The UMTS Iub and Iur Interfaces

Agenda

General Iub interface

Iub procedures

General Iur interface

Iub functions

Carrying informationuser voice, user data and cell-broadcast [MS External networks]

Radio resources control (RRC) signaling [MSRNC]

NAS signaling (CC, SM, MM, SS) [MSCore]

Node-B managementLogical resources [NBAP]

Physical resources [O&M]

Managing AAL2 links between RNC and Node-B[ALCAP (Q.2630)]

Iub protocol stacks

User data

RRC

NAS

Node-B mngt

AAL2

Set VPI/VCI of NBAP and ALCAP

Iub procedures – cell setup

NBAP messages report and configure logical entities and capabilities in the Node-B.

Node-B RNC

Iub procedures – common Tr. Ch. (1)

NBAP messages set Common Transport Channels that serve users in a specific cell.

AAL2 links are set between the RNC and the Node-B (ALCAP or alternative methods).

Node-B RNC

Iub procedures – Common Tr. Ch. (2)

Node-B RNC

Extract Channel type (FACH, RACH, PCH, DCH), Channel ID, TFS, Binding ID

Extract from ALCAP messages Binding ID, Path ID (VPI/VCI), CID

Iub procedures – RRC connection (1)

RRC and NBAP messages set Dedicated Transport Channels for specific users.

MS RNCNode-B

Iub procedures – RRC connection (2)

MS RNCNode-B

Extract RLC mode, Logical channel ID, Radio bearer ID

Iub channels – protocol architecture

RLC layer

Main Functionalities:

Data transfer in 3 modes:Transparent – without protocol information

Unacknowledged – no guarantee, with protocol information (sequence number etc.)

Acknowledged – with guaranteed data transfer

Segmentations and ReassemblySDU’s of higher layer (RRC, AMR,PDCP) are segmented and reassembled on the RLC entities of the transmitting receiving sides.

Data Flow for not-transparent MAC and RLC

Iub procedures – NAS (1)

Call and session signaling (CC, SM, MM) manage a user’s connection and mobility towards the core network.

MS RNCNode-B

Iub procedures – NAS (2)

Call and session signaling (CC, SM, MM) manage a user’s connection and mobility towards the core network.

MS RNCNode-B

Iub procedures – user traffic

User voice and data information is carried over the Dedicated and possibly the Common Transport Channels.

AMR is used on CS calls

PDCP and IP are used on PS calls

IUR

The Iur interface is the interface between two RNC’s.

When a UE leaves the area controlled by an RNC to another RNC, the UE’s related data is now transferred to the new RNC over the Iur interface.

The original RNC is now referred to as Serving RNC and the new RNC is now referred to as Drift RNC.

Dedicated channels with the same characteristics are formed between the new DRNC to the relevant Node-B, according to messages received on the Iur.

AAL2 decode is the same as Iub (same protocol stack)

AAL5 protocol stack is different

Physical interface

Iub

Use RADCOM’s Performer Analyzer

to monitor and analyze the Iu and Iub links

Iur protocol stack

Main Iur messages (1)

Dedicated signaling channelRNSAP: Radio Link Setup Request

RNSAP: Radio Link Setup Response

ALCAP: Establish Request

Main Iur messages (2)

Dedicated traffic channelRNSAP: Radio Link Reconfiguration Request

RNSAP: Radio Link Reconfiguration Response

ALCAP: Establish Request

Channel DeletionRNSAP: Radio Link Deletion

RADCOM’s Solution

Line of platforms: Cellular Performer

LAN/WAN/ATM interfaces

GEAR and GenFEP

Portable or rack-mount

Extensive VoIP solutions

Powerful cellular capabilities

GEARInside

GEARInside

Supported interfaces

A complete range of interfaces:GPRS/UMTS Core: Gn, Gi, Gp, Gr, Gs, Gd, Gc, Gf, Ga

GPRS RAN: Abis, Gb, A, R

UMTS UTRAN: Iub, Iur, Iu-CS, Iu-PS

CDMA2000: A1, A3, A7, A8, A9, A10, A11, A12, A13

All networks: GSM, GPRS, EDGE, UMTS, CDMA2000

Data and voice solutions

The most updated protocol support

Over 120 GPRS protocols and variants

Over 190 UMTS protocols and variants

ETSI/3GPP R98, R99, R4, R5

3GPP versions up to June 2002

3GPP2 IOS 3.x and 4.x

ITU-T, ANSI and IETF protocols

[EDGE]

[CDMA2000 EV-DO]

New application layer protocols: MMS, H.324M, WAP, RADIUS, etc.

Summary

The Iub and Iur interfaces use resembling messages and procedures.

Many protocol layer identifiers and a complex mechanism of channels creation require an enhanced decoding solution.

The Iub and Iur add-ons, along with the broader view of the Consultants, enable the decode and troubleshooting of these interfaces.

Recommended reference:Radio Interface protocol Architecture (release 1999) TS 25.301

Further information

If you are interested in hearing more about RADCOM’s Cellular Performer, click below:

www.radcom.com/radcom/test/CellularPerformer.htm