mrn – 9 – umts - politecnico di milanohome.deib.polimi.it/capone/wn/mrn-en-9-umts.pdf · cdma...

Politecnico di Milano Facoltà di Ingegneria dell’Informazione

MRN – 9 – UMTS

Mobile Radio Networks Prof. Antonio Capone

3GPP standards evolution

GSM GPRS

EDGE

UMTS TD-SCDMA

HSDPA

HSUPA

HSPA+ R7

HSPA+ R8

LTE FDD TDD LTE

Advanced

2G 3G 4G

TDMA FDMA

CDMA

OFDMA

A. Capone: Mobile Radio Networks 2

Macro, Micro, Pico Celle


Intranet Access

Intranets Internet Services Mobile Internet PSTN

PDA/ Tablet

Business User

Business + Consumer

Consumer Business + Consumer

Business + Consumer

Internet Access Customized Infotainment

Multimedia Messaging

Location Based Service Voice

PDA/ Tablet Laptop SmartPhone SmartPhone Laptop Mobile Phone Mobile Phone

Services and Applications


UMTS architecture: Network domains


User Domain

Radio Access Domain

Core Network

Uu Interface (radio interface)

Uu Interface (radio interface)

Infrastructure Domain

Other PLMN Other Networks


USIM Domain

Mobile Equipment

Domain

Access Network Domain

Serving Network Domain

Transit Network Domain

Home Network Domain

User Equipment Domain Infrastructure Domain

Core Network Domain

Cu Uu Iu

Yu Zu



o  User Equipment (UE) Domain n  The USIM is the user identity modulo with all security tools

and keys; the Mobile Equipment domain is the mobile station

o  Access Network Domain n  It can be the new UTRAN (UMTS Terrestrial Radio Access

Network) or the BSS-GSM o  Core Network (CN) Domain

n  It’s the backbone of the operator network and allows the management of circuit and packet switched services and the access to external networks through gateways


User Equipment Domain

o MS = ME domain + USIM domain o ME = MT (Radio) + TE (Applications)


Radio Network Controller

Core Network

NodeB Network Management

Mobile Terminals

Radio Access Network

Iub Iur

Iub

Iu

UTRAN


UTRAN: Network nodes o  RNS (Radio Network Subsystem)

n  It’s the part of the network that allows the access to the core network from the User Equipment (UE)

o  RNC (Radio Network Controller) n  Within the RNS, the RNC manages the radio resources of a group

of base stations (NodeB)

o  Node B n  It’s the UMTS base station and manages one or more cells

o  Uu Interface n  Air interface between UE and Node B

o  Iu Interface n  Interface between CN and RNS

o  Iur Interface n  Interface between different RNSs

o  Iub Interface n  Interface between RNC and Node B


ATM layer with QoS

Physical transport (usually optical)

Transport layer


Communication services o  Bearer service

n  Communication service able to provide bit pipes between point

o  Teleservice n  Communication includes in this case also the

application protocols and formats. Some teleservices (like telephone voice calls) are considedered fundamental and standardized

o  Supplementary service n  Modify or add information to a teleservice. It

cannot be offered as a stand alone service


Quality parameters

o  In UMTS bearer services can guarantee some quality parameters like: n  Maximum transfer delay n  Delay variation n  Bit error ratio n  Data rate

o  Four UMTS QoS Classes n  conversational, streaming, interactive,

background


TE MT UTRAN CN Iu edge node

TE CN gateway

End-to-end service

UMTS bearer service

Radio access bearer service CN b.s.

Local b.s. Ext. b.s.

Radio b.s. Iu b.s. Backbone

Radio Access Bearer Radio Bearer

UE Core network

Bearer services in UMTS


Conversational Streaming Interactive Background

low delay

low delay variation

speech video streaming

audio streaming

low round-trip delay

www applications

delay is not critical

store-and- forward applications

(e-mail, SMS) file transfer

reasonably low delay

basic applications

basic QoS requirements

QoS classes

video telephony/

conferencing



QoS classes

o  Low delay (< 400 ms) and low delay variation o  BER requirements not so stringent o  In the radio network => real-time (RT)

connections o  Speech (using AMR = Adaptive Multi-Rate

speech coding) o  Video telephony / conferencing:

n  ITU-T Rec. H.324 (over circuit switched connections) n  ITU-T Rec. H.323 or IETF SIP (over packet switched

connections)



UE Source

Buffer

QoS classes

o  Reasonably low delay and delay variation o  BER requirements quite stringent o  Traffic management important (variable bit rate) o  In the radio network => real-time (RT) connections

o  Video streaming o  Audio streaming

o  video or audio information is buffered in the UE, o  large delay => buffer is running out of content!



QoS classes

o  Low round-trip delay (< seconds) o  Delay variation is not important o  BER requirements stringent o  In the radio network => non-real-time (NRT)

connections

o  Web browsing o  Interactive games o  Location-based services (LCS)



QoS classes

o  Delay / delay variation is not an important issue o  BER requirements stringent o  In the radio network => non-real-time (NRT)

connections

o  SMS (Short Message Service) and other more advanced o  Messaging services (EMS, MMS) o  E-mail notification, e-mail download o  File transfer


Core network


GSM/GPRS core network GSM Radio access network (BSS)

Internet

PSTN

BTS

BTS

BSC

MSC

VLR

SGSN

LR

GMSC

HLR

AuC

EIR

GGSN

LR

MS

PCU

GSM/GPRS network

IP Backbone


Core network (GSM/GPRS-based) Radio access network UTRAN

UE

Iu CS

Iur

Iub

Uu

Gn Iu PS

Internet

PSTN

BS

BS

RNC

RNC

MSC

VLR

SGSN

LR

GMSC

HLR

AuC

EIR

GGSN

LR

Iub

UMTS network – Rel. 99

IP Backbone


2G => 3G: RAN

MS => UE (User Equipment), often also called (user) terminal

New air (radio) interface based on WCDMA access technology

New RAN architecture -  Iur interface is available

for soft handover, -  BSC => RNC

Radio access network UTRAN

UE

Iu CS

Iur

Iub

Uu

Iu PS

BS

BS

RNC

RNC

Iub



2G => 3G: CN

MSC is upgraded to 3G MSC

SGSN is upgraded to 3G SGSN

GMSC and GGSN remain the same

AuC is upgraded (more security features in 3G)

Core network (GSM/GPRS-based)

Iu CS

Gn Iu PS

Internet

PSTN MSC

VLR

SGSN

LR

GMSC

HLR

AuC

EIR

GGSN

LR IP Backbone



Circuit Switched (CS) core network

PS

TN

MSC Server

PS core as in Rel.’99

GMSC Server

SGW

MGW

SGW

MGW


New option in Rel.4

UTRAN

GERAN (GSM and EDGE Radio

Access Network)


MSC Server takes care of call control signalling

The user connections are set up via MGW (Media GateWay)

“Lower layer” protocol conversion in SGW (Signalling GateWay)

RANAP / ISUP

SS7 MTP

IP Sigtran

Circuit Switched (CS) core network

PS

TN

MSC Server

PS core as in Rel.’99

GMSC Server

SGW

MGW

SGW

MGW



CS core

PS

TN

SGSN GGSN

Internet

HSS IMS (IP Multimedia System)

PS core


UTRAN

GERAN (GSM and EDGE Radio

Access Network)

MGW


CS core

PS

TN

SGSN GGSN

Internet / other IMS

HSS

PS core

The IMS can establish multimedia sessions (using IP transport) via PS core between UE and Internet (or another IMS)

Call/session control using SIP (Session Initiating Protocol)

Interworking with the PSTN is required for some time ...

IMS (IP Multimedia System)

MGW



Gf Gi

Iu

GiMr

Gi

Ms

Gi

R UuMGW

Gn

Gc

Signalling and Data TransferInterface

SignallingInterface

TE MT UTRAN

Gr

SGSN GGSN

EIR

MGCF

R-SGW *)

MRF

MultimediaIP Networks

PSTN/Legacy/External

Applications &Services *)

Mm

Mw

Legacy mobilesignallingNetw ork

Mc

Cx

AlternativeAccess

Network

Mh

CSCF

CSCFMg

T-SGW *)

T-SGW *)

HSS *)

HSS *)

Applications& Services *)

MSC server GMSC server

McMc

D C

SCP

CAP

MGWNb

Nc

Iu

Iu

R-SGW *)Mh

CAPCAP

R UmTE MT

BSS/GERAN

GbA

*) those elements are duplicated for figurelayout purpose only, they belong to the samelogical element in the reference model

Iu



UMTS Protocols


UMTS Protocols o  Different protocol stacks for user and control

plane o  User plane (for transport of user data):

n  Circuit switched domain: data within ”bit pipes” n  Packet switched domain: protocols for implementing

various QoS or traffic engineering mechanisms o  Control plane (for signalling):

n  Circuit switched domain: SS7 based (in core network)

n  Packet switched domain: IP based (in core network) n  Radio access network: UTRAN protocols

Data streams

RLC

MAC

Phys.

UE UTRAN 3G MSC GMSC

Uu Iu Gn

RLC

MAC

Phys. WCDMA

TDM

Frame Protocol (FP)

AAL2

ATM

Phys.

AAL2

ATM

Phys.

TDM

User plane (Circuit Switched)

PDCP

RLC

GTP

UDP

IP

GTP

UDP

IP

IP IP

GTP

UDP

PDCP

RLC

MAC

Phys.

MAC

Phys.

AAL5

ATM

Phys.

AAL5

ATM

Phys.

IP

L2

L1

GTP

UDP

IP

L2

L1

UE UTRAN SGSN GGSN

Uu Iu Gn

WCDMA

User Plan (Packet Switched)

PHY

MAC

RLC

RRC

Signalling radio bearers

(User plane) radio bearers

e.g. MM, CC, SM transparent to UTRAN

Logical channels

Transport channels

PDCP L3

L2

L1

Radio Interface Protocols

Radio Interface


Frequency map

A. Capone: Mobile Radio Networks

Frequency map o  Two frequency bands for TDD and FDD. o  FDD (Frequency Division Duplex): it’s a symmetric band

assignment, one for the uplink and one for he downlink o  TDD (Time Division Duplex) it’s a asymmetric channel


W-CDMA


Spreading o  The number of chips in the spreading code is called

Spreading Factor (SF). The chip rate in UMTS is 3.84 Mcps.


Scrambling

o  Spreading codes of the same transmitter are mutually orthogonal

o  Code of different transmitters have low cross correlation regardless of the time offset

o  For this purpose, different scrambling codes are used for each transmitter


Orthogonal codes tree

o  The orthogonal spreading codes are generated with different lengths using the OVSF (Orthogonal Variable Spreading Factor) tree.

o  The Spreading Factor (SF) is equal to the number of codes


Radio Interface

o At the radio interface some channels are for signaling and others for user data.

o Some channels are for packet switched access while others for circuit switching

o Different types of channels maps the RAB (Radio Access Bearers) requested by services


Logical/Transport/Physical channels


RLC RLC

MAC

FP

Phy

FP

UE Base station RNC

AAL 2

MAC

AAL 2

Phy

Logical channels

Physical channels

Transport channels

: :

WCDMA

: :

Logical/Transport/Physical channels

.

Radio protocols


CCCH DCCH

PCH DCH DSCH FACH BCH DCH CPCH RACH

DCCH CTCH CCCH BCCH PCCH

Uplink Downlink

DTCH DTCH

Logical channels

Transport channels

Logical è Transport channels

PCH DCH DSCH FACH BCH

DCH

CPCH RACH

PRACH PCPCH SCCPCH PCCPCH DPDCH

DPCCH

SCH CPICH

AICH

PICH

CSICH

Physical channels

Transport channels

DPCH CD/CA-ICH

Uplink Downlink

PDSCH

Transport è Physical channels

Physical channels

Node B

UE

P-CCPCH- Primary Common Control Physical Channel SCH - Sync Channel

P-CPICH - Primary Common Pilot Channel S-CPICH - Secondary Common Pilot Channel(s)

Broadcast Channels (to all UEs in the cell)

DPDCH - Dedicated Physical Data Channel

DPCCH - Dedicated Physical Control Channel

F-PDSCH - Physical Downlink Shared Channel

Dedicated Connection Channels

PICH - Page Indication Channel

Paging Channels

S-CCPCH - Secondary Common Control Physical Channel

PCPCH - Common Physical Packet Channel

AP-AICH - Acquisition Preamble Indication Channel

CD/CA-AICH - Collision Detection Indication Channel

CSICH - CPCH Status Indication Channel

PRACH - Physical Random Access Channel

AICH - Acquisition Indication Channel

Random Access e Packet Access Channels


Physical channels: downlink o  Common Downlink Physical Channels

n  P-CCPCH Common Control Physical Channel (Primary) o  Broadcast delle informazioni della cella o  Broadcast della SFN e Timing reference per tutti i canali DL

n  SCH Synchronization Channel o  Fast Synch. codes 1 and 2; time-multiplexed con P-CCPCH

n  S-CCPCH Common Control Physical Channel (Secondary) o  Trasmette l’informazione di segnalazione e controllo per gli UE

in idle-mode n  P-CIPCH Common Pilot Channel n  S-CIPCH Secondary Common Pilot Channel (for sectored

cells) n  PDSCH Physical Downlink Shared Channel

o  Trasmette dati ad alta velocità a più utenti o  Dedicated Downlink Physical Channels

n  DPDCH Dedicated Downlink Physical Data Channel n  DPCCH Dedicated Downlink Physical Control Channel

o  Trasmette la segnalazione e il controllo per i mobili in connessione


Physical channels: downlink (2) o  Downlink Indication Channels

n  AICH (Acquisition Indication Channel) o  Acknowledges that BS has acquired a UE Random Access attempt o  (Echoes the UE’s Random Access signature)

n  PICH (Page Indication Channel) o  Informs a UE to monitor the next paging frame

n  AP-AICH (Access Preamble Indication Channel) o  Acknowledges that BS has acquired a UE Packet Access attempt o  (Echoes the UE’s Packet Access signature)

n  CD/CA-ICH o  Confirms that there is no ambiguity between UE in a Packet

Access attempt o  (Echoes the UE’s Packet Access Collision Detection signature) o  Optionally provides available Packet channel assignments

n  CSICH o  Broadcasts status information regarding packet channel

availability A. Capone: Mobile Radio Networks 50

Physical channels: uplink

o  Common Uplink Physical Channels n  PRACH Physical Random Access Channe

o  Used by UE to initiate access to BS

n  PCPCH Physical Common Packet Channel o  Used by UE to send connectionless packet data

o  Dedicated Uplink Physical Channels n  DPDCH Dedicated Uplink Physical Data Channel n  DPCCH Dedicated Uplink Physical Control Channel

o  Transmits connection-mode signaling and control to BS


Logical channels: downlink o  Common Downlink Logical Channels

o  BCCH (Broadcast Control Channel) n  Broadcasts cell site and system identification to all UE

o  PCCH (Paging Control Channel) n  Transmits paging information to a UE when the UE’s location is unknown

o  CCCH (Common Control Channel) n  Transmits control information to a UE when there is no RRC Connection

o  SHCCH (Shared Channel Control Channel) n  Control channel associated with shared traffic channels (TDD mode only)

o  CTCH (Common Traffic Channel) n  Traffic channel for sending traffic to a group of UE’s.

o  Dedicated Downlink Logical Channels

o  DCCH (Dedicated Control Channel) n  Transmits control information to a UE when there is a RRC Connection

o  DTCH (Dedicated Traffic Channel) n  Traffic channel dedicated to one UE


Logical channels: uplink o  Common Uplink Logical Channels

o  CCCH (Common Control Channel) n  Common signalingg channel in the uplink

o  Dedicated Uplink Logical Channels

o  DCCH (Dedicated Control Channel) n  Transmits control information from UE

o  DTCH (Dedicated Traffic Channel) n  Traffic channel dedicated to one UE


Transport channels: downlink o  Common Downlink Transport Channels

o  BCH (Broadcast Channel) n  Continuous transmission of system and cell information

o  PCH (Paging Channel) n  Carries control information to UE when location is unknown n  Pending activity indicated by the PICH (paging indication channel)

o  FACH (Forward Access Channel) n  Used for transmission of idle-mode control information to a UE n  No closed-loop power control

o  DSCH (Downlink Shared Channel) n  Carries dedicated control and/or traffic data; shared by several UE’s

o  Dedicated Downlink Transport Channels o  DCH (Dedicated Channel)

n  Carries dedicated traffic and control data to one UE


Transport channels: uplink

o  Common Uplink Transport Channels n  RACH Random Access Channel

o  Carries access requests, control information, short data o  Uses only open-loop power control o  Subject to random access collisions

n  CPCH Uplink Common Packet Channel o  Carries connectionless packet data to PCPH

o  Dedicated Uplink Transport Channels n  DCH Dedicated Channel

o  Carries dedicated traffic and control data from one UE


TFCI Data TPC Data

10 ms radio frame

0 1 2 14

2560 chips

Pilot

DPCH - Downlink

TPC: Transmit Power Control TFCI: Transport Format Combination Indicator

(DPCH = Dedicated Physical Channel)

(Dedicated Physical Data/Control Channel)

Data

Pilot TFCI FBI TPC

DPDCH (I-branch)

10 ms radio frame (38400 chips)

0 1 2 14

2560 chips

DPCCH (Q-branch)

Dual-channel QPSK modulation:

DPDCH/DPCCH

FBI: Feedback Information TPC: Transmit Power Control TFCI: Transport Format Combination Indicator

Iu

Iur

Iub

Iub

DRNC

SRNC

UE

BS

BS

RNC

RNC

Leg 1

Leg 3

Signal combining point is in SRNC (downlink: in UE)

BS Leg 2

Core network

Soft handover

Iu

Iur

Iub

Iub

DRNC

SRNC

UE

BS

BS

RNC

RNC Macrodiversity combining point in

SRNC

Core network

Rake receiver

Multipath propagation

Microdiversity combining point in base station

Micro/Macro diversity

High Speed data services HSPA


Releases 3GGP for UMTS o  Release 99

n  UMTS con servizi voce e dati base o  Release 5

n  HSDPA o  Release 6

n  HSUPA o  Release 7

n  HSPA+ con 64 QAM o  Release 8

n  HSPA+ con 2x2 MIMO o  Release 9/10

n  HSPA+ Multicarrier


Data services – UMTS Rel. 99

o  Maximum Throughput DL: 2 Mbps (with 4 channel at 768 kbps with SF4)

o  Throughput DL : 384 kbps o  Latency between 100 and 200 ms


UMTS vs HSDPA


10 ms

2 ms

Dedicated channels

High speed shared channel Feedback on channel quality

Data services - Rel. 5: HSDPA

o  Peak throughput DL 14 Mbps o  HSDPA vs. UMTS

n  Higher order modulation n  Variable coding

o  Main characteristics n  High data rate physical channels n  Small TTI n  Fast Scheduling n  User Diversity n  Higher order modulation (16 QAM) n  Flexibility to radio channel adaptation n  Fast HARQ

o  These technical solutions allow to react quickly to channel variations n  Increasing throughput n  Low delay


HSDPA - HS-PDSCH

o  The new channel introduced by HSDPA is the HS-PDSCH (High Speed – Physical Downlink Shared Channel) with SF 16

o  5 MHz → 15 HS-PDSCH o  The time granularity for resource assignment

(TTI) is also transmitted to 2 ms o  Each user, every 2 ms, can use a variable

number of channels (fino a 15) of HS-PDSCH


HSDPA transmission scheme


High Speed Downlink Shared Channel (HS-DSCH) High Speed Signalling Control Channel (HS-SCCH) High Speed Dedicated Physical Control Channel (HS-DPCCH)

Scheduling in HSDPA o  The dynamic resource allocation by the scheduler

(per 2ms TTI) is signaled to the users on a new downlink control channel called High Speed Signalling Control Channel (HS-SCCH).

o  The following information is carried on the HS-SCCH: n  UE Identity (UE ID) via a UE specific CRC which allows

addressing specific UEs on the shared control channel. n  Transport Format and Resource Indicator (TFRI) which

identifies the scheduled resource and its transmission format.

n  Hybrid-ARQ-related information to identify redundancy versions for the combining process.

o  Each user can monitor up to 4 HS-SCCHs. A. Capone: Mobile Radio Networks 67

Scheduling in HSDPA

o  For the support of channel based scheduling and HARQ the following feedback signaling is transmitted on the High Speed Dedicated Physical Control Channel (HS-DPCCH) in the uplink: n  Channel Quality Information (CQI) to inform the

scheduler about the instantaneous channel condition. n  HARQ ACK/NACK information to let the sender know the

outcome of the decoding process and to request retransmissions.


HSDPA – Fast Scheduling

o  TTI equal to 2 ms

o  The radio resources could be assigned to the user with the best channel

o  This would be a unfair but channel variations among users are uniformly experienced.

o  The scheduler in any case allows to guarantee quality


HSDPA - Modulations

o  QPSK (2 bits per symbol) [UMTS-R99]

o  16 QAM (4 bits per symbol)

o  Adaptive modulation


HSDPA – Link Adaptation and HARQ

o  Fast Link Adaptation

n  Based on channel coding FEC codes with different rates

are adopted

o  HARQ (Fast Hybrid Automatic Repeat Req)

n  FAST : managed by NodeB and not by BSC/RNC

n  HYBRID : Transmissions and retransmissions are

combined together to increase information rate


HSDPA - Terminals

o  There are different types of HSDPA terminals n  Number of HS-PDSCH supported n  Buffer size for soft-combining n  Supported modulations and rate

o  Throughput classes 1.2, 7.2, 14.4 Mbps


Data services Rel. 6 - HSUPA o  USUPA improves performance for the uplink o  The new characteristics are similar to those of HSDPA for

the downlink o  Introduction of the Enhanced Dedicated Physical

Channel (in HSDPA this was Shared) o  TTI of 2 ms o  Scheduling in the NodeB o  Fast Hybrid ARQ o  Latency of 30 – 70 ms o  It could be used even without the HSDPA o  Additional terminal categories with maximum throughput

of 2 and 5 Mbps


HSDPA vs HSUPA o  HSUPA brings some of the advanced

functionalities of HSDPA in the uplink

o  In particular, evolved Data Channel (eDCH) is introduced

o  Differently from HSDPA, HSUPA uses power control (range of 70dB)


HSUPA channels

o  For the support of the new functionality several new physical channels were introduced. n  E-DPDCH: E-DCH Dedicated Physical Data Channel

for dedicated uplink data transmission. During data transmission so-called Scheduling Information such as buffer status, data priority and power headroom can be piggybacked.

n  E-DPCCH: E-DCH Dedicated Physical Control Channel with the associated control data for E-DPDCH detection and decoding. For the support of the scheduler there is a Happy Bit that informs if the UE has sufficient resources for transmission.


HSUPA channels

n  … n  E-HICH: E-DCH HARQ Acknowledgement Indicator

Channel to transmit HARQ feedback information (ACK/NACK)

n  E-RGCH: E-DCH Relative Grant Channel to grant dedicated resources (up, down, hold) to a UE

n  E-AGCH: E-DCH Absolute Grant Channel is a shared channel that allocates an absolute resource for one or several UE.


HSUPA transmission scheme


Based on the rate request (Scheduling In- formation or Happy Bit) the Node B may respond with a resource allocation via the absolute or a relative grant. The UE will use the grant for data transmission and the Node B will acknowledge the received packets.

Scheduling in HSUPA

o  The NodeB selects the data rate to use base on the feedback received by the UE

o  Decisions on scheduling are taken by the NodeB based on the QoS parameters of all connections

o  The NodeB also manages retransmissions, using advanced techniques for storing and recombining packets that are partially correctly received


UMTS Release 7 – HSPA+ o  HSPA+ Release 7 includes

n  HSDPA and HSUPA (HSPA)

n  2x2 MIMO

n  Higher order modulations (DL 32 QAM )

n  Continuous Packet Connectivity

o  HSPA+ and LTE performance in term of throughput and spectral efficiency are comparable

o  Throughput max DL: 21 Mbps


UMTS Release 8 – HSPA+

o  HSPA+ Release 8 includes n  2x2 MIMO

n  Higher order modulation (DL 64 QAM ) n  Continuous Packet Connectivity

o  It’s the last step of the evolution of UMTS data services in 3GPP

o  Throughput max DL: 42 Mbps (2x2 MIMO) o  Throughput max UL: 11.5 Mbps


HSPA+ network architecture

o  The concept of flat network (then used in LTE) is introduced in HSPA+

o  Through a tunnel, the User Plane uses a direct connection from NodeB to GGSN without crossing RNC and SGSN


HSPA+ MIMO

o Multi-antenna techniques allows to exploit multi-paths between transmitter and receiver

o  In particular, MIMO techniques allow to transmit multiple flows on different radio paths increasing the throughput


mrn – 9 – umts - politecnico di milanohome.deib.polimi.it/capone/wn/mrn-en-9-umts.pdf · cdma...

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