2013년이동및무선통신단기강좌 3gpp lte(-a): part ii mac &...
TRANSCRIPT
2013-09-05
1
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
2013-09-05
2
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
2013-09-05
3
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
6
2013-09-05
4
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
2013-09-05
5
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
10
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
2013-09-05
6
Core Network Elements
11
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
2013-09-05
7
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
2013-09-05
8
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
3GPP TS 36.300 V11.6.0 “E-UTRA and E-UTRAN; Overall description”, June, 2013
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.
16
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
3GPP TS 36.300 V11.6.0 “E-UTRA and E-UTRAN; Overall description”, June, 2013
2013-09-05
9
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)
5
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.
2013-09-05
10
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
2013-09-05
11
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
2013-09-05
12
Header Compression
Header Fields Classification
23
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
24
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
2013-09-05
13
Header Compression
ROHC compression with U,O,R operation mode
25
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/
2013-09-05
14
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)
27
Discard of Data Packets
To prevent excessive delay and queuing in the transmitter
28
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
2013-09-05
15
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
29
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
* 3GPP TS 36.323 v11.2.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification”(Release 11), April, 2013
PDCP PDU format
PDCP Data PDU
30
<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>
* 3GPP TS 36.323 v11.2.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification”(Release 11), April, 2013
2013-09-05
16
PDCP PDU format
PDCP Control PDU
31
* 3GPP TS 36.323 v11.2.0: “Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification”(Release 11), April, 2013
<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
User Plane ProtocolPacket Data Convergence ProtocolRadio Link ControlMedium Access Control
32
2013-09-05
17
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
34
< 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
2013-09-05
18
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 >
2013-09-05
19
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 >
2013-09-05
20
Data flow through L2 protocol stack
39A. Larmo et al., "The LTE link-layer design," Communications Magazine, IEEE , April 2009.
User Plane ProtocolPacket Data Convergence ProtocolRadio Link ControlMedium Access Control
40
2013-09-05
21
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
2013-09-05
22
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
2013-09-05
23
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
2013-09-05
24
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
2013-09-05
25
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
2013-09-05
26
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
2013-09-05
27
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
2013-09-05
28
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
2013-09-05
29
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
2013-09-05
30
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
• Additional Slides
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
• Additional Slides
2013-09-05
31
Scheduling Algorithms
Fair algorithmsMinimize UE latency Ex. Min-Max : Maximizes the minimum allocated rate
Total Throughput reduced
61
max min{ ( )}iit
• Additional Slides
Scheduling Algorithms
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
• Additional Slides
2013-09-05
32
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
Retransmission – HARQ
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
2013-09-05
33
Retransmission – HARQ
HARQ type HARQ combines FEC and ARQ Three types HARQ Type I HARQ
• Chase combining» Initial transmission and retransmission have same puncturing pattern
65
Retransmission – HARQ
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
2013-09-05
34
Retransmission – HARQ
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).
2013-09-05
35
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
2013-09-05
36
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)
2013-09-05
37
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.
2013-09-05
38
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.
2013-09-05
39
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
2013-09-05
40
NAS/RRC State
79
NAS/RRC State
80
When UE is attached to the network (MME) and not using any service
2013-09-05
41
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
2013-09-05
42
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
2013-09-05
43
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
2013-09-05
44
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
2013-09-05
45
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
2013-09-05
46
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
2013-09-05
47
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
2013-09-05
48
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
2013-09-05
49
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.”
2013-09-05
50
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.”
2013-09-05
51
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
3GPP TS 36.323, “E-UTRA; PDCP specification.”
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
3GPP TS 36.323, “E-UTRA; PDCP specification.”
2013-09-05
52
Mobility in RRC_CONNECTED: Detailed Handover Procedure (1/3)
103
Ad
mis
sio
n
Co
ntr
ol
S1-Based handover
Mobility in RRC_CONNECTED: Detailed Handover Procedure (2/3)
104
2013-09-05
53
Mobility in RRC_CONNECTED: Detailed Handover Procedure (3/3)
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
2013-09-05
54
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
2013-09-05
55
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
2013-09-05
56
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
2013-09-05
57
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
2013-09-05
58
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
2013-09-05
59
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
2013-09-05
60
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
2013-09-05
61
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
2013-09-05
62
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
Summary of Initial Attach Procedure
Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
2013-09-05
63
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
Summary of Initial Attach Procedure
Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
2013-09-05
64
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
Summary of Initial Attach Procedure
Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
2013-09-05
65
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
Summary of Initial Attach Procedure
Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
2013-09-05
66
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
Summary of Initial Attach Procedure
Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
2013-09-05
67
Summary of Control Plane: EPS Session Establishment (1)
133TEID: Tunnel Endpoint ID Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
Summary of Control Plane: EPS Session Establishment (2)
134TEID: Tunnel Endpoint ID Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
2013-09-05
68
Summary of Control Plane: EPS Session Establishment (3)
135 Netmanias, “EMM Procedure: 1. Initial Attach for Unknown UE (2편),” September, 2011
Summary of Control Plane: EPS Session Establishment (4)
136
2013-09-05
69
Summary of Control Plane
137
LTE-Advanced FeaturesHeterogeneous NetworksCarrier AggregationCoMP
138
2013-09-05
70
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
2013-09-05
71
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.
2013-09-05
72
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>
2013-09-05
73
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.
2013-09-05
74
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
2013-09-05
75
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.
2013-09-05
76
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.
2013-09-05
77
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.
2013-09-05
78
Heterogeneous Network: Market Status
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.
Heterogeneous Network: Market Status
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
* Informa Telecoms & Media, “Small cell Market Status,” 2012. 6.
2013-09-05
79
Heterogeneous Network: Market Status
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
* Informa Telecoms & Media, “Small cell Market Status,” 2012. 6.
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
2013-09-05
80
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
2013-09-05
81
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
2013-09-05
82
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
2013-09-05
83
Protocol Architecture for CA (2/3)
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
Protocol Architecture for CA (3/3)
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
2013-09-05
84
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
2013-09-05
85
Status of Commercial Services for CA (2/6)
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
Status of Commercial Services for CA (3/6)
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.
2013-09-05
86
Status of Commercial Services for CA (4/6)
SKT: “아무나 가질 수 없는 속도 LTE-A” 세계최초 Carrier Aggregation 상용화 서비스한시적 (7월) 데이터 2배 제공
171
Status of Commercial Services for CA (5/6)
LGU+: “100% LTE 가 아니면 요금을 안받겠습니다.”세계최초 100%LTE 상용화 (Voice 와 data를 동시서비스)WCDMA(3G)망 없음
172
2013-09-05
87
Status of Commercial Services for CA (6/6)
173
KT: “난 데이터가 2배 라구요!”Multi carrier/Carrier Aggregation 서비스 안함한시적으로 데이터량 2배 제공 (2013. 7~10월)
LTE-Advanced FeaturesHeterogeneous NetworksCarrier AggregationCoMP
174
2013-09-05
88
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.
2013-09-05
89
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
2013-09-05
90
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.
2013-09-05
91
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.
2013-09-05
92
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
2013-09-05
93
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
186• 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.
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
2013-09-05
94
LIPA & SIPTO
Solution 1 – variant 2
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
Solution 2 – variant 1
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.)
188• 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.
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
2013-09-05
95
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
189• 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.
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
190• 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.
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
2013-09-05
96
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
191• 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.
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
192• 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.
(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
2013-09-05
97
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
193• 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.
Release 12 IssuesOffloadingWLAN Network SelectionDevice-to-Device CommunicationsMachine Type Communication (MTC)
194
2013-09-05
98
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.
2013-09-05
99
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
2013-09-05
100
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
2013-09-05
101
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
2013-09-05
102
Release 12 IssuesOffloadingWLAN Network SelectionDevice-to-Device CommunicationsMachine Type Communication (MTC)
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.
2013-09-05
103
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.
2013-09-05
104
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
207* 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.
Use case and business model
Data Relay D2D Communications can be used to relay data for devices
that are not “directly cellular”.
208* 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.
2013-09-05
105
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
2013-09-05
106
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
2013-09-05
107
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)
2013-09-05
108
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
2013-09-05
109
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
Public Safety Use Case
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
2013-09-05
110
Public Safety Use Case
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
Public Safety Use Case
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
2013-09-05
111
Public Safety Use Case
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
2013-09-05
113
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.
2013-09-05
114
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.
2013-09-05
115
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.
2013-09-05
116
Release 12 IssuesOffloadingWLAN Network SelectionDevice-to-Device CommunicationsMachine Type Communication (MTC)
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
117
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
• 3GPP TS 22.368 v12.2.0, “Service Requirements for Machine-Type Communications(MTC)(Release 12),” 2013. 03.
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
2013-09-05
118
Communication Scenarios
235
MTC Devices communicatingwith one or more MTC Server
MTC Devices communicatingwith each other
• 3GPP TS 22.368 v12.2.0, “Service Requirements for Machine-Type Communications(MTC)(Release 12),” 2013. 03.
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
2013-09-05
119
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
2013-09-05
120
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).
2013-09-05
121
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
2013-09-05
122
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
2013-09-05
123
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
(Release 10)," July 2012. Netmanias, "EMM Procedure: 1. Initial Attach for Unknown UE (2편)," September, 2011 http://www.netmanias.com/bbs/view.php?id=techdocs&no=74 윤영우, "3GPP LTE Rel-12 & Onwards 주요 요소 기술 및 표준 동향", 전자공학회지, 제 40권 4호, pp.328-339, 2013년 4
월 3GPP, RWS-120046, Samsung Electronics, "Technologies for Rel-12 and Onwards," June 2012. 3GPP, RWS-120010, NTT DOCOMO, "Requirements, Candidate Solutions & Technology Roadmap for LTE Rel-12
Onward," June 2012. C. H. Lee and J. H. Kim, "Parallel Measurement Method of System Information for 3GPP LTE Femtocell," in Proc.
ICNS 2011, Venice, Italia, 22-27. May 2011. Informa Telecoms & Media, "Small cell Market Status," 2013. 2. J.Wannstrom, "Carrier Aggregation explained", http://www.3gpp.org/Carrier-Aggregation-explained , May, 2012 SKT hompage, "SK텔레콤, 30일 84개시 중심가로 ‘LTE-A’ 확대", http://www.sktelecom.com, July, 2013. LGU+ homepage, "LG유플러스, 세계 최초 ‘100% LTE’ 상용화", www.uplus.co.kr, July, 2013. 윤영우, "LTE-Advanced 표준 기술 (REL-10 동향 및 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".
245
References 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. 김지수, 김재현 "기지국 협력 통신 네트워크 효율성 성능평가," in Proc. 한국통신학회 하계학술대회 , 제주도, 2010년 06월. 김현숙, "3GPP Traffic Offload", FMC 포럼 컨버젼스 기술 및 표준 워크샵, 2012. 12. 12. NEC corporation, "Mobile Traffic Offload: NEC’s Cloud Centric Approach to Future Mobile Networks," 2013. 04. Konstantinos Samdanis, Tarik Taleb, Stefan Schmid, "Traffic Offload Enhancements for eUTRAN," IEEE
COMMUNICATIONS SURVEYS & TUTORIAL, 2012. 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. 3GPP TS 23.402 V12.1.0, "Architecture enhancements for non-3GPP accesses", June 2013. 3GPP TS 24.312 V12.1.0, "Access Network Discovery and Selection Function (ANDSF) Management Object (MO)",
June 2013. 3GPP TS 23.865 V1.0.0, "WLAN network selection for 3GPP termianls", June 2013. 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. 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. S2-131505 "Solution for direct discovery and communication", April, 2013 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. Government Technology white paper, "A How-To Guide for LTE in Public Safety," 2010 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 . 조수현, "KT Vision : M2M Services and Technologies", KRNET 2011, 2011년 6월 27일. 최상호, "SKT Vision : M2M Based Mobile Service", KRNET 2011, 2011년 6월 27일. 유상근, 홍용근, 김형준, "스마트모바일 서비스 – M2M 기술 및 표준 동향", 전자통신동향분석 제 26권 제 2호, 2011년 4월. Andreas Kunz, "Machine Type Communications in 3GPP From Release 10 to Release 12", GLOBECOM 2012 ONIT
WS, Dec. 2012
246