Lte epc ieee_comsoc_rao_april_8_2010

Motorola General Business

Mobile Broadband Evolution – LTE and EPC

Srini RaoSrini RaoFellow of Technical StaffFellow of Technical Staff

Motorola Enterprise Mobility SolutionsMotorola Enterprise Mobility Solutions

Agenda

• LTETimelineOverview

• Applications• EPC

OverviewInterworking and mobility

• 3GPP access• Non-3GPP access

QoS and PolicyRoamingVoice over LTE

• CSFB, VoLGA, IMS VoIP/One Voice, over the top • Voice Handover

• Future DirectionsLTE-Advanced

• SummaryMotorola General Business

Srini Rao LTE EPC IEEE ComSoC Boston April 8, 2010 2

LTE Timeline

2005 2009 2010 20122006 2007 2008 2011

Trials

First LTE LaunchTeliaSonera

Trials

Deployments

StandardsRel 8

LTE / EPCRel 9 Rel 6

HSPARel 7

HSPA+Rel 10

LTE - Advanced

Verizon target s LTE Launch in

30 Markets

AT&T trials in 2010, Initial

deployment in 2011

59 LTE Network commitments in 28 countries around the world – GSA Mar 2010China Mobile trials TD-LTE in 2010



Terminology

• Long Term Evolution (LTE)3GPP (Third Generation Partnership Project) work item known as LTE

• Evolution of GSM/GPRS, WCDMA/HSPA radio networksLTE strictly refers to air interface, often entire technology (including core network) loosely referred to as LTE (or LTE/SAE)

• Evolved Packet Core (EPC)Outcome of 3GPP work item - System Architecture Evolution (SAE)

• Evolve GPRS and HSPA packet core networks to an all-IP based core• Other terms

Evolved UTRAN (E-UTRAN)• Radio access network is referred to as E-UTRAN

Evolved Packet System (EPS)• End-to-end system including LTE terminals, E-UTRAN, and Core network



LTE DriversUMTS-HSPA Voice and Data Traffic1

• Explosive growth in mobile data trafficRise in adoption of broadband wireless

devices• Smart phones, modems, integrated PCs/Laptops

Popularity of video, appsFlat rate data plans

• Need for improved cost efficiencyExpected cost per Mbps on HSPA is 14% of cost

on EDGE, and LTE would be 3% of EDGE cost2

Cost per MB expected to drop from € 0.06 for WCDMA to € 0.03 for HSPA and € 0.01 for LTE (2x5 MHz)3

Source: Dr. Klaus-Jurgen Krath, T-Mobile International

1. Source: HSPA to LTE-Advanced, Rysavy Research / 3G Americas, Sep. 20092. Kris Rinne, SVP Architecture and Planning, AT&T, 4G World, Sep. 20093. Source: Analysys Mason, 2008, from UMTS Forum white paper Feb. 2009



Key LTE Target Requirements1

• Peak data rates (for 20 MHz, 1 Tx and 2 Rx antennas at terminal)100 Mbps downlink (DL)50 Mbps uplink (UL)

• Improved spectral efficiency (in bits/s/Hz)3-4 times higher than HSPA (3GPP Release 6) DL2-3 times higher than HSPA UL

• Reduced latencyUser plane latency (one way radio delay) < 5 msControl plane latency (idle to active) < 100 ms

• Spectrum and bandwidth flexibility for deploymentChannel bandwidths 1.4, 3, 5, 10, 15 and 20 MHz, asymmetric allocation (different UL, DL BWs)Support both paired and unpaired spectrum (FDD and TDD modes using common air interface)

• Cost efficiencySimpler all-IP flat architectures, Self-Organizing Network (SON) capability etc. to reduce CAPEX and OPEX

1. From 3GPP TR 25.913



LTE Radio Interface

From UMTS Long Term Evolution (LTE) Technology Introduction, Rohde &Schwarz, Sep 08

• Multiple access schemeOFDMA DLSC-FDMA UL

• Similar to OFDMA, more power efficient • lower peak-to-average power ratio

• Adaptive Modulation and CodingDL/UL QPSK, 16QAM, 64QAMConvolutional and Turbo codes

• MIMO Spatial multiplexing(2 or 4)x(2 or 4) DL and ULMulti-user MIMOPeak rates up to 300/75 Mbps DL/UL for 4x4 MIMO

• LSTI (LTE/SAE Trial Initiative)10 operators in trials Peak rates for FDD and TDD normalized to 20 MHz > 100 Mbps DL, 30 – 50 Mbps ULMeasured end-end round trip latencies < 30 ms

• Verizon trial (10 MHz FDD)Average rates 5-12 Mbps DL, 2-5 Mbps UL, peak rates 40-50 Mbps DL, 20–25 Mbps UL

No. of Resource blocks ranging from 6 (1.4 MHz) to 100 (20 MHz)



LTE Frequency Bands

TDD2400 MHz–2300 MHz 2400 MHz–2300 MHz 40TDD1920 MHz–1880 MHz 1920 MHz–1880 MHz 39TDD2620 MHz–2570 MHz2620 MHz–2570 MHz 38TDD1930 MHz–1910 MHz1930 MHz–1910 MHz 37TDD1990 MHz–1930 MHz1990 MHz–1930 MHz 36TDD1910 MHz–1850 MHz1910 MHz–1850 MHz 35TDD2025 MHz–2010 MHz 2025 MHz –2010 MHz34TDD1920 MHz–1900 MHz1920 MHz–1900 MHz33

...

FDD746 MHz–734 MHz716 MHz–704 MHz 17FDD768 MHz–758 MHz798 MHz–788 MHz14FDD756 MHz–746 MHz787 MHz–777 MHz13FDD746 MHz–728 MHz716 MHz–698 MHz12FDD1495.9 MHz –1475.9 MHz1447.9 MHz –1427.9 MHz 11FDD2170 MHz–2110 MHz1770 MHz–1710 MHz10FDD1879.9 MHz–1844.9 MHz1784.9 MHz–1749.9 MHz9FDD960 MHz–925 MHz915 MHz–880 MHz8FDD2690 MHz–2620 MHz2570 MHz–2500 MHz7FDD885 MHz–875 MHz840 MHz–830 MHz6FDD894MHz–869 MHz849 MHz–824 MHz5FDD2155 MHz–2110 MHz1755 MHz –1710 MHz4FDD1880 MHz–1805 MHz1785 MHz–1710 MHz 3FDD1990 MHz–1930 MHz1910 MHz–1850 MHz 2FDD2170 MHz–2110 MHz 1980 MHz–1920 MHz 1

Duplex ModeDownlink (DL) BS transmitUplink (UL) UE transmitOperating

Band

From 3GPP TS 36.101

Verizon to deploy LTE in 700 MHz spectrum (10 + 10 MHz in Band class 13)AT&T to deploy LTE in 700 MHz and AWS spectrum (Band class 4)2.6 GHz TDD band being added in U.S. for Clearwire



LTE Enables New Applications

HD Video Streaming(720i H264)DL 6-8Mbps

DL Data Rate



Video Blogging / Live videoUL SD-2Mbps / HD-6-8Mbps

UL Data RateLatency

MMOG (Online Gaming)<50msec latency

Latency

Permanent Sync DL/UL 1-2Mbps

UL Data RateCost per bit

Peer2Peer ∞Mbps DL/UL

Data RateCost per bit

Evolved Packet Core (EPC)



Why is Core Evolution needed?

• 2G/3G mobile core networks designed for low-speed, best-effort data• Increased scalability of core elements to handle significant increase in

number of connections, bandwidth, and mobility• High throughput and low latency requirements• Key aspects of EPC

All-IP flat network architectureSeparation of control and data planesEnd-to-end QoS management and service control through policy control and charging (PCC) architectureNo circuit-switched coreSupport for multiple access networks

• Not coveredProtocol alternatives for S5/S8 interface GTP versus PMIPv6 – assuming GTP primarily for simplicityRelated topic of on-path versus off-path policySecurity – authentication, authorization, etc.Charging



2G/3G to LTE

Access Packet Core Services

GSM/GPRS

BTS BSC MGW

Circuit Core

MSC ServerWCDMA/HSPA

Node B

LTE/SAE

eNodeB

MME

RNC

Serving GW

PDN GW

SGSN

GGSN

PSTNPSTN

IP Networks(IMS, Internet

etc.)

IP Networks(IMS, Internet

etc.)



Network Architecture Overview

UE

MME

HSS

Serving GW

PDNGW

PCRF

IP Networks (IMS, Internet etc.)


S6a

S11

S1-U

S1-MME

LTE-Uu S5

Gx

Rx

SGieNB

S10

X2

Mobility Management Entity• Key control and Signaling Element• Gateway Selection• Idle state terminal location management• Bearer control

Home Subscriber Server• User subscription data

Policy and Charging Rules Function

• Gating and QoS policy control• Flow-based charging control

Serving Gateway• Bearer plane element interfacing E-UTRAN• Mobility anchor for inter-eNB and inter-3GPP access mobility

Packet Data Network (PDN) Gateway• Bearer plane element interfacing PDNs• Terminal IP address allocation• Policy enforcement• Packet filtering• Charging

Evolved Node B• Radio Resource Management• User plane IP header compression and encryption



UE

MME

SGSN

HSS

Serving GW

PDNGW

PCRF



WCDMA/HSPA

WCDMA/HSPA

GSM/GPRS

GSM/GPRS

S6a

Gr

S1-U

S1-MME

LTE-Uu S5

Gx

Rx

SGi

Gn

eNB

S10

X2

Interworking and Mobility – 3GPP Access (Gn/Gp SGSN)

S12

Gn

S11

• Handovers to/from 2G/3G similar to inter-SGSN handover withMME acting as an SGSNPDN GW acting as a GGSN

• SGSN must select a PDN GW for LTE capable terminals in 2G/3G• Model applicable for GTP based S5/S8 interface• HSS needs to support or interwork with Gr interface• Direct tunnel support via S12 interface for 3G



UE

MME

SGSN

HSS

Serving GW

PDNGW

PCRF



WCDMA/HSPA

WCDMA/HSPA

GSM/GPRS

GSM/GPRS

S6a

S4

S1-U

S1-MME

LTE-Uu S5

Gx

Rx

SGi

S3

eNB

S10

X2

Interworking and Mobility – 3GPP Access (S4 SGSN)

S12

S11

• Addition of new S3 and S4 interfaces• Support for Idle mode Signaling Reduction (ISR)• Enables EPC-only core for all 3GPP accesses, including ability to handover between

and within 2G & 3G radio networks• Direct tunnel support via S12 interface for 3G



Interworking and Mobility – non-3GPP Access(Optimized Handover for HRPD/EV-DO)

HRPD High Rate Packet Data

AN Access Node

HSGW HRPD Serving GW

AAA Authentication, Authorization, Accounting

LTE-UuUE

MME

HSS

Serving GW

PDNGW

PCRF



S6a

S11

S1-U

S1-MME

S5

Gx

Rx

SGieNB

AAA

HRPD AN HSGW

S101 S103

IOS

S2a

STa

SWx

S6b

• Optimized handover supported in both idle and active states and E-UTRAN to/from HRPDCommon user subscription data in HSSTerminal in E-UTRAN receives HRPD system info on broadcast channel or via dedicated signalingPre-registration (and handover signaling) using S101 interfacePDN GW acts as a common IP anchor pointUser data between HSGW and PDN GW transported over S2a interface supporting PMIPv6

• Serving GW forwards packets destined to terminal via S103 interface to HSGW



Interworking and Mobility – Non-3GPP Access (Generic)

LTE-UuUE

MME

HSS

Serving GW

PDNGW

PCRF



S6a

S11

S1-U

S1-MME

S5

Gx

Rx

SGieNB

TrustedNon-3GPP(WiMAX, CDMA)


S2a

STa

SWx

UntrustedNon-3GPP(WiFi etc.)


ePDG

SWa

S6b

S2b

SWn

AAA

SWmePDG evolved Packet Data Gateway

• Trusted (e.g. WiMAX, CDMA) versus untrusted (e.g. public WiFi) Non-3GPP networks• Trusted access networks connect to PDN GW via S2a similar to optimized HRPD• For untrusted networks, terminal connects to ePDG using IPSec tunnels

ePDG interfaces to PDN GW via S2b using PMIPv6• Network based versus client based mobility

For client based mobility, terminal connects to PDN GW via S2c interface (not shown) using DSMIPv6 or MIPv4



QoS Concepts

• EPS Bearer is a logical aggregate of one or more IP flowsIP flows (aka service data flows or SDFs) may belong to one or more services

• EPS Bearer provides connectivity to Packet Data Networks (PDNs)Bearer extends from UE to PDN GWAll Service data flows within a bearer receive same level of QoS

• Default bearer established when UE connects to a PDNRemains in place as long as the PDN connection is aliveProvides UE with low latency always-on IP connectivity to PDNQoS level of default bearer assigned based on subscription

• Dedicated bearers are setup when new IP flows that require specific packet forwarding treatment are started

• Dedicated bearers can be Guaranteed Bit Rate (GBR) or non-GBRDefault bearer is always non-GBR



EPC Bearer Model (GTP based S5/S8)

PDN GW

Service Data Flows

eNBUE

Service Data Flows

UL Packet Filter

Radio Bearer S1 Bearer

Application / Service Layer

S5/S8 BearerS GW

DL Packet Filter



QoS Parameters• QoS Class Identifier (QCI)

A scalar value mapped to specific bearer level packet forwarding treatment

• e.g. scheduling weights, queue management thresholds, link layer protocol configuration etc.

9 standardized values of QCI definedEach bearer assigned one and only one

QCI• Allocation and Retention Priority (ARP)

Decision to accept or reject due to resource limitations (typically GBR bearers)

Decision (e.g., by eNB) which bearer(s) to drop (e.g. at handover)

• Guaranteed Bit Rate (GBR) and Maximum Bit Rate (MBR)

Apply to GBR bearers In Release 8, MBR equals GBR

• Aggregate Maximum Bit Rate (AMBR)APN-AMBR total bit rate allowed for a

user for all non-GRR bearers associated with an APN (Access Point Name)

UE-AMBR total bit rate allowed for a user for all non-GRR bearers

separate UL and DL values of AMBR

QCI ResourceType

Priority Packet DelayBudget

Packet ErrorLoss Rate

Example Services

1 2 100 ms 10-2 Conversational Voice

2 GBR 4 150 ms 10-3 Conversational Video (Live Streaming)

3 3 50 ms 10-3 Real Time Gaming

4 5 300 ms 10-6 Non-Conversational Video (Buffered Streaming)

5 1 100 ms 10-6 IMS Signalling

6 6 300 ms 10-6 Video (Buffered Streaming)TCP-based (e.g., www, e-mail, chat, ftp, p2p file

sharing, progressive video, etc.)7 Non-GBR 7 100 ms 10-3 Voice, Video (Live Streaming), Interactive Gaming

8 8 300 ms 10-6 Video (Buffered Streaming)TCP-based (e.g., www, e-mail, chat, ftp, p2p file

9 9 sharing, progressive video, etc.)

From 3GPP TS 23.203



Policy and Charging Control (PCC) PCRF Policy and Charging Rules Function

PCEF Policy and Charging Enforcement Function

SPR Subscription Profile Repository

AF Application Function

OFCS Offline Charging System

OCS Online Charging System

PCEFPDN GWUE

MME

HSS

Serving GW

PCRF



S6a

S1-U

S1-MME

LTE-Uu S5

Gx

Rx

SGi

S3

eNB

S10

X2

SPRSp

AF

OCS

OFCS

Gy

Gz

S11

• Policy control gating control – allow or block IP flowsQoS control – provide authorized QoS (eg. QoS

class, bit rates etc.) decision to PCEF which enforces it

• Charging control – online and offline• PCC rule includes SDF template, precedence, gate status, QoS control info (QCI, ARP, bit rates etc.), charging control info

• PCC enables a centralized mechanism for service-aware QoS and charging control• PCRF controls dynamic policies based on

subscription info from SPR, Session info from AF, operator provisioned policies, access network info from PCEF etc.

alternatively, static policies can also be provisioned in PCEF



Policy Control Use Case for IMS Voice

PCEFPDN GWUE

MME

HSS

Serving GW

PCRF



S6a

S11

S1-U

S1-MME

LTE-Uu S5

Gx

Rx

SGi

S3

eNB

S10

X2

SPRSp

AF(P-CSCF)

OCS

OFCS

Gy

Gz

4. Policy Decision

6. Bearer binding

1. Application Signaling (SIP/SDP)

2. App Info

3. Subscription Info

5. PCC rule

6. Activate / modify bearer



Network Architecture for Roaming (Home Routed)

LTE-UuUE

MME

HSS

Serving GW

PDNGW

hPCRF

IP Networks

(IMS, Internet)

IP Networks

(IMS, Internet)

S6a

S11S1-MME

S8

GxRx

SGi

S1-UeNB



S2a

STa

SWx



ePDG

SWa

S6b

S2b

SWn

SWm

vPCRFS9

GxbGxc AAAProxy

SWd

Gxa

AAA

Home Network

Visited Network

• Serving GW in visited network and PDN GW in home connected via S8 interfaceAll traffic for the terminal IP connection routed via home network

• No direct policy control across home/visited network boundaryOnly through interaction between home PCRF and visited PCRF via S9 interfacevPCRF may accept or reject (not modify) policy decisions made by hPCRF

• If S8 is based on GPRS Tunneling Protocol (GTP), vPCRF and S9 are not required



Network Architecture for Roaming (Local Breakout)

LTE-UuUE

MME

HSS

Serving GW

hPCRF

IP Networks

IP Networks

S6a

S11S1-MME

S5

Gx

Rx

SGi



S1-UeNB



S2a

SWx


STa


ePDG

SWa

S6b

S2b

SWn

SWm

S9

GxbGxc

SWd

Gxa

AAA

Home Network

Visited Network

Rx

Visited IP Networks

Visited IP Networks

AAAProxyPDN

GW

vPCRF

• Both Serving GW and PDN GW in visited network Traffic routed from terminal to IP network directly

• Application Function (AF) may be in Home or Visited networkIf AF is in visited network, Rx signaling transported to home PCRF via visited PCRF using S9 interface

Voice Options for LTE

• LTE/SAE networks have no circuit coreInitial roll-outs likely will support data only devices such as USB dongles

• Voice based on legacy circuit coreCS (Circuit Switch) Fallback (CSFB)Voice over LTE via Generic Access Network (VoLGA)

• Voice based on IMS3GPP Multimedia Telephony (MMTel) / One Voice

• Over the top VoIP



Circuit Switch Fallback (CSFB)

• Use legacy CS domain for voice in 2G/3G (GSM, WCDMA, CDMA1x)• MSC upgraded to interface with EPC

new SGs interface with MME for GSM/WCDMAS102 interface between MME and 1x Interworking

Solution (1xCS IWS) for CDMApaging request delivered via LTEpaging response etc. and call originations via

2G/3G• Feature in 3GPP Rel 8 standard

Supported by NTT DoCoMo, KDDI and othersOptimizations to address call setup delays in Rel 9

(for CDMA) and Rel 10 for GSM/WCDMA

CS Voice

CS Voice

Signaling

EPC

2G/3G Core

SGs

MSC

MME

• Suitable for initial stages of LTE deployment prior to IMS introduction • Dual RX terminal alternative to new interface requirements• SMS also supported over LTE using the interfaces with 2G/3G MSC

No fallback to 2G/3G needed • Handover of concurrent LTE data sessions depend on 2G/3G network capability



Voice over LTE via Generic Access (VoLGA)

• Based on 3GPP UMA/GAN standard for voice over WiFi

VoLGA Access Network Controller (VANC) is a modification of GANC

• CS signaling and bearers tunneled over IP• Developed in VoLGA Forum, not a 3GPP standard

Driven by T-Mobile

VoIP

EPC

2G/3G Core

MSC

VANCCS Voice



IMS based VoIP (MMTel / One Voice)

• SIP based VoIP for terminals in LTE using IMS Multimedia Telephony (MMTel) standard• Support for voice call handover to CS domain in 2G/3G for broader coverage

Single Radio Voice Call Continuity (SR-VCC)• One Voice profile defined to promote a standardized solution for initial deployment of cellular IMS based VoIP network

Supported by several Operators including AT&T and Verizon

VoIP

EPC

2G/3G Core

MSC

MME

IMS



Voice Handover Mechanisms

• Single Radio Voice Call Continuity (SRVCC)

VoIP call on LTE to circuit voice call on GSM, WCDMA or CDMA 1x

Enhanced MSC server with Sv interface to MME in GSM/WCDMA

1xCS Interworking Solution (1xCS IWS) in CDMA1x with S102 interface to MME

• Call anchored on IMS (SCC-AS)• Network layer mechanism

VoIP

EPC

2G/3G Core

Sv

MSC

MME

IMS

CS Voice

CS Voice



Voice Handover Mechanisms Cont’d

• IMS based Service Centralization and Continuity (SCC)

VoIP call on WLAN to circuit voice call on UTRAN/GERAN or CDMA 1x

Calls anchored on IMS SCC-AS• Application layer mechanism

when access networks do not provide support for voice handovers

• Terminal makes handover decisions

VoIP

WiFi/WiMAX

2G/3G Core

MSC

IMS

CS Voice

CS Voice



LTE-Advanced

• Key feature of 3GPP Release 10, targeted for March 2011 • Wider Bandwidth

Support for bandwidths larger than 20 MHz (40 MHz, 100 MHz)Carrier Aggregation – aggregate two or more component carriers

• Peak data rates of 1 Gbps DL, 500 Mbps UL• UL and DL Transmission Schemes

Beamforming, MIMO enhancements• Coordinated Multi-Point Tx and Rx (CoMP)

Improve coverage, cell edge throughput and/or system efficiency• Relaying

Relay Nodes forward traffic/signaling between eNB and terminalsImprove coverage of high data rates, extend coverage to shadowed areas etc.

• LTE-Advanced submitted by 3GPP as candidate for ITU-R IMT-Advanced 4G technology solution in October 2009



Summary and Conclusion

• LTE technology is being proven to meet or exceed initial target requirementsLarge ecosystem of operators, vendors etc. committed to LTE

• Commercial network deployments planned 2010 and beyond• EPC represents an efficient all-IP packet core

Supports delivery of mobile Internet services with QoS over broadband radio networksSupports multiple access technologies (all 2G/3G cellular, WiMAX, WiFi etc.) and mobility between these access networks

• LTE and EPC can cost effectively address the demands of future mobile broadband growth



Lte epc ieee_comsoc_rao_april_8_2010

Engineering

Transcript of Lte epc ieee_comsoc_rao_april_8_2010