Umts networkprotocolsandcompletecallflows_01242

Alexander SeifarthCONFIDENTIAL - DRAFTJune 1, 20051
Module 01
UE-UTRAN Signalling Protocols
Version 0.0.1 (07/02/2005)
Author: Alexander Seifarth (a.seifarth@techcom.de)

1. Network Architecture

1.1. Top Level Network Architecture

UE
UTRAN
(UMTS Terrestrial
Radio Access
Network)
UTRAN
(UMTS Terrestrial
Radio Access
Network)
CN
(Core Network)
CN
(Core Network)
Uu Iu
Access Protocols Access Protocols
Non Access Protocols
intra-UTRAN
protocols
intra-CN
protocols

UMTS inherits its top level network architecture from second generation mobile communication networks. Any UMTS
network can be divided into three major network subsystems:
• UE (User Equipment): The UE is built from Mobile Equipment (ME) providing all required hard- and software to gain
access to the network and a UMTS Subscriber Identity Module (USIM). In other words the UE is a 3G enabled cell
phone.
• UTRAN (UMTS Terrestrial Radio Access Network): The major change of UMTS compared to second generation
systems like GSM is the radio access technology. Instead of the classical GSM BSS (Base Station Subsystem) using
TDMA/FDMA radio access there is now UTRAN utilizing CDMA (Code Division Multiple Access). UTRAN currently comes in
three different flavours – FDD mode, TDD mode and low chip rate TDD mode. (This script focuses on FDD mode).
• CN (Core Network): The core network is the same for GSM and UMTS. It is responsible to provide telecommunication
services like mobility handling, circuit switched call services, packet switched data services and messaging service. The CN
can be split into domains – the CS domain and the packet switched domain.
Several signalling protocols provide the communication facilities between these subsystems. To establish the basic
communication links (access links) between UE-UTRAN and UTRAN-CN there are access signalling protocols between
these subsystems. On the other hand for telecom services there are protocols between UE and CN for mobility
management, CS call management, PDP context management, SMS, etc. These protocols belong to the so called non-
access signalling protocols. These non-access protocols are exchanged between UE and CN directly. UTRAN must
transparently pass signalling messages from non-access signalling protocols from UE to CN and vice versa.
Obviously there are also protocols inside UTRAN and inside CN. These are labelled intra-UTRAN or intra-CN protocols
respectively.

1.2. Network Elements and Interfaces

Node B
UE
RNC
Node B
Iub
Iub
RNC
Iur
Iub
Node B
RNS
RNS
BSC
BTS
BSS
Uu
MSC/VLR
Server#1
SGSN #1
SGSN #L
MSC/VLR
Server#N
. . .
. . .
CS
MGW #1
CS
MGW #K
Iu-CS
Iu-PS
Iu-PS
A
Gb
CS-CN
PS-CN

UTRAN is composed of two different network elements:
• RNC (Radio Network Controller): The RNC is responsible for all radio management tasks inside of UTRAN. This
includes channel allocation/modification/removal, handover procedures, security functions, etc.
• Node B: The Node B serves one or more cells. The tasks of the Node B is to terminated the physical layer (WCDMA FDD)
and convert it to the transport protocol on the Iub interface towards RNC. In other words the Node B is a relay point.
Anything above the radio physical layer must pass transparently through the Node B.
Between RNC and Node B there is the Iub interface. Its task is to transfer data (user data, signalling) between UE and
RNC. Furthermore there is an optional interface Iur between two RNC. The Iur interface is related to soft handover
procedures. This interface is similar to the Iub interface used for transparent transfer of data between UE and the so called
serving RNC.
For the connection between UTRAN and CN there is the Iu interface defined. It comes in two different versions – Iu-CS for
the connectivity between RNC and MSC (MSC server, CS Media Gateway MGW) and Iu-PS for RNC-SGSN communication.
The Iu interfaces shall transfer user data (CS speech calls, CS data calls, PDP context data), non-access signalling to and
from the UE and access signalling between RNC and MSC/SGSN.
Iu, Iub and Iur interfaces are currently based on ATM as transport layer technology, but also IP may be used. The IP based
UTRAN is already specified.
In parallel to UTRAN the classical GSM BSS may still be used together with UTRAN. Thus the core network still provides
connectivity for A and Gb interface. Note that in future releases also the GSM BSS may be based on Iu interfaces rather
than the old second generation protocols.

Serving
RNC
Drift
RNC
SGSN
MSC
Server
CS-MGW
Node B Node B Node B
UE
Drift RNC
• relay between Iur
and Iub
• splitting/combining
function [optional]
• local admission
control
Serving RNC
• radio management
(handover decision,
channel de/allocation
• NAS message relay
• Iu management
• backward error
correction
• splitting/combination
function
• local and global
admission control
Iur
IubIubIub
Iu-PSIu-CS

A UE can be in one of two states:
• IDLE: A UE in IDLE mode has no connectivity to UTRAN, in other words there is no signalling relation with an RNC and of
course no radio resources are allocated for the UE.
• CONNECTED: A CONNECTED mode UE has a signalling relation with an RNC which performs all radio management tasks
for this UE. This special RNC is called the serving RNC (S-RNC) for the UE. A single UE has in CONNECTED mode exactly
one serving RNC, in IDLE mode there is no serving RNC for the UE.
During soft handover procedures it can happen, that a UE is connected with a cell that does not belong to the serving
RNC’s area. The RNC managing this cell is called a drift RNC (D-RNC). A D-RNC must have an Iur interface to the serving
RNC of the UE.
The drift RNC must not perform radio management procedures for the UE, this is task of the serving RNC. The drift RNC
provides functionality to relay data between serving RNC and UE. In other words the drift RNC is a Iub/Iur relay. In some
RNC equipment also functionality to combine and split data streams to/from a UE during soft handover can be provided.

1.3. UTRAN/UE Main Functional Protocols Overview

1.3. UTRAN/UE Main Functional Protocols
UE
Node B
RNC
RNC
MSC/VLR
Server
SGSN
Iu-CS
Iu-PS
Uu Iub
IubUu
Iur
RRCRRC
RNSAPRNSAP
RANAPRANAP
RANAPRANAP
Iu-CS
ALCAPALCAP
NBAPNBAP ALCAPALCAP
ALCAPALCAP
WCDMAWCDMA
CS-MGW

There are some main functional protocols within UTRAN that implement the UMTS specific operations. These protocols are:
• RRC (Radio Resource Control): The RRC protocol is exchanged between UE and serving RNC. It provides functions
for radio channel management, handover, security functions, measurements, etc.
• RANAP (Radio Access Network Application Part): RANAP is the main protocol on the Iu interfaces. MSC server and
SGSN use RANAP signalling messages to allocated radio access bearers and to handle relocation of the serving RNC.
• NBAP (Node B Application Part): NBAP is the control protocol on the Iub interface. It allows the RNC to command the
Node B to allocate or delete channels on the air interface, to transport Node B measurements to the RNC. Although there is
a detailed specification of NBAP, most of all available UTRAN equipment implements a propriety version of NBAP.
• RNSAP (Radio Access Network Application Part): RNSAP is used on Iur interface, thus it is an open protocol. The
RNSAP protocol extends the NBAP protocol, so that a serving RNC can allocate radio resources on cells owned by a drift
RNC. Some other functions of RNSAP concern the relocation of the serving RNC function and packet data forwarding from
old to new RNC over Iur.
The mentioned protocols RRC, NBAP, RANAP, RNSAP are UTRAN specific protocols. On Iub, Iur and Iu-CS interfaces real-
time data streams will be transported. Thus before such a real-time data stream can be transferred, an appropriate
transmission bearer must be allocated on the transport network, this requires another protocol:
• ALCAP (Access Link Control Application Part): The term ALCAP is a generic “placeholder” for a transport network
specific control protocol to allocate transport bearers for delay sensitive data. In case of ATM-AAL2 transport network the
ACLAP is the ITU-T protocol Q.2630 (AAL type 2 signalling protocol). If IP/UDP is used instead, the ALCAP is not defined,
because in IP/UDP there is no resource allocation defined.

RNC
RNS
UE
MSC/VLR
Server
SGSN
MMMM CCCC SSSS SMSSMS
GMMGMM SMSM SMSSMS PS dataPS data
CS dataCS data
CS-MGW
NAS Signalling Relay

The non-access signalling protocols between UE and MSC server/SGSN are the direct transfer application part (DTAP)
protocols known from GSM/GPRS.
For the CS services there are:
• MM (Mobility Management): This protocols provides location area update, authentication, IMSI detach procedures
and some others (e.g. identity request, MM information).
• CC (Call Control): Here we find mobile originated and mobile terminated call setup, local and remote call release, as
well as call related supplementary services, mid-call modification and DTMF interaction.
• SS (Supplementary Services): This protocol allows to trigger non-call related supplementary services like USSD,
management of call forwarding and call barring, etc.
For PS core network the following protocols are used:
• GMM (GPRS Mobility Management): This protocol defines GPRS attach, GPRS detach, routing area update,
authentication, service request and some other procedures (e.g. identity request, GMM information).
• SM (Session Management): The SM protocol provides the functionality for PDP context activation, PDP context
deactivation and PDP context modification.
For PS and CS core network domain the short messaging service is possible. The protocols for SMS are identical for both
domains:
• SMS (Short Message Service): The SMS protocol suite consists of SM-CP (Short Message Control Protocol), SM-RP
(Short Message Relay Protocol), SM-TL (Short Message Transfer Layer) and SM-AL (Short Message Application Layer).

1.4. UTRAN Protocol Stacks on Iux Interfaces

1.4. Protocol Stacks on Iux Interfaces – Iu-CS
Serving
RNC
MSC/VLR Server
CS-MGW
Iu-CS (control plane)
Iu-CS (user + transport network control plane)
RANAPRANAP
ALCAPALCAPSCCPSCCP
MTP3BMTP3B
SAALSAAL SAALSAAL SAALSAAL
ATMATM
AAL2AAL2AAL2AAL2. . . . . .
PVC PVC PVC PVC PVC
MMMM CCCC SSSS SMSSMS
Iu
UP
Iu
UP
Iu
UP
Iu
UP
. . .
Iu
UP
Iu
UP
Iu
UP
Iu
UP
. . .
CS call data
User PlaneTransport
Network
Control
Plane
Control Plane

1.4. Protocol Stacks on Iux Interfaces – Iu-CS
On the Iu-CS interface the main functionality is to transfer CS call (speech, video, data) between RNC and CS media
gateway (CS-MGW). CS user data is carried over the Iu UP (Iu User Plane) protocol from RNC to CS-MGW and vice
versa. The Iu UP protocol supports codecs with multiple data rate modes like the AMR codec. Each application has its own
Iu UP instance which is carried as AAL2 call inside a AAL2 virtual channel.
To allocate AAL2 calls inside a AAL2 virtual channel the establishment procedure of the ALCAP protocol (Q.2630) must be
used. In the same way when the application terminates, the associated AAL2 call must be released by ALCAP’s release
procedure. Thus the ALCAP protocol is required between RNC and CS-MGW.
The UMTS specific higher layer control of radio access bearers the AAL2 call belongs to the RANAP protocol is used.
RANAP uses the SCCP (Signalling Connection Control Part) for virtual signalling connection between RNC and MSC
server to identify a single UE.
For signalling message transfer MTP3B (Message Transfer Part level 3 Broadband) is used. This is commonly known
as broadband or high speed SS7. MTP3B provides routing facilities between RNC, MSC server and CS-MGW. The
transmission is done on one or more high speed SS7 signalling links. Such high speed links are provided via SAAL
(Signalling ATM Adaptation Layer) protocol instances. Each SAAL represents one ATM virtual channels together with
retransmission functionality to increase transmission reliability.
The non-access signalling protocol for the circuit switched side (MM, CC, SS, SMS) are carried over RANAP.

1.4. Protocol Stacks on Iux Interfaces – Iu-PS
Serving
RNC
SGSNIu-PS (control plane, user plane)
RANAPRANAP
SCCPSCCP
MTP3BMTP3B
SAALSAAL SAALSAAL SAALSAAL
ATMATM
AAL5AAL5AAL5AAL5. . . . . .
PVC PVC PVC PVC PVC
GMMGMM SMSM SMSSMS PS call data (PDP Contexts)
User PlaneControl Plane
IPIP
UDPUDP
GTP-UGTP-U
. . .

1.4. Protocol Stacks on Iux Interfaces – Iu-PS
On Iu-PS user data consists of PDP context packets. PDP context data is transferred over the GTP-U (GPRS Tunnelling
Protocol – User plane). GTP-U provides so called GTP-U tunnels which are used to identify subscriber and PDP context
and to route PDP context data correspondingly. The GTP-U protocol uses IP/UDP as transport layer. The IP layer routes
between RNC and SGSN. In an ATM environment IP is transmitted over one or more AAL5 virtual channels.
The control stack is similar to Iu-CS. The RANAP protocol is used between SGSN and RNC to allocate radio access bearer
services for PDP contexts. There is no ALCAP on Iu-PS because AAL2 is not used here.
Obviously the non-access signalling protocols on Iu-PS are different to Iu-CS. Between RNC and SGSN we can find GMM,
SM and SMS on RANAP.

1.4. Protocol Stacks on Iux Interfaces – Iub
RNCNode BUE Uu Iub
NBAPNBAP
ALCAPALCAP
TrCH
FP
TrCH
FP
TrCH
FP
TrCH
FP
TrCH
FP
TrCH
FP
SAALSAAL
ATMATM
PVC
SAALSAAL
PVC
...
ALCAPALCAP...
SAALSAAL
PVC
SAALSAAL
PVC
...
AAL2AAL2
PVC
AAL2AAL2
PVC
...
... ...
Control Plane Transport Network
Control Plane
User Plane
Transport Channel Data

1.4. Protocol Stacks on Iux Interfaces – Iub
On the Iub interface data (user data and signalling) to and from the UE must be transported transparently. This UE-RNC is
data is transferred in form of so called transport channels TrCH. Each transport channel is carried over Iub in a Frame
Protocol (FP). Each such frame protocol FP uses a single AAL2 call inside a AAL2 virtual channel as transport resource.
To allocate a AAL2 call for a frame protocol instance, again the ALCAP protocol is required. The ALCAP is carried over a
single SAAL ATM virtual channel. Dependent on the RNC/Node B vendor also one or several ALCAP instances might be
used on Iub.
The main protocol on Iub, the NBAP protocol, may also be split into several parts. Again this depends on the equipment
vendor. Thus one or more SAAL ATM virtual channels are required to transfer NBAP messages over the Iub interface.

1.4. Protocol Stacks on Iux Interfaces – Iur
Drift RNCNode BUE Uu Iub
RNSAPRNSAP TrCH
FP
TrCH
FP
TrCH
FP
TrCH
FP
TrCH
FP
TrCH
FP
SAALSAAL
ATMATM
PVC
SAALSAAL
PVC
ALCAPALCAP
SAALSAAL
PVC
...
AAL2AAL2
PVC
AAL2AAL2
PVC
...
... ...
Control Plane Transport
Network
Control Plane
User Plane
Transport Channel Data
Serving RNCIur
SCCPSCCP
MTP3BMTP3B

1.4. Protocol Stacks on Iux Interfaces – Iur
The Iur interface is comparable to Iub with two differences. First instead of NBAP the RNSAP protocol is used. The second
difference is that RNSAP and ALCAP use broadband SS7 for transfer and routing of signalling messages between serving
RNC and drift RNC.

2. Radio Protocol Architecture and
Channels

Channels
2.1. Radio Protocol Architecture

WCDMA Physical Layer (FDD)WCDMA Physical Layer (FDD)
#1 #2 #n
Medium Access Control (MAC)Medium Access Control (MAC)
Transport Channels (TrCH)
Physical Channels (PhCH)#1 #k
RF
#1 #x #y #z
RLCRLC RLCRLC...
RLCRLC RLCRLC...
#y2
RLCRLC
BMCBMCPDCPPDCP
#1 #x #y #z#y2
RRCRRC
...
MMMM GMMGMM SMSM CCCC SSSS SMSSMS
NAS Protocols CS
App
CS
App
PS
PDP Ctx.
PS
PDP Ctx.
CB
SMS
App
CB
SMS
App
#y1
RLCRLC
#y1
Logical Channels (LogCH)
Radio Bearer (RB)
...
...
RAB RAB

The UMTS radio protocol architecture as it is implemented in the UE has the following protocols:
• WCDMA Physical Layer: The physical layer offers bit transport services in form of so called transport channel TrCH.
To transmit TrCH data over the air the physical layer has access to physical channels PhCH. A PhCH represents the
physical resource and is identified by frequency, scrambling code and channelization code (plus some additional parameters
for certain channels).
• Medium Access Control (MAC): MAC protocol has the task to include or check UE identifiers on transport channels
that are shared between several UE (common transport channels). The transport services are offered to higher layers in
form of logical channels LogCH. Thus the MAC also has to multiplex and demultiplex logical channels onto or from
transport channels.
• Radio Link Control (RLC): To each logical channel there is one RLC instance. The RLC belongs to a single radio
bearer (RB) which represents the transmission resource for a layer 3 application (codec, RRC protocol, PDP context). The
RLC protocol offers reliability in form of sequence numbering and backward error correction. Typically one RLC belongs to
one logical channel, but for acknowledged mode one RLC instance can also utilize two logical channels.
• Packet Data Convergence Protocol (PDPC): This protocol is applicable for radio bearers belonging to PDP contexts
only. The protocol performs IP header compression and optionally also IP datagram numbering.
• Broadcast Multicast Control (BMC): This protocol exists only for cell broadcast SMS radio bearer. This protocol
contains the scheduling messages and the basic CB SMS frames.
• Radio Resource Control (RRC): The main signalling protocol for radio resource management.
For a single application one or more radio bearers have to be allocated. For user applications all radio bearers of a single
application are combined in a radio access bearer (RAB).

Channels
2.2. Logical Channel Types and their Usage

UE Identification in UTRAN
Serving
RNC
Node BUE Uu Iub
No UE IdentificationNo UE Identification
Layer 1 IdentificationLayer 1 Identification
Case UE Identification in RNC
Some information (System Information, CB SMS) does
not require a UE identification.
UE must have a dedicated physical resource. This
resource uniquely identifies the UE for the time the
resource is assigned to it.
UE uses common resources and identifies itself with a
special MAC header identifier (c-RNTI, u-RNTI, dsch-
RNTI) on that resource.
UE has no dedicated resource and no assigned MAC
header identifier, but uses common resources (RRC
signalling only). The RRC message must contain a UE
identifier as layer 3 parameter.

BCCHBCCH
PCCHPCCH
CCCHCCCH
DCCHDCCH
DTCHDTCH
CTCHCTCH
Logical Channel Types
Control Channels
Traffic Channels
Broadcast Control Channel
[dl, ptm]
System Information broadcast; downlink channel;
no UE specific information
Paging Control Channel
[dl, ptm]
Point-to-multipoint paging procedure (Paging Type 1)
UE identification by RRC message itself
Common Control Channel
[ul+dl, ptp]
Point-to-point RRC signalling on common resource
when no MAC identifier available
Dedicated Control Channel
[ul+dl, ptp]
Point-to-point RRC signalling on common or dedic.
resource with MAC identifier available (on common
resource)
Dedicated Traffic Channel
[ul|dl|ul+dl, ptp]
Point-to-point data (CS data, CS speech, PS data) on
common or dedicated resource (requires MAC-ID on
common resource).
Common Traffic Channel
[dl (currently), ptm] Used for cell broadcast SMS. Thus no UE-ID.
ptm: point-to-multipoint
ptp: point-to-point
dl: downlink
ul: uplink

For FDD mode the following logical channel types are defined:
• BCCH (Broadcast Control Channel): The BCCH carries the cell’s system information, which are RRC messages
(System Information Blocks, Master Information Block). The BCCH is not associated with a radio bearer.
• PCCH (Paging Control Channel): The PCCH carries RRC messages ‘Paging Type 1’. This message type is used to page
a UE or to indicate system information changes. Like the BCCH there is no radio bearer associated with the PCCH.
• CCCH (Common Control Channel): The CCCH is a bi-directional RRC signalling channel where layer 3 identification is
required. The UE uses CCCH signalling at the beginning of communication when no DCCH is available. Only radio bearer RB
0 is attached to CCCH. RB 0 is configured via system information, because it works as a start up point.
• DCCH (Dedicated Control Channel): The normal bi-directional RRC signalling and also rate control signalling is
exchanged on a DCCH. Every DCCH is associated with its own radio bearer which must be configured via explicit RRC
signalling from RNC to UE. On DCCH only layer 1 or layer 2 identification is allowed.
• DTCH (Dedicated Traffic Channel): CS call data (speech, video, data) as well as PDP context data is carried over
DTCH. Like for DCCH also on DTCH layer 1 or layer 2 identification is required, layer 3 identification is not possible.
• CTCH (Common Traffic Channel): This channel type is currently used for cell broadcast SMS (CB SMS) only.
It should be obvious that any DTCH or CTCH requires an associated radio bearer. Such radio bearers are granted via RRC
procedure from the RNC to the UE.

Channels
2.3. Transport Channel Types and their Usage

Node B
UE
UE
WCDMA FDD cell
dedicated
physical
channels
common
physical
channel
Dedicated TrCHDedicated TrCH
UE
Common TrCHCommon TrCH
Common TrCHCommon TrCH
Common TrCH
• mapped onto shared
physical resources
• multiple UE can be
assigned to same physical
resource
• requires Layer 2
identification for DCCH,
DTCH
• requires Layer 3
identification for CCCH,
PCCH [opt]
Dedicated TrCH
• mapped onto dedicated
physical resources
• only one UE can use the
physical resource
• automatically provides
Layer 1 identification for
the UE assigned to the
channel
• used with DCCH and
DTCH

2.3. Transport Channel Types and their Usage 1
BCHBCH
PCHPCH
RACHRACH
FACHFACH
Transport Channel Types
Common Channels
Broadcast Channel
[dl, 1/cell]
Carries BCCH.
Paging Channel
[dl, ≦16/cell] Carries PCCH.
Random Access Channel
[ul, ≦16/cell]
Can carry CCCH, DCCH and DTCH. Minimum SF is 32
and maximum transmission time is 10|20 ms.
Forward Access Channel
[dl, ≦16/cell] Can carry CCCH, DCCH, DTCH, BCCH and CTCH.
Minimum SF is 4.
dl: downlink
ul: uplink
DSCHDSCH
CPCHCPCH
HS-DSCHHS-DSCH
Downlink Shared Channel
[dl, ≦?/cell]
Common Packet Channel
[ul, ≦64/cell]
High Speed DSCH
[dl, ≦16/cell]
Carries DCCH and DTCH. A DSCH is always used
together with one or more DCH.
Carries DCCH and DTCH. Minimum SF is 4 and
maximum transmission time is 80 ms.
Carries DCCH and DTCH. Can switch between QPSK
and 16QAM on physical channel.

2.3. Transport Channel Types and their Usage 2
DCHDCH
Transport Channel Types
Dedicated Channels
Dedicated Channel
[ul|dl]
One DCH can carry one or more DCCH or one DCH
can carry one or more DTCH.

A single transport channel has a certain characteristics that describes how bits are transmitted over the air interfaces. This
concerns bit rate, delay and reliability. A special characteristics is whether the associated physical channel used for
transport channel data transmission is dedicated to a single UE or must be shared between several UE. This means that we
have two groups of transport channels – dedicated TrCH and common TrCH.
Common transport channels are created during cell setup or O&M triggered cell reconfiguration. In UMTS FDD mode we
have the following common transport channels:
• BCH (Broadcast Channel): There is exactly one BCH per cell and it is used to carry BCCH. The format of a BCH is fixed
by specification so that any UE camping on a cell can read the BCH.
• PCH (Paging Channel): A PCH carries PCCH. A cell may have up to 16 PCH by specification. A UE selects a PCH
depending on subscriber identity.
• RACH (Random Access Channel): The random access channel is used to carry CCCH, DCCH, DTCH in the uplink. In
case of CCCH any UE in the cell can freely access the RACH, for DCCH/DTCH a UE has to get permission from the RNC to
do so. Especially it is so that for DCCH/DTCH on RACH the UE needs a temporary identifier (C-RNTI) for layer 2
identification.
• FACH (Forward Access Channel): The FACH is the downlink response channel to the RACH. It is used to carry CCCH,
DCCH, DTCH, CTCH and BCCH. For DCCH/DTCH on FACH the already mentioned C-RNTI is required. Note that there is no
fixed timing relationship between transmission on RACH and reception on FACH. Rather a UE that uses RACH/FACH the
FACH must be monitored permanently.
• CPCH (Common Packet Channel): The CPCH is working like the RACH, but is used for DCCH and DTCH only.
Compared to the RACH the CPCH allows higher bit rates and longer transmission periods – thus a higher throughput can be
achieved on CPCH.

• DSCH (Downlink Shared Channel): The downlink shared channel shall be used for packet data in the downlink. The
channel allows multiplexing of DCCH/DTCH of several UE using time and code multiplexing mechanisms. This shall increase
resource usage efficiency.
• HS-DSCH (High Speed Downlink Shared Channel): This channel is one of the new features in UMTS Release 5. The
HS-DSCH has the same function like the normal DSCH. DCCH/DTCH of several UE shall be multiplexed – again time and
code multiplexing is used. The special thing is, that the physical resource allocation and the multiplexing is handled at the
Node B, not at the RNC. Furthermore the associated physical channel allows switch between QPSK and 16QAM.
In contrast to this the dedicated transport channels which are assigned to a single UE will be created and deleted during
normal operation using NBAP/RNSAP- and RRC-procedures. There is only one dedicated transport channel type defined:
• DCH (Dedicated Channel): The dedicated channel carries either several (or one) DCCH or several (or one) DTCH.
Obviously several logical channels on a DCH belong to the same UE. Thus the DCH is the only case where layer 1
identification is in use. A UE can have several DCH simultaneously. A single DCH is either uplink or downlink.

Channels
2.4. Physical Channels and their Usage

2.4. Physical Channels and their Usage 1
P-SCHP-SCH
S-SCHS-SCH
P-CPICHP-CPICH
Physical Channel Types
Synchronisation Channels
Primary Synchr. Channel
[dl, 1/cell]
Transmits Primary Synchr. Code (PSC) to detect cell.
Secondary Synchr. Channel
[dl, 1/cell]
Transmits a Secondary Synchr. Code sequence to
identify scrambling code group and radio frame start.
Primary Common Pilot CH
[dl, 1/cell] Transmits a pre-defined symbol sequence (all –1)
with the primary dl scrambling code of the cell.
dl: downlink
ul: uplink
S-CPICHS-CPICH
P-CCPCHP-CCPCH
Secondary CPICH
[dl, 0...15/cell]
Primary Common Control
Physical Channel
[dl, 1/cell]
Transmits a pre-defined symbol sequence with one
the 15 possible secondary scrambling codes of cell.
Carries BCH with BCCH. Always scrambled by primary
dl scrambling code of the cell.
Measurement Reference Channels
System Information Broadcast

S-CCPCHS-CCPCH
PICHPICH
PRACHPRACH
PhCH for FACH and PCH
Secondary Common
Control Physical Channel
[dl, ≦ 16/cell]
Carries either 1) FACH only, 2) PCH only or 3) FACH
+ PCH multiplexed.
Paging Indicator Channel
[dl, ≦ 16/cell]
Contains paging indicators for discontinuous
reception (DRX) in association with a PCH.
Physical Random Access
Channel
[ul, ≦ 16/cell]
Consists of a preamble part to perform open loop
power control and a data part transferring RACH data.
dl: downlink
ul: uplink
AICHAICH
Acquisition Indicator
Channel
[dl, ≦ 16/cell]
Associated with a single PRACH. Carries the preamble
responses (acquisition indications).
PhCH for RACH

DPCHDPCH
DPCCHDPCCH
PDSCHPDSCH
PhCH for DCH
Dedicated Physical Channel
[dl, dynamical allocation]
Carries one or several DCH of a single UE and
physical layer information (TPC, pilot bits, TFCI).
Data rate ≦1860 kpbs (SF=4). [Physical channel bit rate]
Dedicated Physical Ctrl CH
[ul, dynamical allocation]
[ 1/UE]
Carries physical layer information from a single UE to
Node B (TPC, pilot bits, TFCI, FBI). SF=256 fix.
Physical Downlink Shared
Channel
[dl, dynamical allocation
of codes]
Carries a DSCH with DCCH/DTCH of several UE
multiplexed by time and channelization codes.
Data rate ≦ 1920 kbps (SF=4).[Physical channel bit rate]
dl: downlink
ul: uplink
DPCHDPCH
Dedicated Physical Channel
[dl, dynamical allocation]
A PSDCH must be used by together with DPCH by a
UE. The DPCH contains physical layer control bits.
PhCH for DSCH
DPDCHDPDCH
Dedicated Physical Data CH
[ul, dynamical allocation]
[≦6/UE]
Carries one or several DCH of a single UE to Node B.
Data rate ≦ 960 kpbs (SF=4). [Physical channel bit rate]

PCPCHPCPCH
AP-AICHAP-AICH
CSICHCSICH
PhCH for CPCH
Physical Common Packet
Channel
[ul]
Carries CPCH with DCCH/DTCH of several UE
multiplexed by time (asynchronous) and CPCH access
preambles, collision detection preambles and power
control preambles.
Data rate ≦960 kpbs (SF=4) for max. 80 ms.
Access Preamble
Acquisition Indicator CH
[dl]
Gives positive or negative acquisition indications to
CPCH access preambles for CPCH access preambles.
CPCH Status Indicator CH
[dl]
Gives status indications about availability/non-
availability of CPCH resources.
dl: downlink
ul: uplink
CD/CA-ICHCD/CA-ICH
Collision Detection/
Channel Assignment
Indicator Channel
[dl]
Gives collision indications or channel assignment
indications (code alloc.) for CPCH collision preambles.
DPCHDPCH Dedicated Physical CH
[dl]
Carries physical layer control bits (TPC) used for
closed loop power control of PCPCH.

HS-PDSCHHS-PDSCH
HS-SCCHHS-SCCH
PhCH for HS-DSCH
High Speed Physical
Downlink Shared Channel
[dl, ≦ 15/cell]
Carries a HS-DSCH with DCCH/DTCH of several UE.
Fixed spreading factor 16. Up to 15 HS-PDSCH may
be used in parallel. Can switch between QPSK and
16QAM.
Single HS-PDSCHData rate =960 kpbs (16QAM) and
=480 kbps (QPSK).
HS-DSCH related
Shared Control Channel
[dl, ≦4 per HS-DSCH]
On this channel the physical layer assigns a UE the
HS-PDSCH for the next transmission period.
dl: downlink
ul: uplink
HS-DPCCHHS-DPCCH Dedicated Physical CH
[ul, 1 per UE on HS-DSCH]
Transmits quality indicator (C/I) and
acknowledgements for received data on HS-PDSCH
from UE to Node B.

Channels
2.5. Radio Bearers (RB) and Radio Access Bearers (RAB)

2.5. RB and RAB - Architecture
RB 1
R
R
C
RB 2
RB 3
RB 4
R
R
C
A
M
R
RB 5
RB 6
RB 7
RB 8
Rate
control
Iu UP
UE Serving
RNC
RAB subflow 1
RAB subflow 2
RAB subflow 3
MSC
Server
CS-MGW
Iu UP
AMR
A
B
C
A B C
SGSN
PDP
Ctx.
1
RB 9
PDP
Context 1
RAB (CS)
RAB (PS)
RAB (PS)
PDP
Ctx.
2
PDP
Context 2

2.5. RB and RAB - Architecture
Transmission resources for telecommunication services in UMTS are handled on several levels – each network subsystem is
responsible for its own resources. This allows to handle transmission resources on different time scales.
As shown in the section about the radio protocol architecture within UTRAN each application uses one or more so called
Radio Bearers (RB). Radio bearers are used for signalling (RRC protocol messages, rate control signalling) as well as for
user data applications (CS calls, PDP contexts). But user data applications have to be terminated by the core network.
Thus for each active application the core network establishes one so called Radio Access Bearer (RAB). A RAB can be
considered as a virtual transmission resource between UE and CN.
Depending on the application a single RAB can utilize one or more radio bearers. For PDP contexts it is even possible to
have a RAB without radio bearer. Note that a PDP context can be active with and also without radio access bearer. The
SGSN removes or reallocates the RAB by timer supervision. Whereas the radio bearers are removed and reallocated by the
RNC also by timer supervision.

2.5. RB and RAB – RRC Radio Bearer Usage
RRCRRC
MACMAC
PHYPHY
MMMM GMMGMM SMSM CCCC SSSS SMSSMS
NAS Protocols
high priority
signalling transfer
low priority
signalling transfer
RB 0
RLC
(UL:TM; DL:UM)
CCCH
RB 1
RLC
(UL/DL:UM)
DCCH 1
RB 2
RLC
(UL/DL:AM)
DCCH 2
RB 3
RLC
(UL/DL:AM)
DCCH 3
RB 4
RLC
(UL/DL:AM)
DCCH 4
UL-TrCHDL-TrCH

2.5. RB and RAB – RRC Radio Bearer Usage
The RRC protocol has to use radio bearers for the transmission of its signalling messages.
The very first radio bearer RB 0 is special, because it is configured via system information (BCCH) and acts as a start up
item for signalling. RB 0 is always mapped to CCCH and is thus found on RACH and FACH.
For normal signalling (DCCH) there are RB 1, RB 2, RB 3 and RB 4. RB 1 and RB 2 are used for radio management
procedures only, whereas RB 3 and RB 4 are to be used for non-access signalling (CN procedures). The difference between
RB 1 and RB 2 is the mode of the associated RLC protocol instance. RB 1 is always running with unacknowledged mode, RB
2 always uses acknowledged mode.
RB 3 and RB 4 have to use acknowledged mode, their difference is the priority. RB 3 is for high priority CN signalling (MM,
GMM, SM, CC, SS). In contrast to that RB 4 is for low priority signalling (SMS).

Channels
2.6. Channel Configuration Scenario

DL
RB 1
UM
DCCH 1
RB 2
AM
DCCH 2
RB 3
AM
DCCH 3
RB 4
AM
DCCH 4
RB 5
TM
DTCH 1
RB 6
TM
DTCH 2
RB 7
TM
DTCH 3
RB 8
TM
DCCH 5
RB 9
UM|AM
DTCH 5
PDCP
RLC
RRCRRC
MM, GMM, CC, SS, SM, SMSMM, GMM, CC, SS, SM, SMS
AMR codecAMR codec PDP Ctx.PDP Ctx.
MAC
DCH #31
DCH
#0
DCH
#1
DCH
#2
DCH
#3
DCH
#4
A B C frame
header
PHY
UE with one variable rate AMR CS call, 1 PDP context (active data transfer)
DPCH DPCCH DPDCH UL

The scenario shown here presents the configuration of a UE in UTRA connected mode with two services running:
• one AMR speech call with variable bit rate,
• one PDP context with active data transfer.
The UE uses several radio bearers RB1, …, RB4 for RRC signalling. Obviously these radio bearers are DCCH. For the AMR
codec also four radio bearers are required. RB 5, …, RB 7 carry the encoded speech data in form of the codec’s A, B and C
bits. Every 20 ms the codec produces one set of A, B and C bits. Together with the codec frame header which are mapped
to RB 8 they form the AMR codec frame. The frame header is essential for rate control of AMR codecs. For the PDP context
there is at most one radio bearer RB 9 required. RB 5, 6, 7 and 9 are mapped to DTCH, whereas the radio bearer RB 8 for
the AMR codec frame header is DCCH.
All RRC signalling radio bearers RB 1, …, RB 4 are multiplexed onto the same DCH (UL-DCH + DL-DCH). RB 5, 6, 7 and 8
belong to the codec but require different reliability settings. Thus they are mapped each to their own DCH (UL/DL). The
same is true for the PDP context’s radio bearer RB 9, it also gets its own DCH.
On the physical layer all DCH can be multiplexed to a single DPDCH in the uplink and a DPCH in the downlink. If the data
rate exceeds the capacity of single DPDCH or DPCH, several physical channels might be used in parallel.

Module 02
Radio Layer 2 Protocols MAC, RLC,
PDCP
Version 0.0.1 (10/02/2005)

1. Transport Channel Configuration

1.1. Transport Formats (TF) and Transport Format Sets
(TFS)

1.1. TF and TFS – Transport Blocks and Format
MACMAC PHYPHY
TrCH x
Transport Block TB #0
Transport Block TB #1
Transport Block TB #N-1
. . .
Transport Block Set TBS
Transport Block
Set TBS
Transport Block
Set TBS
Transport Block
Set TBS
time
Transmit Time
Interval TTI
Transmit Time
Interval TTI
Transport Format (TF)
channel coding algorithm
CRC size
rate matching attribute
TTI
TB size (no. of bits)
TBS size (no. of TB in TBS)

| 1.1.1.1.9.1.3.1.1.1.2 dedicatedDynamicTF-Info |
| 1.1.1.1.9.1.3.1.1.1.2.1 rlc-Size |
| 1.1.1.1.9.1.3.1.1.1.2.1.1 octetModeType1 |
|10000--- |1.1.1.1.9.1.3.1.1.1.2.1.1.1 sizeType1 |16 |
| 1.1.1.1.9.1.3.1.1.1.2.2 numberOfTbSizeList |
| 1.1.1.1.9.1.3.1.1.1.2.2.1 numberOfTransportBlocks |
| |1.1.1.1.9.1.3.1.1.1.2.2.1.1 one |0 |
| 1.1.1.1.9.1.3.1.1.1.2.3 logicalChannelList |
| |1.1.1.1.9.1.3.1.1.1.2.3.1 allSizes |0 |
| 1.1.1.1.9.1.3.1.2 semistaticTF-Information |
| 1.1.1.1.9.1.3.1.2.1 channelCodingType |
|1------- |1.1.1.1.9.1.3.1.2.1.1 convolutional |third |
|***b8*** |1.1.1.1.9.1.3.1.2.2 rateMatchingAttribute |185 |
|-011---- |1.1.1.1.9.1.3.1.2.3 crc-Size |crc16 |

Each transport channel has to be configured with a set of transport characteristics that control the data transmission within
the channel.
Data transmission within a transport channel is organized in so called transport blocks (TB). A single transport block TB
contains data from one logical channel. Zero, one or more of these transport blocks (also from different logical channels)
are assembled in a single transport block set (TBS). One TBS has to be transmitted every transmission time interval
(TTI), which can be 10 ms, 20 ms, 40 ms or 80 ms.
The configuration of a single transport channel has to configure the TTI, TB size (bits or octets) and TBS size (in number of
transport blocks). Every transport block TB gets in the physical layer its own cyclic redundancy check (CRC). The size of the
CRC (CRC Size) which can be 0 bits, 8 bits, 12 bits, 16 bits or 24 bits, is a transport channel configuration parameter too.
The transport blocks together with their CRC are channel coded with either a ½ convolutional coding, 1/3 convolutional
coding or a 1/3 turbo coding. The type of channel coding is also part of the TrCH configuration parameter.
A problem of code division multiple access using OVSF channelization code tree is that the number of bits after channel
coding must be adapted to the physical layer frame size. This task is performed by the rate matching function. When too
many bits are coming from the channel encoder a puncturing algorithm will be used to reduce the number of bits, when
too less bits are available some bits will be repeated. The rate matching algorithm is configured with a single rate
matching attribute.
These parameters: TB size, TBS size, TTI, CRC size, Channel Coding and Rate Matching Attribute form a so called
transport format (TF). A single TBS is transmitted with exactly one TF. Several transport formats TF can be configured
in parallel for a single transport channel. All TF of a TrCH are called transport format set (TFS). The physical layer’s
architecture requires that all TF of a TFS have the same settings for TTI, CRC size, Channel Coding and Rate Matching
Attribute.
Whenever a new TrCH shall be created it is the RNC that allocates a TFS for it. The TFS is sent to Node B via NBAP
signalling. The UE gets the TFS either via System Information (BCCH) or via explicit RRC signalling on a CCCH or DCCH.

1.2. Transport Format Combinations TFC

TFS (TrCH 1)
MACMAC
PHYPHY
TrCH 1 TrCH 2
TFI 0
TFI 1
TFI 2
TFI 0
TFI 1
TFS (TrCH 2)
0 kbps
8 kbps
0 kbps
16 kbps
32 kbps
TrCH 1 TrCH 2TFCI Total TrCH Bit Rate
TFI 0 TFI 1
TFI 0 TFI 2
TFI 0TFI 0
TFI 1 TFI 0
TFI 1 TFI 2
TFI 1TFI 1
0
1
2
3
blocked
blocked
16 kbps
32 kbps
0 kbps
8 kbps
40 kbps
24 kbps

A UE can use several transport channels simultaneously. Each transport channel has its own set of transport formats
assigned. This means at every time instant every transport channel transmits a TBS using a certain transport format.
A set of one transport format for every configured transport channel is a transport format configuration (TFC). Which
transport format combinations TFC are permitted is indicated by the RNC to the UE. One major function that uses TFC
restrictions is the admission control, because in the end effect each TFC is associated with a certain required transmission
power.

2. Medium Access Control MAC

2.1. MAC Entities

2.1. MAC Entities
MAC-b
NBAP
MAC-c/sh
MAC-d
MAC-b
MAC-c/sh
MAC-d
NBAP
MAC-d
MAC-hs MAC-hsHS-DSCH
DCH
RACH, FACH,
DSCH, CPCH,PCH
BCH
UE RNCNode B

2.1. MAC Entities
The MAC protocol is split into several entities:
• MAC-b: This entity is responsible for broadcasting the system information downlink. The system information is
assembled by the RNC at sent via NBAP messages to the Node B. From here the MAC-b sends this information periodically
in the cell.
• MAC-c/sh: MAC-c/sh has to manage all common transport and shared logical channels. For DCCH/DTCH on common
transport channels this includes identification of the UE with help of special UE identifiers contained in the MAC header.
• MAC-d: For DCH as well as DCCH/DTCH the MAC-d entities are responsible.
MAC-b and MAC-c/sh are created once per cell, whereas MAC-d is available inside the UE and the serving RNC for each UE.
For high speed downlink packet access a new MAC entity is introduced:
• MAC-hs: This entity manages the high speed downlink shared channel HS-DSCH. It is implemented in the Node B and
gets its data input from MAC-d (serving RNC) directly or indirectly via MAC-c/sh (drift RNC). MAC-hs is especially
responsible to perform the scheduling of downlink packet data.

2.2. MAC – PDU, LogCH Identification, UE Identification
on Layer 2

2.2. MAC-PDU, UE/LogCH Identification
MAC-dMAC-d
DCH #N
PHYPHY
DCH case:
DxCH
#0
DxCH
#1
DxCH
#K-1
. . .
TB #0 (MAC-PDU #0)
TB #1 (MAC-PDU #1)
TB #L-1 (MAC-PDU #L-1)
. . .
MAC
Header
MAC-SDU = LogCH Data
(RLC PDU)
MAC - PDU
DxCH – number (if K>1)
x = T(raffic) | C(ontrol)

MAC-c/shMAC-c/sh
RACH |
FACH |
DSCH |
CPCH
PHYPHY
Common TrCH (RACH, FACH, DSCH, CPCH) case:
CCCH BCCH|
CTCH
DxCH
#K-1
. . .
TB #0 (MAC-PDU #0)
TB #1 (MAC-PDU #1)
TB #L-1 (MAC-PDU #L-1)
. . .
MAC
Header
(RLC PDU)
MAC - PDU
x = T(raffic) | C(ontrol)
DxCH
#0
UE-identifier (for DxCH only)
LogCH Type
from MAC-d

Common TrCH (HS-DSCH) case:
MAC-dMAC-d
HS-DSCH
PHYPHY
DxCH
#0
DxCH
#1
DxCH
#K-1
. . .
MAC-hsMAC-hs
MAC-d Flow
LogCH Type
MAC
Header
(RLC PDU)
MAC-d - PDU
MAC-d
PDU #0
MAC-d
PDU #M-1
. . .MAC-hs
Header
MAC-hs PDU

Two major functions are provided by MAC protocol:
• explicit UE identification on common transport channels,
• multiplexing of logical channels onto/from transport channels.
On a DCH the MAC frame provides in its header the DCCH or DTCH logical channel number if more than one logical
channel is multiplexed onto the DCH.
On common transport channels like RACH, FACH, DSCH, FACH or CPCH the MAC header indicates the type of logical
channel that the transport block carries, the UE identity if the logical channel is DCCH or DTCH and if more than one logical
channel of the same UE and of the same type is contained the logical channel number.
For high speed downlink packet access a single UE can get one or more so called MAC-d flows on Iub interface. Each MAC-
d flow corresponds to a so called re-ordering queue. The MAC-d PDU indicates to which logical channel (DTCH) the data
belongs to. On the air interface the MAC-hs entity assembles several MAC-d PDU of the same user and bundles them in a
MAC-hs PDU. In the MAC-hs PDU the re-ordering queue identity and a sequence number (for retransmission purposes) is
contained. Furthermore size indicators for the contained MAC-d PDU are implemented into the MAC-hs PDU.

• MAC-PDU (non HS-DSCH)
TCTF
UE-ID
Type
UE-ID C/T
MAC Header
RLC PDU (LogCH Data)
• MAC-d PDU (for HS-DSCH)
C/T
MAC Header
RLC PDU (LogCH Data)
MAC SDU
MAC SDU
• MAC PDU (HS-DSCH)
MAC-hs Header
MAC Header MAC-hs SDUs
MAC-d PDU
#0
MAC-d PDU
#1
MAC-d PDU
#N-1
. . .
Version
Flag
Queue
ID
Seq.No.
TSN
Size Index
Id. #0
No. MAC-d
PDUs #0
Flag #0
Size Index
Id. #Y
No. MAC-d
PDUs #Y
Flag #Y. . .

UE
U-RNTI (32 bit)U-RNTI (32 bit)
MAC header UE identifier
C-RNTI (16 bit)C-RNTI (16 bit)
DSCH-RNTI (16 bit)DSCH-RNTI (16 bit)
RNC
MAC PDU
-- (no MAC UE ID)-- (no MAC UE ID) • UE uses CCCH/PCCH/BCCH/CTCH or
DCH/HS-DSCH
• UE uses DCCH/DTCH on RACH/FACH in a
new cell
• UE uses DCCH/DTCH on RACH/FACH/
CPCH (not after cell change)
• UE uses DCCH/DTCH on DSCH
= S-RNC-ID + S-RNTI

• TCTF (Target Channel Type Field): Indicates logical channel type that is carried in the MAC header.
• UE-ID/UE-ID type: Identifies a UE on common transport channels for DCCH or DTCH. The UE-ID can be u-rnti (umts –
radio network temporary identifier), c-rnti (cell-rnti) or dsch-rnti. These identifiers must be allocated for a UE via RRC
signalling before their use.
• C/T (Channel of Type): If several logical channels of the same type are multiplexed onto the same transport channel,
this field is used to distinguish and therefore demultiplex them.
The following information elements are used in HS-DSCH frames only:
• Version Flag: Currently always set to zero. May be used to allow MAC-hs extensions in future.
• Queue ID: Indicates which re-ordering queue inside the UE the data belongs to. This enables independent buffer
management for data of different applications.
• TSN (Transmission Sequence Number): Sequence number for re-ordering purposes in case of disordering or re-
transmission.
• SID (Size Index Identifier): Identifies the size of a number of consecutive MAC-d PDU (see next field). The SID is
dynamically configured via higher layer signalling and is independent for each re-ordering queue.
• Number of MAC-d PDU: Indicates the number of consecutive MAC-d PDU with the same SID.
• Flag: If 0 then another SID fields follows, if 1 then the MAC-d PDU part starts after the flag.

| 2 FP: Transport Block |
|01------ | 2.1 MAC: Target Channel Type Field |DTCH/DCCH (Dedicated Traffic/Cont... |
|--01---- | 2.2 MAC: UE-ID Type |C-RNTI (Cell Radio Network Tempor... |
|**b16*** | 2.3 MAC: UE-ID |0 |
|----0010 | 2.4 MAC: C/T Field |Logical Channel 3 |
| | 2.5 MAC: RLC Mode |Acknowledge Mode |
|1------- | 2.6 RLC: Data/Control |Acknowledged mode data PDU |
|**b12*** | 2.7 RLC: Sequence Number |1 |
|-----1-- | 2.8 RLC: Polling Bit |Request a status report |
|------01 | 2.9 RLC: Header extension type |Octet contains LI and E bit |
|0001010- | 2.10 RLC: Length Indicator |10 |
|-------1 | 2.11 RLC: Extension Bit |The next field is LI and E bit |
|1111111- | 2.12 RLC: Length Indicator |Rest is padding |
|-------0 | 2.13 RLC: Extension Bit |The next field is data |
|**B10*** | 2.14 RLC: Last Data Segment |94 02 08 00 18 00 11 88 10 00 |
|***B4*** | 2.15 RLC: Padding |00 00 00 00 |
• Example: MAC-PDU (Transport Block) DCCH on FACH

The two examples show a trace made on Iub interface. They contain MAC PDU on non-high speed channels.
The first example shows a transport block on DCH. There is no UE-ID because a DCH is already identifying a UE uniquely.
Also there is no TCTF, because on a DCH there can be either DCCH or DTCH but not mixed.
The second example shows a transport block on FACH. The TCTF indicates that DCCH is transported, thus a UE-ID is
required to assign the dedicated data to a UE. In this case the c-rnti is used.

2.3. RACH Access Control

2.3. RACH Access Control – Basic Procedure 1(3)
UE RNCNode B
Uu Iub
MAC PHY PHY MAC
Acess.Request[PHY]
R=random (0≤R<1)
IF (R ≤ P)
TRUE
Wait 10 ms
FALSE
START P = Persistence Value (SIB 7)
M = Preamble Cycle Counter (UE counter)
AccessPreamblePHY:PRACH
. . .
1st
Preamble Cycle
Case: No acquisition indication
1) maximum no. of preambles
2) maximum power on PRACH
NoAck.Indication[PHY]
M= 1

UE RNCNode B
Uu Iub
MAC PHY PHY MAC
Acess.Request[PHY] AccessPreamblePHY:PRACH
AI = -1PHY:AICH
2nd
Preamble Cycle
Case: Negative acquisition indication
NAck.Indication[PHY]
R=random (0≤R<1)
IF (R ≤ P)
TRUE
Wait 10 ms
FALSE
M:=M+1
Wait 10 ms

UE RNCNode B
Uu Iub
MAC PHY PHY MAC
Acess.Request[PHY]
AI = +1PHY:AICH
3rd
Preamble Cycle
Case: Positive acquisition indication
Ack.Indication[PHY]
R=random (0≤R<1)
IF (R ≤ P)
TRUE
Wait 10 ms
FALSE
M:=M+1
NBO1=random
{0 ≤ NBO1min
≤ NBO1
≤ NBO1max
}
Wait TBO1 (= NBO1 x 10 ms)
Wait 10 ms
NBO1min
= minimum value for backoff timer 1 (SIB)
NBO1max
= maximum value for backoff timer 1 (SIB)
Data.Request[PHY] RACH DataPHY:PRACH RACH DATARACH-FP

2.3. RACH Access Control – Basic Procedure
The MAC layer is in control of the PRACH preamble cycles. This means the MAC layer has to trigger PRACH preamble cycles
and to handle negative outcomes of this procedure.
Whenever a data transmission on RACH shall be done the MAC layer will first of all generate a random number R and
compare it against a so called persistence value P. The persistence value P is coming from system information SIB 7, a
block generated by the Node B itself. If the number R is bigger than P (R>P) then the MAC layer will wait 10 ms and
generate a new random number. If R is less or equal to P then the physical layer can start a random number. By
decreasing P the Node B can reduce the number of UE that will simultaneously access the RACH.
When a preamble cycle ends without an indication from the Node B, then the MAC layer will wait another 10 ms and restart
the preamble cycle (of course with random number and persistence check first) again.
When a preamble cycle ends with a negative indication from the Node B, then again the MAC layer has to wait 10 ms. But
afterwards the backoff 1 timer (T_BO1) is started with a time N_BO1 x 10 ms. N_BO1 is a random number that lies within
the range N_BO1min and N_BO1max. These limits are BCCH parameters. When T_BO1 has its time out, then another
preamble cycle including persistence check is done.
Both negative cases (no indication, negative indication) will be aborted when the maximum number of preambles (BCCH
parameter) is exceeded.
In case the preamble cycle is positive, then the RACH data will be transmitted.

3. Radio Link Control (RLC) Protocol

3.1. RLC Modes of Operation

Transparent Mode
TM
Transparent Mode
TM
Unacknowledged Mode
UM
Unacknowledged Mode
UM
Acknowledged Mode
AM
Acknowledged Mode
AM
RLC ModesRLC Modes
• no sequence number
check
• no acknowledgements
• no retransmission
• segmentation/reassembly
may be used or not used
• no RLC overhead
• sequence number check
• no acknowledgements
• no retransmission
is done in RLC
• sequence number and
length indicators included in
RLC frame
• sequence number check
• acknowledgements
• retransmission
is done in RLC
• sequence number and
length indicators included in
RLC frame + RLC control
messages required
MAC Header
RLC SDU
(Data)
cipher
unit
MAC Header
RLC SDU
(Data)
cipher
unit
RLC Seq. No.
Length Indicators
MAC Header
RLC SDU
(Data or Ctrl)
cipher
unit
RLC Seq. No.
Length Indicators

The RLC protocol is used to enhance the reliability of a single radio bearer. Thus there is one instance of RLC protocol per
radio bearer available. Each RLC instance can be set in one of three modes independent of each other:
• Transparent Mode (TM): In transparent mode there is no additional reliability provided by the RLC protocol instance.
Only segmentation and reassembly functions might be used. There is no RLC overhead included in this mode. Ciphering is
done over the whole RLC SDU.
• Unacknowledged Mode (UM): In unacknowledged mode there is at least a sequence number check provided by RLC.
This is used to ensure correct reassembly. Thus there are sequence numbers and length indicators for reassembly control n
the RLC frame. Ciphering is done over the whole RLC PDU except the sequence number.
• Acknowledged Mode (AM): In acknowledged mode the RLC protocol instance provides acknowledgements and
retransmission functionality. The RLC PDU contains now sequence number, length indicators for reassembly control and
RLC status messages for retransmission control. Ciphering is done over the whole RLC PDU except the sequence number.
Which mode is used is configured by the RNC during radio bearer setup procedure. Thus the UE is told via RRC signalling
which RLC mode to use on a radio bearer.
It is possible to combine TM and UM on the same radio bearer. This can be done by assigning uplink and downlink different
modes. It is not possible to combine AM with another mode, because for acknowledgements always uplink and downlink
direction must be used simultaneously in AM.

PCCH
BCCH
CCCH-UL
DCCH
DTCH
CTCH
TM
TM
TM
CCCH-DL UM
TM UM AM
TM UM AM
UM
RLC ModesLogCH Type

3.2. Segmentation/Reassembly Function

MACMAC
RLCRLC
Layer 3 (RRC, applic.)Layer 3 (RRC, applic.)
PHYPHY
RLC SDU #0 RLC SDU #1
#0.0 #0.1 #1.0 #1.1 padding
RLC
header
RLC
header
RLC
header
RLC PDU #0 RLC PDU #1 RLC PDU #2
MAC
header #0.0
RLC
header
Transport Block Set
MAC
header #0.1
RLC
header #1.0
MAC
header #1.1
RLC
header padding

Next to the enhanced reliability functions provided by RLC there is another task done by this protocol – segmentation and
reassembly. The RLC protocol instances have to segment higher layer data so that a transport block of an appropriate size
corresponding to the available transport formats can be formatted.
The RLC protocol can perform segmentation together with concatenation (several RLC SDU or segments of an RLC SDU in
one RLC PDU) and padding. The RLC protocol has been designed for maximum resource efficiency.
In unacknowledged and acknowledged mode the RLC protocol includes length indicators in its PDU to indicate the end of
an higher layer frame (RLC SDU). Sometimes the length indicators can also carry special control meaning.
In transparent mode such length indicators are not used. Rather the RLC protocol reassembles everything that comes in
the same transport blocks. This might not be exactly the inverse of the segmentation process in transparent mode.
Therefore segmentation and reassembly is usually switched off when transparent mode is used. The higher layers have
then to send frame of correct size to match the transport block sizes.

3.3. RLC Transparent Mode Procedures

UE RNC
TMD PDURLC
RLC SDU segments
TMD PDURLC
RLC SDU segments
.
.
.
IF all segments of a SDU
received
reassembly
TMD PDURLC
RLC SDU segments
TMD PDURLC
RLC SDU segments
.
.
.
received
reassembly

|00------ |2.1 MAC: Target Channel Type Field |CCCH (Common Control Channel) |
| |2.2 MAC: RLC Mode |Transparent Mode |
|**b166** |2.3 RLC: Whole Data |'001000010000011101000000001000011'B |
| | |'010000000100110001000000001000000'B |
| | |'111110100110110000000000000000000'B |
| | |'000000000000000000000000000000000'B |
| | |'000000000000000000000000000000000'B |
| | |'0'B |
segmented
SDU data
RLC Transparent Mode DATA

In transparent mode there is only the data transfer procedure defined. It is implemented via the TMD PDU (Transparent
Mode Data). The TMD PDU contains nothing else data from higher layers, no RLC control information is to be found.

3.4. Unacknowledged Mode Procedures

UE RNC
UMD PDURLC
Sequence No. = 2, Length Indicators, RLC SDU segments
UMD PDURLC
.
.
.
received
reassembly
UMD PDURLC
UMD PDURLC
.
.
.
received
reassembly

|**B19*** |2.5 RLC: Data Segment |04 80 11 dc 32 00 01 04 13 f7 eb... |
|0001110- |3.5 RLC: Length Indicator |14 |
|1111111- |3.7 RLC: Length Indicator |Rest is padding |
|**B14*** |3.9 RLC: Last Data Segment |ba dd fc 80 64 53 ca 08 00 40 8c... |
|***B3*** |3.10 RLC: Padding |00 00 00 |

Sequence Number E
• UMD PDU (7-bit Length Indicators)
LI0 E
LIN-1
E=0
. . .
segmented
RLC SDU
padding
Sequence Number E
• UMD PDU (15-bit Length Indicators)
LI0 (low part) E
LIN-1
E=0
. . .
segmented
RLC SDU
padding
LI0 (high part)
LIN-1 (high part)

In unacknowledged mode there is also only one frame defined, the UMD PDU (Unacknowledged Mode Data PDU). It
is used to carry RLC SDU or segments of RLC SDU between UE and RNC.
To enable faithful segmentation and reassembly, length indicators are used to point to the end of the last segment of a
RLC SDU. This means a length indicator is to be found whenever a UMD PDU contains the last (or the only one) segment of
a RLC SDU. In some situations special length indicators will be included that have control meaning (e.g. reset of
reassembly etc.).
Length indicators can be either 7 bit long or 15 bit long. It depends on the largest UMD PDU (transport block size – MAC
header size) in the associated transport channel. If the maximum UMD PDU size is less or equal 125 bytes, then 7 bit
length indicators shall be used, otherwise 15 bit length indicators have to be included in the UMD PDU.
For detection of lost RLC PDU there is a 7 bit long sequence number included in every UMD PDU. If an UMD PDU is lost,
then all RLC SDU with segments in this UMD PDU are discarded by the receiver.

3.5. Acknowledged Mode Procedures

UE RNC
RESET PDURLC
Reset Sequence Number, Hyper Frame Number uplink (HFNI)
RESET ACK PDURLC
Reset
Reset Sequence Number, Hyper Frame Number downlink (HFNI)
RESET PDURLC
Reset Sequence Number, Hyper Frame Number downlink (HFNI)
RESET ACK PDURLC
Reset Sequence Number, Hyper Frame Number uplink (HFNI)

UE RNC
AMD PDURLC
Sequence No. = 12, Poll Bit P, Length Indicators, RLC SDU segments
AMD PDURLC
.
.
.
Data Transfer with Solitary STATUS PDU
STATUS PDURLC
Acknowledgement super fields (SUFI): ACK, BITMAP, LIST, RLIST
AMD PDURLC
AMD PDURLC
.
.
.
STATUS PDURLC
Acknowledgement super fields (SUFI): ACK, BITMAP, LIST, RLIST

UE RNC
AMD PDURLC
AMD PDURLC
.
.
.
Data Transfer with Piggybacked STATUS PDU
AMD PDURLC
Sequence No. = 34, Poll Bit P, Length Indicators, RLC SDU Segments,
Piggybacked STATUS PDU = {Acknowledgement super fields (SUFI): ACK, BITMAP, LIST, RLIST}
AMD PDURLC
AMD PDURLC
.
.
.
AMD PDURLC
Sequence No. = 39, Poll Bit P, Length Indicators, RLC SDU Segments,
Piggybacked STATUS PDU = {Acknowledgement super fields (SUFI): ACK, BITMAP, LIST, RLIST}

Move Receiving Window ProcedureUE RNC
STATUS PDURLC
Move Receiving Window (MRW) super field: SN1,...SNK
STATUS PDURLC
Move Receiving Window Ack (MRWACK) super field
STATUS PDURLC
Move Receiving Window (MRW) super field: SN1,...SNK
STATUS PDURLC
Move Receiving Window Ack (MRWACK) super field

Windowsize ConfigurationUE RNC
STATUS PDURLC
Window (WINDOW) super field: window size
STATUS PDURLC
Window (WINDOW) super field: window size

In acknowledged mode there some more procedures defined. In detail we have
• Reset: The Reset procedure is used to recover after errors in acknowledged mode. A new HFNI (Hyper Frame Number
Indicator) for ciphering can be allocated at Reset procedure. The RESET PDU and RESET ACK PDU are defined for this
procedure.
• Data Transfer with solitary STATUS PDU: For data transfer the AMD (Acknowledged Mode Data) PDU is defined. It
carries a 12 bit long sequence number. A single AMD or a series of AMD PDU can be acknowledged by a stand-alone
acknowledgement in form of a STATUS PDU.
• Data Transfer with piggybacked STATUS PDU: Very often AMD PDU are exchanged in both directions. In this case it
is possible to include STATUS PDU in AMD PDU for acknowledgements. This simply is more efficient with respect to
bandwidth usage.
• Move Receiving Window: In some situations an AMD PDU is transmitted and retransmitted correctly. This situation
can be determined by thresholds (maximum number of retransmissions) or timers (maximum time for data transmission).
Either an error is the result or both sides agree to skip the problematic AMD PDU. For skipping (discarding) the Move
Receiving Window procedure is used. In a STATUS PDU the command to move the receiving window with the sequence
numbers of the AMD PDU to be discarded are indicated. An acknowledgement completes the procedure.
• Window Size: The RLC protocol uses acknowledgements that acknowledges several AMD PDU with one message. The
maximum number of AMD PDU that can be sent without acknowledgement is indicated in the window size procedure. A
STATUS PDU contains a window size field in which the limit is indicated.

|----1--- |2.2.4 RLC: Data/Control |Acknowledged mode data PDU |
|**b12*** |2.2.5 RLC: Sequence Number |2 |
|-1------ |2.2.6 RLC: Polling Bit |Request a status report |
|--01---- |2.2.7 RLC: Header extension type |Octet contains LI and E bit |
|***b7*** |2.2.8 RLC: Length Indicator |9 |
|---1---- |2.2.9 RLC: Extension Bit |The next field is LI and E bit |
|***b7*** |2.2.10 RLC: Length Indicator |Rest is padding |
|---0---- |2.2.11 RLC: Extension Bit |The next field is data |
|**b72*** |2.2.12 RLC: Last Data Segment |df d9 4c ed 0d 21 31 f1 10 |
|**b40*** |2.2.13 RLC: Padding |00 00 00 00 00 |
|----0--- |2.2.4 RLC: Data/Control |Control PDU |
|-----000 |2.2.5 RLC: PDU Type |STATUS |
| |2.2.6 RLC: Acknowledgement Super Field |
|0010---- |2.2.6.1 RLC: SUFI Type |Acknowledgement |
|**b12*** |2.2.6.2 RLC: Last Sequence Number |3 |
| |2.2.7 RLC: Padding |
|**b124** |2.2.7.1 RLC: Padding |'000000000000000000000000000000000'B |
| | |'000000000000000000000000000000000'B |
| | |'000000000000000000000000000000000'B |
| | |'0000000000000000000000000'B |

Sequence Number (high part)
D/C
(1)
• AMD PDU (7-bit Length Indicators)
LI0 E
LIN-1
E=0
. . .
segmented
RLC SDU
Padding| piggybacked STATUS PDU
• AMD PDU (15-bit Length Indicators)
LI0 (low part) E
LIN-1
E=0
. . .
segmented
RLC SDU
padding
LI0 (high part)
LIN-1 (high part)
HEPSeq.Number (low part)
Sequence Number (high part)
D/C
(1)
HEPSeq.Number (low part)

D/C
(0)
• RESET/RESET ACK PDU
HFNI
HFNI
padding
padding
PDU TYPE
0 0 1 / 0 1 0
RSN reserved
HFNI
D/C
(0)
• STATUS PDU
PDU TYPE
0 0 0 SUFI #1
SUFI #1
. . .
SUFI #N
padding
Note: In case of a piggybacked STATUS PDU
the D/C bit is reserved.

Super Fields (SUFI)
0 0 0 0
NO_MORE
0 0 1 0
ACK
LSN high
LSN low
0 0 0 1
WINDOW
WSN high
WSN low
0 0 1 1
LIST
LENGTH
SN1 high
SN1 low L1
. . .
SNLENGTH high
SNLENGTH low LLENGTH
0 1 0 0
BITMAP
LENGTH
FSN high
FSN low BITMAP
. . .
BITMAP Padding
0 1 0 1
RLIST
LENGTH
FSN high
FSN low CW1
. . .
CWLENGTH
padding
0 1 1 0
MRW
LENGTH
SN1 high
SN1 low
. . .
SNLENGTH high
SNLENGTH low NLENGTH
SN2 high
SN2 high
0 1 1 1
MRW_ACK
SNACK low
NLENGTH
SNACK high
Padding

AMD PDU have a similar format like UMD PDU. The sequence of length indicators is used to control reassembly. Each
length indicator points to the end of the last segment of a RLC SDU. Furthermore some special length indicator values are
reserved (e.g. whether a STATUS PDU is carried within the AMD PDU or not, etc.). Again there are 7 bit long length
indicators and 15 bit long length indicators. If the maximum AMD PDU size is less or equal to 126 octets then 7 bit long
length indicators shall be used, otherwise 15 bit length indicators are chosen.
The sequence number of AMD PDU is 12 bit long to enable bigger window size for acknowledgements. The poll bit P is
used to request immediate acknowledgement for a AMD PDU.
STATUS PDU contain one or more so called super fields SUFI. Each SUFI carries special acknowledged mode control
meaning for acknowledgements, window size negotiation, moving receiving window. The following SUFI types are known:
• No More: Indicates end of the STATUS PDU.
• ACK: A simple acknowledgement. Indicates the next expected AMD PDU sequence number (LSN: last sequence number).
• LIST: Indicates gaps of the reception of AMD PDU. Each gap is indicated by its start sequence number (SN: start
number) and its length (L:length). Up to 15 gaps can be indicated in a single LIST super field.
• BITMAP: Indicates positive or negative acknowledgement for a series of consecutive AMD PDU with a bitmap. The first
bit of the bitmap stands for AMD PDU with sequence number FSN (FSN: first sequence number). The second bit of the
bitmap is for FSN+1, and so on. When the bit is ‘0’ the associated AMD PDU is negatively acknowledged.
• MRW/MRW_ACK: Used to move the receiving window. Inside the MRW field each AMD PDU to be discarded is
indicated by its sequence number SN.
• RLIST: A relative list used to indicate gaps in the reception. The method to specify the gap is different to LIST super
field. In a RLIST special code words CW are used to calculate gap start and length.

Module 03
Radio Resource Control Signalling
(RRC)
Version 0.0.1 (21/03/2005)

1. System Information

1.1. System Information Blocks and Segmentation

1.1. System Information Blocks and Segments
UE RNC
SystemInformation (SI)[BCH:BCCH] RRC
SFNPrime (INTEGER 0…4094 step 2), Segment Combination = CHOICE {
Combination 1: no data |
Combination 2: first segment |
Combination 3: subsequence segment |
Combination 4: last segment |
Combination 5: last segment, first segment |
Combination 6: last segment, complete list = {complete block#0, …, complete block#N} |
Combination 7: last segment, complete list = {complete block#0, …, complete block#N}, first segment |
Combination 8: complete list = {complete block#0, …, complete block#N} |
Combination 9: complete list = {complete block#0, …, complete block#N}, first segment |
Combination10: complete SIB of size 215…226 |
Combination11: last segment of size 215…226 }
first
segment
subsequent
segment
subsequent
segment
last
segment
System Information Block (SIB): . . .

1.1. System Information Blocks and Segments
Signalling on the BCCH is done by means of the RRC System Information. On the BCH that carries the BCCH there is only
RLC transparent mode used. Thus the RRC protocol must provide its own sequence numbering and segmentation
functionality.
For segmentation of System Information Blocks (SIB) the RRC protocol defines the System Information (SI) message.
In each SI message one or more segments of a SIB or several SIB can be contained. Several combinations allow to
indicate first, last and subsequent segments, or to bundle several complete blocks in one SI message.
Additionally to the SIB segments the SI message also indicates the cell time via the System Frame Number (0..4095).
The SFN is translated into the SFN prime via th following rule. In each frame with even SFN (SFN mod 2 = 0) it holds
SFN prime = SFN. In radio frames with odd SFN (SFN mod 2 = 1) we have SFN prime = SFN-1. In other words the SFN
prime is increased with every second radio frame by 2.

1.2. Master and Scheduling Information Blocks

UE RNC
MasterInformationBlock (MIB)[BCH:BCCH] RRC
MIB value tag, supported PLMN types = GSM-MAP|ANSI-41|GSM-MAP+ANSI-41,
PLMN identity = MCC + MNC, ANSI-41-CN information,
references to other system information blocks = { SIB Type, value tag, scheduling }
80 ms
80 ms
Master Information Block (MIB)

UE RNC
SchedulingInformationBlock1/2[BCH:BCCH] RRC
[BCH:BCCH] RRC
repetition
rate given
in MIB
[BCH:BCCH] RRC
Scheduling Information Block (SchIB1/2)
SchedulingInformationBlock1/2
repetition
rate given
in MIB
SchedulingInformationBlock1/2

| |masterInfoBlock (= masterInfoBlock) |
| |sib_description |
| |1 sib_choice |
| |1.1 masterInfoBlock |
|-001---- |1.1.1 mib-ValueTag |2 |
| |1.1.2 plmn-Type |
| |1.1.2.1 gsm-MAP |
| |1.1.2.1.1 plmn-Identity |
| |1.1.2.1.1.1 mcc |
|***b4*** |1.1.2.1.1.1.1 digit |2 |
|--0110-- |1.1.2.1.1.1.2 digit |6 |
|***b4*** |1.1.2.1.1.1.3 digit |2 |
| |1.1.2.1.1.2 mnc |
|---0000- |1.1.2.1.1.2.1 digit |0 |
|***b4*** |1.1.2.1.1.2.2 digit |9 |
| |1.1.3 sibSb-ReferenceList |
| |1.1.3.1 schedulingInformationSIBSb |
| |1.1.3.1.1 sibSb-Type |
|***b8*** |1.1.3.1.1.1 sysInfoType1 |44 |
| |1.1.3.1.2 scheduling |
| |1.1.3.1.2.1 scheduling |
| |1.1.3.1.2.1.1 segCount |1 |
| |1.1.3.1.2.1.2 sib-Pos |
|***b6*** |1.1.3.1.2.1.2.1 rep128 |6 |
| |1.1.3.2 schedulingInformationSIBSb |
| |1.1.3.2.1 sibSb-Type |
|------01 |1.1.3.2.1.1 sysInfoType2 |2 |
...
Master Information Block MIB

The individual system information blocks in the RRC protocol divide the information into groups. Two blocks have special
meaning: the master information block and the scheduling information blocks.
In the master information block MIB the PLMN type (GSM-MAP or ANSI-41) is indicated. For GSM-MAP the PLMN identity
(MCC + MNC) is broadcasted also in the MIB. Then for every further system information block the MIB indicates
scheduling information and a value tag (except SIB 7). The value tag indicates changes of the associated SIB by
incremented value.
The master information block always starts at radio frames with SFN mod 8 = 0.

1.3. System Information Blocks (SIB)

UE RNC
SIBx[BCH:BCCH] RRC
SIBx data
[BCH:BCCH] RRC
repetition
rate given
in MIB
SIBx data
[BCH:BCCH] RRC
SIBx
repetition
rate given
in MIB
SIBx data
SIBx
General System Information Transmission

UE RNC
SIB1[BCH:BCCH] RRC
CN common GSM-MAP NAS info = LAC, CS domain system info = {periodic LAU timer T3212, ATT flag},
PS domain system info = {RAC, Network Mode of Operation NMO},
UE timers and constants in idle mode, UE timers and constants in connected mode
SIB2[BCH:BCCH] RRC
URA-ID list = URA#1,.., URA#<maxURA>
SIB3[BCH:BCCH] RRC
SIB4 indicator = true|false, cell identity, cell selection and re-selection info, cell access restriction
SIB4[BCH:BCCH] RRC
cell identity, cell selection and re-selection info, cell access restriction

UE RNC
SIB5[BCH:BCCH] RRC
SIB6 indicator = true|false, PICH power offset, AICH power offset, secondary CCPCH system info,
primary CCPCH info = Tx diversity indicator, PRACH system information list, CBS DRX level 1 information
SIB6[BCH:BCCH] RRC
PICH power offset, AICH power offset, secondary CCPCH system info, CBS DRX level 1 information,
primary CCPCH info = Tx diversity indicator, PRACH system information list
SIB7[BCH:BCCH] RRC
UL interference, dynamic persistence level for PRACH in SIB5/6, expiration time factor
SIB8[BCH:BCCH] RRC
CPCH parameters (UE access parameters), CSICH power offset, CPCH set info (code and resource info)
SIB9[BCH:BCCH] RRC
CPCH persistence levels

UE RNC
SIB10[BCH:BCCH] RRC
DRAC (dynamic resource allocation) system information
SIB11[BCH:BCCH] RRC
SIB12 indicator = true|false,
FACH measurement occasion info = {measurement cycle length info, IF/IRAT measurement indicators}
measurement control system information = {HCS indicator, cell selection/re-selection quantity,
neighbour cell list SF/IF/IRAT, traffic volume measurements}
SIB12[BCH:BCCH] RRC
FACH measurement occasion info = {measurement cycle length info, IF/IRAT measurement indicators}
measurement control system information = {HCS indicator, cell selection/re-selection quantity,
neighbour cell list SF/IF/IRAT, traffic volume measurements}
SIB13|SIB13.1|SIB13.2|SIB13.3|SIB13.4[BCH:BCCH] RRC
ANSI-41 CN information

UE RNC
SIB14[BCH:BCCH] RRC
3.84 Mcps TDD mode system information
SIB15|SIB15.1|SIB15.2|SIB15.3|SIB15.4|SIB15.5[BCH:BCCH] RRC
system information for UE positioning
SIB16[BCH:BCCH] RRC
pre-defined RB/TrCH/PhCH configuration for inter-system handover to UTRAN
SIB17[BCH:BCCH] RRC
3.84 Mcps TDD|1.28 Mcps TDD mode system information
SIB18[BCH:BCCH] RRC
PLMN identities for neighbour cells for idle|connected mode UE

| |sibType1 (= sibType1) |
| |sib_description |
| |1 sib_choice |
| |1.1 sibType1 |
|**b16*** |1.1.1 cn-CommonGSM-MAP-NAS-SysInfo |00 18 |
| |1.1.2 cn-DomainSysInfoList |
| |1.1.2.1 cN-DomainSysInfo |
|0------- |1.1.2.1.1 cn-DomainIdentity |cs-domain |
| |1.1.2.1.2 cn-Type |
|**b16*** |1.1.2.1.2.1 gsm-MAP |01 01 |
|-----01- |1.1.2.1.3 cn-DRX-CycleLengthCoeff |7 |
| |1.1.2.2 cN-DomainSysInfo |
|-------1 |1.1.2.2.1 cn-DomainIdentity |ps-domain |
| |1.1.2.2.2 cn-Type |
|**b16*** |1.1.2.2.2.1 gsm-MAP |08 01 |
|----01-- |1.1.2.2.3 cn-DRX-CycleLengthCoeff |7 |
| |1.1.3 ue-ConnTimersAndConstants |
|----1010 |1.1.3.1 t-301 |ms2000 |
|010----- |1.1.3.2 n-301 |2 |
|---1100- |1.1.3.3 t-302 |ms4000 |
...
|--001--- |1.1.3.22 t-317 |s10 |
| |1.1.4 ue-IdleTimersAndConstants |
|***b4*** |1.1.4.1 t-300 |ms1000 |
|-011---- |1.1.4.2 n-300 |3 |
|----1010 |1.1.4.3 t-312 |10 |
|000----- |1.1.4.4 n-312 |s1 |
System Information Block SIB1

2. RRC Connection Handling
2.1. RRC States

2.1. RRC States
CELL_DCHCELL_DCH CELL_FACHCELL_FACH
URA_PCHURA_PCH CELL_PCHCELL_PCH
UTRA IDLEUTRA IDLE

2.1. RRC States
To manage radio resources of a UE in UMTS a state system with respect to the RRC protocol is introduced. In general a
UE has two main states – UTRA Idle and UTRA Connected. The difference between idle and connected is that in
connected mode there is a serving RNC for the UE, whereas in idle mode there is no serving RNC. Note that a connected
mode UE can have radio resources allocated or not. In idle mode a UE cannot have radio resources.
To make a more detailed specification of a connected mode UE there are four sub-states defined for connected mode:
• CELL_DCH: In this state the UE uses DCH for signalling and might use additional DCH or DSCH for applications. The
UE is subject to soft and hard handover procedures in this state.
• CELL_FACH: In this state the UE listens to FACH for RRC signalling and uses RACH on the uplink side. Also CPCH
might be in use. Mobility is handled in this state via cell reselection, handover procedures like in CELL_DCH state are not
used.
• CELL_PCH: Here the UE has currently no radio resources allocated. Thus the UE waits for incoming paging messages
on the PCH. The UE executes cell reselection, the RNC knows the current serving cell of the UE.
• URA_PCH: This state is similar to CELL_PCH, only this time the RNC knows the current URA (UTRAN Registration
Area) of the UE and not the cell.
In CELL_FACH, CELL_PCH and URA_PCH the UE performs automatic cell reselection. Thus the RNC has to be updated
whenever the area of interest (cell for CELL_FACH and CELL_PCH, URA for URA_PCH) changes.

2.1. RRC States – Cell Reselection in CELL_FACH
UE RNC
TMD Cell Update[RACH:CCCH] RLC/RRC
U-RNTI, STARTCS, STARTPS, cell update cause = cell re-selection , measured results on RACH, …
CELL_FACH
automatic
cell reselection
UMD Cell Update Confirm[FACH:CCCH] RLC/RRC
U-RNTI, new U-RNTI, new C-RNTI, new DSCH-RNTI, new H-RNTI, RRC state indicator = state_X,
CN info, RB to reconfigure or delete, TrCH-UL to add/reconfigure/delete, TrCH-DL to add/reconfigure/
delete, uplink/downlink physical resources
State_X
. . .

2.1. RRC States – Cell Reselection in CELL_PCH
UE RNC
TMD Cell Update[RACH:CCCH] RLC/RRC
U-RNTI, STARTCS, STARTPS, cell update cause = cell re-selection , measured results on RACH, …
CELL_PCH
automatic
cell reselection
UMD Cell Update Confirm[FACH:CCCH] RLC/RRC
State_X
. . .
CELL_FACH

2.1. RRC States –URA Reselection in URA_PCH
UE RNC
TMD URA Update[RACH:CCCH] RLC/RRC
U-RNTI, STARTCS, STARTPS, URA update cause = URA re-selection
URA_PCH
automatic
cell reselection
UMD URA Update Confirm[FACH:CCCH] RLC/RRC
State_X
. . .
CELL_FACH
(new cell is not part of old URA) false
URA_PCH
true

2.1. Mobility Handling in CELL_FACH, CELL_PCH
and URA_PCH
When a UE reselects a cell in CELL_FACH state, it has to perform a CELL UPDATE procedure afterwards in the new cell.
The CELL UPDATE message contains the current UE identifier (U-RNTI), so that the RNC can identify the UE. The
message is sent on RACH via CCCH. Thus the associated response CELL UPDATE CONFIRM is returned to the UE on the
FACH, also CCCH. In this message the UE is assigned a new state or again CELL_FACH.
A similar procedure is done when a UE reselects a cell in CELL_PCH state. The only difference to the update procedure in
CELL_FACH is, that after the cell reselection the UE enters automatically CELL_FACH state and then sends CELL UPDATE
to the RNC. With the CELL UPDATE CONFIRM the UE is sent to a new state or back to CELL_PCH.
In case the UE reselects a cell in URA_PCH state then another procedure is done. First of all the UE checks whether the
new cell still belongs to the old URA. If this is true no update procedure will be performed. Otherwise the UE enters
CELL_FACH state and sends URA UPDATE on RACH. The response CELL UPDATE CONFIRM on the FACH contains again
a new state for the UE. If this state is set to URA_PCH, then the UE goes back to URA_PCH state and enters the master
URA (URA #0 in SIB2) of the new cell.

2. RRC Connection Handling
2.2. RRC Connection Establishment

2.2. RRC Connection Estab. - CELL_FACH
UE RNC
TMD RRC Connection Request[RACH:CCCH] RLC/RRC
pre-defined configuration status indicator = true|false, Initial UE ID, establishment cause,
measured result on RACH
UTRA IDLE
NAS Trigger
UMD RRC Connection Setup[FACH:CCCH] RLC/RRC
Initial UE ID, new U-RNTI, new C-RNTI, RRC state indicator = CELL_FACH, capability update
requirement, signalling radio bearer to setup, TrCH to add/reconfigure
CELL_FACH
UTRA IDLE CELL_FACH
• TMSI + LAI
• PTMSI + RAI
• IMSI
• IMEI
• orig./term. conversational call
• orig./term. streaming call
• orig./term. interactive call
• orig./term. background call
• originating subscribed traffic call
• emergency call
• inter-RAT cell re-selection
• inter-RAT cell change order
• registration
• detach
• orig./term. high/low priority signalling
• call re-establishment
• terminating – cause unknown
AMD RRC Connection Setup Complete[RACH:DCCH] RLC/RRC
STARTCS, STARTPS, UE radio access capability, inter-RAT UE radio access capability
STATUS[RACH:DCCH] RLC/-
Acknowledgement

|TS 25.331 CCCH-UL (2002-09) (RRC_CCCH_UL) rrcConnectionRequest (= rrcConnectionRequest) |
| |uL-CCCH-Message |
| |1 message |
| |1.1 rrcConnectionRequest |
| |1.1.1 initialUE-Identity |
| |1.1.1.1 tmsi-and-LAI |
|***B4*** |1.1.1.1.1 tmsi |'00000111010000000010000110011110'B |
| |1.1.1.1.2 lai |
| |1.1.1.1.2.1 plmn-Identity |
| |1.1.1.1.2.1.1 mcc |
|0010---- |1.1.1.1.2.1.1.1 digit |2 |
|----0110 |1.1.1.1.2.1.1.2 digit |6 |
|0010---- |1.1.1.1.2.1.1.3 digit |2 |
| |1.1.1.1.2.1.2 mnc |
|***b4*** |1.1.1.1.2.1.2.1 digit |0 |
|-0010--- |1.1.1.1.2.1.2.2 digit |2 |
|**b16*** |1.1.1.1.2.2 lac |'0000011111010010'B |
|***b5*** |1.1.2 establishmentCause |registration |
|--0----- |1.1.3 protocolErrorIndicator |noError |
RRC Connection Request

|TS 25.331 CCCH-DL (2002-09) (RRC_CCCH_DL) rrcConnectionSetup (= rrcConnectionSetup) |
| |dL-CCCH-Message |
| |1 message |
| |1.1 rrcConnectionSetup |
| |1.1.1 r3 |
| |1.1.1.1 rrcConnectionSetup-r3 |
| |1.1.1.1.1 initialUE-Identity |
| |1.1.1.1.1.1 tmsi-and-LAI |
|**b32*** |1.1.1.1.1.1.1 tmsi |'00000111010000000010000110011110'B |
| |1.1.1.1.1.1.2 lai |
| |1.1.1.1.1.1.2.1 plmn-Identity |
| |1.1.1.1.1.1.2.1.1 mcc |
|---0010- |1.1.1.1.1.1.2.1.1.1 digit |2 |
|***b4*** |1.1.1.1.1.1.2.1.1.2 digit |6 |
|---0010- |1.1.1.1.1.1.2.1.1.3 digit |2 |
| |1.1.1.1.1.1.2.1.2 mnc |
|0000---- |1.1.1.1.1.1.2.1.2.1 digit |0 |
|----0010 |1.1.1.1.1.1.2.1.2.2 digit |2 |
|***B2*** |1.1.1.1.1.1.2.2 lac |'0000011111010010'B |
|00------ |1.1.1.1.2 rrc-TransactionIdentifier |0 |
| |1.1.1.1.3 new-U-RNTI |
|**b12*** |1.1.1.1.3.1 srnc-Identity |'010111110000'B |
|**b20*** |1.1.1.1.3.2 s-RNTI |'00001011101011110111'B |
|**b16*** |1.1.1.1.4 new-c-RNTI |'0000000000000000'B |
|--01---- |1.1.1.1.5 rrc-StateIndicator |cell-FACH |
|----000- |1.1.1.1.6 utran-DRX-CycleLengthCoeff |3 |
RRC Connection Setup 1( )

| |1.1.1.1.7 capabilityUpdateRequirement |
|1------- |1.1.1.1.7.1 ue-RadioCapabilityFDDUpdateRequ.. |1 |
|-0------ |1.1.1.1.7.2 ue-RadioCapabilityTDDUpdateRequ.. |0 |
| |1.1.1.1.7.3 systemSpecificCapUpdateReqList |
| |1.1.1.1.7.3.1 systemSpecificCapUpdateReq |gsm |
| |1.1.1.1.8 srb-InformationSetupList |
| |1.1.1.1.8.1 sRB-InformationSetup |
|00000--- |1.1.1.1.8.1.1 rb-Identity |1 |
...
| |1.1.1.1.8.1.3.2 rB-MappingOption |
...
| |1.1.1.1.8.1.3.2.1.1.1 ul-TransportChannelType |
| |1.1.1.1.8.1.3.2.1.1.1.1 rach |0 |
|***b4*** |1.1.1.1.8.1.3.2.1.1.2 logicalChannelIdentity |2 |
...
| |1.1.1.1.8.1.3.2.2.1.1 dl-TransportChannelType |
| |1.1.1.1.8.1.3.2.2.1.1.1 fach |0 |
|***b4*** |1.1.1.1.8.1.3.2.2.1.2 logicalChannelIdentity |2 |
RRC Connection Setup 2( )

Umts networkprotocolsandcompletecallflows_01242

Umts networkprotocolsandcompletecallflows_01242

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