The Codex of Business Writing Software for Real-World Solutions 2.pptx
LTE-Advanced Carrier Aggregation CA – from design to implementation and test challenges
1. 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)
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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)
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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
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Intra-band
non-contiguous allocation
Inter-band non-contiguous allocation
Component Carrier (CC)– up to 20 MHz BW
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Band A
Band A
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3GPP Release 10 RF & Performance Requirements
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Component Carrier (CC)– up to 20 MHz BW
Band A
Band A
f
Band A
Band B
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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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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
LTE
LTE-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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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:
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Further on rf-parameters v1020 UE reports in UE-EUTRA-Capability information element:
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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
C7 C6 C5 C4 C3 C2 C1 R Oct 1
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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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
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E2E IP Throughput
CAT6 E2E IP Measurements on UXM
–300Mbps achieved with 2x CCs and 20MHz bandwidth
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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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1.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
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•Designed for next advancements in antenna techniques, component carriers & data rates
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•Enables multiple cells, carrier aggregation, higher order MIMO, and integrated fading
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•Supports LTE FDD and TDD now
Future-ready platform
Extensible architecture
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Versatile touchscreen
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