Overview of the Current Status of 3GPP LTE - · PDF file2 World Class Standards What is LTE? The next step in the evolution of 3GPP radio interfaces to deliver “Global Mobile Broadband”

Overview of the Current Status of3GPP LTE

Adrian ScraseETSI Vice President

International Partnership Projects

Mobile World Congress 11-14 February 2008

Barcelona

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World Class Standards

What is LTE?The next step in the evolution of 3GPP radio interfaces to deliver “Global Mobile Broadband”

A plan first conceived in 2004

Standardization based on clearly defined performance targets

Standardization based on clearly defined economic targets

Standardization based on improved use of the radio spectrum

Standardization based on simplified system design

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LTE: Performance TargetsSignificantly increased data throughput

Downlink target 3-4 times greater than HSDPA Release 6Uplink target 2-3 times greater than HSUPA Release 6

Increased cell edge bit ratesDownlink: 70% of the values at 5% of the Cumulative DistributionFunction (CDF)Uplink: same values at 5% of the Cumulative Distribution Function (CDF)

Significantly reduced latencySignificant reduction in transition times from idle/dormant states to active state (control plane)Radio access network latency less than 5 ms in unloaded conditions for small IP packet (user plane)

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LTE: Mobility and Cell Range TargetsHigh mobility

Optimised for mobile speeds 0 to 15 km/hSupport with high performance between 15 and 120 km/hMobility maintained at speeds between 120 and 350 km/hSupport for voice and real-time services over entire speed range with quality at least as good as UTRAN

Cell ranges up to 5 km With best throughput, spectrum efficiency and mobility

Cell ranges up to 30 kmMobility as defined above; some degradation in throughput and spectrum efficiency permitted

Cell ranges up to 100 kmSupported; degradations accepted

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LTE: Economic TargetsReduced CAPEX and OPEX

Avoidance of complicated architectures and unnecessary interfacesMaximum reuse of existing sitesOptimized terminal complexity and power consumptionEfficient OAM&POptimization of backhaul protocolsMulti vendor environment

….resulting in overall reduced cost/bit

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LTE: System Design

Downlink based on OFDMAOrthogonal Frequency Division Multiple Access (OFDMA) offers improved spectral efficiency, capacity etcQPSK, 16QAM and 64QAM modulation schemes supported

Uplink based on SC-FDMA Single Carrier – Frequency Division Multiple Access (SC-FDMA) is technically similar to OFDMA but is better suited for uplink from hand-held devices (battery power considerations)BPSK, QPSK, 8PSK and 16QAM modulation schemes supported

Designed for both Paired and Unpaired Spectrum use Macro-diversity (soft handover) no longer requiredCircuit-switched connectivity no longer be supported

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LTE: Simplified Architecture

UMTS

LTEMost of the RNC functionalitiesmoved to the eNode B

UMTS RNC “removed”

eNodeB connected directly tothe evolved packet core

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LTE: Simplified Mobility Management

eNB eNB

eNB

MME/UPE MME/UPE

S1

X2

X2

X2

Evolved Packet Core

Evolved UTRAN

(From TR 25.912).MME: Mobility Management entity (identities, mobility states…).UPE: User Plane Entity (paging initiation, IP bearer parameters…)

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LTE: Simplified Mobile States

Cell_DCH

Cell_FACH

URA_PCH

Cell_PCH

Connected mode

Idle

ModeMobile States in UMTS

Mobile States in LTEReduced to 3 states only:

• Idle

• Active

• Detached

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LTE: Use of Radio Spectrum

Spectrum flexibilityLTE to operate in 1.4, 1.6, 3, 3.2, 5, 10, 15 and 20 MHz bandwidths

Clear convergence between paired spectrum and unpaired spectrum solutions:

Initial access, handover procedures, measurements, frame and slot structures

Co-existenceWith GERAN/3G on adjacent channelsWith other operators on adjacent channelsWith overlapping or adjacent spectrum at country bordersHandover with UTRAN and GERAN

Use of more than one transmit/receive antenna (MIMO)Which raises by a factor of 10 the number of users/cell compared to UMTS

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LTE: Spectrum EfficiencySignificantly improved spectrum efficiency and cell edge bitrate

whilst maintaining same site locations

Downlink target (bits/sec/Hz/site): 3-4 times that of Release 6 HSDPA

Uplink target (bits/sec/Hz/site): 2-3 times that of Release 6 Enhanced Uplink

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What about SAE?

The core network upgrade (System Architecture Evolution or SAE) will focus on:

Enhancement of Packet Switched technology to cope with rapid growth in IP traffic, (i.e., higher data rates, lower latency and packet optimised systemThrough fully IP network with simplified network architecture and distributed control

Packet-Switched (PS) only domain (voice services will use this domain)Incorporating IMSSupporting multiple 3GPP radio access technologies (GERAN, UTRAN)Also incorporating non-3GPP access (e.g., WiMAX, WLAN)

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LTE: Relationship with SAE

A high performance air interface demands a high performance core network

Deploying LTE without SAE may be theoretically possible, but it would make no sense to do so!

Therefore, the timeline for delivering SAE specifications has been synchronized to the timeline for delivering LTE specifications

Hence, the combination of LTE and SAE form the very essence of 3GPP Release 8

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LTE: Current Status of Specifications

LTE and SAE form the basis of 3GPP Release 8, scheduled to be functionally frozen in December 2008

LTE Terrestrial Radio Access Networktechnology specifications have alreadybeen approved by 3GPP,and are now under change control

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LTE: Availability of Specifications

All 3GPP specifications can be freely downloaded from http://www.3gpp.org

They can also be freely downloaded from http://www.etsi.org

They are available for free from the ETSI Stand (Hall 2, E47) conveniently presented on a DVD

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LTE: Industrial CommitmentThe following give a clear indication of the industrial interest in LTE:

The population in 3GPP specification groups is now at an unprecedented levelThe volume of contributions with those groups is very highThe intellectual input to the development of LTE is enormous

Recent press announcements from prominent players indicate strong operator and vendor commitment to LTE

Feedback from field trials is highly promisingResults announced by LTSI (LTE/SAE Trial Initiative)Results announced by vendor trials

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LTE: Further Work

Maturity of Specifications

Remainder of 2008devoted to ensuringLTE maturity

Work aided by feedbackfrom LTE trials

Functional freezing ofRelease 8 on target forDecember 2008

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LTE: 3G or 4G?

LTE specifications have already been submitted to the ITUThey are already incorporated in the draft update of the IMT 2000 family (to be approved by ITU later in 2008)They will formally become part of the 3G family (though some might say LTE is really 3,9G)

The ITU will soon start the IMT Advanced processAn ITU Circular Letter is expected to be received soon inviting proposals for inclusion within the IMT Advanced (aka 4G) familyA submission based on LTE is highly likely to be made (for example “LTE advanced”)

But who cares?Users have no interest in whether they have a 2G, 3G or 4G deviceThey only care about what the device can do, and how much it will cost (not necessarily in that order!)

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ConclusionsLTE promises to deliver the true “Global Mobile Broadband”experienceLTE specification development is meticulously planned and executedIndustrial input to the process is of an unprecedented levelOperator and vendor commitment already in place Robust specifications will ensure successful deployment

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Documents

Overview of the Current Status of 3GPP LTE - · PDF file2 World Class Standards What is LTE? The next step in the evolution of 3GPP radio interfaces to deliver “Global Mobile Broadband”