PageAgenda





– Summary and conclusions

Page

The unlicensed spectrum opportunityMultiple ways to help cope the capacity crunch

Enhanced MIMO Het-Nets

Increase available Bandwidth

LTE in the

Unlicensed

Spectrum 7

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The unlicensed spectrum opportunity

Industrial, Scientific and Medical (ISM) radio bands

Portions of the spectrum reserved internationally for Industrial, Scientific and

Medical purposes

• Defined by the ITU Radio Regulations (Article 5)

• Differently regulated by each region (i.e. FCC in US, ETSI in EU)

• Exact frequency allocation depends on country

• Unlicensed operations are typically permitted

• Services operating within these bands must accept interference

2.4GHz~80MHz

5GHz~ 800MHz

60GHz~ 9000MHz

Bluetooth, ZigBee, WLAN WLAN WiGig

What is the Unlicensed Spectrum?

LTE in the

Unlicensed

Spectrum 8

Page

Faster

Data Rates

More Users

Capacity

Indoor

Connectivity

The unlicensed spectrum opportunityOperators Benefits

WLAN ubiquity

and lower cost

infrastructure

LTE in the

Unlicensed Spectrum

LTE in the

Unlicensed

Spectrum 9

PageAgenda





– Summary and conclusions

Page

It’s happening in multiple ways…

3GPP has focused in two areas to help Operators offload traffic in the

unlicensed spectrum:

• WLAN via LTE/WLAN Interworking (via offload or aggregation)

• LTE over unlicensed spectrum

Link

Aggregation

WLAN

LTE

Unlicensed

Carrier

Aggregation

WLAN

Offload

More Capacity

Unified Network

Fair Coexistence

Faster

LTE

Licensed

LTE in the

Unlicensed

Spectrum 11

Page






Link

Aggregation

WLAN

LTE

Unlicensed

Carrier

Aggregation

WLAN

Offload

More Capacity

Unified Network

Fair Coexistence

Faster

LTE

Licensed

LTE in the

Unlicensed

Spectrum 12

Page






Link

Aggregation

WLAN

LTE

Unlicensed

Carrier

Aggregation

WLAN

Offload

More Capacity

Unified Network

Fair Coexistence

Faster

LTE

Licensed

LTE in the

Unlicensed

Spectrum 13

Page






Rel. 12 Rel. 13 Rel. 14Rel. 11Rel. 10

LTE/WLAN

Interworking

LTE over

unlicensed eLAA

WLAN

Offload

RAN Assisted

Interworking

RAN Controlled

Interworking

LAA

LTE-U

Aggregation LWA

LWIP

LTE in the

Unlicensed

Spectrum 14

Offload

Page







LTE/WLAN

Interworking

LTE over

unlicensed eLAA

WLAN

Offload

RAN Assisted

Interworking

RAN Controlled

Interworking

LAA

LTE-U

Aggregation LWA

LWIP

LTE in the

Unlicensed

Spectrum 15

Offload

Page

WLAN Offload: Use Case

1. WLAN Calling offload (3GPP Network access through WLAN)

Receive and place calls, SMS through IMS in areas with poor cellular coverage

3. Seamless Offload (Session mobility)

Higher quality transitions when entering/exiting LTE or WLAN coverage

2. Smart Offload (Network selection)

Select LTE or WLAN based on environment, network conditions and per-service

• Delivery of mobile cellular traffic over WLAN to reduce congestion of the

cellular network by taking advantage of:

o Most of mobile devices usually have a built-in WLAN function

o Readily available WLAN networks

• LTE – WLAN Inter-working standardization is needed to improve QoE:

LTE in the

Unlicensed

Spectrum 16

Page

WLAN

IMS

eNB

WLAN Calling offload using IMS

Internet

ProviderUE

3GPP Network

How could I still be reachable?

Internet

LTE in the

Unlicensed

Spectrum 17

http://www.clker.com/cliparts/f/f/e/4/12065572121317625675no_hope_Wireless_access_point.svg.med.png


Page

WLAN

IMS

eNB

WLAN Calling offload

Internet

ProviderUE

3GPP Network

How could I still be reachable?

1. Trusted WLAN (i.e. Operators owned WLAN network)

2. Un-Trusted WLAN (i.e. WLAN at home or office)

Internet

LTE in the

Unlicensed

Spectrum 18



Page

WLAN

IMS

eNB

WLAN Calling offload (Un-Trusted WLAN)

Internet

UE

3GPP Network

ePDG

PDN

GW

IPSec tunnel

– Step 1: Provisioning of ePDG address.

– Step 2: Secure IPsec tunnel between UE and ePDG via the WLAN access (IKEv2)

– Step 3: Authenticate USIM through IPSec tunnel to ePDG

– Step 4: IMS registration

Internet

Provider

LTE in the

Unlicensed

Spectrum 19



Page

WLAN

IMS

eNB

WLAN Calling offload (Un-Trusted WLAN)

Internet

UE

3GPP Network

ePDG

PDN

GW

– Step 1: Provisioning of ePDG address.

– Step 2: Secure IPsec tunnel between UE and ePDG via the WLAN access (IKEv2)

– Step 3: Authenticate USIM through IPSec tunnel to ePDG

– Step 4: IMS registration

Hello!Internet

Provider

LTE in the

Unlicensed

Spectrum 20



Page

WLAN

IMS

eNB

WiFi Offload: RAN Assisted Network Selection

UE

3GPP Network

Which Network should I use (3GPP or WLAN)?

- RAN Assistance via SIB17 and dedicated RRC signaling

- ANDSF is a semi-static policy provided to the UE that controls the access according to

time of the day, location and network congestion.

- Ultimately, decisions are made by the UE based on evaluation of these policies

WLAN

Provider

ANDSF

ANDSF

Server

Internet

LTE in the

Unlicensed

Spectrum 21



Page

RAN LTE-WLAN Inter-working (Rel 12 and 13)

LTE WLAN

? Rule#1

If LTE is bad and WLAN good

steer to WLAN

Rule#2

If WLAN is good but slow

steer to LTE

…

RAN Assisted (Rel 12)

LTE WLAN

RAN Controlled (Rel 13)

Measurement Report

Steering command

(offload to WLAN or LTE)

• RAN Assisted Interworking (RALWI – Rel 12) provides the UE with parameters

and rules to help take the decision to steer to WLAN or LTE; decission led by the UE

• RAN Controlled Interworking (RCLWI – Rel 13), allows the Network Operator to

control when and where to steer through a steering command:

o Greater control by the Operator

o Harmonized with 3GPP handovers based on UE measurements

LTE in the

Unlicensed

Spectrum 22





Page

Provided by

Commercial

Access Point

Provided

by UXM

E7515A

23

E7515A UXM

WLAN

IMS

eNB

WLAN Calling Demo

InternetInternet

ProviderUE

3GPP Network

ePDG

PDN

GW

– IMS termination (client) and server, provided by E6966B

– ePDG optional in E7515A UXM instrument

– WLAN access point - any which supports IPSec

IPSec tunnel

Provided

by E6966B



Page







LTE/WLAN

Interworking

LTE over

unlicensed eLAA

WLAN

Offload

RAN Assisted

Interworking

RAN Controlled

Interworking

LAA

LTE-U

Aggregation LWA

LWIP

LTE in the

Unlicensed

Spectrum 24

Offload

Page







LTE/WLAN

Interworking

LTE over

unlicensed eLAA

WLAN

Offload

RAN Assisted

Interworking

RAN Controlled

Interworking

LAA

LTE-U

Aggregation LWA

LWIP

LTE in the

Unlicensed

Spectrum 25

Offload

Page

LTE WLAN User Plane Aggregation: Use Case

• Enable link aggregation of LTE and WLAN to increase throughput

- Reliable LTE used as control and mobility anchor to secure QoE

- WLAN (using unlicensed spectrum) is opportunistically used to

increase data rates

• Operators can use deployed WLAN network as standalone for legacy

devices but also to increase data rates in new devices

• The benefits can be realized in:

- Co-located (e.g. a small-cell that integrates both LTE and WLAN)

- Non-co-located (e.g. agreement to use a partner’s WLAN network)

LTE in the

Unlicensed

Spectrum 26

Co-located

Integrated LTE / WLAN small-cells

Non-co-located

Cellular network partering with WLAN operator

Page

• Uses concepts developed in Rel. 12 Dual Connectivity

• Master cell group can only be played by LTE eNBs

• Secondary cell group is replaced by a WLAN Termination (WT)

• In the case of non-co-located, Xw interface is used to connect eNB and WT

• Enables efficient control plane signaling

• Whilst exploiting a small cell WLAN hot spot

LTE WLAN Aggregation (LWA) Use Model

Data Aggregation using WLAN Hot spot

eNode B

WLAN

…00101110 …

Xw

interface

S-GW/

MME

WLAN WLAN

WT

WLAN Mobility Set

LTE in the

Unlicensed

Spectrum 27

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LTE WLAN Aggregation (LWA): Fundamentals

LTE in the

Unlicensed

Spectrum 28

• When non-co-located, eNB and WLAN need to support a new interface (Xw – control and data)

• WLAN nodes assumed to be deployed by Operators/Partners

• User plane split/switch between LTE/WLAN is at PDCP level

• WLAN traffic direction is DL only

Page

LWA (R13): WLAN Access Point Aggregation

eNBUE WT

WT Addition Request

WT Addition Acknowledge

RRC ConnectionReconfiguration

RRC ConnectionReconfigurationComplete

WT admits request from

the eNB to aggregate the

WLAN resource requested

WT Association Acknowledge

WLAN Connection Status Report

UE receives configuration with:

- LWA DRB configuration

- List of WLAN SSID to Add

(creating the MobilitySet)

- LWA WT Counter used to derive

the authentication key with WLAN

UE reports connection

status to WLAN(s) and the

cause of failures if any

UE Capabilities

PS ATTACHDuring the network attach, the

UE shall report LWA capabilities

including WLAN band indicator

(2.4GHz, 5GHz)

UE starts using the new LTE-WLAN aggregated DRB

LTE in the

Unlicensed

Spectrum 29

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LTE WLAN IP Tunneling (LWIP): Fundamentals

• eNB-WLAN communication is over an IP tunnel (supports legacy WLAN deployments)

• When aggregated, packets could be delivered out of order

• User plane split/switch between LTE/WLAN is at IP level

• WLAN traffic direction is DL and UL

(PDCP SDUs)

LTE in the

Unlicensed

Spectrum 30

Page







LTE/WLAN

Interworking

LTE over

unlicensed eLAA

WLAN

Offload

RAN Assisted

Interworking

RAN Controlled

Interworking

LAA

LTE-U

Aggregation LWA

LWIP

LTE in the

Unlicensed

Spectrum 31

Offload

Page







LTE/WLAN

Interworking

LTE over

unlicensed eLAA

WLAN

Offload

RAN Assisted

Interworking

RAN Controlled

Interworking

LAA

LTE-U

Aggregation LWA

LWIP

LTE in the

Unlicensed

Spectrum 32

Offload

Page

LTE over Unlicensed: Licensed Assisted Access

• Opportunistic use of LTE in the Unlicensed Spectrum represents an important

complement to meet traffic demand and help boost data rates

• 3GPP has analyzed different modes of Operations depending on scenarios:

Deployment model Mode of operation

Cells w/ ideal backhaul (co-located or not)

Licensed-Assisted

Carrier

Aggregation

(Rel.13 LAA)

Cells w/out ideal backhaul (non-colocated)Dual Connectivity

(Rel.14 eLAA)

Standalone cellsStandalone

non-3GPP i.e. MulteFire

• Enhanced LAA (eLAA) has been proposed as a new Release 14 Work Item

and will specify LAA support for Uplink and Dual Connectivity in the LAA SCell

• Standalone operation within unlicensed spectrum is not planned yet by 3GPP

LTE in the

Unlicensed

Spectrum 33

(1) License-Assisted

(2) Standalone

Page

• Based on Carrier Aggregation with the Primary Cell being deployed in any

Licensed Band to ensure highest reliability and a set of SCells in unlicensed

spectrum to boost data rates.

LAA Overview and Design Targets

LTE in the

Unlicensed

Spectrum 34

Design targets:

1. Single global solution compliant with any regional regulatory requirement

2. Effective and fair co-existence with WLAN

3. Effective and fair co-existence with others Operators’ LAA deployments

Page

LAA Functionalities

LTE functionality required:

i. Listen-Before-Talk (LBT)

ii. Frame structure type 3:

• Discontinuous transmission with limited usage of channel

• Use of incomplete subframes

• Downlink only

• No PBCH

• Use of Band 46 (5.150 – 5.925 GHz)

iii. Discovery Signals to enable RRM

More information can be found in TR 36.889

“Feasibility Study on Licensed-Assisted Access to Unlicensed Spectrum“

LTE in the

Unlicensed

Spectrum 35

http://www.3gpp.org/dynareport/36889.htm

Page

LAA Functionalities: Listen-Before-Talk (LBT)

LBT (Listen-Before-Talk):

• Is a contention-based protocol that allows many users to use the same radio

channel withouth pre-coordination

• Relies on eNB sensing the radio channel (CCA) before starts a transmission

LAA SCell1

LAA Tx

Need to transmit

Contention Window slot (9us)

LAA DL Transmission

N Random number [0, CW]

1

N=1 Td

Td Defer time (≥21us)

LBT procedure described in TS 36.213 cl. 15.1

CCA = Clear Channel Assesment

Is channel Idle?

Yes!

Transmit

LBT

LTE in the

Unlicensed

Spectrum 36

OFF OFFON

Page






LAA SCell1

LAA SCell2

LAA Tx

N=4

Need to transmit


LAA DL Transmission


1

N=1 Td

1

Td




Is channel Idle?

No. Back-off

Td …

LTE in the

Unlicensed

Spectrum 37

Page






LAA SCell1

LAA SCell2

LAA Tx

N=4Td

4 LAA Tx

Need to transmit


LAA DL Transmission


1

N=1 Td

1

Td Td

2 3




…

LTE in the

Unlicensed

Spectrum 38

Page

LAA Functionalities: Discontinuous transmission

Discontinuous transmission:

• Certain geographical regions prohibit continuous transmission and impose

limits on the maximum duration of a transmission burst in the unlicensed

spectrum.

Table 15.1.1-1: Channel Access Priority Class (TS 36.213)

• The largest burst duration (MCOT - Maximum Channel Occupancy Time)

ranges between 2ms (p = 1, highest priority) and 10ms (p = 4, lowest priority)

Contention Window MCOT

LTE in the

Unlicensed

Spectrum 39

Page

LAA Functionalities: Discontinuous transmission

Discontinuous transmission:

• First subframe in a burst can last 1ms (starts at symbol 0) or 0.5ms (starts

at symbol 7):

- Signaled to the UE via RRC with “subframeStartPosition” in the

Dedicated Physical Configuration

• Last subframe in a burst can last 1ms or the duration of a Special subframe

with normal cyclic prefix ({3,6,9,10,11,12} OFDM symbols)

- Signaled to the UE via DCI Format 1C scrambled with a new CC-RNTI

Note: 's0' means symbol 0 and 's07' means symbol 0 or symbol 7

LTE in the

Unlicensed

Spectrum 40

Page

LAA Functionalities: LAA Cells discovery

LAA Secondary Cells discovery:

• It is needed a way for UEs in the LAA SCell coverage range to enable RRM

measurements and reporting, even when SCells are not aggregated

• Use of Rel.12 Discovery Signals (DS), initially designed for small cells, but with

certain differences when used for LAA SCells:

- RRC signaling (DMTC) allows DS periodicity of 40ms, 80ms and 160ms

- ≥12 OFDM symbols subframe with only CRS, PSS and SS

- DS transmission can happen in any of the 6 first subframes of the period

LTE in the

Unlicensed

Spectrum 41

Page

LAA Conformance Status Update

LAA RAN5 Work Item approved in Dec 2015 (RAN#69)

Conformance Test Cases definition is on going and expect to be

finished and available by late 2016:

• NEW RF test cases: Expected Chapters 7, 8 and 9 (Rx and Perf)

• NEW RRM and PCT test cases

LAA RAN4 Performance requirements expected to be finished by

June 2016 (RAN#72)

LTE in the

Unlicensed

Spectrum 42

Page

T4010S Conformance Test SystemRF, RRM & Design Verification

• Based on the E7515A UXM Wireless Test Set

• Confidently runs 3GPP RF & RRM Conformance

Test on a platform validated for 3GPP test cases

using the same hardware set

• Utilize extended test plans for exhaustive Design

Verification

• Scalable & Compact solution based on a

common hardware set

• Create Custom Test Campaigns with flexibility,

use powerful debug tools for results analysis

• Free-up engineering resource by adopting test

automation

LTE in the

Unlicensed

Spectrum 43

Page

LTE-U, LTE Unlicensed

Background:

• Defined by the LTE-U Forum in 2014 to enable CA using the Unlicensed band

• As 3GPP LAA does, it uses supplemental downlink deployment in the unlicensed

band using carrier aggregation with a licensed LTE cell (3GPP Rel. 12)

• With target on regions without LBT requirements such as US:

oU-NII-1 (LTE-U Band 252 - 5150-5250MHz)

oU-NII-2 (LTE-U Bands 253 and 254 - 5250-5725MHz) – for future usage due to DFS

oU-NII-3 (LTE-U Band 255 - 5725-5850MHz)

LTE in the

Unlicensed

Spectrum 44

Page

LTE-U vs LAA, Main Differences

Standardization Body• LTE-U Forum (2014)

• Regulatory: US

Primary Cell Bands• FDD Only

Secondary Cell Bands• Band 252, 255 (,253, 254 future)

Coexistence:• Max ON duration = 20 ms

• CSAT Rev 1.5

o Duty cycle based transmission

Secondary Cell discovery• DS in sf#5 with SIB

Frame Structure:• Type 1 (FDD)

Standardization Body• 3GPP Release 13 (March 2016)

• Regulatory: Global (used worldwide)

Primary Cell Bands• FDD or TDD

Secondary Cell Bands• Band 46

Coexistence:• Max ON duration = 10 ms

• Listen Before Talk

o CCA before transmission

Secondary Cell discovery• DS in any of the 6 first subframes of the period

Frame Structure• Type 3 (LAA)

o No PBCH

o First subframe can last 1ms or 0.5ms

o Partial last subframe (DCI 1C)

LTE-U (LTE Unlicensed) LAA (License-Assisted Access)

LTE in the

Unlicensed

Spectrum 45

Page

Demonstration: LTE-Unlicensed (LTE-U)

‒ LTE carrier aggregation using

unlicensed 5 GHz ISM band

– Aggregation at the MAC level

– Support for up to 4 SCCs in

unlicensed bands

– Requires E7515A-506 extended

frequency range platform option

Ensure realistic data performance

PHY

MAC

PHY

MAC

RLC

RRC

NAS

PDCP

IP

…001010…

CC1B2 1960MHz

CC2B252 5160MHz

SCC reconfiguration to

B255 5745MHz

TCP/UDP

Validate the latest carrier aggregation techniques for improved data rates

LTE in the

Unlicensed

Spectrum

PageAgenda


– Standardization:

• It’s happening in multiple ways…

– Summary

Page

Summary

RALWI RCLWI LWA LWIP LTE-U LAA

Complete name

RAN Asissted

LTE-WLAN

Interworking

RAN

Controlled

LTE-WLAN

Interworking

LTE WLAN

Aggregation

LTE WLAN

Integration

with

IP Tunneling

LTE

Unlicensed

License

Assisted

Access

3GPP Release 12 13 13 13 12* 13

InfrastructureEPC +

legacy WLAN

EPC +

legacy WLANEPC + WLAN

EPC +

legacy WLANEPC EPC

WLAN relation Offload Offload Aggregation Aggregation co-existence co-existence

Co-existence CSMA CSMA CSMA CSMA CSAT LBT

Aggregation layer IP IP PDCP IP MAC MAC

DL and/or UL DL and UL DL and UL DL only DL (and UL) DL only DL only

LTE in the

Unlicensed

Spectrum 48

*Not a 3GPP feature

Page

Summary


Complete name

RAN Asissted

LTE-WLAN

Interworking

RAN

Controlled

LTE-WLAN

Interworking

LTE WLAN

Aggregation

LTE WLAN

Integration

with

IP Tunneling

LTE

Unlicensed

License

Assisted

Access

3GPP Release 12 13 13 13 12* 13

InfrastructureEPC +

legacy WLAN

EPC +


EPC +

legacy WLANEPC EPC





LTE in the

Unlicensed

Spectrum 49

Unified Network (LTE – WLAN) Single RAT (LTE)

*Not a 3GPP feature

LTE-WLAN

Offload

LTE-WLAN

AggregationLTE Carrier

Aggregation

Page

Summary


Complete name

RAN Asissted

LTE-WLAN

Interworking

RAN

Controlled

LTE-WLAN

Interworking

LTE WLAN

Aggregation

LTE WLAN

Integration

with

IP Tunneling

LTE

Unlicensed

License

Assisted

Access

3GPP Release 12 13 13 13 12* 13

InfrastructureEPC +

legacy WLAN

EPC +


EPC +

legacy WLANEPC EPC





LTE in the

Unlicensed

Spectrum 50

Objectives:

• Better load balance between LTE and WLAN

• Extended coverage (i.e. WLAN Calling)

Network decides how to Offload

UE is provided with help to decide how to Offload

*Not a 3GPP feature

Page

Summary


Complete name

RAN Asissted

LTE-WLAN

Interworking

RAN

Controlled

LTE-WLAN

Interworking

LTE WLAN

Aggregation

LTE WLAN

Integration

with

IP Tunneling

LTE

Unlicensed

License

Assisted

Access

3GPP Release 12 13 13 13 12* 13

InfrastructureEPC +

legacy WLAN

EPC +


EPC +

legacy WLANEPC EPC





LTE in the

Unlicensed

Spectrum 51

Objective:

• Faster Data Rates

- Aggregation at PDCP

- Integrated LTE/WLAN solution

- Aggregation at IP, with public IP

- In-order delivery not guaranteed*Not a 3GPP feature

Page

Summary


Complete name

RAN Asissted

LTE-WLAN

Interworking

RAN

Controlled

LTE-WLAN

Interworking

LTE WLAN

Aggregation

LTE WLAN

Integration

with

IP Tunneling

LTE

Unlicensed

License

Assisted

Access

3GPP Release 12 13 13 13 12* 13

InfrastructureEPC +

legacy WLAN

EPC +


EPC +

legacy WLANEPC EPC





LTE in the

Unlicensed

Spectrum 52

LTE AggregationWLAN Aggregation

Objective:


*Not a 3GPP feature

Page

Summary


Complete name

RAN Asissted

LTE-WLAN

Interworking

RAN

Controlled

LTE-WLAN

Interworking

LTE WLAN

Aggregation

LTE WLAN

Integration

with

IP Tunneling

LTE

Unlicensed

License

Assisted

Access

3GPP Release 12 13 13 13 12* 13

InfrastructureEPC +

legacy WLAN

EPC +


EPC +

legacy WLANEPC EPC





LTE in the

Unlicensed

Spectrum 53

Objective:


*Not a 3GPP feature

Page

It’s Becoming a Reality…

The FCC has requested special approval for any LTE-U equipment

• Strong interest from Operators like Verizon and T-Mobile among others

• WiFi Alliance currently working on a LTE-U eNB test plan

WiFi Calling is being deployed now!

• It is the next step after VoLTE, most Operators planning to roll-out

• Already available worldwide (Verizon, T-Mobile, AT&T, Sprint, EE, Vodafone,

etc…) and more coming in 2016

Although just being defined (Rel-13), LAA and LWA getting a lot of traction

• First LAA trials happening in early 2016 (Deutsche Telekom, SingTel, etc…)

• LWA is seen as an opportunity for smaller and more agile players

LTE in the

Unlicensed

Spectrum 54

Page

Test Opportunities

• Functional test:

o Handovers, re-selections, interoperability, …

• Performance:

o Data Throughput, Audio quality, Battery drain, RF, …

• In-Device co-existence

• 3GPP Conformance

• Carrier Acceptance Test

Test Challenges You Need to Overcome

E7515A UXM Wireless Test Set

LTE in the

Unlicensed

Spectrum 55

World’s first benchtop solution

capable to support 5CC

Page

R&D Design validation Compliance Manufacturing Deployment

Modelling

Integration

PHY/RF

L2/L3

Apps

RF

performance

Regression

Throughput

Battery Drain

Stress

OTA

Regulations

Lab IOT

Operator

GCF/PTCRB

IC

Debug

Module

Product

Sample

Spectrum

clearance

Operations

Installation

Optimization

Repair

Keysight Technologies

i3070 test systems

FieldFoxPropsim channel emulator

A9000 protocol conformance test

Network Analyzers

Modelling tools

VSA/VSGUXM Wireless Test Set

Source measurement units

RF & RRM conformance

Oscilloscopes

EXM Wireless Test Set

Spectrum regulation and

network optimization tools

Thermal test

Anite

LTE in the

Unlicensed

Spectrum 56

Page

The Key to Success in TechnologyWe deliver what’s next. First.

© 2016 Keysight Technologies

THANK YOU!

LTE in the

Unlicensed

Spectrum 57

Page

Backup

LTE in the

Unlicensed

Spectrum 58

Page

FAQs

LTE in the

Unlicensed

Spectrum 59

1. Can LAA be deployed at 2.4 GHz?

LAA has been designed as Band agnostic and therefore can be deployed in any Band.

However, so far, only Band 46 which covers the 5GHz ISM band has been defined by the

3GPP.

The 2.4GHz band is used by many technologies and very populated while 5GHz is less

utilized and therefore has been agreed as the priority for LTE over the unlicensed

spectrum.

I don’t think 2.4GHz will be standardized but we’ll see.

2. Will LTE-WiFi Aggregation use home access points?

Not really… It is not the use case… I don’t want to waste my data plan MBs while I’m

home, right!?!

The use case of LTE-WiFi Aggregation is more oriented to Operators deploying their own

WiFi Network, or partnering with a WiFi Operator of course.

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3. How many unlicensed carriers can be aggregated?

No explicit limit has been defined in LAA as far as know… but given it is based on

Carrier Aggregation, its limit is up to 5 component carriers in total.

However, it is important to take into account that in Release 13 the number of CCs

has been extended up to 32… so that would potentially be the limit today, 31 carriers

in the unlicensed spectrum.

4. Can LWA and LAA be used simultaneously?

Yes, I don’t see any reason why this shouldn’t be possible.

Given LAA is based on Carrier Aggregation, it is seen as just an extension of the

resources available at MAC or physical layer… while LWA would be an aggregation

happening earlier in the Stack, at PDCP… So, yes, it is possible.

I would like to mention that LWA is not compatible with both LWIP and RCLWI.

Any other combination, I think should be possible.

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5. When is going to be uplink supported in LAA?

Uplink in the unlicensed spectrum is not part of the scope of LAA and has been

postponed to Release 14 as part of eLAA, a new feature.

This work is expected to be completed by the 3GPP by sometime in mid-2017.

6. Can LTE-U and LAA be used together?

Yes, kind of… It is possible as soon as the eNB and the UE support both LTE-U and

LAA. It is possible because both use different band identifiers.

That is why I mentioned earlier that LAA could be seen as an upgrade of LTE-U and

Operators deploying LTE-U could just upgrade to LAA and still being able to use LTE-U

UEs although not simultaneously.

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7. What happens if LTE coverage is lost while doing WiFi aggregation?

The connection would be completely lost.

In this case, WiFi is used just to increase data rates but the connection is

established and maintained through LTE.

8. Is it possible to do licensed and unlicensed carrier aggregation

simultaneously?

Yes, it is possible although there is a limit in the maximum number of

aggregated cells of course but that is independent of the spectrum type used.

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9. How is WLAN traffic and flow controlled in LWA?

There are changes in the LTE PDCP layer in order to allow status reports

so that the eNB knows which WLAN packets reached the receiver or not so

that I can retransmit or adjust the flow automatically.

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LTE over Unlicensed: Use Case

• Opportunistic use of LTE in the Unlicensed Spectrum represents an important

complement to meet traffic demand and help boost data rates

• It is an attractive option for Operators:

• Operational cost saving

• Unified Network

• Single radio access type Network (RRM, billing, service continuity, etc…):

oBetter user experience

o Improvements around mobility and roaming

Licensed Anchor

Restricted access

Security

Expensive

Unlicensed Traffic unpredictible

Shared with others

Opportunistic use (supplemental)

Free of charge

LTE in the

Unlicensed

Spectrum 64

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LTE-U and LAA, main differences

LTE-U SCell

PCell

Frame n Frame n+4

Discovery Signal sent with

a 40, 80 or 160ms period in sf#5

(CRS, PSS, SSS, PDCCH/PDSCH for SIB1)Silent subframe

(no CRS, PSS, SSS, PDSCH)

Regular subframe with CRS

(even when no PDSCH)

Data transmitted to UE

• CSAT (Carrier Sensing Adaptive Transmission) is used to secure fair

coexistence with Wi-Fi and other LTE-U deployments:

• Based on duty cycle (ON/OFF) with no collision mechanism (LBT)

• Maximum burst duration (ON) of 20ms

• Minimum OFF duration of 1ms

• As in LAA, SCell ON/OFF state is independent of the activation state.

sf#5 sf#5

LTE in the

Unlicensed

Spectrum 65

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• Its definition includes a User plane (Xw-U) and a Control Plane (Xw-C).

• Xw-U is built on IP transport and GTP-U (GPRS Tunneling Protocol for User

data, TS 29.281) is used on top of UDP/IP to carry the user plane PDUs.

• Detailed definition in progress in TS 36.464 and TS 36.465.

• Xw-U is built on SCTP (Stream Control Transmission Protocol) on top of IP.

• The application layer signalling protocol is referred to as Xw-AP (Xw

Application Protocol, definition in progress in TS 36.463).

LTE-WLAN Aggregation (LWA)

The Xw Interface

GTP-U

UDP

IP

Data link layer

User plane PDUs

Physical layer

SCTP

IP

Data link layer

Xw-AP

Physical layer

SGW eNB

AP

S1-U

Xw-U

MME eNB

AP

S1-MME

Xw-C

Xw-U

Xw-C

LTE in the

Unlicensed

Spectrum 66

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RLC

• LWA bearers are DL only

LWA (R13)PDCP User Plane scheduling

RLC

MAC

MAC

LWAAP

PDCP

schedulerPHY

PHY

802 MAC

802 LLC

IP

Adaptor

1234

12

5

3

4

5

124

35

PHY

802 MAC

802 LLC

Adaptor

PHY

MAC

RLC

PDCP

1

2

4

3

5

1

2

3

4

5

IP

RRH

WiFi AP

UE

LTE bearer

LWA switched

bearer

LWA split bearer

LWA bearer

LTE bearer

LTE eNodeB

S1

Xw

SGW

LWAAP

PDCP status report

LTE in the

Unlicensed

Spectrum 67

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