2013년이동및무선통신단기강좌 3GPP LTE(-A): Part II MAC & …winner.ajou.ac.kr/publication/data/invited/2013LTE.pdf · 2013-11-27 · 2013-09-05 3 3GPP Standards Version

2013-09-05

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2013년 이동 및 무선통신 단기강좌

3GPP LTE(-A): Part IIMAC & Network

2013. 8. 22.Jae-Hyun [email protected]

Wireless Internet aNd Network Engineering Research Lab.

http://winner.ajou.ac.kr

School of Electrical and Computer Engineering

Ajou University, Korea

Contents

Introduction

Network Architecture

User Plane Protocol

Control Plane Protocol

LTE-Advanced Features

Release 12 Issues

Summary2

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Introduction

3

Release of 3GPP specifications

4

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

GSM/GPRS/EDGE enhancements

Release 99 - W-CDMA

Release 4 – TDD

Release 5 – HSDPA, IMS

Release 6 – HSUPA, MBMS, IMS+

Release 7 – HSPA+(MIMO, HOM etc.)

Release 8 – LTE, SAE

Small LTE/SAE enhancementRelease 9

LTE-AdvancedRelease 10

Release 11 – Interconnection

Release 12

ITU-R M.1457IMT-2000 Recommendations

WCDMA 최초 상용화

LTE 국내 상용화

LTE 최초 상용화

WCDMA 국내 상용화

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3GPP Standards

Version Released Information

Release 98 1998 This and earlier releases specify pre-3G GSM networks

Release 99 2000 Q1 Specified the first UMTS 3G networks, incorporating a CDMA air interface

Release 4 2001 Q2 added features including an all-IP Core Network

Release 5 2002 Q1 Introduced IMS and HSDPA

Release 6 2004 Q4Integrated operation with Wireless LAN networks and adds HSUPA, MBMS, enhancements to IMS such as Push to Talk over Cellular (PoC),GAN (Generic Access Network)

Release 7 2007 Q4

Focuses on decreasing latency, improvements to QoS and real-time applications such as VoIP. This specification also focus on HSPA+(High Speed Packet Access Evolution), SIM high-speed protocol and contactless front-end interface (Near Field Communication enabling operators to deliver contactless services like Mobile Payments), EDGE Evolution.

Release 8Frozen

Dec. 2008LTE, All-IP Network (SAE). Release 8 constitutes a refactoring of UMTS as an entirely IP based fourth-generation network.

Release 9Frozen

Dec. 2009SAES Enhancements, WiMaX and LTE/UMTS Interoperability

Release 10Frozen

Mar. 2011LTE Advanced fulfilling IMT Advanced 4G requirements. Backwards compatible with release 8 (LTE). Multi-Cell HSDPA (4 carriers).

Release 11Frozen Sep. 2012 /

Some works are still in progress

Advanced IP Interconnection of Services. Service layer interconnection between national operators/carriers as well as third party application providers

Release 12Stage 1 frozen

Mar. 2013 /In progress

(Content still open (as of October 2012).)

5

Network Architecture

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Evolution of Network Architecture

7

Evolution Path of Core Network

8

E-UTRAN(Evolved Universal Terrestrial Radio Access Network)

X2

S1

• NB : NodeB• RNC : Radio Network Controller• SGSN : Serving GPRS Support Node• GGSN : Gateway GPRS Support Node

• eNB : E-UTRAN NodeB• aGW : Access Gateway• MME : Mobility Management Entity• UPE : User Plane Entity

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UMTS Architecture(Release-5)

9

RNC

RNC SGSN

Node B

PSTN

SS7

HSSHLR

GGSN

InternetGi(IP)

Iur

Iu

CSCF

R-SGW

PCMGn

Cx

Iub

MGWGi

CSCF

MGCFMg

T-SGW

SS7

McGrMRF

Mr

Gi

RNC : Radio Network Controller SGSN : Serving GPRS Support Node GGSN : Gateway GPRS Support Node CSCF : Call State Control Function MGCF : Media Gateway Control Function MRF : Multimedia Resource Function

SS7 : Signal System No.7 R-SGW : Roaming Signaling Gateway T-SGW : Transport Signaling Gateway

Radio Access Network (RAN)(UTRAN)

3G Core Network (CN) External Network

Overall Architectural Overview

EPS (Evolved Packet System) network elements

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Evolved Packet Core (EPC)E-UTRAN

3GPP TS 36.300 V11.6.0 “E-UTRA and E-UTRAN; Overall description”, June, 2013

Interface for data planeInterface for control plane

E-SMLC: Evolved Serving Mobile Location Centre GMLC: Gateway Mobile Location Centre

HSS: Home Subscriber Server PCRF: Policy Control and Charging Rules Function

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Core Network Elements

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Network Elements Features

PCRF(Policy Control and Charging Rules Function)

Policy control decision making Controlling the flow-based charging functionalities in the PCEF (Policy Control

Enforcement Function) which resides in the P-GW• QoS authorization (QoS class identifier and bit rates)

HSS(Home Subscriber Server)

Contains users’ SAE subscription data such as EPS-subscribed QoS profile and any access restrictions for roaming

Information about the PDNs to which the user can connect Identity of the MME to which the user is currently attached or registered

E-SMLC(Evolved Serving Mobile Location Centre)

Manage the overall coordination and scheduling of resources required to find the location of a UE attached to E-UTRAN

Calculate the final location of UE based on the estimates it receives Estimate the UE speed and the achieved accuracy

GMLC (Gateway Mobile Location Centre)

Contain functionalities required to support location services Send positioning requests to the MME and receives the final location estimates

Core Network Elements

12

Network Elements Features

P-GW (PDN Gateway) IP address allocation for the UE QoS enforcement and flow-based charging according to the PCRF

S-GW (Serving Gateway)

All user IP packets are transferred through the S-GW LMA (Local Mobility Anchor) when the UE moves between eNode-Bs Retains the information about the bearers when the UE is in idle state Temporarily buffers downlink data while the MME initiates paging of the UE to

re-establish the bearers Collecting information for charging (the volume of data sent/rcvd) Mobility anchor for inter-working with GPRS and UMTS

MME(Mobility Management Entity)

Process the signaling between the UE and the CN (Core Network) (NAS: Non-Access Stratum)

Bearer & Connection management• Establishment, maintenance and release of the bearers• Establishment of the connection and security between the network and

UE

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Access Network

Overall architecture E-UTRAN consists of eNBs eNBs are interconnected with each other by X2 interface eNBs are connected by means of S1 interface to the EPC S1 interface supports a many-to-many relation between MMEs/S-GW

and eNBs

13 3GPP TS 36.300 V11.6.0 “E-UTRA and E-UTRAN; Overall description”, June, 2013

S1

S1

S1 S

1X2X2 S

1 S1

S1 S5

S1

Access Network

The eNB hosts following functions RRM (Radio Resource Management)

Radio Bearer Control Radio Admission Control Connection Mobility Control Dynamic allocation of resources to UEs (scheduling)

Processing user plane data IP header compression and encryption of user data stream AS security Selection of an MME at UE attachment when no routing to an MME

can be determined from the information provided by the UE Forwarding of user plane data towards S-GW

Measurement and measurement reporting configuration for mobility and scheduling

Scheduling and transmission of control messages from the MME paging messages broadcast information PWS (Public Warning System) messages

CSG (Closed Subscriber Group) handling

Transport level packet marking in the uplink (ex. Setting the DSCP (DiffServ Code Point)

14 3GPP TS 36.300 V11.6.0 “E-UTRA and E-UTRAN; Overall description”, June, 2013

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Interfaces

X2 and S1 user plane aspect IP packet for a UE is encapsulated and tunneled using GTP-U (GPRS Tunneling

Protocol – User Plane) Local transport protocol is UDP

• No flow control, No error control

X2 and S1 control plane aspect S1AP (S1 Application Protocol) is used to transport the signaling message

between eNode-B and the MME Local transport protocol is SCTP

• Guarantees delivery of signaling messages• Support multiple SAE bearers

15

Access Layer

SCTP

S1-AP

L1

L2

IP

SCTP

HeNB MME

S1-AP

S1-MME

L2

IP

User plane for S1-U interface Control plane for S1-MME Interface


SCTP : Stream Control Transmission Protocol

EPS Bearer Service Architecture

EPS bearer / E-RAB is established when the UE connects to a PDN Default bearer remains established throughout the lifetime of the PDN connection

Dedicated bearer Any additional EPS bearer/E-RAB that is established to the same

PDN is referred to as a dedicated bearer.

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P-GWS-GW PeerEntity

UE eNB

EPS Bearer

Radio Bearer S1 Bearer

End-to-end Service

External Bearer

Radio S5/S8

Internet

S1

E-UTRAN EPC

Gi

E-RAB S5/S8 Bearer


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QoS and EPS Bearers

Multiple applications have different QoSrequirements Different bearers are set up within EPS each being associated with a QoS

GBR bearers Permanent allocation of dedicated transmission resources ex) VoIP

Non-GBR bearers Do not guarantee any particular bit rate ex) web browsing, FTP transfer

Each bearer has an associated QCI, and an ARP Priority and packet delay budget RLC mode, scheduling policy, queue management and rate shaping policy

17GBR : Minimum Guaranteed Bit Rate QCI: QoS Class Identifier ARP: Allocation and Retention Priority

Standardized QCI for LTE

QCI(QoS Class Identifier)

ResourceType

Priority

PacketDelay

Budget

PacketError Loss

RateExample Services

1

GBR

2 100ms 10-2 Conversational Voice

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

3 3 50ms 10-3 Real Time Gaming

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

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Non-GBR

1 100ms 10-6 IMS Signaling

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

progressive video, etc.)

7 7 100ms 10-3 Voice, Video (Live Streaming)Interactive Gaming

8 8300ms 10-6

Video (Buffered Streaming),TCP-based (e.g., www, e-mail, chat, ftp, p2p file sharing,

progressive video, etc.)9 9

18 3GPP TS 23.203 v12.1.0, “Policy and charging control architecture,” Jun. 2013.

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User Plane ProtocolPacket Data Convergence ProtocolRadio Link ControlMedium Access Control

19

Overview

20

PDCP layer Process RRC messages in the control

plane and IP messages in the user plane Header compression Security reordering and retransmission during

handover

RLC layer Segmentation and reassembly ARQ Reordering for HARQ

MAC layer Multiplexing of data from different

radio bearer Achieve QoS for each radio bearer Report the eNodeB to the buffer size

for uplinkPDCP : Packet Data Convergence Protocol RLC: Radio Link Control MAC: Medium Access Control HARQ : Hybrid Automatic Repeat RequestQoS : Quality of Service

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PDCP overview

Functions Header compression/

decompression of user plane data

Security Ciphering and deciphering for

user plane and control plane data Integrity protection and

verification for control plane data

Handover support In-sequence delivery and

reordering of upper layer PDUs at handover

Lossless handover for user plane data mapped on RLC Acknowledge Mode (AM)

Discard for timeout user plane data

21

* 3GPP TS 36.323 v11.2.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification”(Release 11), April, 2013

Header Compression

Robust Header Compression (ROHC) Introduced RFC3095 and RFC 4815 Increase channel efficiency by reducing overhead Robust at unreliable link Three different mode : Unidirectional mode(U-mode), Bidirectional

Optimistic mode(O-mode), and Bidirectional Reliable mode(R-mode) Compression example VoIP (in the active period)

• payload 5,11~32 bytes ([email protected]~12.2kbps)+ header 40/60 bytes (RTP 12+UDP 8+IPv4 20/IPv6 40) payload 32 bytes + header 4~6 bytes

22 acticom mobile networks, http://www.acticom.de/en/

Wireless Link

Payload RTP UDP IP

CompressorDe-Compressor

Framing/Error Detection

RoHC Context

Payload H

CompressedHeader

RoHC Context

PayloadIP RTP UDP

CompressorDe-Compressor

Framing/Error Detection

Sender Receiver

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Header Compression

Header Fields Classification

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Type Description

Inferred” They are never sent and they can be known by other component in the header

Static* Send only once, their valuesnever change during the stream

Static-def**

Send only once, they give the definition of the stream

Static-known^

They are never sent and their values are known

Changing< Header fields with a changing value. The change can be periodic or randomly. They are always send

Ver* ToS< Flow ID**

Length” Next Header* Hop Limit<

Source Address**

Destination Address**

Source Port** Destination Port**

Length” Checksum<

Ver^ P* E* CCnt< M< P.Type< Sequence Number<

Timestamp<

Source Synchronization Indentification(SSRC)**

Source Contribution Identification (1st)<

Contributing source (CSRC)<

Source Contribution Identification (last)<

Application Data

0 15 31

IPv6

UDP

RTP

Header Compression

Header Fields Classification

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Type Description

Inferred” They are never sent and they can be known by other component in the header

Static* Send only once, their valuesnever change during the stream

Static-def**

Send only once, they give the definition of the stream

Static-known^

They are never sent and their values are known

Changing< Header fields with a changing value. The change can be periodic or randomly. They are always send

Static Info

ROHC header

Application Data

1 byte

3~5 bytes

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Header Compression

ROHC compression with U,O,R operation mode

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Security

LTE security distribution NAS security Carried out for NAS messages / between UE and MME NAS messages are integrity protected and ciphered with extra NAS

security header

AS security (PDCP) Carried out for RRC and user plane data / between UE and eNB RRC messages are integrity protected and ciphered U-plane data is only ciphered

26 3GLTEINFO, http://www.3glteinfo.com/lte-security-architecture-20110325/

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Security

Ciphering Prevent unauthorized user from seeing the content of

communication For control plane (RRC) data and user plane data PDCP Control PDUs (ROHC feedback and PDCP status reports)

are not ciphered

Integrity protection Used to detect whether a text is tampered during delivery Control plane (RRC) data For RN, User plane data 32-bit Message Authentication Code for Integrity (MAC-I)

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Discard of Data Packets

To prevent excessive delay and queuing in the transmitter

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Discard Timer Related to buffer/delay

management Defines maximum wait time

ProcessWhen a PDCP SDU is received

from upper layer, discard timer for the SDU is started

When a discard timer expires, either the PDCP SDU is discarded or indication is sent to lower layer

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PDCP PDU format

PDCP Data PDU User plane PDCP Data PDU Long PDCP SN (12bits) (DRBs mapped on RLC AM or UM) Short PDCP SN (7bits) (DRBs mapped on RLC UM) Integrity protection for RN user plane (DRBs mapped on RLC AM or

RLC UM) Extended PDCP SN (15 bits) (DRBs mapped on RLC AM)

Control plane PDCP Data PDU For control plane SRBs

PDCP Control PDU Interspersed ROHC feedback packet DRBs mapped on RLC AM or RLC UM

Status report DRBs mapped on RLC AM

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D/C SN or Type MAC-I

Data(DRB)

O SN (7,12, 15 bits) Δ

Data(SRB)

X SN (5 bits) O

ROHC feedback

O Type X

StatusReport

O Type X


PDCP PDU format

PDCP Data PDU

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<User plane PDCP Data PDU with long PDCP SN (12 bits)>

<User plane PDCP Data PDU with short PDCP SN (7 bits)>

<User plane PDCP Data PDU with extended PDCP SN (15 bits)>

<RN user plane PDCP Data PDU with integrity protection><Control plane PDCP Data PDU for SRBs>


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PDCP PDU format

PDCP Control PDU

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<PDCP Control PDU for interspersed ROHC feedback packet>

<PDCP Control PDU for PDCP status report using a 12 bit SN>

<PDCP Control PDU for PDCP status report using a 15 bit SN>• FMS: PDCP SN of the first missing PDCP SDU


32

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RLC Overview

Radio Link Control(RLC) Located between RRC/PDCP and MAC Error correction through ARQ Segmentation/Concatenation/Reassembly of RLC SDUs 3 transfer modes TM (Transfer Mode)

• Only used for RRC messages which do not need RLC configuration• through BCCH, DL/UL CCCH and PCCH

UM (Unacknowledged Mode)• Utilized by delay-sensitive and error-tolerant real-time applications• through DL/UL DTCH, MCCH or MTCH

AM (Acknowledged Mode)• Utilized by error-sensitive and delay-tolerant non-real-time applications• through DL/UL DCCH or DL/UL DTCH

33

SDU: Service Data Unit BCCH: Broadcast Control Channel CCCH: Common Control ChannelPCCH: Paging Control Channel DTCH: Dedicated Traffic Channel MCCH: Multicast Control ChannelMTCH: Multicast Traffic Channel DCCH: Dedicated Control Channel

TM RLC entity

Features No segmentation/ No concatenation No RLC headers Deliver TMD PDUs Only for RRC messages which do not need RLC configuration

SI messages Paging messages RRC messages which are sent when no SRBs other than SRB0

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< Model of TM RLC entity >

BCCH : Broadcast Control Channel PCCH : Paging Control Channel SRB: Signaling Radio BearerCCCH : Common Control Channel SI: System Information TMD: Transparent Mode Data

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UM RLC entity

Features Segment or concatenate RLC SDUs Add or remove RLC headers Reorder received RLC PDUs Reassembly of RLC SDUs Used by delay-sensitive and error-tolerant real-time applications VoIP, MBMS

35DTCH : Dedicated Traffic Channel MCCH : Multicast Control Channel SDU: Service Data UnitMTCH : Multicast Traffic Channel MBMS: Multimedia Broadcast/Multicast ServiceUMD: Unacknowledged Mode Data

< Model of UM RLC entity >

concatenation

UM data transfer

36< Example of PDU loss detection with HARQ reordering >

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AM RLC entity

Features Similar function of UM RLC entity Support ARQ (Stop and Wait) Detect the loss of AMD PDU and request retransmission to peer Deliver AMD PDU, AMD PDU segment and STATUS PDU Used by error-sensitive and delay-tolerant non-real-time applications

Interactive/background type services: Web-browsing, file downloading

37

< Model of AM RLC entity >

ARQ: Automatic Repeat reQuest

AM data transfer

Retransmission and resegmentation Status reports from receiving side ACK/NACK

RLC data PDU is stored in retransmission buffer Resegment the original RLC PDU into smaller PDU segments

38< Example of RLC re-segmentation >

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Data flow through L2 protocol stack

39A. Larmo et al., "The LTE link-layer design," Communications Magazine, IEEE , April 2009.


40

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MAC overview

41

Transport channel name Direction AcronymBroadcast Channel Downlink BCHDownlink Shared Channel Downlink DL-SCHPaging Channel Downlink PCHMulticast Channel Downlink MCHUplink Shared Channel Uplink UL-SCHRandom Access Channel Uplink RACH

Logical channel name Type AcronymBroadcast Control Channel Control BCCHPaging Control Channel Control PCCHCommon Control Channel Control CCCHDedicated Control Channel Control DCCHMulticast Control Channel Control MCCHDedicated Traffic Channel Traffic DTCHMulticast Traffic Channel Traffic MTCH

Functions Channel Mapping Building MAC PDU Random access Scheduling Power saving by Discontinuous

Reception(DRX) Error correction through HARQ Multiplexing / Demultiplexing Transport Format Selection Priority handling Logical Channel prioritization

• 3GPP TS 36.300 V11.5.0, "E-UTRA and E-UTRAN; Overall description; Stage 2(Release 11)", Mar, 2013.• 3GPP TS 36.300 V11.6.0, “E-UTRA and E-UTRAN; Overall description”, June, 2013.

Channel Mapping in LTE

42

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Downlink Channel Mapping(MAC-PHY)

43•PDCCH(Physical Downlink Control Channel)•PHICH(Physical HARQ Indicator Channel)

•PxxCH : Physical xx Channel

MAC

PHY

Uplink Channel Mapping(MAC-PHY)

44•PUCCH(Physical Uplink Control Channel)

MAC

PHY

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Logical Channels

45

Control Channel Description

Broadcast Control Channel (BCCH)

Broadcasting system control information

Paging Control Channel (PCCH)

Transfers paging information and system information change notifications Used for paging when the network does not know the location cell of the UE.

Common Control Channel (CCCH)

Transmitting control information between UEs and network For UEs having no RRC connection with the network.

Multicast Control Channel (MCCH)

A point-to-multipoint downlink channel Transmitting MBMS control information from the network to the UE, for one or several MTCHs Only used by UEs that receive or are interested to receive MBMS.

Dedicated Control Channel (DCCH)

A point-to-point bi-directional channel Transmits dedicated control information between a UE and the network Used by UEs having an RRC connection.

Traffic Channels Description

Dedicated Traffic Channel (DTCH) A point-to-point channel, dedicated to one UE Transfer of user information Exists in both uplink and downlink.

Multicast Traffic Channel (MTCH) A point-to-multipoint downlink channel for transmitting traffic data from the network to the UE Only used by UEs that receive MBMS

Transport Channels

Downlink Channels Description

Broadcast CHannel (BCH) Transport the parts of the SI

Downlink Shared CHannel(DL-SCH)

Transport downlink user data or control messages Transport remaining parts of the SI that are not transported via the BCH

Paging CHannel (PCH) Transport paging information Inform UEs about updates of the SI and PWS messages

Multicast CHannel (MCH) Transport MBMS user data or control messages that require MBSFN combining

46

Uplink Channels Description

Uplink Shared Channel(UL-SCH)

Transport uplink user data or control messages

Random Access Channel(RACH)

Access to the network when the UE does not have accurate uplink timing synchronization or UE does not have any allocated uplink transmission resource

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LTE Radio Frame Structure

Type 1 : for FDD Radio frame(10ms) = 10 subframes(1ms) = 20 slots(0.5ms) 10 subframes for downlink, 10 subframes for uplink Uplink and downlink transmissions are separated in the

frequency domain Data is split into TTI blocks of T=1ms (one subframe)

47

LTE Downlink Subframe Structure(for Type 1)

48

1 Slot Consists 7 symbols

Resource Block 1 slot X 12 subcarriers

=84 REs BPSK(1/2): 42bits 64QAM(3/4): 378bits

Resource Element Amount of data in a

symbol in a subcarrier BPSK(1/2): 0.5bits 64QAM(3/4): 4.5bits

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LTE Radio Frame Structure

Type 2 : for TDD radio frame(10ms) = 2 half-frames(5ms) = 8 subframes(1ms) + 2

special subframes (DwPTS, GP, UpPTS) Subframe 1 always consists special fields, although subframe 6 is by

configuration

49

One radio frame =10 ms

One half frame =5 ms

# 0 # 2 # 3 # 4 # 5 # 7 # 8 # 9

1 ms

DwPTS UpPTSGPDwPTS UpPTSGP

• DwPTS : Downlink Pilot Time Slot• GP : Guard Period• UpPTS : Uplink Pilot Time Slot

Configuration

Switch-point periodi

city

Subframe number

0 1 2 3 4 5 6 7 8 9

0 5 ms D S U U U D S U U U1 5 ms D S U U D D S U U D2 5 ms D S U D D D S U D D3 10 ms D S U U U D D D D D4 10 ms D S U U D D D D D D5 10 ms D S U D D D D D D D6 5 ms D S U U U D S U U D

Uplink(U)/Downlink(D)/Special frame(S) Allocation

Building MAC PDU(MAC PDU Format)

MAC PDU = MAC Header + MAC Payload MAC subheader Logical Channel ID (LCID), Length(L) field

MAC control element Used for MAC-level peer-to-peer signaling

Buffer status report / UE’s available power headroom in uplink/ DRX command, etc.

Headerless MAC PDU MAC PDU constructed without header Use it when MAC PDU is used to transport data from the PCCH or BCCH

PCCH or BCCH : one-to-one corresponding between MAC SDU and MAC PDU

50

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Random Access(RA) Procedure

Purpose RA is performed when UE didn’t assigned resource for data transmission

Contention based Perform when eNB doesn’t know the presence of UE or UE have data to transmit

while UE lost timing information Examples

• Initial access from RRC_IDLE• RRC Connection Re-establishment procedure• UL data arrival during RRC_CONNECTED requiring random access procedure

» E.g. when UL synchronisation status is "non-synchronised" or there are no PUCCH resources for SR available

Non-contention based Perform when eNB know the incoming of UE or eNB have data to transmit while

UE lost timing information Examples

• Handover• For positioning purpose during RRC_CONNECTED requiring RA• DL data arrival during RRC_CONNECTED requiring random access procedure

» E.g. when UL synchronisation status is “non-synchronised”

51

Random Access Procedure- Contention based(1)

52

(0) Selection of preamble : select a preamble in preamble groups

Preambles for contention based access(2 groups, select a group by message size)

Total 64 preambles(spreading codes) in each cell

Preambles forcontention-free access

(1) Preamble Transmission on RACH

• Set transmission power : according to DL estimation on RSRP• Power ramping : increase transmission power by number of retrials

(2) RA Response (PDCCH tagged with RA-RNTI + PDSCH)• Send response for a UE if single preamble is detected• This message includes UL resource grant, timing alignment

information for sending third message• Assign a temporary ID for UE(TC-RNTI)

• RSRP : Reference Signal Received Power• RA-RNTI : Random Access Radio Network Temporary Identifier

•TC-RNTI : Temporary Cell Radio Network Temporary Identifier

• No RA Response for UE Backoff Back to Selection of preamble

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Random Access Procedure- Contention based(2)

53

(3) First PUSCH TX – Includes TC/C-RNTI

• Conveys actual random access procedure message• If multiple UEs selected same RACH and preamble in (1), collision occurs• No collision eNB detects one C-RNTI and get message from PUSCH

• UE considers as success, and TC-RNTI is promoted to C-RNTI• If (3) is collided No arrival of Contention Resolution for UE Backoff Back to Selection of preamble

(4) Contention Resolution on DL

Random Access Procedure- Non-Contention based

54

(0) RA Preamble Assignment

(1) RA Preamble

(2) RA Response

• eNB assigns to UE a non-contention Random Access Preamble before RA(ex> before handover)

• Transmits non-contention RA Preamble

• Conveys at least timing alignment information and initial UL grant for handover, timing alignment information for DL data arrival, RA-preamble identifier

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Data Transmission after RA- Downlink Scheduling(1) Dynamic Scheduling Signal and transmit data without periodicity Signaling is required at each transmission

55

Signaling for dynamic scheduled data

•PDCCH(Physical Downlink Control Channel)•DL-SCH(Downlink Shared Channel)

Data Transmission after RA- Downlink Scheduling(2) Semi-persistent scheduling Schedule periodical transmission Only the one signaling at first transmission is required Reduce signaling overhead

Scheduling periodicity is configured by RRC

56

Signaling for semi-persistent data(example : period = 4)

No additional signalling for semi-persistent scheduled data

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Data Transmission after RA- Uplink Scheduling Procedure eNodeB notifies the TX slot which can be used by UE for uplink transmission UE sends data through UL-SCH and activates HARQ process

HARQ mechanism : Stop-and-Wait

eNodeB signals transmission result by HARQ ACK/NACK to UE For NACK, eNodeB schedule for retransmission through PDCCH

57

Subframe

• Example for N=4 : UE/eNB response after 4 subframe

•PDCCH(Physical Downlink Control Channel)•UL-SCH(Uplink Shared Channel)•PHICH(Physical HARQ Indicator Channel)

Wireless Packet Scheduling Algorithm

Features of Scheduling Algorithms for Wireless Network Each user experience different transmission speed Channel environment differ by randomly through time Bursty error occurs User’s channel capacity changes by fading Require to estimate channel environment

58

• Additional Slides

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Signaling for Resource Allocation

For resource allocation, eNodeB requires… Channel Quality Information(frequency specific) Traffic information(volume and priority, queue

status

Signaling tradeoff Data rate ↔ Overhead

CQI measurement DL : through the feedback of CQIs by UEs UL : by Sounding Reference Signals(SRS) transmitted by

UE to estimate ch. quality Frequency of the CQI reports is configurable

Reduce overhead ↔ Accuracy

Information about queue status DL : directly available at eNB UL : specific reporting mechanism

59


Scheduling Algorithms

Opportunistic algorithm / High Rate User First (HRUF) Simplest algorithm considering wireless channel Optimizing the total throughput Assign resources to user with best CQI

Fairness problem occurs If the an user with best channel continuously generates traffic, then other

users cannot be assigned wireless resource Other users cannot transmit their traffic Fairness and QoS are not

assured

60

max ( )i t

( )i t : Maximum transmission rate of user i


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Fair algorithmsMinimize UE latency Ex. Min-Max : Maximizes the minimum allocated rate

Total Throughput reduced

61

max min{ ( )}iit



Proportional Fair Share Scheduling (PFSS) AlgorithmMaximize Throughput with some degree of fairness Algorithm Basically, schedule UE when its instantaneous channel quality is

high relative to its own average channel Reduce priority of UE by volume of received traffic increase

fairness

62

( )max

ˆ ( )i

i

t

t

1 ( -1)( ) 1- ( -1)

e e

served rate in slot tt t

T T

Te : Estimation interval

m : resource block

f : subframe

2( ) log 1 ( , )i kt SNR m f

Large Te tends to maximize the total average throughputSmall Te tends to maximize fairness


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Retransmission – HARQ

Downlink : Asynchronous adaptive HARQ Asynchronous Retransmission with additional explicit signaling to indicate the HARQ

process number to the receiver

Adaptive HARQ Modulation and coding scheme(MCS), resource allocation can be

changed Non-adaptive HARQ : retransmit with previous MCS and resource

63


Uplink : Synchronous Non-adaptive/adaptive HARQ Uplink : Synchronous HARQ Synchronous

• Retransmission occur at predefined times relative to the initial transmission to reduce control signaling

64

Grant

Data

PDCCH

UL-SCH

Grant

New/ReTxData

PHICHACK /NACK

HARQfeedback seen

by the UE

PDCCHseen by the UE

UE behaviour

ACK or NACK

NewTransmission

New transmission accordingto PDCCH

ACKor NACK

Retrans-mission

Retransmission according toPDCCH(adaptive retransmission)

ACK NoneNo (re)transmissionPDCCH is required to resumeRetransmissions

NACK None Non-adaptive retransmission

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HARQ type HARQ combines FEC and ARQ Three types HARQ Type I HARQ

• Chase combining» Initial transmission and retransmission have same puncturing pattern

65


HARQ type HARQ combines FEC and ARQ Three types HARQ Type II HARQ

• Incremental redundancy» The information bits does not retransmitted » The retransmitted packet has different puncturing pattern

66

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HARQ type HARQ combines FEC and ARQ Three types HARQ Type III HARQ

• Incremental redundancy» Initial transmission and retransmission have different puncturing pattern» Information bits will be retransmitted

67

Power Saving/Fast Wake-up –Discontinuous Reception(DRX)

68

Power saving in UMTS Through the state change from CELL_DCH to IDLE_MODE Fast recovering to CELL_DCH takes undesired delay

•DCH (Dedicated Channel)•FACH (Forward access channel)•PCH (Cell Paging channel)•URA_PCH (URA Paging channel).

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Power Saving/Fast Wake-up –Discontinuous Reception(DRX)

69

RRC_CONNECTED

RRC_IDLE

• DRX UE only listens at certain Intervals• DRX reduced battery consumption• DRX resume transfer even quicker• DRX reduced signaling

Power Saving in LTE/LTE-Advanced : Discontinuous Reception(DRX) Power saving with maintaining connected states When need power saving Change to DRX mode while maintain RRC_CONNECTED state UE can fast wake-up, because it maintain connectivity with eNodeB

Power Saving/Fast Wake-up –Discontinuous Reception (DRX) UE does not monitor the downlink channels during

such DRX period HARQ Round Trip Time (RTT) Short cycle, Long cycle Wake-up and check downlink during “on duration” only By two timer, control wake-up interval(=short DRX cycle and long

DRX cycle)

70

①

③

ActivateInactivity timer

ActivateShort DRX Cycle Timer

④

② ⑤

⑥ enter short DRX mode enter long DRX mode

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Control Plane Protocol

71

Control Plane Protocol Overview

Non-access stratum PLMN selection Tracking area update Paging Authentication EPS bearer establishment,

modification and release

Access stratum control plane radio-specific functionalities The AS interacts

with the NAS (upper layers)

72RRC: Radio Resource Control PDCP: Packet Data Convergence ProtocolRLC: Radio Link Control PLMN: Public Land Mobile Network EPS: Evolved Packet System

eNB

PHY

UE

PHY

MAC

RLC

MAC

MME

RLC

NAS NAS

RRC RRC

PDCP PDCP

PHY

MAC

IP

S1-AP

SCTP

PHY

MAC

IP

S1-AP

SCTP

LTE-Uu(radio interface)

S1-MME(logical interface)

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Control Plane Protocol Overview: NAS Overview Highest stratum of c-plane (UE <-> MME) S1-MME (eNB – MME)

Main functions EPS mobility management UE mobility

EPS session management IP connectivity between the UE and a P-GW

Security integrity protection and ciphering of NAS signaling messages.

73 3GPP TS 24.301 V10.7.0 “UMTS; LTE; NAS; EPS; Stage 3”, July, 2012 3GPP TS 24.401 V8.9.0 “ LTE; GPRS enhancements for E-UTRAN access”, March, 2010

Control Plane Protocol Overview: RRC Overview AS of c-plane (UE <-> eNB) LTE-Uu interface

Main functions Broadcast SI related to NAS and AS Paging Establishment of an RRC connection (UE<->E-UTRAN) Security functions (key management) Establishment of p-to-p Radio BearersMobility functions QoS management functions UE measurement reporting NAS direct message transfer (NAS<->UE)

74 3GPP, "TS 36.331 V10.5.0 Radio Resource Control (RRC) Protocol specification (Release 10)," ed, 2012.

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NAS/RRC State

Protocol State Description

NAS(UE,MME)

EMM-Deregistered • UE is detached• No EMM context has been established in UE and MME.

EMM-Registered • UE has been attached• IP has been assigned• An EMM Context has been established • A default EPS Bearer has been activated• The MME knows the location of the UE(TA).

ECM-Idle • No NAS signalling connection (ECM connection)• No UE context held in E-UTRAN(eNB)• The MME knows the location of the UE(TA)

ECM-Connected • NAS signalling connection (ECM connection; a RRC connection & a S1 signalling connection)

• The MME knows the location of the UE(cell)

RRC(UE,eNB)

RRC-Idle • RRC connection has not been established.

RRC-Connected • RRC connection has been established.

75TA: Tracking Area EMM: EPS Mobility Management ECM: EPS Connection ManagementMME: Mobility Management Entity1. Netmanias, “EMM and ECM States,” http://www.netmanias.com, 2013.

NAS/RRC State

76

When UE is switched on for the first time after subscription

When UE is switched on after a long time after the power has been turned off

There exists no UE context in the UE and MME.

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NAS/RRC State

77

When UE is switched on within a certain period of time after the power has been turned off

When ECM connection is released during communication due to radio link failure

Some UE context can still be stored in the UE and MME (e.g., to avoid running an AKA procedure during every attach procedure).

NAS/RRC State

78

When UE is attached to the network (MME) and using services

The mobility of UE is handled by handover

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NAS/RRC State

79

NAS/RRC State

80

When UE is attached to the network (MME) and not using any service

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NAS/RRC State

81

Control Plane Protocol Overview: RRC States

RRC_IDLE UE known in EPC and has IP

address UE location known on Tracking

Area level Paging in TA controlled by EPC UE-based cell-selection and TA

update

RRC_CONNECTED UE known in EPC and E-

UTRAN/eNB UE location known on cell level Unicast data transfer is possible eNB-based mobility DRX supported for power

saving

82

2.

3.

5.HO

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Control Plane Protocol Overview: UE Operation in RRC States

RRC_IDLEMonitors a paging channel incoming calls system information change ETWS, CMAS

measurement cell (re-)selection Acquire system information

(MIB, SIBs)

RRC_CONNECTEDMonitors a Paging channel

and/or SIB1 detect system information change

Monitor control channelsassociated and data channel

Provide channel quality and feedback information

measurement and reportingAcquire system information

83DRX: Discontinuous Reception ETWS: Earthquake and Tsunami Warning SystemCMAS: Commercial Mobile Alert Service

Control Plane Protocol Overview: UE Camping Procedure

84 Bong Youl (Vrian) Cho, “LTE RRC/RRM”, TTA LTE/MIMO Standards/Technology Trainning, May 2012

AS

PHY

RRC

NAS

(2) TriggerSystemAcquisition

(4) ScheduleBroadcast ControlChannel read

(6) Process SIB1Check PLMNIs Cell reserved?Is CSG Id valid?Cell belong to Forbidden TA?Cell barred?If fail, go back to (3)If ok, go to (7)

(8) All SIBsobtained

(10) Service Obtained(Camped)

(1) PLMN selectionRead USIMRead stored info on MESelect Band, PLMN, etc

(3) AcquisitionScan Band/Freq

(5) Read MIB/SIB1Using SI-RNTI

(7) SIB2 and Other SIBs(9) Cell isSelected and UE camps

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RRC Services

Services provided to upper layers Broadcast of common control information Notification of UEs in RRC_IDLE receiving call, ETWS, CMAS

Transfer of dedicated control information information for one specific UE

Services expected from lower layers PDCP Integrity protection and ciphering

RLC Reliable and in-sequence transfer of information

• without introducing duplicates• with support for segmentation and concatenation

85ETWS: Earthquake and Tsunami Warning System CMAS: Commercial Mobile Alert Service

RRC Functions

86

Broadcast of system information

NAS common information For UEs in RRC_IDLE

• Cell (re-)selection parameters• Neighboring cell information

For UEs in RRC_CONNECTED• Common channel configuration information

RRC connection control

Paging Establishment/modification/release of RRC connection or DRBs Initial security activation RRC connection mobility Radio configuration control (ARQ, HARQ, DRX) QoS control Recovery from radio link failure

Inter-RAT mobility Security activation Transfer of RRC context information

Measurement configuration control and reporting

Establishment/modification/release of measurements Setup and release of measurement gaps Measurement reporting

Transfer of information Dedicated NAS information Non-3GPP dedicated information UE radio access capability information

Others Generic protocol error handling Support of self-configuration and self-optimization

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Connection Control

Security activation Ciphering of both control plane RRC data (SRBs 1 and 2) and

user plane data (all DRBs) Integrity protection which is used for control plane data only

Connection establishment, modification and release DRB establishment, modification and release

87SRB: Signaling Radio Bearers DRB: Date Radio Bearers

Connection Establishment and Release

88

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DRB Establishment: Signaling Radio Bearers SRB: radio bearers that are used only for the

transmission of RRC and NAS messages SRB0 For RRC messages Using the CCCH logical channel

SRB1 For RRC messages (which may include a piggybacked NAS message) For NAS messages prior to establishment of SRB2 All using DCCH logical channel

SRB2 For NAS messages Using DCCH logical channel Lower-priority than SRB1 Always configured by E-UTRAN after security activation

89CCCH: Common Control Channel DCCH: Dedicated Control Channel

DRB Establishment : Signaling Radio Bearers

90

An EPS bearer is mapped (1-to-1) to a DRB A DRB is mapped (1-to-1) to a DTCH logical channel All logical channels are mapped (n-to-1) to the DL-SCH

or UL-SCH DL-SCH or UL-SCH are mapped (1-to-1) to the

corresponding PDSCH or PUSCH

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Mobility Control

Criteria for cell selection or reselection Radio link quality: primary criterion UE capability Subscriber type Cell type

E-UTRAN provides a list of neighboring frequencies and cells; white-list or black-list

91

Mobility in RRC_IDLE: PLMN and Cell Selection PLMN selection The NAS handles PLMN selection based on a list of available PLMNs

provided by the AS

Cell selection (EMM-DEREGISTERED) The UE searching for the strongest cell on all supported carrier

frequencies of each supported RAT Using NAS’s support and stored information from a previous access Requirement: not take too long

Cell reselection (EMM-REGISTERED) Move the UE to the best cell of the selected PLMN

92

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Mobility in RRC_IDLE: Cell Reselection

93

RRC_IDLE Mobility

Measurement and evaluation of serving cell

Measurement of neighbour cells

Evaluation of neighbour cells for cell reselection

Acquisition of the system information of the target cell

Cell reselection to the target cell

Mobility in RRC_IDLE: Cell Selection Criteria

94

Cell selection: received level & qualitySrxlev &Squal

Srxlev rxlevmeas rxlevmin rxlevminoffsetSqual qualmeas qualmin qualminoffset

rxlevmeas: Measured cell RX level value (RSRP)

qualmeas: Measured cell quality value (RSRQ)

rxlevmin: Minimum required RX level in the cell (dBm), in SIB1

qualmin: Minimum required quality level in the cell (dB), in SIB1

rxlevminoffset, qualminoffset: offsets which may be configured to

prevent ping-pong between PLMNs, in SIB1

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Mobility in RRC_CONNECTED

95

Mobility in RRC_CONNECTED: Handover

UE

Measurement Report

RRCConnectionReconfiguration

Handover Preparation

Source eNB Target eNB

Random access procedure

RRCConnectionReconfigurationComplete

UE RRC context information(UE capabilities, current AS-

configuration, UE-specific RRM information

Handover command

information for random access(mobility control, radio resource configuration), dedicated radio resource security configuration, C-RNTI

96

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Mobility in RRC_CONNECTED: Handover Handover from Macro cell to macro cell HO triggering condition UE satisfies A3 condition during TTT

-> HO request to S-eNB -> HO execution

97

• A3 satisfaction

• H/O completion

• HO execution

TTTHO delay

Hyst + offset

Mobility in RRC_CONNECTED : Seamless Handover Seamless handover OBJECTIVE : Interruption Time Minimization Used for all RBs carrying control plane data and user plane data

mapped on RLC UM Loss tolerant and delay sensitive

eNB forwards only non-transmitted SDUs via X2 to target eNB If transmission was started but has not been successfully

received packets are lostMinimum complexity because context is not transferred

between eNB via X2 ROHC, COUNTS context is reset

98 3GPP TS 36.323, “E-UTRA; PDCP specification.”

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Mobility in RRC_CONNECTED : Seamless Handover Seamless handover in the downlink

99

SDUs are transmitted to eNBin sequence

손실된패킷은재전송되지않음

전송하지못한패킷은 X2로전달

Reordering은 UE가수행

3GPP TS 36.323, “E-UTRA; PDCP specification.”

Mobility in RRC_CONNECTED : Lossless Handover Lossless handover OBJECTIVE : In-Sequence Delivery without Losses Possible because PDCP adds a sequence number to packets Applied for radio bearers that are mapped on RLC-AM Delay-tolerant and loss-sensitive

Un-acknowledged packets are forwarded via X2 an retransmitted they may be received twice

ROHC context is reset

100 3GPP TS 36.323, “E-UTRA; PDCP specification.”

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Mobility in RRC_CONNECTED : Lossless Handover Lossless handover in the uplink

101

SDUs are delivered to the GW in sequence

Serving eNB transfers via X2, out-of-sequence SDUs

STATUS TRANSFER contains Sequence and Hyper Frame Numbers

Unacknowledged SDUs are retransmitted duplicity of P4


Mobility in RRC_CONNECTED : Lossless Handover Lossless handover in the downlink

102

SGW transmits End Marker to serving eNB

Target eNB knows when it can start to transmit SDUs from SGW

SDUs are delivered to the UE in sequence


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Mobility in RRC_CONNECTED: Detailed Handover Procedure (1/3)

103

Ad

mis

sio

n

Co

ntr

ol

S1-Based handover


104

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105

Res

ou

rce

R

ele

ase

Step 2: HO Execution

Step 1: HO Preparation

UE Source eNB Target eNB

MME

<GTP-U>End Marker

Serving GW

<S1AP>Handover Notify

<S1AP>UE Context Release Command

Step 3: HO Completion

Deliver bufferd and in transit packets to target eNB <GTP-U> End Marker

Downlink data

Packet data Packet data

<GTP-C>Modify Bearer Request

<GTP-C>Modify Bearer Response

Switch DL Path

Downlink data

Uplink dataUplink data

<S1AP>UE Context Release Complete<GTP-C>Delete Indirect Data Forwarding Tunnel Request

<GTP-C>Delete Indirect Data Forwarding Tunnel Response

Measurements

Measurement Configuration: RRCConnectionReconfiguration messageMeasurement objects: carrier frequency or list of cells Reporting configurations: RSRP/RSRQ, number of cellsMeasurement identities Quantity configurations: filteringMeasurement gaps: time periods

UE may measure and report Serving cell Listed cells Detected cells on a listed frequency

106RSRP: Reference Signal Received Power RSRQ: Reference Signal Received Quality

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Measurements: Measurement report triggering

107

Event Condition

A1 Serving becomes better than threshold:

A2 Serving becomes worse than threshold:

A3Neighbor becomes offset better than Pcell:

A4 Neighbor becomes better than threshold:

A5PCell becomes worse than threshold1 and neighbor becomes better than threshold2:

1 & 2

A6(Rel-10)

Neighbour becomes offset better than SCell:

B1 Inter RAT neighbor becomes better than threshold:

B2PCell becomes worse than threshold1 and inter RAT neighbor becomes better than threshold2: 1 & 2

Mserving/Mn/Mp/Ms: measurement result of serving cell/neighbor cell/Pcell/SCell Of/Oc: frequency/cell specific offsetPCell: Primary (serving) Cell SCell: Secondary (serving) Cell <- carrier aggregation 3GPP, "TS 36.331 V10.5.0 Radio Resource Control (RRC) Protocol specification (Release 10)," ed, 2012.

Measurements: Reference Signal Received Power

RSRPUEs measure RSRP over

the cell-specific RSsPeriodic measurement Intra-freq.: 200ms Inter-freq.: 480ms

(proportion to the DRX cycle)

Requirements intra-frequency: 8 cells inter-frequency: 4 cells * 3

carriers = 12 cells

108

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Measurements: Reference Signal Received Quality Reference Signal Received Quality (RSRQ)

RSRQ ∝

RSSI the total received power

• interference from all sources• serving and nonserving cells• adjacent channel interference and thermal noise

LTE Rel-8 RSRQ was applicable only in RRC_CONNECTED state

• Handover

LTE Rel-9 RSRQ was also introduced for RRC_IDLE

• Cell reselection

109RSSI : Received Signal Strength Indicator

Measurements: System Information Blocks

110ETWS: Earthquake and Tsunami Warning Service CMAS: Commercial Mobile Alert SystemMBMS: Multimedia Broadcast/Multicast Services

SIB Contents

MIB • parameters which are essential for a UE’s initial access to the network

SIB1• parameters needed to determine if a cell is suitable for cell selection• information about the time-domain scheduling of the other SIBs

SIB2 • common and shared channel information

SIB3-8• parameters used to control intra-frequency, inter-frequency and inter-

RAT cell reselection

SIB9 • signal the name of a Home eNodeB (HeNBs)

SIB10-12 • ETWS notifications and CMAS warning messages

SIB13 • MBMS related control information

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Measurements: RRC messages to transfer SI (example) MIB(SIB1) message is carried by PBCH(PDSCH) created every 40(80) msec broadcasted every 10(20) msec

Other SI messages are created and broadcasted dynamically on the PDSCH

111

Message Content Period Applicability

MIB Most essential parameter 40 ms Idle/connected

SIB1 Cell access related parameters, scheduling information 80 ms Idle/connected

1st SI SIB2: Common and shared channel configuration 160 ms Idle/connected

2nd SI SIB3: Common cell reselection information and intra-frequency cell reselection parameters other than the neighbouring cell informationSIB4: Intra-frequency neighbouring cell Information

320 ms Idle only

3rd SI SIB5: Inter-frequency cell reselection information 640 ms Idle only

4th SI SIB6: UTRA cell reselection informationSIB7: GERAN cell reselection information

640 ms Idle only

PBCH: Physical Broadcast Channel PDSCH: Physical Downlink Shared ChannelSFN: System Frame Number

Paging

Pagingtransmit paging

information to a UE inRRC-IDLE -> RRC-CONNECTED

MME initiates pagingPhone callDL trafficSI changeETWS notification

112

eNB

[NAS: Service Request][eNB UE signalling connection ID]

Random access procedure

<RRC>Paging<S1AP>Paging

<NAS>Service Request

<S1-AP>Initial UE MESSAGE

<S1-AP>Initial Context Setup Request[NAS message]

[MME UE signaling connection ID][Security Context]

[UE Capability Information][Bearer Setup:serving S-GW TEID,

QoS Profile]

<RRC>Radio Bearer Setup

<RRC>Radio Bearer Setup Complete

<S1-AP>Initial Context Setup Complete[eNB UE signalling connection ID][Bearer Setup Confirm:eNB TEID]

P-RNTI check

Monitor PDCCH at certain UE-specific subframes

MMEUE

TA: Tracking Area PDCCH: Physical Downlink Control Channel RNTI: Radio Network Temporary IdentifierP-RNTI: Paging RNTI ETWS: Earthquake and Tsunami Warning service

Send to all eNBs in a TA

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Paging: Tracking Area

TAI: Global Unique IDPLMN ID + TAC

In order to paging, MME needs TAI Ex) MME1 sends paging to

UE1 => broadcast all the eNBs in TAI1 & TAI2

TAI listUE receives TAI list when it is

connected

TAUWhen UE move out from

own TAI listPeriodic TAU

113TAI: Tracking Area Identifier TAC: Tracking Area Code TAU: Tracking Area Update

Radio Resource Management: RRM Functions

114

Power control Scheduling Cell search Cell reselection Handover Radio link or connection monitoring Connection establishment and re-establishment Interference management Location services Self-Optimizing network (SON)Network planning

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Radio Resource Management: LTE RRM Characteristic

115MBMS: Multimedia Broadcast/Multicast Service

Characteristics Details

Interference fluctuation • Fast time and frequency domain scheduling

Wide range of DRX • DRX: 0~2.5 sec

Different RATs• LTE, 3GPP & non-3GPP legacy RATs• Different channel structure

Various cell sizes• Macro / femto / pico• A few ‘m’ ~ tens of ‘km’

Various frame structure• FDD(synchronized or unsynchronized), TDD

Low latency requirements• Measurements & reports• HO

Power Control

LTE power control is not as critical as in WCDMA LTE uplink resources are orthogonal

-> no intra-cell interference (theory) frequency selective scheduling

Power ControlMaximize system capacityMinimize inter-cell interference

116SRSs: Sounding Reference Signals RB: Resource Block RE: Resource Element

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Power Control: UL Power Control Uplink power control: PUSCH, PUCCH and the SRSs

(unit of RB) ∙ ∆

Semi-static basic open-loop operating point : cell specific power level : factor to trade off the fairness of uplink scheduling against total

cell capacity• PUCCH: always 1 -> maximize fairness for cell edge UE

: downlink pathloss estimate calculated in the UE

dynamic offset updated from subframe to subframe ∆ : MCS dependent power offset : TPC command related power

• TPC command: relative power offset comparing to its previous Tx power, or absolute power

117

SRSs: Sounding Reference Signals RB: Resource Block RE: Resource ElementTPC: Transmitter Power Control 3GPP, "TS 36.213 v10.6.0 LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures

(Release 10)," July 2012.

Downlink power allocation (unit of RE) Cell specific RS EPRE (Energy per RE)

: semi-static (eNB signals UE)

or PDSCH RE’s position (index 0, 4)

10log : 0dB for all

transmission modes except multi-user MIMO

: UE specific parameter from higher layer

: 2 (transmit diversity with 4 antenna ports) or 1 (otherwise)

∙ : cell specific parameter

from higher layer

PDSCH power to RS, where NO RSs are present, is UE specificand signaled by higher layer as

Cell-specific RS power, signaled in SIB2

Power Control: DL Power Allocation

118RE: Resource Element 3GPP, "TS 36.213 v10.6.0 LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures

(Release 10)," July 2012.

EPRE

Subcarrier Index

PDCCH power depending on /

For PDSCH power in same symbol as RS an additional cell specific offset is applied, that is signaled by higher layer

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Cell Search

Cell Search UE acquires the carrier frequency, timing and cell identity of

cells

Cell search within E-UTRAN Identify one of the 504 unique Physical Cell Identities (PCIs)

RequirementsMaximum permissible cell identification delay(∝ DRX cycle)Minimum synchronization signal quality : the energy per Resource Element (RE) of the synchronization

signal : total received energy of noise and interference on the same RE

119

Case Max. Delay Min. /

Intra-frequencyDRX (0~40ms)

800ms -6dB

Inter-frequencyDRX(0~160ms)

3.84s -4dB

Radio Link Failure Handling

1st phase Layer 1 monitors downlink quality and indicates problems to RRC RRC filters L1 indications and starts a timer if no recovery within 1st phase, triggers 2nd phase

Layer 2 monitors random access attempts and indicates problems to RRC RRC triggers 2nd phase

2nd phase – Radio Link Failure (RLF): Possible recovery through an RRC Connection Reestablishment

procedure reestablishment may be performed in any cell to which the UE’s context

is made available If no recovery within 2nd phase, UE goes autonomously to IDLE

120

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Inter-Cell Interference

LTE is designed for frequency reuse 1 (To maximize spectrum efficiency) All the neighbor cells are using same frequency channels no cell-planning to deal with the interference issues

Shared channels RB scheduled to cell edge user can be in high interference

->low throughput / call drops

Control channels Neighbor interference -> radio link failures at cell edge.

121

Inter-Cell Interference Coordination

ICIC mitigates interference on traffic channels only Power and frequency domain to mitigate cell-edge interference from

neighbor cells

X2 interface is used to share the information between the eNBs

A.Neighbor eNBs use different sets of RBs improves cell-edge SINR decrease in total throughput

B.Center users: complete range of RBsCell-edge users: different sets of RBs

C.Scheme B + different power schemes For center/cell edge user: low/high power

122

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Summary of Control Plane: Initial Attach Procedure

123

Summary of Initial Attach Procedure

S-GW: Serving Gateway P-GW: Packet Data Network Gateway HSS: Home Subscriber Server PCRF: Policy and Charging Rule Function SPR: Subscriber Profile Repository IMSI: International Mobile Subscriber Identity Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011 http://www.netmanias.com/bbs/view.php?id=techdocs&no=74

Summary of Control Plane: Acquisition of IMSI

124


Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011

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Summary of Control Plane: Acquisition of IMSI

125GUMMEI: Globally Unique MME ID ECGI: E-UTRAN Cell Global Identifier TAI:Tracking Area Identity Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011

Summary of Control Plane: Authentication

126



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Summary of Control Plane: Authentication

127MCC: Mobile Country Code MNC: Mobile Network CodePLMN: Public Land Mobile Network ID PLMN=MCC+MNC Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011

Summary of Control Plane: NAS Security Setup

128



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Summary of Control Plane: NAS Security Setup

129 Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011

Summary of Control Plane: Location Update

130



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Summary of Control Plane: Location Update

131APN: Access Point Name QCI: QoS Class identifier ARP: Allocation and Retention Priority AMBR: Aggregated Maximum Bit Rate Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011

Summary of Control Plane: EPS Session Establishment

132



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Summary of Control Plane: EPS Session Establishment (1)

133TEID: Tunnel Endpoint ID Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011


134TEID: Tunnel Endpoint ID Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011

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135 Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011


136

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Summary of Control Plane

137

LTE-Advanced FeaturesHeterogeneous NetworksCarrier AggregationCoMP

138

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Heterogeneous Networks

Objective Coverage extension Interference mitigation Capacity increase

Nodes Macro cells (eNBs) RRH (Remote Radio Head)

Antenna extension with wired backhaul (Fiber) Tx power: 46 dBm

Relay Perform a role of eNB in a UE perspective Wireless backhaul Tx power: 30 dBm

Pico cells (Pico eNBs) Similar to macro eNBs but with lower power Wired backhaul (X2 interface) Tx power: 23-30 dBm

Femto cells (HeNBs) CSG/OSG/Hybrid Indoor deployment by the customer usually without planning HeNB gateway can (optionally) be deployed to manage a large number of HeNBs (Rel-9/10) High speed internet access for backhaul Tx power: <23 dBm

139CSG: Cell Subscriber Group OSG: Open Subscriber Group

Small cells

D Lopez-Perez, A Valcarce, G De La Roche, J Zhang, “Enhanced intercell interference coordination challenges in heterogeneous networks”. IEEE Wirel Commun. 18(3), 22–30, 2011

Heterogeneous Networks

140

RelayMacroPico

Core Network

Femto

Internet

RRH

X2 interface

Fiber

Wireless

High speedInternet

Khandekar, A.; Bhushan, N.; Ji Tingfang; Vanghi, V., "LTE-Advanced: Heterogeneous networks," Wireless Conference (EW), 2010 European , vol., no., pp.978,982, 12-15 April 2010

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Heterogeneous Networks:Hot issues for Small cell Networks Dual connectivity UE maintain connections with macro cell and small cellMacro cell manages the C-plane of UE connections Small cell manages only U-plane protocols of UE connections

Mobility enhancement Lite handover algorithm to reduce handover overhead between

macro cell and small cell User-centric cooperative handover scheme

Interference handling Interference between macro cell and small cell, small cell and

small cell Transmission power control of small cell according to amount

of traffic Bandwidth sectoring for small cells

141윤영우, “3GPP LTE Rel-12 & Onwards 주요요소기술및표준동향”, 전자공학회지, 제 40권 4호, pp.328-339, 2013년 4월.

Heterogeneous Networks:Hot issues for Small cell Networks Cell discovery Efficient cell searching considering small cell interferences and

plenty of cells Effective cell discovery considering unplanned small cells

Improved spectral efficiency High modulation scheme (e.g. 256QAM) with high received

power in small cells Reducing reference signal overhead

142윤영우, “3GPP LTE Rel-12 & Onwards 주요요소기술및표준동향”, 전자공학회지, 제 40권 4호, pp.328-339, 2013년 4월.

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Heterogeneous Networks:Current works Cloud-RAN* (삼성전자) Separate Digital Unit and Radio Unit in eNB CCC (Cloud control center) control multiple RRH Support CA, CoMP, ICIC(Inter-cell interference) Inter-eNB CA is an alternative to fiber based cloud-RAN

143*3GPP, RWS-120046, Samsung Electronics, “Technologies for Rel-12 and Onwards,” June 2012.

<CCC architecture> <Inter-eNB CA architecture>

Heterogeneous Networks:Current works Phantom cell* (NTT Docomo)Macro cell manages control signals for small cells Small cell manage only data transmission High bandwidth efficiency

144*3GPP, RWS-120010, NTT DOCOMO, “Requirements, Candidate Solutions & Technology Roadmap for LTE Rel-12 Onward,” June 2012.

<Phantom cell architecture>

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Heterogeneous Networks:Current works Soft Cell* (Ericsson & ST-Ericsson) Dual connectivity – anchor and booster carriers Logical connection on anchor and booster carrier Does not necessarily imply simultaneous UE physical-layer Rx/Tx of

booster and anchor carrier(s)

145

Anchor carrier Macro node connection System information, basic RRC Low-rate/high-reliability user data Based on Rel-8 – Rel-11 structures

Booster carrier Pico node connection (when beneficial) Offloading of large data volumes Ultra-lean transmissions, minimum amount of

overhead

* 3GPP, RWS-120003, Ericsson & ST-Ericsson, “Views on Rel-12,” June 2012.

Heterogeneous Networks:Current works Hyper-dense LTE network* (Qualcomm) Capacity is increased with a dense deployment of

self-backhauled small cells (“3rd layer of small cell”)

146* 3GPP, RWS-120007, Qualcomm, “3GPP RAN Rel-12 & Beyond,” June 2012.

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Heterogeneous Networks: Current works Handover between macro cell

and femto cell HeNB compared to eNB Small coverage Low tx power Random deployment by users Indoor deployment

147

eNBeNB• Symmetric signal power• Lower interference• Same tx power of neighbor eNBs

eNBHeNB• Asymmetric signal power• Higher interference from eNB to HeNB• Large PL due to wall-loss• Higher interference -> worse HeNB RSRQ

• Require different event for HO decision Relative value Absolute value

Heterogeneous Networks: Current works Femto cell Handover Inbound handover Femto-to-femto handover Outbound handover

148

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Mea

sure

d v

alue

Femto cell Inbound HO (아주대)

Femto cell inbound handover: Macro -> Femto cell HO triggering condition Signal power level: macro eNB >> femto HeNB UE satisfies A4 condition during TTT

-> HO request to S-eNB -> HO execution

149• Satisfaction A4 event

• H/O completion

• HO execution

TTTHO delay

thresholdhyst

Femto cell Inbound HO: SI Measurement (아주대) System Information Essential parameters by which the network can control the cell

selection process

In the macro HO procedure, the UE gets the SI of target cell from serving eNB

But, in the inbound HO from macro cell to CSG cell S-GW don’t manage the cell information of femto cells

UE have to measure SI of target cells

150 C.-H. Lee and J.-H. Kim, “System Information Acquisition Schemes for Fast Scanning of Femtocells in 3GPP LTE Networks,” IEEE Communications Letters, vol. 17, no. 1, pp. 131–134, Jan. 2013.

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Femto cell Inbound HO: SI Measurement (아주대)

Serial methodsUE measures MIB & SIB1

packets cell-by-cellScheduled/Autonomous

Parallel methodUE measures all MIB

packetsUE measures SIB1 packets

in order of the expected arrival time.Autonomous

151 C.-H. Lee and J.-H. Kim, “System Information Acquisition Schemes for Fast Scanning of Femtocells in 3GPP LTE Networks,” IEEE Communications Letters, vol. 17, no. 1, pp. 131–134, Jan. 2013.

Femto cell Inbound HO: SI Measurement (아주대) Simulation environment OPNET

152

• Assumption– UE find 6 femtocells

during every neighbor search

• Simulation parameters

C.-H. Lee and J.-H. Kim, “System Information Acquisition Schemes for Fast Scanning of Femtocells in 3GPP LTE Networks,” IEEE Communications Letters, vol. 17, no. 1, pp. 131–134, Jan. 2013.

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Femto cell Inbound HO: SI Measurement (아주대)

153

Measurement Delay Scheduled > Autonomous methods Serial > Parallel methods

However, autonomous methods have possibility of packet drop, because the serving cell cannot know whether the UE is disconnected or not

Nu

mb

er

of

com

pa

nies

Heterogeneous Network: Market Status

154* Informa Telecoms & Media, “Small cell Market Status,” 2013. 2.

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155

Selection of pricing models for femtocell services

Femtocell deployment segmentation according to target group

MarketPricing model

Deployment examples

Consumer

Add-ons for unlimited

calling

MOLD TELECOM, Sprint, YES OPTUS

FreeSoftbank, Vodafone(Greece), SFR

Low upfront fee

Vodafone(UK, Italy, Hungary), Verizon

Monthly feeSprint, Movistar, NTT DoCoMo

EnterpriseHigh upfront

feeAll operators

Target Group

Number of deployme

ntsExamples

Consumer 26Vodafone UK, AT&T,

Cosmote

Enterprise 6T-Mobile UK, Network

Norway, Orange France

Consumer &

Enterprise8

Vodafone NZ, Verizon Wireless, Sprint

Public 5Vodafone Qatar, SK

Telecom, TOT Thailand

Rural 1Softbank (using

satellite backhaul)

* Informa Telecoms & Media, “Small cell Market Status,” 2013. 2.


156

Company Country Offering Example Pricing CapabilitiesLaunch

date

Sprint US

Consumer and Enterprise: Airave

US$4.99 per month (US$10 for unlimited calling, US$20 for family plans)

Up to 6 users 2007 .9

Verizon USConsumer and Enterprise: Network Extender

US$249.99 Up to 3 users 2009.1

Vodafone UKConsumer: SureSignal(UMTS/HSPA)

Various options£50 upfrontFreefor >£45 contracts

Up to 4 users 2009. 72010. 1

at&t USConsumer: 3G MicroCell US$159 Up to 4 3G

users2009.9

SFR FranceConsumer: Home3G(UMTS/HSPA)

€199 upfront Up to 4 3G users

2009.11

NTT Docomo

JapanConsumer: MyArea(UMTS/HSPA)

US$10 per month Up to 4 3G users

2009.11


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157

Company Country Offering Example Pricing CapabilitiesLaunch

date

Softbank JapanConsumer: Femtocellservice(WCDMA)

Free of chargeUp to 4 3G users

2010. 6

KDDI JapanConsumer: au Femtocell(CDMA2000 1xEV-DO)

Free of charge (in coveragedeadspots)

Up to 4 3G users

2010. 6

SKtelecomSouth Korea

Public: Femtocells fordata offload

Deployed in public areas

Up to 4 3G users

2010.12

Vodafone ItalyConsumer and Enteprise:Booster PrivatiBooster

Consumer: €240Enterprise: €780

Consumer/Enterprise: Up to 4/8 users

2011. 5

Orange FranceEnterprise: Couverture SiteConfort

Upfront fee: €1,400Monthly fee:€70Multi-FAP plans available

Up to 4 users 2011. 5


Heterogeneous Network: Commercial Products in Korea Service providers deploy small cells

SKT 2010.12: 3G femto cell 2011. 5: 3G femto cell + WiFi AP 2012. 5: LTE femto cell + WiFi AP

Power over Ethernet 2013. 4: Femto Remote Solution

Reduce Femto cell interference

KT 3G femto cell

VDSL No HO supported

2012. 6: LTE femto cell 100Mbps optical fiber

2013. 6: Home Femto cell LGU+ 2013.7: LTE femto cell

Use different carrier frequency with macro cell

158

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LTE-Advanced FeaturesHeterogeneous NetworksCarrier AggregationOffloading

159

Carrier Aggregation Overview

What is the Carrier Aggregation (CA)? Two or more component carriers (CCs) are aggregated UE may simultaneously receive or transmit one ore multiple CCs

corresponding to multiple serving cells

Motivation BW aggregation is required for IMT-Advanced Peak data rate: 1 Gbps in the downlink, 500 Mbps in the uplink BW requirement set by ITU-R: up to 100 MHz

160

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Carrier Aggregation Modes

Contiguous carrier aggregation Possibly only one FFT module

and one radio frontend Similar propagation

characteristics

Non-contiguous carrier aggregation Aggregation of fragmented

spectrum Intra- or single-band Inter- or multi-band

161

FFT: Fast Fourier transform

Band A CC1 CC2 CC3<Contiguous Carrier Aggregation>

Carrier Aggregation

Band A CC1 CC2<Non-contiguous Carrier Aggregation (Intra)>

Carrier Aggregation

Band A CC1 CC2

<Non-contiguous Carrier Aggregation (Inter)>

Carrier Aggregation

Band B

f

f

f

Carrier Aggregation in LTE

Carrier aggregation in previous 3GPP 3GPP2 1xEV-DO Rev. B (multiple 1.25 MHz carriers) 3GPP HSPA (up to 4 DL / 2UL carriers, of 5 MHz each) Contiguous, same band, same BW

Carrier aggregation in LTE Contiguous and non-contiguous Various carrier BW (1.4, 3, 5, 10, 15, 20 MHz) Various frequency band (SKT: 800MHz, 1.8GHz, KT: 900MHz,

1.8MHz, LG U+: 800MHz, 2.1GHz)

Control channel design for UL/DL Backward compatibility Reuse of Rel. 8/9 RF designs and implementation at the eNB and

UE

162

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Serving Cells in CA

Primary serving cell (PCell) The RRC connection is handled by the PCell,

Secondary serving cell (SCell) SCell information is obtained via dedicated signaling on PCell SCells provide additional radio resources

163J.Wannstrom, “ Carrier Aggregation explained”, http://www.3gpp.org/Carrier-Aggregation-explained , May, 2012

Primary Serving Cell(PSC),Primary Component Carrier (PCC),RRC connection and data

Secondary Serving Cell(SSC),Secondary Component Carrier (SCC),User data only

Protocol Architecture for CA (1/3)

Rel. 10 UE can be configured with multiple serving cellsWhen in RRC_CONNECTED state Each serving cell corresponds to a different DL CC

164

HARQ HARQ

DL-SCHon CC1

...

Segm.ARQ etc

Multiplexing UE1 Multiplexing UEn

BCCH PCCH

Unicast Scheduling / Priority Handling

Logical Channels

MAC

Radio Bearers

Security Security...

CCCH

MCCH

Multiplexing

MTCH

MBMS Scheduling

PCHBCH MCH

RLC

PDCP

ROHC ROHC...

Segm.ARQ etc

...

Transport Channels

Segm.ARQ etc

Security Security...

ROHC ROHC...

Segm.ARQ etc

...Segm. Segm.

...

...

...

DL-SCHon CCx

HARQ HARQ

DL-SCHon CC1

...

DL-SCHon CCy

* 3GPP TS 36.300 V11.2.0 “E-UTRA and E-UTRAN; Overall description”, June, 2012

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Control plane UE only has one RRC connection with the network UE (re-)establishes RRC connection on a single cell RRC signaling is used to add, remove, or reconfigure additional

serving cells

UE is assigned a single C-RNTI (Cell Radio Network Temporary Identifier) Uniquely identify the RRC connection of the UE For scheduling purposes on the PDCCH transmitted on any of the

activated DL CCs

MAC is used for dynamic management of serving cells to be used among the configured set of serving cells

165


Data plane CA is only exposed to the MAC sublayerMAC performs unicast scheduling and priority handling across

all active serving cells of a UE in a way that is transparent to upper layers Each transport block and its potential HARQ retransmission are

mapped to a single serving cell Independent HARQ process for each DL or UL CC

166

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CA scheduling

Normal scheduling Scheduling grant and resource on same carrier

Cross-carrier scheduling Scheduling grant and resource NOT on the same carrier Schedule resources on SCC without PDCCH The CIF (Carrier Indicator Field) on PDCCH (represented by the red

area) indicates on which carrier the scheduled resource is located.

167

PCC SCC PCC SCC PCC SCC PCC SCC

Status of Commercial Services for CA (1/6)

Bandwidth allocation for KT, SKT, LGU

168

Uplink Downlink

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Hot Issues about Bandwidth allocation

169

Frequency

SKT-LTE

-20Mhz

800MHz~

LGU-LTE

-20Mhz

KT-LTE

-20Mhz

1.8GHz~

SKT-LTE

-20Mhz

LGU-CDMA-20Mhz

Primary Primary Secondary

경매-LTE

-15Mhz

KT-WCDMA -40Mhz

SKT-WCDMA -60Mhz

LGU-LTE

-20Mhz

2.1GHz~ Frequency

Secondary

경매-LTE

-35Mhz

경매-LTE

-40Mhz

경매-LTE

-40Mhz

2.6GHz~ Frequency


Commercial services for Multi-carrier(MC) and CA *Multi-carrier technology Select one of frequency bands to optimize the load balancing

when LTE data traffic increases

SKT LTE-A network deployment for 850Mhz & 1.8GHz frequency band

• Deployment completion in 84 major cities, Korea (2013. 07)• Starting MC service (2012.07)• Starting CA service (2013.06)

LG U+ LTE-A network deployment for 800Mhz & 2.1GHz frequency bands

• Deployment completion in Seoul and major cities, Korea (3Q of 2013)• Deployment completion in rest cities, Korea (4Q of 2013)• Starting MC service (2013.05)• Starting CA service (2013.07)

170 SKT hompage, “SK텔레콤, 30일 84개시중심가로 ‘LTE-A’ 확대”, http://www.sktelecom.com, July, 2013. LGU+ homepage, “LG유플러스, 세계최초 ‘100% LTE’ 상용화”, www.uplus.co.kr, July, 2013.

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SKT: “아무나 가질 수 없는 속도 LTE-A” 세계최초 Carrier Aggregation 상용화 서비스한시적 (7월) 데이터 2배 제공

171


LGU+: “100% LTE 가 아니면 요금을 안받겠습니다.”세계최초 100%LTE 상용화 (Voice 와 data를 동시서비스)WCDMA(3G)망 없음

172

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173

KT: “난 데이터가 2배 라구요!”Multi carrier/Carrier Aggregation 서비스 안함한시적으로 데이터량 2배 제공 (2013. 7~10월)

LTE-Advanced FeaturesHeterogeneous NetworksCarrier AggregationCoMP

174

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CoMP

CoMP (Coordinated MultiPoint transmission and reception) The coordination of transmissions from multiple cells (especially

at the cell edge Basic CoMP schemes can be realized in Release 8 between the

cells controlled by a given eNodeB The evolution of LTE-Advanced for Release 11 or beyond

175* 윤영우, “LTE-Advanced 표준기술 (REL-10 동향및 REL-11 전망)”, 한국통신학회지(정보와통신), 2011.5* S.Seia, I. Toufik, M. Baker, “LTE The UMTS Long Term Evolution –From Theory to Practice, Second Edition”.

CoMP

CoMP schemes Coordinated scheduling / beamforming Share the channel and scheduling information between the coordin

ated cells to reduce interference in a UE Scheduling UE / beamforming

Coherent joint transmission Multipoint transmission to single UE

Dynamic switching (Fast cell selection) Dynamically handover to the selected cell

176* S.Seia, I. Toufik, M. Baker, “LTE The UMTS Long Term Evolution –From Theory to Practice, Second Edition”.* NTT DOCOMO, ‘R1-090314: Investigation on Coordinated Multipoint Transmission Schemes in LTE-Advanced Downlink’, www.3gpp.org, 3GPP TSG RAN WG1, meeting 55bis, Ljubljana, Slovenia, January 2009.

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CoMP

CoMP schemes

177

* S.Seia, I. Toufik, M. Baker, “LTE The UMTS Long Term Evolution –From Theory to Practice, Second Edition”.* NTT DOCOMO, ‘R1-090314: Investigation on Coordinated Multipoint Transmission Schemes in LTE-Advanced Downlink’, www.3gpp.org, 3GPP TSG RAN WG1, meeting 55bis, Ljubljana, Slovenia, January 2009.

Fast cell selection (FCS)

Coherent

<Coordinated scheduling> <Coordinated beamforming>

<Coherent joint transmission> < Dynamic switching>

CoMP Related Example : BS Cooperation BS cooperation 성능 분석 BS cooperation 네트워크 관점의 성능 평가

시뮬레이터 구현 사항

178*J. S. Kim, K. C. Go, S. K. Oh and J. H. Kim, "Performance Evaluation of BS Cooperative Communication in Networks-Wise," in Proc. ICUIMC 2013, Kota Kinabalu, Malaysia, Jan. 17 - Jan. 19, 2013.

기지국 구성 1 서빙기지국, 2 협력기지국, 16 dummy 기지국

기지국 당 단말 수 10개 단말

기지국 반경 1 Km

채널 모델

Pathloss model 130.19+37.6log10(R) (R in km)

Shadowing Model Log-normal dist(mean: 0, variation: 8 dB)

Thermal Noise Density

-174dBm/Hz

신호 결합 및 측정 Soft combining ,

Bandwidth 10Mhz (1024 FFT)

Frame 5 msec (TDD)

MCS level QPSK ½, 16QAM ½, 64QAM½

Cell load 90%

Triggering 셀내 위치기반 동작 / SINR 신호기반 동작

자원할당 방법 협력기지국간 동일 Band 할당

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CoMP Related Example : BS CooperationMessages for BS cooperation BS cooperation 동작을 위한 MAC 메시지 플로우 설계 IEEE 802.16e system 기반 유/무선 Control message 설계

179

Message overhead (무선) Cooperative Service

Request (208 bits)• Cooperative Service

request info• CQI info• Location infoCooperative Service

Response (381 bits)• Cooperative service

response info• Resource allocation info• Synch info

CoMP Related Example : BS Cooperation셀 경계 사용자 비율에 따른 성능*

BS cooperation 사용에 따른 셀 경계 사용자의 Throughput 향상 BS cooperation 사용자 증가 시 자원 overhead증가로 전체 셀

Throughput 감소

180

<Average cell-edge throughput> <Total network throughput>

NO-CO: No coopration, CO-DM: Dynamic point Muting cooperation, CO-JT: Joint Transmission Cooperation

*J. S. Kim, K. C. Go, S. K. Oh and J. H. Kim, "Performance Evaluation of BS Cooperative Communication in Networks-Wise," in Proc. ICUIMC 2013, Kota Kinabalu, Malaysia, Jan. 17 - Jan. 19, 2013.

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Release 12 IssuesOffloadingWLAN Network SelectionDevice-to-Device CommunicationsMachine Type Communication (MTC)

181

3GPP Traffic Offloading

182

Rel-8 Rel-9 Rel-10 Rel-11 Rel-12

Femto • H(e)NB• LIPA (local IP access)• SIPTO (selected IP traffic offload)

• LIMONET (LIPA Mobility and SIPTO at the localnetwork)

Wi-Fi• Seamless Handover

• MAPCON (multi access PDN connectivity)

• IFOM (IP flow mobility) • NSWO (non-seamless WLAN offload)

• SMOG (S2a mobility based on GTP)

• SaMOG (S2a mobility based on GTP and WLAN access)

• LOBSTER (location-based selection of gateway for WLAN)

• WLAN_NS(WLAN network selection for 3GPP terminals)

• FS_SAMOG• FS_NBIFOM(network-based IP flow mobility)

• FS_WORM(optimized offloading to WLAN in 3GPP RAT mobility)

Policyaspects

• ANDSF (access network discoveryand selection)

• ANDSF–ISRP (inter-system routing policy)

• DIDA (data identification in ANDFS)

• BBAI (broadband forum access interworking)

• OPIIS (operator policies for IP interface selection)

• P4C (PCC control for supporting fixed broadband access networks)

• 김현숙, “3GPP Traffic Offload”, FMC 포럼컨버젼스기술및표준워크샵, 2012. 12. 12.

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Benefits of Traffic Offloading

Mobile Operators Devices can connect directly to servers without going through

core networksMobile Operators can offer CDN(contents delivery network)

services

End-users RTTs can be expected to reduce and consequently throughput

increases from the end-users’ viewpoint

Service Provider Reduced RTTs and increased throughput can be expected by

using storage in backhaul networks and providers can offer “fact access” to end-users as premium services to obtain extra revenues from the service providers’ view point Service providers can offer very rich and geographical oriented

services by using storage in eNBs

183• NEC corporation, “Mobile Traffic Offload: NEC’s Cloud Centric Approach to Future Mobile Networks,” 2013. 04.

Data Offloading

Different data offloading techniques Path 1: WLAN solutions allow data offload directly to the

Internet without utilizing service provider’s resources

184• Konstantinos Samdanis, Tarik Taleb, Stefan Schmid, “Traffic Offload Enhancements for eUTRAN,” IEEE COMMUNICATIONS SURVEYS & TUTORIAL, 2012.

Path 2 : Femtocells or H(e)NBs permit data offload via a Local Gateway(L-GW)

Path 3 : maintaining home/enterprise related traffic local, via LIPA

Path 4 : Data offload may be positioned at or above particular eNBs for eUTRAN

Path 5 : Radio Network Controller (RNC) for UTRAN

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LIPA & SIPTO

Key issues Legal interception QoS Single/multiple PDN support Deployed behind NAT Operator control for SIPTO

185• 3GPP TR 23.829 V10.0.1, “3GPP technical specification group services and system aspects; local IP access and selected IP traffic offload (Release 10),” 2011. 10.

Backhaul

Residential / Enterprise network

H(e)NB H(e)NB

-GW

Mobile Operator Core Network

UE

LIPA L-GW

LIPA & SIPTO

Solution 1 – variant 1

Local PDN GW (L-GW) function is collocated with the HeNB Paging of Idle mode UEs is triggered by sending the first

downlink user packet or a “dummy” packet on S5 All other downlink user packets are buffered in the L-GW


UUEE

HHeeNNBB

LL--GGWW

MMMMEE

SSGGWW

SS55SS11--UU

EEPPCC

IIPP bbaacckkhhaauullHHoommee nneettwwoorrkk

PPGGWW SS55

SS1111

HHoommee rroouutteerr// NNAATT

SSeeGGWW

SS11--mmmmee

SeGW: security gateway, SGW: serving gateway, PGW: PDN gateway, MME: mobility management entity

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LIPA & SIPTO


L-GW can be either collocated with the HeNB or as a standalone node

L-S11 interface between the L-GW and the MME is used to manage the session for LIPA traffic

L-GW needs to be selected close to the HeNB Open issues Whether Mobility is supported/required for LIPA Whether the standalone L-GW architecture is supported for LIPA, and

if it is, how187• 3GPP TR 23.829 V10.0.1, “3GPP technical specification group services and system aspects; local IP access and

selected IP traffic offload (Release 10),” 2011. 10.

CNRAN

UE

LIPA Traffic

P-GW

CN Traffic

S1-U

S11

L-S11

S5 S-GW

MME

S1-MMEL-GW

HeNB

LIPA & SIPTO


UEs are only required to activate one PDN connection for LIPA The OPM has the ability to drag/insert the LIPA traffic from/into

PDN connection per operator policies (dst addr, Port #, etc.)


Home/Enterprise Network

UE

HeNB

IP Backhaul

GW / NAT

EPC

SeGW

MME

SGW S5 PGWS1-u

S1’-c S11

Internet

Offload Processing Module (OPM)

OPM

NAT Function BlockRouting Function Block

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LIPA & SIPTO

Solution 3 GGSN allocation to offload point LIPA and SIPTO are enabled by the SGSN selecting a GGSN that

provides enhanced (e.g. shorter) traffic routeing capabilities located within the RAN The RAN providing the SGSN with the IP address(es) of one or more

GGSNs that the RAN believes offers good traffic routeing capabilities The SGSN using the information from the RAN and HSS to

potentially override the normal GGSN selection algorithm The SGSN using the permitted CSG/APN information and

information supplied by the RAN to cause the release of a PDP context, if required by the service continuity restrictions, when the mobile leaves the CSG


LIPA & SIPTO

Solution 4 Selected IP Traffic Offload at Iu-PS

The traffic is offloaded after the RNC and before the SGSN in the Traffic Offload Function(TOF)

Using Deep Packet Inspection(DPI) in the TOF a great level of granularity can be achieved

TOF can be a separate entity, or collocated with RNC/HNB GW


UE

Uu Iub

RNC TOF SGSN

Iu Iu

NB GGSN

Gn

VAS

Internet

Gi

HNB GW

Iu

HNB

Iuh

UE

Uu

Gi

CG LIG

Ga

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LIPA & SIPTO

Solution 5

Selected IP Traffic Offload solution based on local PDN GW selection

The L-PGW is not co-located with the H(e)NB but is close by in the network

The GW selection mechanism in the MME/SGSN takes into account the location of the user for the PDN connection/PDP context activation, and selects a GW that is geographically/topologically close


S5

RAN

UE

eNB

CN

P-GW S-GW

CN Traffic

MME

S1-U

S11S5

L-PGW

SIPTO Traffic

LIPA & SIPTO

Solution 6

L-GW is collocated with HeNB “L-GW extension tunnel” between the L-GW and the PDN GW


(H ome ) NB

SGi

S12

S3 S1 - MME

PCRF Gx

S6a

HSS

Operator's IP Services

Rx

S10

UE

SGSN

LTE - Uu

MME

S11

S5 Serving Gateway

PDN Gateway

S1-U

S4

GERAN/ UTRAN

(H ome ) eNB

L- GW

… added functionality

Local Network or

Internet SGi

Gi

GGSN GERAN/UTRAN

SGSN

UE Uu

… added interface

Gn Iu

L- GW

ExtensionTunnels

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LIPA & SIPTO

Conclusion on the LIPA architecture Solution 1 – variant 1 is selected as the basis for LIPA to be

included in normative specifications Supporting both a collocated and stand-alone L-GW as well as

mobility (w/o mobility for Rel-10)

Impacts to L-GW configurations LIPA_enabled flag (per APN and per CSG) in the user's

subscription data stored in the HSS/HLR and transferred to the MME/SGSN

(E-)RAB setup messages: addition of new correlation identifier (user plane L-GW TEID)

Adding the transmission of the IP address of the L-GW in UE-associated signalling in the uplink, or, alternatively, DNS-based L-GW selection

Possible Multicast support in the L-GW



194

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3GPP/Non-3GPP access network selection

195

Access Network Selection for Offloading*

Procedure Get target system information by

ANDSF UE connects to target system Authentication of UE Receive QoS information through PCRF Access to same PGW, and do binding

update by PMIP

Features PMIP: Anchor point PGW UE: LTE/Non-3GPP dual radio terminal Get address of PGW by saving address

information to HSS

• PMIP: Proxy Mobile IP• PCRF: Policy and Charging Rules Function

* 3GPP TS 23.402 V12.1.0, “Architecture enhancements for non-3GPP accesses”, June 2013.

SGi

PCRF

Gx

HSS

SWn

Operator's IP Services (e.g. IMS, PSS, etc.)

SWm

SWx

UntrustedNon-3GPP IP

Access SWa

HPLMN

Non-3GPP Networks

S6b

Rx

PDN Gateway

Trusted Non-3GPP IP Access

STa

S2c S2c

ePDG3GPP AAA

Server

UE

Gxa

Gxb

Gxc

S5

S6a

S2c

3GPP Access

Serving Gateway

ANDSF*

196

Definition A framework for specifying and delivering access network selection policy to UE

Purpose To assist UE to discover non-3GPP access networks

Function Provide the information to UE

ISMP: Network selection rules for a UE with no more than one active access network connection

ISRP: Network selection rules for a UE with more than one active access network connection

Discovery information: a list of networks that may be available in the vicinity of the UE UE location: geographical coordinates, a cellular cell or area, a WLAN location (SSID,

BSSID) UE profile

• ANDSF: Access Network Discovery and Selection Function• ISMP: Inter-System Mobility Policy• ISRP: Inter-System Routing Policy

* 3GPP TS 24.312 V12.1.0, “Access Network Discovery and Selection Function (ANDSF) Management Object (MO)”, June 2013.

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Key issues related to WLAN network selection* Key issue 1 Support WLAN access through roaming agreements Current ANDSF support WLAN network selection policies based on

SSID only• Providing SSID preferences to UEs

197* 3GPP TS 23.865 V1.0.0, “WLAN network selection for 3GPP terminals”, June 2013.

Key issues related to WLANnetwork selection Solution for key issue 1 ANDSF policies with extended selection preferences Use Realms and/or OUIs instead of using SSID

• Realm/OUI identify and prioritize the discovered WLAN access networks» Ex) WLANs that interwork with Realm=PartnerX.com have the highest access priority

198

• OUI: Organizational Unique Identifier

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Key issues related to WLANnetwork selection Key issue 2 Interaction between WLAN network selection and network-

provided policies for WLAN selection ANDSF rules are evaluated only after WLAN network selection is

performed• WLAN network selection priority list in the UE• ANDSF rules cannot trigger the UE to select another WLAN access network

Solution for key issue 2WLAN selection based on ANDSF rules Use enhanced ISMP/ISRP rules

• SSID preferences• Additional preferences

» Realms (preferred service providers), OUIs, available backhaul bandwidth, connectivity capability, etc.

199

Key issues related to WLANnetwork selection Key issue 3 Delivery of consistent information for WLAN network selection Conflicting between the information from different sources or different

management objects• WFA Hotspot 2.0 specifications

» WFA Hotspot 2.0: Provide seamless handoff without additional authentication

• Relevant components» ANDSF management object and USIM in 3GPP

Key issue 4 Use WLAN load information for network selection ANDSF does not provide load information or congestion indication of

WLAN networks: BSS load and backhaul parameters The policies for WLAN network selection may be enhanced to take

these parameters into account

200

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Key issues related to WLANnetwork selection Key issue 5 Use WLAN access network type and venue information for

network selection Access network type: private, public, free, personal, emergency, etc. Venue information: venue type and name

• Help to identify the venue where WLAN network may be deployed (e.g. school, hotel, etc.)

Key issue 6 Use connection capability during WLAN network selection Connection capability

• To provide information on the connection status within the WLAN network

ANDSF does not take into account the connection capability of the WLAN networks• WLAN network may block the IP flows of the UE

201

Key issues related to WLANnetwork selection Solution for key issue 3, 4, 5, and 6 Provide both ANDSF MO(with ISMP, ISRP etc.) and HS2.0 MO to

the UE Example of HS2.0 MO: the load of the AP

ANDSF MO enhanced with policies related to information elements available in HS2.0 Example: ISRP and ISMP as extensions to the prioritized access

descriptions

202

• HS: Hotspot• MO: Management Object

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203

D2D Communications

What is D2D communication ? Refer to the technologies that enable devices to communicate

directly without an infrastructure of access points or base stations, and the involvement of wireless operators. Proximate discovery

• There is also a broad range of other potential applications that is contributing to industry enthusiasm and activity.

204

* 3GPP TR 22.803 V12.2.0, “Feasibility study for Proximity Services (ProSe) (Release 12),” 2013.06 * L. Lei, Z. Zhangdui, L. Chuang, and S. Xuemin, "Operator controlled device-to-device communications in LTE-advanced networks," IEEE Wireless Communications, vol. 19, pp. 96-104, 2012.

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D2D vs. MTC

205

D2D MTC

Device Type • Cell phones or other devices inhuman-to-human communications

• Machine-to-Machine communications without the involvement of human activities

CommunicationType

• Directly communication between devices

• Communication via infrastructureof LTE networks

Related Spec. • 3GPP TR 22.803 • 3GPP TS 22.368 • 3GPP TR 23.887

Application • Social matching• Push advertising• Multiplayer gaming• Local voice service• Contents sharing

• Metering• Remote Maintenance/Control• Health care• Tracking & Tracing• Security system

* 3GPP TR 22.803 V12.2.0, “Feasibility study for Proximity Services (ProSe) (Release 12),” 2013.06 * 3GPP TS 22.368 V12.2.0, “Service requirements for Machine-Type Communications (MTC);Stage 1(Release 12),” 2013. 03 * 3GPP TR 23.887 V1.0.0, “Machine-Type and other Mobile Data Applications Communications Enhancements (Release 12),” 2013. 06.

Use Case and Business Model

Local Voice Service D2D communications can be used to offload local voice traffic

when two geographically proximate users want to talk on the phone.

206* L. Lei, Z. Zhangdui, L. Chuang, and S. Xuemin, "Operator controlled device-to-device communications in LTE-advanced networks," IEEE Wireless Communications, vol. 19, pp. 96-104, 2012.

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Use case and business model

Local Data Service D2D Communications can be used to provide local data service

when two geographically proximate users or devices want to exchange data


Use case and business model

Data Relay D2D Communications can be used to relay data for devices

that are not “directly cellular”.


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Introduction of Proximity Service

209

Proximity Services (ProSe) Proximity services that identify mobiles in physical proximity and

enable optimized communications between them

ProSe Discovery A process that identifies that a UE is in proximity of another,

using E-UTRA Open ProSe Discovery

• is ProSe Discovery without explicit permission from the UE being discovered

Restricted ProSe Discovery• is ProSe Discovery that only takes place with explicit permission from the

UE being discovered.

3GPP TR 22.803 V12.2.0 “Feasibility study for Proximity Services(ProSe)”, June, 2013

E-UTRA: Evolved Universal Terrestrial Radio Access

Introduction of Proximity Service

210

ProSe Communication A communication between two UEs in proximity by means of a

E-UTRAN communication path established between the UEs. The communication path could for example be established directly between the UEs or routed via local end(s) ProSe Group Communication

• a one-to-many ProSe Communication, between two or more UEs in proximity, by means of a common communication path established between the UEs.

ProSe Broadcast Communication• a one-to-all ProSe Communication, between all authorized UEs in

proximity, by means of a common communication path established between the UEs.

3GPP TR 22.803 V12.2.0 “Feasibility study for Proximity Services(ProSe)”, June, 2013

E-UTRAN: Evolved Universal Terrestrial Radio Access Network

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ProSe Communication

211

Data paths for ProSe communication path ProSe E-UTRA Communication path could be established Directly path between the ProSe-enabled UEs using E-UTRA Locally routed path via local eNB(s)

ProSe-assisted WLAN direct communication path is established directly between the ProSe-enabled UEs using WLAN

Direct mode Locally-routedE-UTRA: Evolved Universal Terrestrial Radio Access

ProSe Communication

212

Control paths for ProSe communication path General Case The system can decide to perform ProSe Communication using

control information exchanged between the UE, eNB, EPC by the solid arrows

The UEs can in addition exchange control signalling via the ProSeCommunication path as shown by dashed arrow

UEs served by the same eNB UEs served by the different eNBs

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ProSe Communication

213

Disaster Case (Public Safety UE) The Public Safety UEs can rely on pre-configured radio resources to

establish and maintain the ProSe Communication Public safety Radio resource Management Function, which can

reside in a Public Safety UE, can manage the allocation of radio resources for Public Safety ProSe Communication as shown with the dashed arrows

UEs without network support

With pre-configured radio resources

With resource controller UE

General Use Case

214

Restricted ProSe Discovery use case This use case describes a basic scenario for ProSe Discovery that

can be used for any application A social networking application is used as an example

Relationship(explicit permission)

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General Use Case

215

Open ProSe Discovery use case This use case describes a case in which UEs discover other UEs

without permission by the discoverable UEs

General Use Case

216

Discovery use case with roaming subscribers This use case describes discovery between UEs in different

PLMNs under roaming condition

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Public Safety Use Case

217

ProSe discovery within network coverage This use case describes the scenario where a given UE discovers

one or more other UEs while in LTE coverage, with ProSeDiscovery always enabled

ProSe discovery out of network coverage This use case describes the scenario where a given UE discovers

one or more other UEs while out of E-UTRAN coverage, with ProSe Discovery always enabled

Within network coverage Out of network coverage


218

Can discover but not discoverable This use case describes the scenario where a given UE is able to

discover other UEs, but is not discoverable by other UEs

I don’t want to be discovered

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110


219

ProSe relay This use case describes the scenario where a given UE acts as a

communication relay for one or more UEs

Without relay With relay


220

ProSe group This use case describes the scenario where a user wants to

communicate the same information concurrently to two or more users using ProSe Group Communications

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221

ProSe broadcast This use case describes the scenario where a given UE initiates a

ProSe Broadcast Communication transmission to all UEs within transmission range

Reference model

222

Architecture reference model

Basic Concept1. UE obtains configuration for direct services from

Direct Services Provisioning Function (DPF) in a secure way

2. Direct Services Provisioning Function (DPF) exists in every PLMN

3. UE obtains configuration from Direct Services Provisioning Functions (DPFs) in PLMNs is authorised to perform direct discovery

S2-131505 “Solution for direct discovery and communication”, April, 2013

New reference pointsS141 : Reference point between UE and H-DPF or between UE and a DPF in a local PLMN where the UE is authorised by the H-DPF to perform direct services. It enables PLMN-specific direct services authorizationS142 : Reference point between DPF in local PLMN and H-DPF. It enables PLMN-specific direct services authorizationU2 : Reference point used for all the control and user plane information exchange needed in order to perform direct discovery between two UEs

2013-09-05

112

Reference model

223

Signaling flow for UE provisioning from DPF

Authorisation for direct discovery1. Is the UE allowed to

announce in this PLMN?2. Is the UE allowed to

“monitor” in this PLMN?

PLMN: Public Land Mobile NetworkMCC: Mobile Country CodeFQDN: Fully Qualified Domain Name

Reference model

224

Two roles for the UE in ProSe Discovery Announcing UE : The UE announces certain information that

could be used from UEs in proximity that have permission to discover

Monitoring UE : The UE that receives certain information that is interested in from other UEs in proximity

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Public Safety Network

What is Public Safety Network? Public safety networks provide communications for services like

police, fire and ambulance

Before: P25 and TETRA Poor interoperability of PTT(Push To Talk) Narrowband System Narrowband systems can’t handle real-time video, detailed maps

and blueprints, high-resolution, photographs and other files.

LTE system can provide greater interoperability and the broadband capabilities to the public safety network

225

P25: Project 25TETRA: TErrestrial Trunked Radio*T. Doumi, M. F. Dolan, S. Tatesh, A. Casati, G. Tsirtsis, K. Anchan, and D. Flore, "LTE for public safety networks," IEEE Communications Magazine, vol. 51, pp. 106-112, 2013.

Why LTE ?

Greater interoperability and enhanced interagency cooperation: Sophisticated priority access mechanisms authorize and prioritize

communication, so mission-critical data gets top priority.

Standardized protocols and interfaces: Roaming capabilities are built in.

Unprecedented broadband capabilities: LTE provides high capacity, allowing a wide variety of applications

that have rich, multimedia content. It provides low latency, enabling real-time services (VoIP, video).

Cost effective: LTE’s simplified architecture lowers operating costs. It leverages a rich, open ecosystem from commercial networks.

Highly reliable and secure: LTE offers advanced quality of service. It supports encryption/ciphering to enable secure communications.

226*Government Technology white paper, "A How-To Guide for LTE in Public Safety," 2010.

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Network Model

227*Government Technology white paper, "A How-To Guide for LTE in Public Safety," 2010.

Feature & Requirements of Public Safety Networks Feature Requirements

Group call • A group call involves the communication of speech to all members of the group

• Data messaging can also be sent in parallel to speech

QoS • A segment of emergency group call speech will need higher priority to guarantee that it is not delayed by regular daily activities.

Robustness • It demands that alternative paths be available in the event of congestion and resource outages

Direct Mode • When part of a public safety network fails, the remainder of the network must continue to provide services to the greatest extent possible

• Direct mode is the ability of two or more public safety devices to communicate directly without the use of network infrastructure

228*T. Doumi, M. F. Dolan, S. Tatesh, A. Casati, G. Tsirtsis, K. Anchan, and D. Flore, "LTE for public safety networks," IEEE Communications Magazine, vol. 51, pp. 106-112, 2013.

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LTE Enhancement for Public Safety

Direct Communication over LTE ProSe (Proximity Services) Device-to-device discovery and communication

DTD (Device-to-Device) Communication One-to-one, one-to-many/unicast, one-to-many/broadcast, and

one-hop relay functionalities

Group Communication over LTE GCSE (Group Communication System Enablers) Low-latency communication bearer setup Priority access for group calls QoS for group call bearers

eMBMS (enhanced Multimedia Broadcast Multicast Service) Broadcast capability Interface between PTT service application and BM-SC

229

PTT: Push-To-TalkBM-SC: Broadcast multicast service center

* 3GPP TR 22.803 V12.2.0, “Feasibility study for Proximity Services (ProSe) (Release 12),” 2013.06 * 3GPP TR 23.768 V0.2.0, “Study on architecture enhancements to support Group Communication System Enablers for LTE (GCSE_LTE) (Release 12) ,” 2013. 06 .

Public Safety Spectrum

230**T. Doumi, M. F. Dolan, S. Tatesh, A. Casati, G. Tsirtsis, K. Anchan, and D. Flore, "LTE for public safety networks," IEEE Communications Magazine, vol. 51, pp. 106-112, 2013.

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231

Machine Type Communication(MTC)

Machine Type Communication(MTC) Data communication with two or more objects Does not require human’s participation during communication Provide network connection to most/all ‘things’

Similar system : Wireless Sensor Network WPAN/WLAN/Ad-hoc based network Hard to provide QoS Mobility, end-to-end communication, compatibility problem

It is not business area of network operators Install/maintenance by users hard to invest/maintain the system

MTC makes new business area to network operators

232• 조수현, “KT Vision : M2M Services and Technologies”, KRNET 2011, 2011년 6월 27일.

• 최상호, “SKT Vision : M2M Based Mobile Service”, KRNET 2011, 2011년 6월 27일.

• 3GPP TS 22.368 v12.2.0, “Service Requirements for Machine-Type Communications(MTC)(Release 12),” 2013. 03.

2013-09-05

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MTC Applications

233

Service Area MTC Applications

Security Surveillance systems, Backup for landline, Control of physical access(e.g. to buildings), Car/driver security

Tracking & Tracing Fleet management, Order management, Pay as you drive, Asset tracking, Navigation, Traffic information, Road tolling, Road traffic optimization/steering

Payment Point of sales, Vending machines, Gaming machines

Health Monitoring vital signs, Supporting the aged or handicapped, Web access telemedicine points, Remote diagnostics

Remote Maintenance/Control Sensors, Lighting, Pumps, Valves, Elevator controlVending machine control, Vehicle diagnostics

Metering Power, Gas, Water, Heating, Grid control, Industrial metering

Consumer Devices Digital photo frame, Digital camera, eBook


Features/Requirements of MTC

234

Requirement Description

Low Mobility The network must provide simplified mobility management

Time Controlled The network shall provide mechanisms than can send or receive data only during defined time intervals

Small Data Transmissions The network shall support transmissions of small amounts of data with minimal network impact

Infrequent Mobile Terminated The network shall be able to maintain information on when the MTC Device is not reachable

MTC Monitoring The network shall provide mechanisms to detect several MTC related events

Secure Connection The network shall provide network security for connection

Group Based MTC Features The system shall be optimized to handle MTC Groups

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Communication Scenarios

235

MTC Devices communicatingwith one or more MTC Server

MTC Devices communicatingwith each other


Comparison between Machine-to-Machine(M2M) Communication and MTC

236

Other M2M : Can use M2M Networkand gateway

Path to Access Networks Can be any standardized network system by 3GPP, TISAPN, IETF, etc

3GPP : No M2M Networks Devices directly attached to 3GPP Access Networks

•PDN:Packet Data Network•SM-SC:Short Message Service Centre•PGW:PDN Gateway

•HSS:Home Subscriber Server •HPLMN:Home Public Land Mobile Network•VPLMN:Visited Public Land Mobile Network

•eNB:eNodeB•RNC:Radio Network Controller•BSC:Base Station Controller

•TISAPN:Telecommunicationsand Internet converged Services and Protocols

• 유상근, 홍용근, 김형준, “스마트모바일서비스 – M2M 기술및표준동향”, 전자통신동향분석제 26권제 2호, 2011년 4월.

ETSI M2M Architecture 3GPP MTC Architecture

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MTC in Release 10~11

Key Issue Description

MTC subscriptions Activation/deactivation of MTC features

Signaling congestion control MTC related signaling congestion and overload.

IP addressingMTC device using a private non-routable IPv4 addressand thus not reachable by the MTC server.

MTC device trigger MTC server polls data from MTC devices

MTC identifiersAddressing issue due to the huge amount of MTCdevices and shortage of MSISDNs

Group based optimizationGrouping of MTC devices for ease of control, management, charging facilities, etc., by the operators, and help in reducing redundant signaling.

Online small data transmissionMTC devices frequently send or receive only smallamounts of data.

Offline small data transmissionMTC devices infrequently send or receive only smallamounts of data.

MTC monitoring Monitoring of MTC devices in locations with high risk.

Low Power Consumption Battery power saving for MTC devices.MTC devices communicating

with one or more MTC serversCommon service requirements for communicationbetween MTC devices and MTC servers.

Low mobility MTC device does not move frequently.

Time controlledData transmission is only performed in a predefined time period.

Decoupling MTC server from 3GPP architecture

MTC server may be deployed outside of the mobilenetwork.

Potential overload issues caused by roaming MTC devices

Imbalance of signaling vs. data traffic in the Visited Public Land Mobile Network (VPLMN).

237• 3GPP TS 22.368 v12.2.0, “Service Requirements for Machine-Type Communications(MTC)(Release 12),” 2013. 03.• Andreas Kunz, “Machine Type Communications in 3GPP From Release 10 to Release 12”, GLOBECOM 2012 ONIT WS, Dec.

2012

Rel-10 15 key issues were

identified Signaling congestion

control and overload control

Rel-11 IP addressingMTC identifiers Device triggering

Signalling Congestion and Overload Control

238

Low access priority

Attach withIMSI at PLMN

change

Periodic PLMN search

time limit

Handling of the invalid USIM state

UE message can be rejected,

usage of waiting/back-off

timers

UE does not perform TAU with GUTI at

PLMN change

Minimum timebetween

searches for preferred

PLMNis increased

PLMN forbidden lists are kept even

if UE is switched off

and on

• IMSI(International Mobile Subscriber Identity) : 가입자 ID(전화번호)• PLMN(Public Land Mobile Network) : 네트워크식별번호• TAU(Tracking Area Update)• GUTI(Globally Unique Temporary Identifier) : 사용자의임시 ID

Numerous devices make congestion even though they transmit small data

Solution

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MTC Device Identifiers/Addressing

Objective Assign ID and address to MTC devices to enable a MTC server in a public addressing domain to send

messages to a MTC device in a private addressing domain

Solution Identifier 15-digit IMSI telephone number for large-scale deployment

Addressing IPv6 addressing IPv4 addressing with private IPv4 domain

239

IPv4 Address SpacePrivate IPv4 Address Space

MTCDevice MNO

MTCServer

• MNO : Mobile Network Operator

MTC in Release 12

Rel-12 Triggering

enhancements Group based features Small data

transmissionMonitoring UE power

consumptions optimizations

240

Key Issue Description

MTC subscriptions Activation/deactivation of MTC features

Signaling congestion control MTC related signaling congestion and overload.

IP addressingMTC device using a private non-routable IPv4 addressand thus not reachable by the MTC server.

MTC device trigger MTC server polls data from MTC devices

MTC identifiersAddressing issue due to the huge amount of MTCdevices and shortage of MSISDNs

Group based optimizationGrouping of MTC devices for ease of control, management, charging facilities, etc., by the operators, and help in reducing redundant signaling.

Online small data transmissionMTC devices frequently send or receive only smallamounts of data.

Offline small data transmissionMTC devices infrequently send or receive only smallamounts of data.

MTC monitoring Monitoring of MTC devices in locations with high risk.

Low Power Consumption Battery power saving for MTC devices.MTC devices communicating wit

h one or more MTC serversCommon service requirements for communicationbetween MTC devices and MTC servers.

Low mobility MTC device does not move frequently.

Time controlledData transmission is only performed in a predefined time period.

Decoupling MTC server from 3GPP architecture

MTC server may be deployed outside of the mobilenetwork.

Potential overload issues caused by roaming MTC devices

Imbalance of signalling vs. data traffic in the Visited Public Land Mobile Network (VPLMN).

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Outlook of MTC in 3GPP Release 12

Triggering enhancements intended for device triggering by using reference points between

MTC-IWF and serving nodes (i.e., SGSN, MME, and MSC), as well as triggering efficiency optimizations.

Group based features optimizations to a group of MTC UEs that share one or more MTC

features.

Small data transmission intended for use with MTC UEs that send or receive small amounts

of data. Also, frequent small data transmission will be considered.

Monitoring intended for monitoring MTC UE related events such as loss of

connectivity, change of the location of MTC UE, etc.

UE power consumptions optimizations intended for optimizations to prevent battery drain of MTC UEs.

241• MTC-IWF : Interworking function between (external) MTC Server and operator core network

Summary

242

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Summary

3GPP LTE Network Architecture

User Plane Protocol• Packet Data Convergence Protocol / Radio Link Control / Medium Access Control

Control Plane Protocol• Radio Resource Control / Mobility control / Radio Resource Management

LTE-Advanced Features• Heterogeneous Networks / Carrier Aggregation / CoMP

Release 12 Issues• Offloading / WLAN Network Selection / Device-to-Device Communications /

Machine Type Communication

243

Thank you !

Q & A244

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References 3GPP TS 36.300 V11.6.0 "E-UTRA and E-UTRAN; Overall description", June, 2013 3GPP TS 23.203 v12.1.0, "Policy and charging control architecture," Jun. 2013. 3GPP TS 36.323 v11.2.0, "Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol

(PDCP) specification(Release 11) ", April, 2013 acticom mobile networks, http://www.acticom.de/en/ 3GLTEINFO, http://www.3glteinfo.com/lte-security-architecture-20110325/ A. Larmo et al., "The LTE link-layer design," Communications Magazine, IEEE , April 2009. 3GPP TS 36.321 V11.3.0, "Medium Access Control (MAC) protocol specification (Release 11)", Jun, 2013. 3GPP TS 24.301 V10.7.0, "UMTS; LTE; NAS; EPS; Stage 3", July, 2012 3GPP TS 24.401 V8.9.0, "LTE; GPRS enhancements for E-UTRAN access", March, 2010 3GPP TS 36.331 V10.5.0, "Radio Resource Control (RRC) Protocol specification (Release 10)," ed, 2012. Netmanias, "EMM and ECM States," http://www.netmanias.com, 2013. Bong Youl (Vrian) Cho, "LTE RRC/RRM", TTA LTE/MIMO Standards/Technology Training, May 2012 3GPP TS 36.213 v10.6.0 "LTE Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures

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