03 rn30033 en06gln0_ran_overview

1 © Nokia Siemens Networks Presentation / Author / DateFor internal use

Module 3: RAN Overview and Features


Objective

• Objective of the part one of the module 3 is to give first an overview of the different interfaces in RAN

– Iub– Iu-CS– Iu-PS– Iur– Iu-BC

• Second part of the module 3 is concentrating on features that are related to transport in the RAN


UNI stands for User-Network-Interface, like IubNNI stands for Network-Network-Interface, like Iu-CS, Iu-PS and Iur

RAN Architecture

The following session gives a quick introduction to the RNC related interfaces:• Iub• Iu-CS• Iu-PS• Iur• Iu-BC

A interface

Gn interface

3G-SGSN

Iu-CS

Iu-PS

Iur

S-AXC

Iub

Iub

UNI

UNI

UNI

NNI

NNI

NNI

Iu-BC

RNC

BTS

BTS

BTS

BTSBTS

BTS

BTS

BTS

RNC

MGW

MSS/MSC

3G-CBC

GGSN

SGSN


Protocol Structures for RNCs Logical Interfaces

TransportNetworkLayer

RadioNetworkLayer

Q.2630.1

D-NBAP

DC

H

FP

AAL2

Transport NetworkUser Plane

ATM

Transport NetworkControl Plane

Physical Transmission layer

AAL5

SSCF-UNISSCOP

AAL5

Q.2150.2SSCF-UNI

SSCOP

RA

CH

FP

FACH

FP

PCH

FP

DS

CH

FP

CP

CH

FP

User PlaneControl Plane

AAL5

SSCF-UNISSCOP

C-NBAP


SAAL

TransportNetworkLayer

RadioNetworkLayer RANAP Iu User

Plane Protocol



ATM



AAL5

SCCPMTP-3b

SSCF-NNISSCOP

AAL5

GTP-UUDP

IP

User PlaneControl Plane

SAAL

IubTransportNetworkLayer

RadioNetworkLayer

Q.2630.1

RNSAP DCH FP

AAL2



ATM

Control Plane


User Plane


AAL5

SCCPMTP-3b

SSCF-NNISSCOP

Q.2150.1

CCH FP

SAAL

Iur

Iu-PSTransportNetworkLayer

RadioNetworkLayer

Q.2630.1

RANAP DCH FP

AAL2



ATM

Control Plane


User Plane


CCH FP

SAAL

Iu-CS

AAL5

SCCPMTP-3b

SSCF-NNISSCOP

Q.2150.1


Iub End to End Logical Connections

A2SU

C-NBAP VCC

AAL2UP VCC

RNC

D-NBAP VCC

AAL2SIG VCC

BTSICSU

OSS net.

O&M VCCOMU

ESA

FTM in FlexiAXC/WAM in Ultrasite

AAL2 Routing &Digit Analysis

The VCCs can be transported in one or many VPCs


Iub - Signaling Procedures

AAL2sig: Transport Network Control Plane (Signalling for AAL2 connections)• Establishing AAL2 connections• Maintaining of the AAL2 connections• Terminating of AAL2 connections • Error checking• Carrying signaling for lower ATM adaptation layer (SAAL-UNI, SAAL-NNI)C-NBAP: The main loading components of Common NBAP links are:• Radio Link setup requests and responses• Radio Resource Indication messages • Thus, C-NBAP bandwidth requirement depends on the call setup and radio link

addition (soft handover) amounts, and the Radio Resource Indication periodD-NBAP: Dedicated NBAP (D-NBAP) transfers, for example:• Radio Link Measurement Reports (RLM)• Radio Link Deletion commands• Radio Link Reconfiguration messages• Radio Link branch addition commands (softer handovers)• Thus, the D-NBAP capacity requirement depends, for example, on the number of

calls, call lengths, number of softer handovers, and Radio Link Measurement report period.


Iub Interface configuration

• The Iub is the logical interface between the Radio Network Controller (RNC) and the WCDMA Base Station (WBTS)

• The Iub traffic has the following sub flows and they are configured differently depending on the BTS type and configuration

– Signaling is 6-7% of the Iub capacity divided 1:2:1 for CNBAP:DNBAP:AAL2SIG– User plane can be one or many and from RAS05.1ED onwards it can be put into several

VPCs and the use plane VCCs can be either CBR or UBR+ from RAS06 onwards– O&M

▪ 1 per BTS, connected to MWAM (after IP router), capacity 64kbps per BTS▪ O&M also known as DCN, TCP/IP, IPOAM, Ip Over ATM

C-NBAP – AAL5-CBRD-NBAP – AAL5-CBRAAL2sig – AAL5-CBRAAL2UP – AAL2-CBR

O&M – AAL5-UBR

BTSRNC

AAL2UP – AAL2-UBR+

CBRVP

CBRVP

CBRVP

UBRVP

CBRVP

Different alternatives to configure VPs

unshaped

UBRVP


Iu-CS End to End Logical Connections

A2SUA2SU A2SU

MTP3SL VCC

AAL2UP VCC

MGW

MTP

AAL2 RANAP

MTP3b

ICSU AAL2 sig

SS7

RANAP

RNC

SCCP

SNM

SNTMTP

ICSU AAL2 RANAP

MTP3b

ICSU AAL2 sig

SS7

RANAP

SCCP

SNM

SNT




Iu-CS Interface configuration

• The Iu-CS is the logical interface between the Radio Network Controller(RNC) and the Media Gateway (MGW). The Iu-CS traffic has the following sub flows:

– AAL2 UP, carries the entire CS user traffic, the amount of UP-VCCs depends on the expected traffic.▪ The Iu-CS-UP per VCC is limited because of available CIDs on AAL2 layer

• 248 CIDs are available for AAL2-Channels▪ Expecting a voice-dominant traffic mix, entire UP is split down into several VCCs

with 9-10 kcps each. – MTP3b signaling link, embeds RANAP and AAL2sig

▪ Amount depends on total CS Erlang value, please refer to table above▪ Capacity: 1000 cps per Signaling Channel

UP - AAL2-CBRUP - AAL2-CBR

UP - AAL2-CBRUP - AAL2-CBR

MTP3SL - AAL5-CBRMTP3SL - AAL5-CBR

CBRVP RNCMGW


GTPU A2SU

AAL2 Routing &

Digit Analysis

AAL2 SigGPLC

Iu-PS End to End Logical Connections

MTP3SL VCC

AAL5UP VCC

RNC SGSN

AA IPIP

UDP

MTP

ICSU RANAP

MTP3b

ICSU

SS7

RANAP

SCCP

SNMSNT MTP

RANAP

MTP3b

SMMU

SS7

RANAP

SCCP

SNMSNT

IP I/F


Iu-PS Interface configuration

• The Iu-PS is the logical interface between the Radio Network Controller (RNC) and the Serving GPRS Support Node (SGSN). The Iu-PS traffic has the following sub flows:

• AAL5 UP, carries the entire IP user traffic on ATM– The amount of UP-VCCs depends on the amount of available GTPUs; thus to RNC type

and expansion stage– In practise user plane capacity also depends on packet size (varying! assumed 512

Byte average)– Depending on extension stage RNC has 2-8 GTPUs.– To each existing GTPU one UP is assigned (not considering redundancy)

• MTP3b signalling link, embeds RANAP signalling– Amount depends on total PS traffic volume, please refer to table above– Capacity: 1000 cps per Signalling Channel

MTP3SL - AAL5-CBRMTP3SL - AAL5-CBR

UP - AAL5-UBRUP - AAL5-UBR

UP - AAL5-UBRUP - AAL5-UBRUBR

VP

CBRVP

CBRVPRNC SGSN

or


Iur Interface configuration• The Iur is the logical interface for the interconnection of one RNC to any neighboring RNC• There are 3 different possibilities to connect the Iur interface between 2 RNCs:

– Direct physical connection between RNCs– Transport traffic via MGW and using cross-connections or Nodal function

Sig VCC UP VCC

Iurconnection

Iu-CS connection

Direct Iur connection VCC cross connection or AAL2 switching

Iu-CS and Iur connections

SIG VCC

UP VCC

The Iur interface can be e.g. an IMA-group between two RNCs, either directly connected in case both RNCs are on same site or using Leased Lines to a remote RNC.

AAL2 switching: Iur traffic can be transported within the Iu-CS UP-VCC. Due to the Nodal Function in the MGW, the Iur traffic can be switched on AAL2 level (Digit Analysis Tree) within the MGW to the other RNC.

VCC cross connectionThe Iur traffic can be transported in it’s own VCC together with the Iu-CS traffic. In this case the MGW acts like a Cross-Connect

RNC

RNC

MGW

RNC

RNC

MGW


Iur End to End Logical Connections

The Iur is the logical interface between two RNCs. The Iur traffic has the following sub flows:

1. AAL2 UP, carries the entire Iur user traffic in one or more AAL2-CBR-VCC. – Capacity depends on expected Iur traffic mix– Average Iur capacity is pretty low, but the possibility of several PS384 in SHO has to be

considered 1 or more UP-VCC, depends on traffic mix respectively CID limitation!2. MTP3SL, embeds RNSAP and AAL2sig, is transported within an AAL5-CBR-VCC.

– Capacity is around 3 % of UP, regardless using physical connections, VC-XCON or AAL2-switching

• Notes: – Each neighboring RNC requires one Iur interface– Iur capacities to be included in RNC throughput and RNC connectivity

A2SUA2SU A2SUA2SU

MTP3SL VCC

AAL2UP VCC

RNC

MTP

AAL2 RANAP

MTP3b

ICSU AAL2 sig

SS7

RNSAPRNC

SCCP

SNMSNTMTP

ICSU AAL2 RANAP

MTP3b

ICSU AAL2 sig

SS7

RNSAP

SCCP

SNMSNT




Iu-BC Interface configuration

• The cell broadcast centre (CBC) is a core network element that the operator uses for centralized control of message transfer throughout a cell.

• These broadcast messages are transferred to the mobile station via a logical channel on the radio interface, the cell broadcast channel (CBCH)

• In Nokia RAN, the CBC (cell broadcast centre) is connected to the RNC via Iu-BC. The recommended size for Iu-BC is 64 kbit/s, corresponding to 151 cps in a UBR-VCC.

Service area broadcast messages can contain information on the following:• emergencies• traffic reports• road accidents• delayed public transportation• weather reports• theatre programmes• telephone numbers or tariffs

A interface

Gn interface

3G-SGSN

Iu-CS

Iu-PS

Iur

S-AXC

Iub

Iub

Iu-BC

RNC

BTS

BTS

BTS

BTSBTS

BTS

BTS

BTS

RNC

MGW

MSS/MSC

3G-CBC

GGSN

SGSN

03 rn30033 en06gln0_ran_overview

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