RN33022EN40GLA0 CS Call Setup 1 RN33022EN40GLA0 CS Call Setup 2
RN33022EN40GLA0 CS Call Setup 3 RN33022EN40GLA0 CS Call Setup 4
RN33022EN40GLA0 CS Call Setup 5 RN33022EN40GLA0 CS Call Setup 6 In
case of a mobile terminated call (MTC), the process starts with
paging. Paging is the procedure by which a mobile network attempts
to locate the UE within its location area before any other
network-initiated procedure can take place. If the UE originates
the call, paging is not needed and the UE directly requests RRC
connection setup. After having established an RRC connection, the
UE starts setting up a Signaling connection to the core network
(CN). Finally, the radio access bearer setup procedure builds a
radio access bearer service between the UE and the CN. And the call
is established. RN33022EN40GLA0 CS Call Setup 7 This procedure is
used to transmit paging information to selected UEs in idle mode
using the paging control channel (PCCH). Upper layers in the
network may request paging, to e.g. establish a Signaling
connection. In addition, UTRAN may initiate paging to trigger
reading of updated system information. For CN originated paging,
UTRAN should set the IE "Paging cause" to the cause for paging
received from upper layers. If no cause for paging is received from
upper layers, UTRAN should set the value "Terminating cause
unknown". When the UE receives a PAGING TYPE 1 message, it shall
compare the IE "UE identity" with all of its allocated CN UE
identities. When they are match, UE must indicate reception of
paging and forward the IE "CN domain identity", the IE "UE
identity" and the IE "Paging cause" to the upper layers. Otherwise,
UE may ignore the paging. Note that another type of paging exists:
paging type 2. This paging takes place when there exists an RRC
connection for the UE, for example, UE is using packet-switched
service and a paging for circuit-switch is requested from the MSS.
RN33022EN40GLA0 CS Call Setup 8 The UE initiates RRC Connection
Establishment procedure when upper layers in the UE requests the
establishment of a Signaling connection and the UE is in idle mode
(no RRC connection exists). Both entities, UE and UTRAN, need to
set certain timers during this procedure to determine
retransmission needed or initiate failure case. When the procedure
is successful, the RRC Signaling connection exists between the UE
and RNC. This connection can be used by Layer 3 (L3) protocols for
further call processing. RN33022EN40GLA0 CS Call Setup 9 Using the
RRC connection in previous step, UE is able to send CONNECTION
MANAGEMENT (CM) SERVICE REQUEST message to the core network, which
is the MSS in case of circuit-switched call. CM SERVICE REQUEST can
be implicit or explicit operation. In implicit operation,
authentication and ciphering messages from CN follows without a
special message to reply the CM SERVICE REQUEST. In explicit
operation, the CM SERVICE ACCEPT is used to reply CM SERVICE
REQUEST. Explicit operation is only used in some special cases such
as emergency call setup. RN33022EN40GLA0 CS Call Setup 10
RN33022EN40GLA0 CS Call Setup 11 The RAB Assignment procedure is
the procedure to obtain necessary resource to carry user plane
traffic for the UE. The procedure is initiated by the CN. Not shown
in the figure are the details for resource allocation and
assignment for Iu, Iub and Uu interface. RN33022EN40GLA0 CS Call
Setup 12 RN33022EN40GLA0 CS Call Setup 13 The UE initiates set-up
of an RRC connection by sending RRC message RRC CONNECTION REQUEST
on CCCH. Important parameters for message: Initial UE Identity,
Establishment cause, Measured CPICH Ec/N0. Message example: RRC
CONNECTION REQUEST UL-CCCH-Message message rrcConnectionRequest
initialUE-Identity imsi Digit: 5 Digit: 2 Digit: 0 Digit: 0 Digit:
5 Digit: 1 Digit: 0 Digit: 0 Digit: 0 Digit: 0 Digit: 0 Digit: 0
Digit: 0 Digit: 1 Digit: 8 establishmentCause:
originatingConversationalCall protocolErrorIndicator: noError
measuredResultsOnRACH currentCell modeSpecificInfo fdd
measurementQuantity cpich-Ec-N0: 44 RN33022EN40GLA0 CS Call Setup
14 Let us assume, that the S-RNC accepts the UEs RRC Connection
Establishment request. It starts an interaction with the Node B to
establish a radio link connection over the interface Iub using
RADIO LINK SETUP REQUEST message. This interaction is also used to
inform the Node B about the radio link configuration parameters for
uplink and downlink transmission via the interface Uu. In other
words, the Node B is fully prepared to serve as intermediate mode
between the mobile phone and the RNC. Important parameters for
RADIO LINK SETUP REQUEST: Cell id, Transport Format Set, Transport
Format Combination Set, frequency, UL scrambling code, Power
control information. RN33022EN40GLA0 CS Call Setup 15 Node B
allocates resources, starts PHY reception, and responses with NBAP
message RADIO LINK SETUP RESPONSE. Parameters: Signaling link
termination, Transport layer addressing information for the Iub
Data Transport Bearer. RN33022EN40GLA0 CS Call Setup 16 In
ATM-based Iub interface, SRNC initiates set-up of Iub Data
Transport bearer using ALCAP protocol. This request contains the
AAL2 Binding Identity to bind the Iub Data Transport Bearer to the
DCH. The request for set-up of Iub Data Transport bearer is
acknowledged by Node B. RN33022EN40GLA0 CS Call Setup 17 The Node B
and SRNC establish synchronism for the Iub and Iur Data Transport
Bearer by means of exchange of the appropriate DCH Frame Protocol
frames Downlink Synchronization and Uplink Synchronization. Then
Node B starts DL transmission. RN33022EN40GLA0 CS Call Setup 18 The
UE gets the radio link configuration parameters with the RRC
CONNECTION SETUP message, which is transmitted in the transport
channel FACH. This message is used to establish Signaling radio
bearers between the UE and the RNC. The message itself holds 4
information elements groups: UE information elements to identify
the UE. Radio bearer information elements, which specify the
properties of the Signaling bearers, which are established with
this RRC message. Transport channel information elements to define
the transport channel characteristics, in other words the TFCS.
Physical Channel information elements, which specify parameters
relevant for the PHY layer to make the physical channels available.
RN33022EN40GLA0 CS Call Setup 19 Initial UE ID: The common
transport channel FACH is used to send the RRC Connection Setup
message from the RNC to the UE. All UEs listening to the same FACH
bearing S-CCPCH must be capable to detect, whether the RRC message
is for them. For UE identification, the IMSI or TMSI and LAI can be
used. RRC Transaction ID: Several RRC transactions can run in
parallel. This number associates the message to one transaction.
Activation Time: The transmission of transport channel frames has
to be synchronized between the UE and the S-RNC. This is also
called L2 synchronization. The Connection Frame Number (CFN) is an
element of the L2 synchronization. The network has to make sure,
that the UE gets a radio frame with a specific CFN (approximately)
To = 1024 chips before is starts to send a radio frame with the
same CFN. The Activation Time indicates, when the UE can expect the
transmission to start. New U-RNTI and New C-RNTI: Common transport
channels are shared resources, which can be used by several UEs.
The MAC-layer will add the required addressing information U-RNTI
and C-RNTI. UE, SRNC, C-RNC and Node B identify each other by
called Radio Network Temporary Identifiers (RNTI). The S-RNC
allocates a S-RNTI to the UE to address the UE. When the UE
accesses a new cell, the C-RNC allocates a C-RNTI to the UE, with
which it addresses the UE. The U-RNTI is a concatenation of the
SRNTI and the S-RNCs RNC-ID. The U-RNTI is unique worldwide, and is
used by the S-RNC to address the UE on common radio channels,
during paging, etc. RRC State Indicator: This indicator tells the
UE, in which internal RRC connected sub-state is has to move to.
RN33022EN40GLA0 CS Call Setup 20 Capability Update Requirement: The
Nokia Siemens Networks default setting for the IE Capability Update
Requirement derivates from the default values in the UMTS standard:
UE radio access FDD cap. - Boolean value = TRUEUE radio access TDD
cap. - Boolean value = FALSE System specific capability update
requirement list (not used in RAN1, in RAN1.5system specific
capability update requirement is always required from GSM system)
System specific capability update requirement (not used in RAN1,
used in RAN1.5): - static value = GSM Each RB set between a UE and
UTRAN has a unique number. Each of them can be mapped on one or two
logical channels. This was part of the RB setup information. The
information carried on radio bearers must be mapped on transport
channels. But on which transport channels can the higher layer
information be transmitted? How can higher layer information be
segmented? This is described with the information elements for TrCH
IEs: UL/DL. This information is used by the RRC to configure the
RLC, MAC, and PHY layer.A very important IE is the Transport Format
Set. The Transport Format Set information element describes the the
allowed TFs, which can be transmitted via this TrCH. A TF and TFS
definition can be found in the first module of the course. This
information element also describes, which logical channels (and
with them which radio bearers) are mapped on this TrCH.The PhyCH
IEs: UL/DL (Physical Channel information elements) deliver relevant
information for the PHY layer to configure the physical channels.
One of the PhyCH IEs is the carrier frequency band, where the
Signaling connection is established. As can be seen, a UE can be
immediately re-directed to another frequency band for the Signaling
bearer setup. Also the available UL and DL radio resources have to
be described. RN33022EN40GLA0 CS Call Setup 21 The UE has received
the RRC CONNECTION SETUP message and returns the RRC CONNECTION
SETUP COMPLETE message to the S-RNC. This message is transmitted
via the logical channel DCCH on the radio Signaling bearer, which
offers acknowledged mode of operation (RB2). RN33022EN40GLA0 CS
Call Setup 22 The information elements in the RRC CONNECTION SETUP
COMPLETE message can be grouped into UE information elements and
Other information elements. The UE IEs RRC Transaction Identifier
and the START list elements are mandatory. The remaining IEs are
optional. With the UE radio access capability IE, the UE can
transmit its capabilities, ranging from its layer and channel
capabilities to its measurements and multi-mode capabilities. The
optional IE Inter-RAT UE radio access capability can be use to
inform the S-RNC about the UE's cdma2000 and GSM MS classmarks. If
these optional IE cannot be used by either the UE or UTRAN, their
content can also be transmitted with the RRC message UE CAPABILITY
INFORMATION. RN33022EN40GLA0 CS Call Setup 23 RN33022EN40GLA0 CS
Call Setup 24 RN33022EN40GLA0 CS Call Setup 25 When ATM-based Iub
interface is used, ALCAP or AAL2 Signaling is required to setup the
AAL type 2 channel for RRC connection. The address used by ALCAP is
called NSEA (NSAP Service Endpoint Address) or A2EA (AAL2 Service
Endpoint Address). This NSEA address is obtained from the NBAP
reply message RADIO LINK SETUP RESPONSE. With the NSEA, the RNC
selects an available AAL2 minipacket channel. This is followed by
the ALCAP message ESTABLISH REQUEST from the RNC toward the NodeB.
In the ESTABLISH REQUEST, the choice of AAL2 minipacket channel is
specified as Path Identifier (Path ID or PID) and Channel
Identifier (CID). The NodeB replies with ALCAP message ESTABLISH
CONFIRM. The AAL type 2 path identifier has field size of 4 octets.
A value of 0 in all octets indicates Null. Channel identifier has
field size of 1 octet. It can have value in the range of 8 to 255.
A value of 0 indicates Null. The above figure shows the link
between the three Signaling messages. Transport layer address and
binding ID are copied from RADIO LINK SETUP RESPONSE to ESTABLISH
REQUEST. The Originating Signaling Association Identifier (OSAID)
in ESTABLISH REQUEST is copied into the Destination Signaling
Associaition Identifier (DSAID) in ESTABLISH CONFIRM message.
RN33022EN40GLA0 CS Call Setup 26 RN33022EN40GLA0 CS Call Setup 27
To ensure maximal independence of those two planes, the Binding ID
should be used only when necessary:Binding ID shall thus be used
only in Radio Network Control plane Application Part messages in
which a new association between the planes is created and in ALCAP
messages creating new transport bearers. Binding ID for each
transport bearer shall be allocated before the setup of that
transport bearer.The Binding ID is sent on one direction using the
Application Part protocol and is returned in the other direction by
the ALCAP protocol. When an Application Part procedure with an
allocated Binding ID is applied for modifying an existing Radio
Network User Plane connection, the decision to use the Binding ID
(and the ALCAP procedures) shall be done by that end of the
reference point that decides whether to use the existing transport
bearer or to set up a new transport bearer. The Binding ID shall
already be assigned and tied to a radio application procedure when
the first ALCAP message is received in a node. The association
between the connection Id in the Application Part protocol (e.g.
identifying a RAB) and the corresponding connection Id in the ALCAP
protocol (e.g. identifying the AAL2 channel for that RAB) that was
created with the help of Binding ID shall be memorised by both
peers of each reference point for the lifetime of the corresponding
transport bearer. The Binding ID may be released and re-used as
soon as both the Application Part procedure and the ALCAP procedure
that used it are completed in both peers of the reference point.
RN33022EN40GLA0 CS Call Setup 28 Step 1: Application Part AP-1,
which can be either NBAP, RANAP or RNSAP, assigns the Binding
Identifier and sends a Radio Network Control Plane Set-up
(Response) message (which of the two messages depends on the
involved interface - Iu/Iur or Iub). The message contains the
originating node Transport layer address and the Binding
Identifier. Step 2: As reception of the Radio Network Control Plane
Set-up message, the peer entity AP-2 requests ALCAP-2 to establish
a transport bearer. The Binding Identifier is passed to ALCAP-2.
Step 3: ALCAP-2 sends an ALCAP Establish Request to the peer entity
ALCAP-1. The message contains the Binding Identifier in the SUGR
(Served User Generated Reference) field. The Binding Identifier
allows correlating the incoming transport connection with the
Application Part transaction in step 1. RN33022EN40GLA0 CS Call
Setup 29 AFI = Authority and Format Identifier HO-DSP =
Higher-Order Domain Specific Part ESI = End System Identifier,
48bit number administered by Institute of Electrical and Electronic
Engineers (IEEE) SEL = Selector used for multiplexing of
applications within endpoint In the NSN RAN, usually the fields
HO-DSP, ESI, SEL are not used and automatically filled with 00 or
FF. RN33022EN40GLA0 CS Call Setup 30 Digit analyses are created by
the system for the Iub interface when creating the Routing and
Digit analysis for the AAL2 connections (COCO object
creation/modification or WBTS creation/modification). It is also
possible to give the numbering manually. The system automatically
adds the used AFI (authority and format identifier) to the
beginning of the digit sequence when the numbering generation
option is used. One AAL2 VCC for WAM RAN1.5.2ED2 level A2EA
generation rule: "49" (AFI) + 5 digits (WBTS Identifier) + 3 digits
(AAL2UPTPId) The address is generated from the corresponding WBTS
id and AAL2 user plane TP id. For example, the A2EA for the WBTS id
144 with AAL2 tp id 5 would be 4900144005. Several AAL2 VCCs for
WAM RAN04 level A2EA generation rule: "49" (AFI) + 5 digits
(WBTSId) + 2 digits (WAMId) + 1 digit "0" (filler) The address is
generated from the corresponding WBTS id and WAM id. For example,
the A2EA for the WBTS id 12448 with WAM id 3 would be 4912448030.
One A2EA for BTS (Flexi BTS) generation rule: "49" (AFI) + 5 digits
(WBTSId) + 3 digits "0" (filler) The address is generated from the
corresponding WBTS id. For example, the A2EA for the WBTS id 1244
would be 4901244000. The length of the digit sequence will be 40 in
the system. The additional characters at the end of the digit
sequence are filled with 0xF when the digit is stored to the
system. AAL2 Multiplexing is an optional feature in UltraSite WBTS.
With this feature, all the WAM in the WBTS shares the same ALCAP
and user plane VCs. Only 1 ALCAP VC is used. Furthermore the user
plane VCs for all WAM share the same Path Identifier.
RN33022EN40GLA0 CS Call Setup 31 A2EA digit analysis can be
interrogated from the RNC using ZRII command. The above figure
shows the case for UltraSite WCDMA BTS without AAL2 Multiplexing
feature. RN33022EN40GLA0 CS Call Setup 32 The above figure shows
the case when the AAL type 2 connection is establish between two
endpoints separated by an AAL type 2 switch. This situation can
arise, for example, during Iur connection establishment where the
endpoints are two different RNCs while the middle AAL type 2 switch
is the MGW situated in between. RN33022EN40GLA0 CS Call Setup 33
RN33022EN40GLA0 CS Call Setup 34 RN33022EN40GLA0 CS Call Setup 35
RN33022EN40GLA0 CS Call Setup 36 RN33022EN40GLA0 CS Call Setup 37
RN33022EN40GLA0 CS Call Setup 38 RN33022EN40GLA0 CS Call Setup 39
If IP-based Iub interface is used, there is no ALCAP involved in
the RRC connection setup. However, the IE Transport Layer Address
and Binding ID are still in used. The Transport Layer Address
contains IP address while the Binding ID contains the UDP port
carrying user plane Frame Protocol (FP). The information in RADIO
LINK SETUP REQUEST contains the IP address and port for the RNC
side while the information in RADIO LINK SETUP RESPONSE contains
the IP address and port for the NodeB side. RN33022EN40GLA0 CS Call
Setup 40 The figure shows RADIO LINK SETUP REQUEST message example.
RN33022EN40GLA0 CS Call Setup 41 The figure shows RADIO LINK SETUP
RESPONSE message example. RN33022EN40GLA0 CS Call Setup 42 The
following topic discuss the relation between KPI counters and
Signaling flow as a reference only. KPI analysis or optimization
will not discuss in this training RN33022EN40GLA0 CS Call Setup 43
To evaluate the RRC performance, it is divided into sub phases as
shown in the slide. They are: RRC setup phase RRC Access phase RRC
Active phase RN33022EN40GLA0 CS Call Setup 44 RRC Setup Phase The
RRC Setup phase begins when the RNC receives the RRC CONNECTION
REQUEST message from the UE. This triggers the first event:
increment of Performance Indicator for attempted RRC connections,
named here as RRC_CONN_STP_ATT.The sum of measurements equals the
total number of RRC connection establishment attempts. The Setup
phase is completed when the RNC sends the RRC CONNECTION SETUP
message to the UE. At this point event 2: increment of PI
RRC_CONN_STP_COMP is triggered. RRC Access Phase RRC Access phase
starts from the end of a successful Setup phase, i.e. the
transmission of the RRC CONNECTION SETUP message.The Access phase
is completed when the RNC receives the RRC CONNECTION SETUP
COMPLETE message from the UE. At this point, event 3 is triggered
as the CONN_ACC_COMP Performance Indicator is incremented. RRC
Active Phase The RRC Active phase begins from the reception of the
RRC CONNECTION SETUP COMPLETE message.The Active phase is
successfully completed when a RANAP message IU RELEASE COMMAND is
received, indicating an intentionally terminated RRC connection. If
an unintentional RRC connection release takes place, the PI
RRC_CONN_ACT_FAIL is, indicating an RRC connection drop.The active
RRC connection can fail for various reasons, e.g. failure in the Iu
interface, pre-emption, i.e. release of resources in order to make
room for higher priority RAB such as emergency call, or failure due
to air interface or Node B. RN33022EN40GLA0 CS Call Setup 45
RN33022EN40GLA0 CS Call Setup 46 RN33022EN40GLA0 CS Call Setup 47
RN33022EN40GLA0 CS Call Setup 48 RN33022EN40GLA0 CS Call Setup 49
RN33022EN40GLA0 CS Call Setup 50 RN33022EN40GLA0 CS Call Setup 51
RN33022EN40GLA0 CS Call Setup 52 Common ID The purpose of the
Common ID procedure is to inform the RNC about the permanent NAS UE
identity (IMSI) of a user. This is used by the RNC, for example, to
create a reference between the permanent NAS UE identity of the
user and the Radio Resource Control (RRC) connection of that user
for UTRAN paging coordination. The procedure uses
connection-oriented Signaling. The figure below describes the
Common ID procedure. Security Mode CommandThe purpose of the
Security Mode Control procedure is to allow the CN to pass cipher
and integrity mode information to the UTRAN. The UTRAN uses this
information to select and load the encryption device for user and
Signaling data with the appropriate parameters, and also to store
the appropriate parameters for the integrity algorithm. The
procedure uses connection-oriented Signaling CommonID Message
Example CommonID extension flag:0 preamble:0 protocolIEs
padding:000000 length:00 01 id: 23 contents:00 17 criticality:
ignore contents (in bits):01 padding:000000 opentype length:09
PermanentNAS-UE-ID extension flag:0 iMSI: '62029903000040F1'H
length (in bits):101 padding:0000 contents:62 02 99 03 00 00 40 F1
RN33022EN40GLA0 CS Call Setup 53 RN33022EN40GLA0 CS Call Setup 54 *
Before RAC Assignment Request start In Rel5 MSS use MEGACO send
message Add Request to MGW and MGW reply by message Add Reply
RN33022EN40GLA0 CS Call Setup 55 RN33022EN40GLA0 CS Call Setup 56
For IP-based IuCS interface, the Transport Layer Address contains
IP address while the Binding ID contains the UDP port carrying user
plane Real Time Protocol (RTP). The IP address and UDP port in RAB
ASSIGNMENT REQUEST corresponds to the MGW side. The IP address and
UDP port in RAB ASSIGNMENT RESPONSE corresponds to the RNC side.
RN33022EN40GLA0 CS Call Setup 57 RN33022EN40GLA0 CS Call Setup 58
RN33022EN40GLA0 CS Call Setup 59 RN33022EN40GLA0 CS Call Setup 60
RN33022EN40GLA0 CS Call Setup 61 RN33022EN40GLA0 CS Call Setup
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