WCDMA Principles

Wide Band Division Multiple Access (WCDMA)
Designed By Engineer Ali Monaty
PH. No. 00964-7714483228
Ali.monaty9984@gmail.com
Presentation about WCDMA
The third generation mobile communication system (3G) was first put
forward by ITU in 1985 and named future public land mobile
telecommunication system (FPLMTS) at that time. In 1996, it was
renamed international mobile telecommunication -2000 (IMT-2000).
IMT-2000 means that the system works on the 2000 MHz band, supports
up to 2000 kbps service rate, and will be put into commercial use in
2000. The main systems include WCDMA, CDMA2000 and TD-SCDMA.
Bands WCDMA Used
 Main bands
o 1920 – 1980MHz / 2110 – 2170MHz
 Frequency channel number = central frequency X 5, for main
band:
 UL frequency channel number : 9612 – 9888
 DL frequency channel number : 10562 - 10838

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Frequency Division Multiple Access (FDMA): frequency division,
sometimes called channelization, means dividing the whole available
spectrum into many single radio channels (transmit/receive carrier pair).
Each channel can transmit one-way voice or control information. Under
the control of the system, any user can be accessed to any of these
channels.
For FDMA system, the frequency separation needs to be enough to
avoid mutual interference between different users.
Time Division Multiple Access (TDMA): means that the wireless carrier
of one bandwidth is divided into multiple time division channels in terms
of time (or called timeslot). Each user occupies a timeslot and
receives/transmits signals within this specified timeslot. Therefore, it is
called time division multiple access. TDMA is a complex architecture and
the simplest case is that a single channel carrier is divided into many
different timeslots, each of which transmits one-way burst-oriented
information. The key part in TDMA is the user part, in which each user is

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allocated with one timeslot (allocated when a call begins). The user
communicates with a base station in a synchronous mode and counts
the timeslot. When his own timeslot comes, the mobile station starts a
receiving and demodulation circuit to decode the burst-oriented
information sent from the base station. Likewise, when a user wants to
send any information, he should first cache the information and waits
for his timeslot to come. When the timeslot arrives, the information is
transmitted at a burst-oriented transmission.
Code Division Multiple Access (CDMA): is a multiple access mode
implemented by Spread Spectrum Modulation. Unlike FDMA and TDMA,
both of which separate the user information in terms of time and
frequency, CDMA can transmit the information of multiple users on a
channel at the same time. That is to say, mutual interference between
users is permitted. The key is that every information before transmission
should be modulated by different Spread Spectrum Code-Sequence to
broadband signal, then all the signals should be mixed then send. The
mixed signal would be demodulated by different Spread Spectrum Code-
Sequence at the different receiver. Because all the Spread Spectrum
Code-Sequence is orthogonal, only the information that was be
demodulated by same Spread Spectrum Code-Sequence can be reverted
from the mixed signal.
In CDMA system, different users share the total power of the system.
That means, the capacity of the CDMA system is restricted by the power.
Therefore, power usage needs to be strictly controlled.

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(WCDMA Network Architecture)
and Node(user Equipment)n UEhis is an air interface betweet:Uu
.B
this is an interface between Node B and RNC.:Iub
: this interface Between Two RNCs.Iur
this interface between RNC and CN.:IU
It is the hardware that is connected to the mobile phone:Node B
network that communicates directly with mobile handsets. In
as the airWCDMAcontrast with GSM base stations, Node B uses
interface technology. As in all cellular systems, such
radio, the Node B containsGSMandUMTSas
transmitter(s) and the receiver(s) used to communicatefrequency

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directly with mobile devices, which move freely around it. In this
of cellular network, the mobile devices cannot communicatetype
directly with each other but have to communicate with the Node B.
(Radio Network Controller) is a governing element in:RNC
) and is responsible forUTRANradio access network (UMTSthe
that are connected to it. The RNC carriesBsNodecontrolling the
mobility, some of theradio resource managementout
is the point where encryption is donefunctions andmanagement
before user data is sent to and from the mobile. The RNC
connects to the Circuit Switched Core Network through Media
(Serving GPRS Support Node)SGSNhe) and to tMGWGateway (
.Packet Switched Core Networkin the
includes a series of physical entities to realize)NetworkCore(:CN
user location management, network function and service control,
such as (G) MSC, HLR, SCP, SMC, GSN etc.
CN can be divided into three types: Home Network Domain,
Network Domain.Transit Network Domain and Transit
Core Network is split into CS domain and PS domain. CS domain
is based on original GSM network. PS domain is based on original
GPRS network.
switched service. Network-CS domain: used to provide Circuit
sical entities includemode can support TDM, ATM and IP. Phy
-switching equipment (such as MSC/VLR, GMSCs), and inter
working equipment (IWF).
switched service. Network-PS domain: used to provide Packet
BG etc.CG,mode is IP. Physical entities include SGSN, GGSN,
HLR: (Home Location Register) is a central database that contains
details of each mobile phone subscriber that is authorized to use
the GSM core network. There can be several logical, and physical,
HLRs per public land mobile network (PLMN), though
one international mobile subscriber identity (IMSI)/MSISDN pair
can be associated with only one logical HLR (which can span
several physical nodes) at a time.

PH. No. 00964-7714483228
The HLRs store details of every SIM card issued by the mobile
phone operator. Each SIM has a unique identifier called an IMSI
which is the primary key to each HLR record.
Another important item of data associated with the SIM are the
MSISDNs, which are the telephone numbers used by mobile
phones to make and receive calls. The primary MSISDN is the
number used for making and receiving voice calls and SMS, but it
is possible for a SIM to have other secondary MSISDNs
associated with it for fax and data calls. Each MSISDN is also
a primary key to the HLR record. The HLR data is stored for as
long as a subscriber remains with the mobile phone operator.
The main function of the HLR is to manage the fact that SIMs and
phones move around a lot. The following procedures are
implemented to deal with this:
 Manage the mobility of subscribers by means of updating their
position in administrative areas called 'location areas', which
are identified with a LAC. The action of a user of moving from
one LA to another is followed by the HLR with a Location area
update procedure.
 Send the subscriber data to a VLR or SGSN when a subscriber
first roams there.
 Broker between the G-MSC or SMSC and the subscriber's
current VLR in order to allow incoming calls or text messages to be
delivered.
 Remove subscriber data from the previous VLR when a
subscriber has roamed away from it.
 Responsible for all SRI related queries (i.e. for invoke SRI, HLR
should give sack SRI or SRI reply).
VLR: (visitor location Register) is a database of the subscribers
who have roamed into the jurisdiction of the MSC (Mobile
Switching Center) which it serves. Each main base station in the
network is served by exactly one VLR (one BTS may be served by
many MSCs in case of MSC in pool), hence a subscriber cannot
be present in more than one VLR at a time.

PH. No. 00964-7714483228
The data stored in the VLR has either been received from the
HLR, or collected from the MS (Mobile station). In practice, for
performance reasons, most vendors integrate the VLR directly to
the V-MSC and, where this is not done, the VLR is very tightly
linked with the MSC via a proprietary interface. Whenever an MSC
detects a new MS in its network, in addition to creating a new
record in the VLR, it also updates the HLR of the mobile
subscriber, appraising it of the new location of that MS. If VLR data
is corrupted it can lead to serious issues with text messaging and
call services.
The primary functions of the VLR are:
 To inform the HLR that a subscriber has arrived in the particular
area covered by the VLR.
 To track where the subscriber is within the VLR area (location
area) when no call is ongoing.
 To allow or disallow which services the subscriber may use.
 To allocate roaming numbers during the processing of incoming
calls.
 To purge the subscriber record if a subscriber becomes inactive
whilst in the area of a VLR. The VLR deletes the subscriber's
data after a fixed time period of inactivity and informs the HLR
(e.g., when the phone has been switched off and left off or
when the subscriber has moved to an area with no coverage for
a long time).
 To delete the subscriber record when a subscriber explicitly
moves to another, as instructed by the HLR.
AuC: (Authentication center) is a function to authenticate each SIM
card that attempts to connect to the GSM core network (typically
when the phone is powered on). Once the authentication is
successful, the HLR is allowed to manage the SIM and services
described above. An encryption key is also generated that is
subsequently used to encrypt all wireless communications (voice,
SMS, etc.) between the mobile phone and the GSM core network.
If the authentication fails, then no services are possible from that
particular combination of SIM card and mobile phone operator

PH. No. 00964-7714483228
attempted. There is an additional form of identification check
performed on the serial number of the mobile phone described in
the EIR section below, but this is not relevant to the AuC
processing.
Proper implementation of security in and around the AuC is a key
part of an operator's strategy to avoid SIM cloning.
The AuC does not engage directly in the authentication process,
but instead generates data known as triplets for the MSC to use
during the procedure. The security of the process depends upon
a shared secret between the AuC and the SIM called the Ki.
The Ki is securely burned into the SIM during manufacture and is
also securely replicated onto the AuC. This Ki is never transmitted
between the AuC and SIM, but is combined with the IMSI to
produce a challenge/response for identification purposes and an
encryption key called Kc for use in over the air communications.
PSTN: public switched telephone network (PSTN) is the aggregate
of the world's circuit-switched telephone networks that are operated
by national, regional, or local telephony operators,
providing infrastructure and services for public telecommunication.
The PSTN consists of telephone lines, fiber optic
cables, microwave transmission links, cellular
networks, communications satellites, and undersea telephone cables, all
interconnected by switching centers, thus allowing any telephone in
the world to communicate with any other. Originally a network of
fixed-line analog telephone systems, the PSTN is now almost
entirely digital in its core network and includes mobile and other
networks, as well as fixed telephones.
is often integrated to the HLR. The)equipment identity register(:EIR
) whichIMEI(identified by theirEIR keeps a list of mobile phones
are to be banned from the network or monitored. This is designed
to allow tracking of stolen mobile phones. In theory all data about
ld be distributed to all EIRs in theall stolen mobile phones shou
world through a Central EIR. It is clear, however, that there are
some countries where this is not in operation. The EIR data does
not have to change in real time, which means that this function can
than the function of the HLR. The EIR is abe less distributed

PH. No. 00964-7714483228
database that contains information about the identity of the mobile
equipment that prevents calls from stolen, unauthorized or
defective mobile stations. Some EIR also have the capability to log
nd store it in a log file.Handset attempts a
Operation Maintenance Center (OMC) is used to monitor:OMC
),UEorand maintain the performance of each Mobile Station (MS
) andRNCorBase Station (BS), Base Station Controller (BSC
and WCDMA) within a GSMCNorMobile Switching Center (MSC
system.
The OMC has three main functions which are:
1. To maintain all telecommunications hardware and network
operations with a particular market.
2. Manage all charging and billing procedures.
3. Manage all mobile equipment in the system.
The OMC is dedicated to each of these tasks and has provisions
for adjusting all base station parameters and billing procedures, as
well as for providing system operators with the ability to determine
of subscriberthe performance and integrity of each piece
equipment in the system.

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WCDMA Time Slots

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(WCDMA Channels)
1-3G UMTS Logical Channels:
The 3G logical channels include:
 Broadcast Control Channel (BCCH) (downlink). This
channel broadcasts information to UEs relevant to the cell,
such as radio channels of neighboring cells, etc.
 Paging Control Channel (PCCH) (downlink). This channel
is associated with the PICH and is used for paging messages
and notification information.
 Dedicated Control Channel (DCCH) (up and downlinks)
this channel is used to carry dedicated control information in
both directions.
 Common Control Channel (CCCH) (up and downlinks).
This bi-directional channel is used to transfer control
information.
 Shared Channel Control Channel (SHCCH) (bi-
directional). This channel is bi-directional and only found in the
TDD form of WCDMA / UMTS, where it is used to transport
shared channel control information.
 Dedicated Traffic Channel (DTCH) (up and downlinks).
This is a bidirectional channel used to carry user data or traffic.
 Common Traffic Channel (CTCH) (downlink) A
unidirectional channel used to transfer dedicated user
information to a group of UEs.

PH. No. 00964-7714483228
2-3G UMTS Transport Channels:
The 3G UMTS transport channels include:
 Dedicated Transport Channel (DCH) (up and downlink).
This is used to transfer data to a particular UE. Each UE has
its own DCH in each direction.
 Broadcast Channel (BCH) (downlink). This channel
broadcasts information to the UEs in the cell to enable them
to identify the network and the cell.
 Forward Access Channel (FACH) (down link). This is
channel carries data or information to the UEs that are
registered on the system. There may be more than one FACH
per cell as they may carry packet data.
 Paging Channel (PCH) (downlink). This channel carries
messages that alert the UE to incoming calls, SMS messages,
data sessions or required maintenance such as re-
registration.
 Random Access Channel (RACH) (uplink). This channel
carries requests for service from UEs trying to access the
system
 Uplink Common Packet Channel (CPCH) (uplink). This
channel provides additional capability beyond that of the
RACH and for fast power control.
 Downlink Shared Channel (DSCH) (downlink).This
channel can be shared by several users and is used for data
that is "burst" in nature such as that obtained from web
browsing etc.
3-3G UMTS Physical Channels:
The 3G UMTS physical channels include:
 Primary Common Control Physical Channel
(PCCPCH) (downlink). This channel continuously
broadcasts system identification and access control
information.

PH. No. 00964-7714483228
 Secondary Common Control Physical Channel
(SCCPCH) (downlink) This channel carries the Forward
Access Channel (FACH) providing control information, and
the Paging Channel (PACH) with messages for UEs that are
registered on the network.
 Physical Random Access Channel (PRACH) (uplink). This
channel enables the UE to transmit random access bursts in
an attempt to access a network.
 Dedicated Physical Data Channel (DPDCH) (up and
downlink). This channel is used to transfer user data.
 Dedicated Physical Control Channel (DPCCH) (up and
downlink). This channel carries control information to and from
the UE. In both directions the channel carries pilot bits and the
Transport Format Combination Identifier (TFCI). The downlink
channel also includes the Transmit Power Control and
Feedback Information (FBI) bits.
 Physical Downlink Shared Channel (PDSCH) (downlink).
This channel shares control information to UEs within the
coverage area of the node B.
 Physical Common Packet Channel (PCPCH) This channel
is specifically intended to carry packet data. In operation the
UE monitors the system to check if it is busy, and if not it then
transmits a brief access burst. This is retransmitted if no
acknowledgement is gained with a slight increase in power
each time. Once the node B acknowledges the request, the
data is transmitted on the channel.
 Synchronization Channel (SCH) The synchronization
channel is used in allowing UEs to synchronize with the
network.
 Common Pilot Channel (CPICH) This channel is
transmitted by every node B so that the UEs are able estimate
the timing for signal demodulation. Additionally they can be
used as a beacon for the UE to determine the best cell with
which to communicate.
 Acquisition Indicator Channel (AICH) The AICH is used to
inform a UE about the Data Channel (DCH) it can use to
communicate with the node B. This channel assignment

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occurs as a result of a successful random access service
request from the UE.
 Paging Indication Channel (PICH) This channel provides
the information to the UE to be able to operate its sleep mode
to conserve its battery when listening on the Paging Channel
(PCH). As the UE needs to know when to monitor the PCH,
data is provided on the PICH to assign a UE a paging
repetition ratio to enable it to determine how often it needs to
'wake up' and listen to the PCH.
 CPCH Status Indication Channel (CSICH) This channel,
which only appears in the downlink carries the status of the
CPCH and may also be used to carry some intermittent or
"burst" data. It works in a similar fashion to PICH.
 Collision Detection/Channel Assignment Indication
Channel
(CD/CA-ICH) this channel, present in the downlink is used to
indicate whether the channel assignment is active or inactive
to the UE.
By using the logical, physical and transport channels it is possible
to carry the data for the control and payload in a structured manner
and provide efficient effective communications. The 3G UMTS
channels are thus an essential element of the overall system.

WCDMA Principles

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