Carrier_Aggregation_Presentation_ITUASP COE training.pdf

7/28/2019 Carrier_Aggregation_Presentation_ITUASP COE training.pdf

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Carrier AggregationCarrier Aggregation

Pr. SamiPr. Sami TabbaneTabbane

ITU ASP COE Training on

Wireless Broadband Roadmap Development

11-14 September Bangkok (Thailand)

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SummarySummary

I. Introduction: Trends in broadband wireless

systems and Spectrum pressures

II. Carrier aggregation in LTE-A and other

similar systems using carrier aggregation (e.g.,

CDMA2000). Integration of carrier aggregation

in the standards

III.Carrier aggregation and performance

IV.Cognitive radio: generalization of carrier

aggregation concept

V. Conclusions


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I. IntroductionI. Introduction

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StateState of art of existing WB Systemof art of existing WB System

ITU-T: Definition of the characteristics of the generation (2, 3,

4, ), validation of proposed standards and allocation of

spectrum,

3GPP: European standardization body (GSM family),

3GPP2: North-American standardization body (CDMA

family),

IEEE: data networks standards (802.xx family),

Standardization bodies


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Typical user data rates

3G basic

HSPA

LTE

LTE-

Advanced

100 kbps 1 Mbps 10 Mbps 100 Mbps

150-350 kbit/s

1.0 5 Mbit/s

5 60 Mbit/s

30 300 Mbit/s

StateState of art of existing WBof art of existing WB SystemSystem

3GPP systems,3GPP systems,

Building on ReleasesBuilding on Releases

Release 10 LTE-Advanced meeting the

requirements set by ITUs IMT-Advanced

project.

Also includes quad-carrier operation for

HSPA+.

Release 99: Enhancements to

GSM data (EDGE). Majority of

deployments today are based on

Release 99. Provides support for

GSM/EDGE/GPRS/WCDMA

radio-access networks.

Release 4: Multimedia

messaging support. First steps

toward using IP transport in the

core network.

Release 5: HSDPA. First phaseof Internet Protocol Multimedia

Subsystem (IMS). Full ability to

use IP-based transport instead of

just Asynchronous Transfer

Mode (ATM) in the core

network.

Release 6: HSUPA. Enhanced

multimedia support through

Multimedia Broadcast/Multicast

Services (MBMS). Performance

specifications for advanced

receivers. Wireless Local Area

Network (WLAN) integration

option. IMS enhancements. Initial

VoIP capability.

Release 7: Evolved EDGE. Specifies HSPA+, higher order modulation and MIMO. Performance enhancements, improved

spectral efficiency, increased capacity, and better resistance to interference. Continuous Packet Connectivity (CPC) enables

efficient always-on service and enhanced uplink UL VoIP capacity, as well as reductions in call set-up delay for Push-to-Talk

Over Cellular (PoC). Radio enhancements to HSPA include 64 Quadrature Amplitude Modulation (QAM) in the downlink DL

and 16 QAM in the uplink. Also includes optimization of MBMS capabilities through the multicast/broadcast, single-frequency

network (MBSFN) function.

Release 8: HSPA Evolution,

simultaneous use of MIMO and 64

QAM. Includes dual-carrier HSPA

(DC-HSPA) wherein two WCDMA

radio channels can be combined for

a doubling of throughput

performance. Specifies OFDMA-

based 3GPP LTE.

Defines EPC.

Release 9: HSPA and LTE enhancements

including HSPA dual-carrier operation in

combination with MIMO, EPC

enhancements, femtocell support, support forregulatory features such as emergency user-

equipment positioning and Commercial

Mobile Alert System (CMAS), and evolution

of IMS architecture.

Text adaptedfrom3G AmericasWhitePaper,September 2010

Release 11

Interworking -3GPP EPS and fixed BB

accesses, M2M, Non voice emergency

communications, 8 carrier HSDPA, Uplink

MIMO study


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ReleasesReleases and bitratesand bitrates

expectationsexpectations

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Peak data ratesPeak data rates in LTE and LTEin LTE and LTE--AA

8


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TheoreticalTheoretical spectrumspectrum efficienciesefficiencies

LTE is the most spectral efficient wireless technology but it cannot

be expected that early LTE deployments achieve this theoretical

spectral efficiency.

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Main LTE data ratesMain LTE data rates

improvement techniques:improvement techniques:

-- Link adaptationLink adaptation

-- MIMO andMIMO and beamformingbeamforming

-- Fast schedulingFast scheduling

-- Hybrid ARQHybrid ARQ

-- 10


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LTE physical layerLTE physical layer

Flexible bandwidth (with resolution of 180 kHz)

Possibility to deploy in bandwidth of


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Example of link adaptationExample of link adaptation

MIMO andMIMO and BeamformingBeamforming


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Fast schedulingFast scheduling

Scheduling depending on the channel

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Hybrid ARQHybrid ARQ

Principle: Reuse of the errored frames for the decoding of

the retransmissions.

Drawback: Requires a large buffer.

Loss of the frame #2 => retransmission request

Link layer

Physical

layer

Time

2error

Storage in the

HARQ buffer

+ Combines theerrored frame with

the retransmitted one


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II. Carrier aggregationII. Carrier aggregation

in LTEin LTE--A and otherA and other

systemssystems

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LTELTE--A improvements (1)A improvements (1)

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LTELTE--A improvementsA improvements (2)(2)

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Impacts of various techniques inImpacts of various techniques in

improving the data ratesimproving the data rates

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CarrierCarrier aggregationaggregation in LTEin LTERelease-10 carrier aggregation supports the following features:

Peak data rates of 1 Gbps on downlink and 500 Mbps on uplink.

Up to five carriers can be aggregated, each carrier is called a component carrier.

Each component carrier can have any of the bandwidths supported in LTE Rel-8 (1.4, 3,

5, 10, 15 and 20 MHz). As a result, LTE carrier aggregation can support operation on

transmission bandwidths of up to 100 MHz by aggregating five 20 MHz carriers.

Each component carrier is fully backward compatible to Release-8/9. This backward

compatibility to Release 8/9 allows the technologies developed for LTE Release-8/9 to

be fully reused in Release-10. It also allows the coexistence of Release 8 and 9 UEs

together with Release-10

UEs, which is very important for seamless system transition from Release 8 and 9 to

Release 10.

A carrier aggregation capable UE can simultaneously receive and transmit in one or

multiple component carriers.

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Carrier aggregation in LTECarrier aggregation in LTE

Carrier Aggregation (CA): multiple component

carriers are aggregated and jointly used for

transmission to/from a single terminal. There are up

to five component carriers, possibly each of

different bandwidth, which can be aggregated,allowing for transmission bandwidth up to 100 MHz

backwards compatibility where, each component

carrier (CC) uses the release-8 structure.


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Key Features in LTE Release 10Key Features in LTE Release 10

Support of Wider Bandwidth (Carrier

Aggregation)

Advanced MIMO techniques Extension to up to 8-layer transmission in downlink

Introduction of single-user MIMO up to 4-layer transmission

in uplink

Heterogeneous network and eICIC (enhanced Inter-Cell

Interference Coordination) Interference coordination for overlaid deployment of cells with

different Tx power

Improvement of cell-edge throughput and coverage

Relay

Coordinated Multi-Point transmission and

reception (CoMP)

100 MHz

f

CC

LTELTE--A features for increasedA features for increased bitratesbitrates

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Carrier aggregation benefitsCarrier aggregation benefits

Maximize the total peak data rate and throughput

performance by combining peak capacities and throughput

performance available at different frequencies

Provide a higher and more consistent quality of

service by load-balancing across frequencies and systems.

Mitigate the relative inefficiencies that may be

inherent in wireless deployments in non-contiguous or

narrow (5 MHz or less) channel bandwidths, often spread

across different spectrum bands.

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Carrier aggregation in HSDPACarrier aggregation in HSDPA

8C-HSDPA is a further extension of the multicarrier operation with

eight carriers. Similar to the 4 carrier feature, in 8C-HSDPA the

transmissions are independent. The carriers do not need to be

adjacent. The activation/deactivation of the secondary carriers is

done by the serving NodeB through physical layer signaling. The

uplink signaling is carried over a single carrier. 26


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HSPA + LTEHSPA + LTE CarrierCarrier AggregationAggregationSame mechanisms as the intra-RAT carrier aggregation schemes. It bring similar

data rate gains:

Data rates ofcarrier aggregation UEs boosted by utilizing unused resources

from overlapping cell(s) operating on different carrier(s)

Data rates ofall UEs improved by fast (TTI level) load balancing

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III. Carrier aggregationIII. Carrier aggregation

performanceperformance

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Carrier aggregation impact onCarrier aggregation impact onthroughputsthroughputs

Improves average cell throughput both in uplink and downlink due to more

efficient utilization of radio resource by statistical multiplexing29

InterInter--band Carrier Aggregation enables to benefit from differentband Carrier Aggregation enables to benefit from different

propagation characteristic ofpropagation characteristic of different frequencydifferent frequency bandsbands

Carriers at different frequency bands have different propagation losses and different interfering

systems. Far-off UE are better served with a low frequency carrier and near cell center UE with a high

frequency carrier.

Inter-band Carrier Aggregation provides more flexibility to utilize fragmented spectrum allocations.30


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Average downlink data rate before and after refarming of one

HSPA carrier (assuming low-to-medium system loading, 10MHz

LTE and 2x5MHz HSPA before refarming)

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UE capabilities and carrierUE capabilities and carrier

aggregationaggregation

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Different types of carrierDifferent types of carrieraggregation in LTE (1)aggregation in LTE (1)

ExampleExample of carrier aggregationof carrier aggregation

in different frequencyin different frequency bandsbands

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ComponantComponant carriers after carriercarriers after carrieraggregationaggregation

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Symmetric/Asymmetric carrierSymmetric/Asymmetric carrier

aggregation inaggregation in LTELTE


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A. Intra-band aggregation with frequency-contiguous component

carriers

Contiguous bandwidth wider than 20 MHz.

B. Intra-band aggregation with non-contiguous component

carriers

Multiple CCs belonging to the same band. Countries where spectrum

allocation is non-contiguous within a single band.

C. Inter-band aggregation with non-contiguous component

carriers

Carriers in different operating bands are aggregated. Inter

modulation and cross-modulation within the UE device when

multiple transmitter and receiver chains are operated simultaneously.37

Intra/InterIntra/Inter--band carrierband carrieraggregation inaggregation in LTE (1)LTE (1)

Spectrum Aggregation Scenarios forSpectrum Aggregation Scenarios for FDDFDD

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Intra/InterIntra/Inter--band carrierband carrier

aggregation in LTE (2)aggregation in LTE (2)

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IntraIntra--Band Carrier Aggregation RFBand Carrier Aggregation RF

parameters with 2 aggregatedparameters with 2 aggregated carrierscarriers

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Carrier Aggregation

Bandwidth Class

Aggregated Transmission

BW Configuration

A 100

B 100

C 100 - 200

The 6 LTE carrier aggregation bandwidthThe 6 LTE carrier aggregation bandwidth

classesclasses

N.B.: classes D, E, & F are in the study phase.

Downlink Multiple Access Scheme withDownlink Multiple Access Scheme with CACA

Downlink OFDMA with component carrier (CC) based structure

One transport block is mapped within one CC

Parallel-type transmission for multi-CC transmission

Cross-carrier scheduling is possibleDL control channels (such as PDCCH, PCFICH,and PHICH) are updated to support cross-carrier scheduling.

Add a Carrier Indicator Field (CIF) to DCI.42


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Advantages of CAAdvantages of CA

Lot of permutations and combinations, some of them are a bit

more difficult to implement due to interference problems caused

(intermodulation products of transmitted signals on different

frequency bands).

Only intraband carrier aggregation is supported in uplink in LTE

Release 10 (higher range of band combinations will be supported in

later releases).

Carrier aggregation provides almost as high spectrum efficiency

and peak rates as single wideband allocation.

In heterogeneous deployment scenarios, the performance can be

better since flexible frequency reuse can be arranged between local

area nodes to provide better inter-cell interference coordination.43

CA between operatorsCA between operators

The system bandwidth will increase substantially,

up to 80 MHz

For two cooperating operators with 2*20 MHz

each. The average data rates can reach 80 or 160

Mbps, and the peak data rates can be up to 400 or

800 Mbps.

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Drawbacks of CA (1)Drawbacks of CA (1)Loss in throughput: by the vulnerability due to channel aggregation or bonding in

LTE-A and HSPA+ networks.

Channel aggregation is susceptible to about 70% loss of throughput in LTE

networks and about 11-15% in HSPA+ networks compared to systems with no

aggregation or bonding.

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Drawbacks of CA (2)Drawbacks of CA (2)

Interference coordination,

UE compatibility (frequency

bands, bandwidths, ), Radio planning constraints,

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IV. Cognitive radio:IV. Cognitive radio:

generalization of thegeneralization of the

carrier aggregationcarrier aggregationconceptconcept

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The origin: ApparentThe origin: Apparent

Spectrum ScarcitySpectrum Scarcity

Spectrum measurement across the 900 kHz 1 GHz band (Lawrence, KS, USA)

Spectrum Holes


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RF Spectrum OccupancyRF Spectrum Occupancy

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Spectrum measurement across the 928 948 MHz band (Worcester, MA, USA)

The Idea: DynamicThe Idea: Dynamic SpectrumSpectrum

AccessAccess

Fill withsecondary

users


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White Space ConceptWhite Space Concept

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Cognitive Radio: DefinitionCognitive Radio: Definition

Cognitive radio is an intelligent wireless communication system

that is aware of its surrounding environment (i.e., outside world),

and uses the methodology of understanding-by-building to learn

from the environment and adapt its internal states to statistical

variations in the incoming RF stimuli by making corresponding

changes in certain operating parameters (e.g., transmit-power,

carrier-frequency, and modulation strategy) in real-time, with twoprimary objectives in mind:

highly reliable communications whenever and wherever needed;

efficient utilization of the radio spectrum.

S. Haykin, Cognitive Radio: Brain-Empowered WirelessCommunications, IEEE J-SAC, Feb. 2005.


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Cognitive RadioCognitive Radio

Cognitive radio technology is expected to improve

spectrum access through:

Increased spectrum efficiency of licensed spectrum users

Secondary markets by allowing licensees to lease their

spectrum access e.g. by machine-controlled negotiation

between systemsAutomated frequency coordination between licensees

Opportunistic spectrum use by unlicensed devices while

protecting incumbents from harmful interference

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TerminologyTerminology

Primary User (PU):

Licensed user

Has exclusive rights for the spectrum

Secondary User (SU): Unlicensed user

Opportunistically utilizes the white spaces

Has to vacate the spectrum band as soon as a PU

appears

Also called cognitive user

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Frequency

T

I

M

E

Spectral Adaptation Waveforms

Example of OFDMExample of OFDM Carriers Selected for Use That FallCarriers Selected for Use That Fall

into Available Spectruminto Available Spectrum

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ConclusionsConclusions

To achieve up to 1 Gbps peak data rate in the downlink

and 500 Mbps in the uplink in future IMT-Advanced

mobile systems, Carrier Aggregation (CA) technology is

introduced by the 3GPP to support very-high-data rate

transmissions over wide frequency bandwidths (e.g., up

to 100 MHz) in its new LTE-Advanced standards.

In CA, communication is achieved through the

simultaneous use of multiple LTE carriers called

Component Carriers (CCs) enabling broadband

transmission exceeding 20 MHz.

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