lte-advanced carrier aggregation ca – from design to implementation and test challenges

LTE-Advanced Carrier Aggregation (CA) – from design to implementation and test challenges

Andjela Ilic-Savoia

Keysight Technologies

November 2014

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Agenda

LTE-A Carrier Aggregation technology, and relevance in the 4G and beyond era

• Key Features of LTE-Advanced

• What is CA and why do we need it?

• Bands and CA Deployment Scenarios

• Definitions and UE Categories

• How does CA work: Where is the impact and Protocol implications

• What’s coming in Rel-11, 12

• Summary

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Keysight Technologies Began Operations, Aug 1, ‘14

• Agilent announced Sept. 19, 2013, it would separate into:

• an Electronic Measurement company (now Keysight)

• a Life Sciences, Diagnostics and Applied Markets company (to

retain the Agilent name)

3

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FY13 $2.9 billion revenue | 18.9% operating margin | 31% ROIC | best in class financial profile

Communications Industrial, computer,

semiconductor

Aerospace/defense

Keysight in Electronic Measurement The industry leader

(1) Presented on a non-GAAP basis; reconciliations to closet GAAP equivalent provided. See reconciliations for definition of ROIC.

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Key LTE-Advanced Features

Carrier Aggregation Enhanced MIMO

Het Nets

Higher data rates

(bps) Higher spectral

effiency

(bps/Hz)

Higher spectral

effiency

per coverage area

(bps/Hz/Km2)

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What is Carrier Aggregation?

• Combining (using) multiple LTE carriers together in order to

increase data throughput

• Extends the maximum transmission bandwidth, up to 100 MHz, by

aggregating up to five LTE carriers – a.k.a component carriers

(CCs)

• Initially defined in the 3GPP Release 10 standard

• To preserve compatibility with existing devices, all aggregated

carriers look exactly “like R8/R9” carriers.

• Can be supported in Downlink only or both in Downlink and Uplink

• Supported for FDD and TDD modes

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Why Carrier Aggregation?

• Lack of sufficient contiguous spectrum forces use of carrier

aggregation to meet peak data rate targets

• Motivation:

• Achieve wider bandwidths (for throughput, throughput

and also throughput)

• Facilitate efficient use of fragmented spectrum

• Efficient interference management for control channels

in heterogeneous networks(cross scheduling optional)

≈ f

7

Why Carrier Aggregation - Industry Inflection Point Data Traffic Growth Driven By Smartphones

LTE-Advanced Carrier Aggregation

Benefits:

• Faster IP Data

• Wider bandwidths

• Reduced latency

• Improved spectrum efficiency

LTE Technology & Smartphones, 2014

Continued growth and opportunity

• 263 LTE networks in 97 countries*

• 1371 LTE devices*

• 918.6M Smartphone shipments**

• Global shift (US 15%, China 33%; India growing 460% in 2013-’17)*

Industry Trends

*Source GSMA, Jan 2014

150 Mbps

IP data

150 Mbps

IP data

LTE Carrier # 1

20 MHz Bandwidth

LTE Carrier # 2

20 MHz Bandwidth

LTE-A Carrier Aggregation Solution: 10 or 20 MHz fragments aggregated to get 30 - 40MHz channel bandwidth

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Band A Band B

Carrier Aggregation Modes

Intra -band

contiguous

allocation

f

≈ f

Intra-band

non-contiguous

allocation

Inter-band

non-contiguous

allocation

Component Carrier (CC)– up to 20 MHz BW

f

Band A

Band A

9

GPP Release 10 RF & Performance Requirements

f

Component Carrier (CC)– up to 20 MHz BW

Band A

Band A f

Band A Band B

≈ f

Not supported in Rel 10

Maximum 2 CCs supported

for both uplink & downlink,

FDD & TDD

Maximum 2 CC supported

ONLY for FDD-downlink

Intra -band contiguous

Intra-band non-contiguous

Inter-band allocation

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Rel-10 Defined CA Bands

Release 10 defines three CA bands:

• Intra-band contiguous CA:

• Band 1 (FDD) is defined as CA band CA_1 (IMT-2000 band)

• Band 40 (TDD) are defined as CA_40 (2300 MHz TDD band)

• For inter-band non-contiguous CA:

• R8 operating bands 1 and 5 are defined as one CA band named CA_1-5. (IMT-2000 and US Cellular 800 MHz bands)

Relaxing the constraint on Rel-10 CA

• An important aspect of frequency bands when it comes to the 3GPP releases is that they are “release independent”.

• This means that a band defined in a later release can be applied to an earlier release.

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Rel-11 Carrier Aggregation Combinations

Band Lead company Uplink Downlink Uplink Downlink Mode

CA-B3_B7 TeliaSonera 1710 - 1785 1805 - 1880 2500 - 2570 2620 - 2690 FDD

CA-B4_B17 AT&T 1710 – 1755 2110 - 2155 704 – 716 734 - 746 FDD

CA-B4_B13 Ericsson (Verizon) 1710 – 1755 2110 - 2155 777 - 787 746 - 756 FDD

CA-B4_B12 Cox Communications 1710 – 1755 2110 - 2155 698 – 716 728 - 746 FDD

CA-B20_B7 Huawei (Orange) 832 – 862 791 - 821 2500 - 2570 2620 - 2690 FDD

CA-B2_B17 AT&T 1850 – 1910 1930 - 1990 704 – 716 734 - 746 FDD

CA-B4_B5 AT&T 1710 – 1755 2110 - 2155 824 – 849 869 - 894 FDD

CA-B5_B12 US Cellular 824 – 849 869 - 894 698 – 716 728 - 746 FDD

CA-B5_B17 AT&T 824 – 849 869 - 894 704 – 716 734 - 746 FDD

CA-B20_B3 Vodafone 832 – 862 791 - 821 1710 - 1785 1805 - 1880 FDD

CA-B20_B8 Vodafone 832 – 862 791 - 821 880 – 915 925 - 960 FDD

CA-B3_B5 SK Telecom 1710 - 1785 1805 - 1880 824 – 849 869 - 894 FDD

CA-B7 China Unicom 2500 - 2570 2620 - 2690 2500 - 2570 2620 - 2690 FDD

CA-B1_B7 China Telecomm 1920 - 1980 2110 - 2170 2500 - 2570 2620 - 2690 FDD

CA-B4_B7 Rogers Wireless 1710 – 1755 2110 - 2155 2500 - 2570 2620 - 2690 FDD

CA-B25_25 Sprint 1850 - 1915 1930 - 1995 1850 - 1915 1930 - 1995 FDD

CA-B38 Huawei (CMCC) 2570 - 2620 2570 - 2620 2570 - 2620 2570 - 2620 TDD

CA-B41 Clearwire 2496 - 2690 2496 - 2690 2496 - 2690 2496 - 2690 TDD

© 2012 Agilent Technologies

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Band Lead company Uplink Downlink Uplink Downlink Mode

CA-B1_B18 KDDI 1920 - 1980 2110 - 2170 815 - 830 860 - 894 FDD

CA-B1_B21 NTT DoCoMo 1920 - 1980 2110 - 2170 1447.9-1462.9 1495.9-1510.9 FDD

CA-B11_B18 KDDI 1427.9–1427.9 1475.9- 1495.9 815 - 830 860 - 894 FDD

CA-B3_B8 KT 1710 - 1785 1805 - 1880 880 – 915 925 - 960 FDD

CA-B2_B4 TMO-US 1850 – 1910 1930 - 1990 1710 – 1755 2110 - 2155 FDD

CA-B1 KDDI 1920 - 1980 2110 - 2170 1920 - 1980 2110 - 2170 FDD

CA-B3_B3 SK Telecom 1710 - 1785 1805 - 1880 1710 - 1785 1805 - 1880 FDD

CA-B4_B4 TMO-US 1710 – 1755 2110 - 2155 1710 – 1755 2110 - 2155 FDD

… … …


Rel-11 Carrier Aggregation Combinations Continued…

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PCC (Primary Component Carrier)

• Random access procedure

• Handles the RRC/NAS connection

procedures

• Measurement and mobility (handovers)

procedures based on PCC

SCC (Secondary Component Carrier)

• Activated only when in CONNECTED mode

(can you guess why this req?)

• Can be dynamically activated/deactivated

(through MAC PDU)

• PUSCH is optional (asymmetric CA, only on

DL)

CA – How is it used?

Uplink

Downlink

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CA Deployment Scenarios (1 of 2)

Scenario #2:

• F1 and F2 cells are co-located and overlaid, but F2

has smaller coverage

• Only F1 provides sufficient coverage and F2 is

used to improve throughput.

• Likely scenario when F1 and F2 are of different

bands

F1 F2

Scenario #3:

• F1 and F2 cells are co-located but F2 antennas are

directed to the cell boundaries of F1 so that cell edge

throughput is increased.

• F1 provides sufficient coverage and F2 potentially “fills the

holes”

• Likely scenario when F1 and F2 are of different bands

Scenario #1:

• F1 and F2 cells are co-located and overlaid, providing

same coverage.

• Likely scenario when F1 and F2 are of the same band.

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CA Deployment Scenarios (2 of 2)

Scenario #4:

• F1 provides macro coverage and on F2 Remote Radio

Heads (RRHs) are used to improve throughput at hot

spots.

• Likely scenario when F1 and F2 are of different bands.

Scenario #5:

• Similar to scenario #2, but frequency selective

repeaters are deployed to extend coverage for one of

the frequencies.

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To specify different CA combinations some new definitions are used:

• Aggregated Transmission Bandwidth Configuration (ATBC): total number of aggregated physical resource blocks (PRB).

• CA bandwidth class: indicates a combination of maximum ATBC and maximum number of CCs in each band. In R10 and R11 three classes are defined:

• Class A: ATBC ≤ 100, maximum number of CC = 1

example: CA_1A_5A: BC1 and BC5, Inter-band, can do 2x up to 10MHz

• Class B: ATBC ≤ 100, maximum number of CC = 2

• Class C: 100 < ATBC ≤ 200, maximum number of CC = 2

example: CA_1C: BC1, Intra-band cont., can do 2x up to 20MHz

• Class D, E, F: ATBC up to 500 For Future Study

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UE Categories

UE

Category

Data Rate DL/UL

(Mbps)

Downlink Uplink

Max number

of layers

Max number

of layers

Support for

64QAM

1 10 / 5 1 1 No

2 50 / 25 2 1 No

3 100 / 50 2 1 No

4 150 / 50 2 1 No

5 300 / 75 4 1 Yes

6 300 / 50 2 or 4 1 or 2 No

7 300 / 100 2 or 4 1 or 2 No

8 3000 / 1500 8 4 Yes

LT

E

LT

E-A

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New UE Categories Combinations of Carrier Aggregation and Layers

• There are multiple combinations of CA and layers that can meet

the data rates for the new and existing UE categories

• The following tables define the most cases for which

performance requirements may be developed

UE category capability

[#CCs/BW(MHz)]

DL layers

[max #layers]

Category 6

1 / 20MHz 4

2 / 10+10MHz 4

2 / 20+20MHz 2

2 / 10+20MHz 4 (10MHz)

2(20MHz)

Category 7

1 / 20MHz 4

2 / 10+10MHz 4

2 / 20+20MHz 2

2 / 10+20MHz 4 (10MHz)

2(20MHz)

Category 8 [2 / 20+20MHz] 8?

UE category capability

[#CCs/BW(MHz)]

UL layers

[max #layers]

Category 6

1 / 20MHz 1

2 / 10+10MHz 1

1 / 10MHz 2

Category 7

2 / 20+20MHz 1

1 / 20MHz 2

2 / 10+20MHz 2 (10MHz)

1 ( 20MHz)

Category 8 [2 / 20+20MHz] 4?

Downlink Uplink

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CA – where is the impact?

• MAC, PHY and RF are the most impacted layers

• Aggregated carriers behave separately, including error correction,

until demodulation is complete.

• Data aggregation happens in MAC layer

• Single instance of PDCP/RLC for aggregated carriers – as if only

one carrier

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SCC communicated to UE in RRC Reconfiguration

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Protocol implications – how to agree to establish CA

During initial attach procedure, UE informs eNB of it’s capabilities in UE-

EUTRA-Capability information element: 23

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Further on rf-parameters v1020 UE reports in UE-EUTRA-Capability information element: 24

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Protocol implications – how to agree to establish CA

– SCC is enabled at MAC layer, and signaled to UE via

RRC Reconfig:

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MAC implications how to Activate/deactivate SCC

Oct 1C6C7 C5 C4 C3 C2 C1 R

Figure 6.1.3.8-1: Activation/Deactivation MAC control element

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Carrier Aggregation Design Challenges: one example

Need to design front-end components that help reduce harmonics

and other intermodulation products.

710

MHz

740

MHz 2130 MHz

Band 17 Band 4

Example: Band 17-4 combination

Third harmonic

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Evolution of carrier aggregation Rel-12 Dual connectivity for LTE

By allowing CA between sites it is possible to provide

continuous CA coverage using a low frequency

macro (umbrella) cell and local capacity

using a higher frequency small cell

Macro umbrella cell

Small

cell Small

cell

Small

cell

The separation of the sites means

that enhancements are required at the

physical layer including multiple timing advances

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Evolution of carrier aggregation Rel-13 Multi-RAT dual connectivity

The ultimate flexibility is achieved if CA is performed

across radio access technologies (RATs) and

in particular with today’s dominant small

cell technology: WLAN.

Macro umbrella cell

Small

cell WLAN

WLAN

This level of integration

will force solutions to the issues

of authentication and billing which

continue to limit the potential of WLAN today.

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LTE-Advanced Release 11, 12 &13 RAN stats

3GPP Releases 11, 12 and early 13 represent a

huge growth in features and complexity

• 58 Study items for feasibility of new work

• 75 new features (excl. carrier aggregation), 51 with new

performance requirements

• 129 new carrier aggregation combinations with

corresponding performance requirements

• 4 performance only requirements for features from

earlier releases

• 29 new conformance tests (expect ~180 at completion)

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Release 9: Summary of Key Radio Features

• Home base station (femtocell)

• MBMS – completion of MBSFN

• Positioning Support (AGNSS)

• Local Area Base Station (picocell)

• Self Organizing Networks (SON)

• Multicarrier / Multi-RAT Base Station (Multi Standard Radio)

• Dual layer beamforming (TM8)


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Rel-10: Stage 3 Frozen March 2011 Summary of Key Radio Features

• Simultaneous PUCCH and PUSCH

• Clustered SC-FDMA

• Relaying – continued in Release 11

• Enhanced Inter-cell Interference Coordination (eICIC)

• Minimization of Drive Test (MDT)

• Machine Type Communications (MTC)

• SON enhancements for self healing

• Transmit diversity, two- and four-layer spatial multiplexing

• Eight-layer spatial multiplexing including UE-specific RS (TM9)


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Rel-11: Stage 3 Frozen Sept 2012 Summary of Key Radio Features

• New carrier aggregation combinations (18)

• Verification of radiated multi-antenna reception performance of UEs in

LTE (MIMO OTA)

• Signaling and procedure for interference avoidance for in-device

coexistence

• Coordinated multi-point operation for LTE (CoMP)

• Further Enhanced Inter-cell Interference Coordination (FeICIC)


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Rel-12: New Frequency Bands

Three new FDD frequency bands will be defined:

• Downlink 1670 MHz–1675 MHz, uplink 1646.7 MHz–1651.7 MHz

• for ITU Region 2 (US)

• Downlink 461MHz–468 MHz, uplink 451–458 MHz

• for Brasil

• Downlink 2350–2360 MHz, uplink 2305–2315 MHz

• US Wireless Communications Service (WCS) band

There is also a study item for:

• Uplink 1980–2010 MHz and downlink 2170 MHz– 2200 MHz.

• This is currently widely allocated for satellite communications but terrestrial use now being considered, particularly for ITU Region 3.

• The potential for 110 MHz pairing with band 1 is also being considered.


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The following proposals from the workshop were identified as most likely to be

developed:

• Dynamic TDD

• Frequency separation between macro and small cells, using higher frequency

bands in small cells (e.g., 3.5 GHz)

• Inter-site carrier aggregation and macrocell-assisted small cells

• Interworking with Wi-Fi

• Continuous enhancements for machine-type communications, SON, MDT

• Proximity services and device-to-device communications(LTE-Direct)


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3GPP Rel-12 Workshop June 2012

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Rel-12: Stage 1 March 2013, Stage 3 2014? Current Work Items

– The Release 12 work items that have been defined so far are:

• New frequency bands

• 13 new carrier aggregation scenarios

• Bringing the total to 31 for Rel-11 & 12 to date

• Carrier-based Het-Net ICIC for LTE

• Extends existing co-channel ICIC to include network-based carrier selection

• New Carrier Type for LTE

• The so-called “lean” carrier – not backwards compatible with Rel-8. Less control channel overhead, can be switched on and off based on load

• Further Downlink MIMO Enhancement for LTE-Advanced

• Further enhancements for H(e)NB mobility

• Inter H(eNB) and H(e)NB to macro


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Thank You!

Name: Andjela Ilic-Savoia

E-mail:[email protected]

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Extras…

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End-to-end IP data throughput test 3GPP 37.901 Application Layer Data Throughput Testing

Application

Server System

Simulator

Channel

emulator

Test UE App

Layer

Protocol

System Simulator Channel emulator

profiles

FTP over

TCP/IP

LTE

- settable parameters

and

power levels, closed

loop CQI

LTE

- static, EPA5, EVA5,

EVA70, EVA200, ETU70 UDP over

IP

sf0 sf1 sf2 sf3 sf4 sf5 sf6 sf7 sf8 sf9

- 3GPP 37.901 is defined with no PDSCH data in sub-frames 0 and 5

- For LTE CAT4 this reduces the headline rate from 150Mbps to 120Mbps (20MHz channel)

- 3GPP 37.901 Application layer Throughput also excludes TCP/UDP protocol overhead and re-transmissions which reduce

the measurement result further

PDSCH data

DL

UL

DL

40

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E2E IP Throughput

CAT6 E2E IP Measurements on UXM

– 300Mbps achieved with 2x CCs and 20MHz bandwidth

41

Page LTE-A

CA CC#1

LTE-A

CA CC#2

W-CDMA

HSPA+

LTE

Interference

& AWGN

Multipath

fading

CA

& MIMO

Adaptive

modulation

& coding

Doppler

Real world conditions Affecting UE Performance

Need network and channel emulation to verify

LTE/LTE-A device performance

• Fading conditions

• Doppler speed

• Degree of spatial diversity

• Noise and interference conditions

• Transmission mode used

• Influence of adaptive modulation & coding

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End-to-end IP data throughput test for LTE/LTE-A chipsets/ UE’s

2. Receiver test complexities and challenges with 2CC CA, 4x2 MIMO and fading

3. Quickly setup multiple test sequences that require different parameters for each sequence

Overcome LTE-A UE Design Test Challenges with Agilent’s New UXM Assess design readiness with greater confidence

3. Test Parameter changes 1. E2E IP Throughput 2. Rx characterization

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• Unique receiver test Flexible channel allocation and closed-loop testing

• Trusted transmitter test X-Series measurement science

• Sustained bidirectional 300 Mbps/50 Mbps E2E IP data

• Most highly integrated solution: multiple cells, carrier aggregation, 4x2 DL MIMO, integrated fading and built-in application server

Ensure realistic category 6 performance

Achieve design confidence

LTE-Advanced carrier aggregation

Cat 6

device

DL: 300 Mbps

UL: 50 Mbps

Gain new insights for LTE-Advanced Wring out designs with a broad range of integrated capabilities

44

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Be ready for 4G and beyond Expand capabilities with most advanced platform architecture

• Designed for next advancements in

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• Two receiver paths per cell

• Enables multiple cells, carrier aggregation,

higher order MIMO, and integrated fading

• Multi-format capable

• Supports LTE FDD and TDD now

Future-ready platform

Extensible architecture

• High-speed interconnects,

upgradeable processors and

expansion slots

Versatile touchscreen

• Next-generation ease of use,

flexibility for the future

45

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Agilent Technologies webcast

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