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LTE in the Unlicensed Spectrum
Manuel Blanco
Product Marketing engineer
March 29, 2016
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
Page Agenda
– The unlicensed spectrum opportunity
– It’s happening in multiple ways:
• WLAN inter-working
• LTE in the Unlicensed Spectrum
– Summary
Page
But before we start… More Traffic, Faster, Everywhere!
LTE in the
Unlicensed
Spectrum 4
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
Page Agenda
– The unlicensed spectrum opportunity
– It’s happening in multiple ways:
• WLAN inter-working
• LTE in the Unlicensed Spectrum
– Summary and conclusions
Page
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 6
Page
Faster
Data Rates
More Users
Capacity
Indoor
Connectivity
The unlicensed spectrum opportunity Operators Benefits
WLAN ubiquity
and lower cost
infrastructure
LTE in the
Unlicensed Spectrum
LTE in the
Unlicensed
Spectrum 7
Page Agenda
– The unlicensed spectrum opportunity
– It’s happening in multiple ways:
• WLAN inter-working
• LTE in the Unlicensed Spectrum
– 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 9
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
Rel. 12 Rel. 13 Rel. 14 Rel. 11 Rel. 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 10
Offload
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
Rel. 12 Rel. 13 Rel. 14 Rel. 11 Rel. 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 11
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 12
Page
WLAN
IMS
eNB
WLAN Calling offload
Internet
Provider UE
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 13
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 14
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 15
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 16
Page
Provided by
Commercial
Access Point
Provided
by UXM
E7515A
17
E7515A UXM
WLAN
IMS
eNB
WLAN Calling Demo
Internet Internet
Provider UE
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
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
Rel. 12 Rel. 13 Rel. 14 Rel. 11 Rel. 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 18
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 19
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 20
Page
LTE WLAN Aggregation (LWA): Fundamentals
LTE in the
Unlicensed
Spectrum 21
• 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
LTE WLAN IP Tunneling (LWIP): Fundamentals
• eNB-WLAN communication is over an IP tunnel (supports legacy WLAN deployments)
• When aggregated, packets could 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 22
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
Rel. 12 Rel. 13 Rel. 14 Rel. 11 Rel. 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 23
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 cells Standalone
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 24
(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 25
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 26
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 27
OFF OFF ON
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 SCell2
LAA Tx
N=4 Td
4 LAA Tx
Need to transmit
Contention Window slot (9us)
LAA DL Transmission
N Random number [0, CW]
1
N=1 Td
1
Td Td
2 3
Td Defer time (≥21us)
LBT procedure described in TS 36.213 cl. 15.1
CCA = Clear Channel Assesment
…
LTE in the
Unlicensed
Spectrum 28
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 29
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 30
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 31
Page
T4010S Conformance Test System RF, 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 32
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 33
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 34
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…
CC1 B2 1960MHz
CC2 B252 5160MHz
SCC reconfiguration to
B255 5745MHz
TCP/UDP
Validate the latest carrier aggregation techniques for improved data rates
LTE in the
Unlicensed
Spectrum
Page Agenda
– The unlicensed spectrum opportunity
– 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
Infrastructure EPC +
legacy WLAN
EPC +
legacy WLAN EPC + WLAN
EPC +
legacy WLAN EPC 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 37
Unified Network (LTE – WLAN) Single RAT (LTE)
*Not a 3GPP feature
LTE-WLAN
Offload
LTE-WLAN
Aggregation LTE Carrier
Aggregation
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
Infrastructure EPC +
legacy WLAN
EPC +
legacy WLAN EPC + WLAN
EPC +
legacy WLAN EPC 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 38
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
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
Infrastructure EPC +
legacy WLAN
EPC +
legacy WLAN EPC + WLAN
EPC +
legacy WLAN EPC 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 39
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
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
Infrastructure EPC +
legacy WLAN
EPC +
legacy WLAN EPC + WLAN
EPC +
legacy WLAN EPC 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 40
Objective:
• Faster Data Rates
*Not a 3GPP feature
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 41
World’s first benchtop solution
capable to support 5CC
Page
R&D Design validation Compliance Manufacturing Deployment
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L2/L3
Apps
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performance
Regression
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Stress
OTA
Regulations
Lab IOT
Operator
GCF/PTCRB
IC
Debug
Module
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Sample
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clearance
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Oscilloscopes
EXM Wireless Test Set
Spectrum regulation and
network optimization tools
Thermal test
Anite
LTE in the
Unlicensed
Spectrum 42
Page
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LTE in the
Unlicensed
Spectrum 43
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