MOBILE NETWORKS
1
MOBILE TELEPHONY DEFINITION
• Provision of Telephone Services to freely moving phones
• Mobile phones connect to either terrestrial cellular network of
base Stations (cell sites) or to orbiting satellites
• Mobile phones send and receive Radio signals over specified
frequency bands or Spectrums
• Mobile networks Interconnect to the fixed telephone network
allowing any phone in the world to be dialed
2
PRESENTATION OUTLINE
• Mobile Networks History
• WCDMA Overview
• Mobile Core Networks
• Layers and Protocols
• Evolution towards 4G
3
HISTORY
4
INTERNATIONAL STANDARDIZATION
• ITU (International Telecommunication Union)
– Radio standards and spectrum
• IMT-2000
– ITU’s umbrella name for 3G which stands for International
Mobile Telecommunications 2000
• National and regional standards bodies are collaborating in
3G partnership projects
– ARIB, TIA, TTA, TTC, CWTS. T1, ETSI
• 3G Partnership Projects (3GPP & 3GPP2)
– Focused on evolution of access and core networks
5
EVOLUTION OF DATA STANDARDS
3G
2G
1G
0G
4G
Zero Generation Mobile
Systems (0G)
The radio telephone system preceded modern
cellular mobile telephony technology (1G).
The radio telephone system contained one
central antenna tower per region. The central
antenna required radio phones to have a
powerful transmitter, capable of transmitting up
to 50 miles. The number of radio telephones per
region was limited by the number of available
channels.
Unlike closed radio systems, radio telephones
were connected to the public telephone network
and were typically mounted in cars, trucks, and
briefcases.
6
EVOLUTION OF DATA STANDARDS
4G
3G
2G
1G
First Generation Cellular
Communication (1G)
The 1G cellular telephone system divided cities into
small cells. This division allowed extensive frequency
reuse across a city, allowing millions to use cell
phones simultaneously.
1G cell phone technology encompassed analog
standards introduced in the 1980s and continued
until replaced by 2G digital cell phones.
0G
7
EVOLUTION OF DATA STANDARDS
4G
3G
2G
1G
0G
Second Generation Cellular
Communication (2G)
2G digital technologies can be divided into two
standards:
TDMA (Time Division Multiple Access)
- GSM: Originally from Europe but used
worldwide
- iDEN: Proprietary network used by Nextel
in the US
- PDC: Used exclusively in Japan
CDMA (Code Division Multiple Access)
- IS-95: Commonly referred to as CDMA and
used in the Americas and parts of Asia
8
EVOLUTION OF DATA STANDARDS
4G
3G
2G
1G
Third Generation Cellular
Communication (3G)
3G networks provide the ability to transfer voice
data and non-voice data (music downloads, emails
and instant messaging) over the same network
simultaneously.
3G networks deliver broadband capacity and
support greater numbers of voice and data
customers at lower incremental costs than 2G.
0G
9
EVOLUTION OF DATA STANDARDS
4G
3G
2G
1G
Fourth Generation Cellular
Communication (4G)
4G is not one defined technology or standard, but
rather a collection of technologies and protocols
aimed at creating fully packet-switched
networks optimized for data.
4G networks are projected to provide speeds of
100 Mbps while moving and 1 Gbps while
stationary.
0G
10
EVOLUTION TOWARDS 3G
3G
2.75G
Intermediate
Multimedia
2.5G
2G
Multimedia
Packet Data
Digital Voice
1G
Analog Voice
GPRS
GSM
EDGE
W-CDMA
(UMTS)
384 Kbps
Up to 2 Mbps
115 Kbps
NMT
9.6 Kbps
TDMA
TACS
9.6 Kbps
GSM/
GPRS
TD-SCDMA
(Overlay)
115 Kbps
2 Mbps?
iDEN
9.6 Kbps
iDEN
PDC
(Overlay)
9.6 Kbps
AMPS
CDMA 1xRTT
CDMA
14.4 Kbps
/ 64 Kbps
PHS
1984 - 1996+
1992 - 2000+
cdma2000
1X-EV-DV
PHS
(IP-Based)
144 Kbps
64 Kbps
2001+
2003+
Over 2.4 Mbps
2003 - 2004+
11
3G : BUILDING ON RELEASES
Release 99: Enhancements
to GSM data (EDGE). Majority
of deployments today are
based on Release 99.
Provides support for
GSM/EDGE/GPRS/WCDMA
radio-access networks.
Release 10 LTE-Advanced
meeting the requirements set
by ITU’s IMT-Advanced
project.
Release 4: Multimedia
messaging support. First
steps toward using IP
transport in the core network.
Release 9: HSPA and LTE
enhancements including
HSPA dual-carrier
operation in combination
with MIMO, EPC
enhancements, femtocell
support, support for
regulatory features such as
emergency user-equipment
positioning and Commercial
Mobile Alert System (CMAS),
and evolution of IMS
architecture.
Also includes quad-carrier
operation for HSPA+.
Release 5: HSDPA. First
phase of Internet Protocol
Multimedia Subsystem
(IMS). Full ability to use IPbased transport instead of
just Asynchronous Transfer
Mode (ATM) in the core
network.
Release 6: HSUPA.
Enhanced multimedia support
through Multimedia
Broadcast/Multicast Services
(MBMS). Performance
specifications for advanced
receivers. Wireless Local Area
Network (WLAN) integration
option. IMS enhancements.
Initial VoIP capability.
Release 7: Evolved EDGE. Specifies HSPA+, higher order modulation and MIMO. Performance enhancements,
improved spectral efficiency, increased capacity, and better resistance to interference. Continuous Packet
Connectivity (CPC) enables efficient “always-on” service and enhanced uplink UL VoIP capacity, as well as
reductions in call set-up delay for Push-to-Talk Over Cellular (PoC). Radio enhancements to HSPA include 64
Quadrature Amplitude Modulation (QAM) in the downlink DL and 16 QAM in the uplink. Also includes optimization of
MBMS capabilities through the multicast/broadcast, single-frequency network (MBSFN) function.
Release 8: HSPA Evolution,
simultaneous use of MIMO
and 64 QAM. Includes dualcarrier HSPA (DC-HSPA)
wherein two WCDMA radio
channels can be combined
for a doubling of throughput
performance. Specifies
OFDMA-based 3GPP LTE.
Defines EPC.
12
WCDMA OVERVIEW
13
NETWORK ARCHITECTURE
PSTN : Public Switched Telephone Network
ISDN : Integrated Service Digital Network
PLMN : Public Land Mobile Network
Access
Network
ISDN
PSTN
Mobile Core
Network
Access
Network
Other
PLMN
Access
Network
2G/3G : Same Core Network
IP
Backbone
4G : Enhanced Core Network
14
ACCESS TECHNIQUES
Frequency
Division
Multiple
Access
Code
Division
Multiple
Access
Time
Division
Multiple
Access
Time
Time
2
Code
Code
3
1
1
2
•Users separated in
frequencies
AMPS, NMT, TACS
Code
3
2
1
3
Frequency
25 kHz (NMT)
30 kHz (AMPS)
Time
Frequency
200 kHz (GSM)
Frequency
1.25 MHz (CDMA2000)
5 MHz (WCDMA)
•Several users share the
same frequency – separated in
time
•Many users share the same
frequency and time
•In practice: combined with
FDMA
•Can be combined with FDMA More than one carrier
GSM, PDC, IS-136 (TDMA)
•Users separated by code
WCDMA, CDMA2000
15
EVOLUTION OF SERVICES
Mobile Broadband
Voice
High-quality Voice, W-AMR
Voice over IP
Enh. UL 6 Mbps uplink and
HSDPA with MIMO 84+ Mbps
downlink
Mobile TV
Video telephony
Multi-Party Conferencing
HSDPA conversational
Enh. UL conversational
Interactive up to 384 kbps
HSDPA Streaming
Broadcast/Multicast Services (MBMS)
Music and video clips
Positioning
High Accuracy, A-GPS
HSDPA Streaming
Enh. UL Streaming
Combinational services
High quality voice + Very fast Mobile Broadband
High quality video telephony + Mobile TV
16
RADIO ACCESS BEARER – RAB
Definition by 3GPP:
“The service that the access
stratum (layer) provides to
the non-access stratum to
transfer user data between
User Equipment and CN.”
Applications
Email, Web browsing,
Video streaming,
SMS MMS…etc
Radio Access Bearer
Radio Bearer
UE
Node B
Iu Bearer
RNC
CN
Radio Access Bearers
Speech 12.2 kbps
Circuit Switched 64 kbps
Packet Switched 64 kbps
Packet Switched 128 kbps
Packet Switched 384kbps
…etc
17
QoS CHARACTERISTICS FOR RAB
Traffic class
Conversational class
conversational RT
Streaming class
streaming RT
Interactive class
Interactive best effort
Background
Background best
effort
Fundamental
characteristics



Request
response pattern


Preserve
payload content
Destination is
not expecting
the data within
a certain time

Preserve
payload content

Example of the
application
Preserve time
relation (variation)
between information
entities of the
stream
Conversational
pattern (stringent
and low delay )
- voice
Preserve time
relation
(variation)
between
information
entities of the
stream
- streaming video
- Web browsing
- background download of emails
• Delay < 0.5 s
Conversational/Streaming
• Delay > 1 s
Interactive/Background
18
TYPES OF TRAFFIC
• Circuit Switch - CS
– ie Voice,Video Call
• Packet Switch – PS (Data)
– ie Interactive RAB 64 etc
R99 traffic
• Packet Switch – PS (Data)
– ie HSDPA RAB
HSPA traffic +
Later Releases
Info
Info
Info
A
B
A
• R99 - Preserve Payload (Throughput), Varying power
• HSPA – Preserve Power, Varying Payload (Throughput)
Info
B
19
WDCMA CONCEPTS & CHARACTERISTICS
•
•
•
•
•
•
•
•
Wideband Direct Sequence Code Division Multiple Access
3.84 Mcps chip rate
Carrier spacing of 5 MHz
Asynchronous base stations supported, no need for GPS
synchronization
Coherent in both up- and downlink based on pilot
symbols/channels
FDD, standard supports coexistence of FDD and TDD modes
Frame length 10 ms
– user data rate can be changed on a frame basis
Designed for GSM co-existence
WCDMA Coverage
GSM Coverage Area
20
PSEUDO NOISE / SCRAMBLING CODES
PN code 1
PN code 3
PN code 1
PN code 4
Node B 1 transmits on PN code 1
Different UEs using different PN codes
PN code 2
PN code 5
PN code 2
PN code 6
Node B 2 transmits on PN code 2
Different UEs using different PN codes
21
CHANNELIZATION CODES
CC1 & CC2
CC3,CC4 & CC5
In the Downlink Channelization Codes are used to distinguish
between data channels from the same Base Station
CC1,CC2,CC3
CC1 & CC2
In the Uplink Channelization Codes are used to distinguish
between data channels from the same mobile
22
MODULATION TECHNIQUES
• In telecommunications, modulation is the process of varying a
periodic waveform, i.e. a tone, in order to use that signal to convey a
message
• Normally a high-frequency sinusoid waveform is used as carrier
signal
• WCDMA (R99) employs QPSK modulation techniques
• HSDPA employs 16QAM, later 64QAM with HSPA+
23
ONE CELL FREQUENCY REUSE
• In CDMA, all cells use the same carrier frequency
– Frequency reuse = 1
• No frequency planning!
FDMA/TDMA (reuse > 1)
f7
f6
f2
f5
f3
f4
f7
f6
f2
f1
f5
f3
f4
f7
f6
f2
WCDMA (reuse = 1)
f5
f1
f3
f1
f4
f1
C7
Code planning is used instead
C6
C2
f1
f1
f1
f1
C5
C3
C4
C7
f1
f1
f1
f1
f1
C6
C2
C1
C5
C3
f1
f1
f1
f1
C4
C7
C6
C2
f1
f1
f1
C5
C3
C4
24
UPLINK CHANNEL MAPPING
25
DOWNLINK CHANNEL MAPPING
26
SOFT-ER HANDOVER IN WCDMA
27
HSPA SPEED EVOLUTION
Downlink
Uplink
3.6 Mbps
20-40 Mbps
15 codes
14 Mbps
64QAM
Multi Carrier
12 Mbps
2x2 MIMO
21 Mbps 28 Mbps
16QAM
5.8 Mbps
Both
42 Mbps
2 ms TTI
1.4 Mbps
Multi Carrier
4x4 MIMO
Higher Modulation
Combinations
80-160 Mbps
0.384 Mbps
Higher Speed, Lower cost per GByte
28
WCDMA RELEASES SPEED EVOLUTION
1.44
2 ms TTI
2 ms TTI
2 ms TTI
10 ms TTI
29
MOBILE CORE NETWORKS
30
2G/3G NETWORK NODES & INTERFACES
BSS
Abis
BTS
Core Network CS Domain
A
E
MSC VLR
BSC
PCU
STP
GMSC
PSTN
ISDN
D,C
Iu-CS
Iub
NodeB
Iu-PS
RNC
Gb
Gs
Gc
Gr
Gn
Iur
NodeB
HLR AuC
SGSN
Gi
GGSN
IP
Core Network PS Domain
RNC
UTRAN
BTS : Base Transceiver Station
BSC : Base Station Controller
PCU : Packet Control Unit
RNC : Radio Network Controller
MSC : Mobile Switching Center
HLR : Home Location Register
VLR : Visitor Location Register
GMSC : Gateway MSC
AuC : Authentication Center
SGSN : Serving GPRS Support Node
GGSN : Gateway GPRS Support Node
STP : Signal Transfer Point
31
PS DOMAIN : PDP CONTEXT
PDP contexts deal with allocation of IP addresses to UE, and Quality of Service (QoS) parameters.
Addresses can be allocated dynamically or statically. If allocated dynamically, this significantly reduces
the total number of addresses required per PLMN. The support of static IP address allocation enables
subscribers to provide their own IP addresses
This can be useful when accessing secure networks that use the calling IP address as a form of security
check.
32
GSN SELECTION & ADDRESSING
GSN (GPRS Support Node) is a multi processor system. Several processors are
used to handle the different tasks of a GSN. The processors are connected over an
Ethernet Switch and the Internet Protocol (IP) is used for the communication
between the different processors. This requires several different types of IP
addressing:
• IP addressing for node internal communication
• IP addressing for external communication on the node-edge interfaces
33
RELEASE 4 NETWORK ARCHITECTURE
GERAN Core Network CS Domain
MSC Server
Mc
BTS
Nc
MSC Server
Nb
MGW
MGW
BSC
PCU
SCP
CAP
Iu-CS
HSS
VAS
IM
S
Iu-PS
NodeB
RNC
SGSN
NodeB
PSTN
ISDN
RNC
UTRAN
GGSN
IP
Core Network PS Domain
GERAN : GSM EDGE Radio Access Network
IMS : IP Multimedia Subsystem
MGW : Media Gateway
HSS : Home Subscriber Services
34
RELEASE 5 NETWORK ARCHITECTURE
GERAN
BTS
SCP
CAP
HSS
SGSN
GGSN
VAS
IP/ATM BSC
Iu
IP/ATM
CN PS Domain
IM
S
NodeB
RNC
IP
RNC
PSTN
ISDN
IP/ATM
NodeB
UTRAN
35
ALL IP MOBILE BACKHAUL
Mobile backhaul
2G
Microwave
BSC
Copper
RNC
3G
Fibre
AGW
LTE
Access, LRAN
Metro, HRAN
NodeB sites
• Microwave first choice
• Optical first choice
IP RAN
• Carrier Grade Ethernet
• Carrier Grade Ethernet
Native IP/Eth
interfaces
• Copper or fiber if available
•Microwave trunk in difficult
terrain
• Evolution:seamless
migration
Switch sites
IP RAN
Native IP/Eth
interfaces
• Evolution: packet overlay
One common management system
RAN evolves towards IP, Backhaul becomes Ethernet based
36
LAYERS & PROTOCOLS
37
WCDMA PS USER PLANE PROTOCOLS
Uu
Iub
IuPS
IP
PDCP
RLC
MAC
PHY-up
PDCP
RLC
MAC
PHY-up
PHY
PHY
CDMA
CDMA
UE/MTE
FP
ALCAP
AAL2
SAAL
ALCAP
FP
SAAL
AAL2
ATM
ATM
PHY
PHY
NODE B
RNC
SGSN
38
WCDMA PROTOCOL LAYERS
R
adio
N
etw
ork
Layer
C
ontrol P
lane
U
serP
lane
A
pplication
P
rotocol
D
ata
S
tream
(s)
Transport Transport Network
U
ser P
lane
N
etw
ork
Layer
S
ignalling
B
earer(s)
Transport N
etw
ork
C
ontrol P
lane
Transport N
etw
ork
U
ser P
lane
A
LC
A
P
(s)
S
ignalling
B
earer(s)
D
ata
B
earer(s)
P
hysical Layer
Transport Network could be IP/Ethernet or ATM/SDH or IP/ATM/SDH
RADIO NETWORK LAYER ALWAYS THE SAME
39
UTRAN OSI MODEL & PROTOCOLS
40
LAYER 3 – RRC
• The layer 3 is the upper layer in UTRAN OSI Model.
• It consists of only one protocol called as Radio Resource Control (RRC)
protocol.
• RRC protocol layer belongs to control plane.
• Most of the control signaling between the UE and the WCDMA RAN
are RRC.
• The main function of RRC is to establish a Signaling Radio Bearer
between the UE and the RNC to handle most of control signals.
• RRC provides the control of handset from RNC. It includes function to
control radio bearer, Physical channels, mapping of different channel
types, Handover, measurement control and other mobility procedure.
• The RRC messages carries all parameters required to set up, modify
and release layer 2 and layer 1 protocol entities.
• Some of the layer 1 & 2 parameters that are configured by the RRC:
 Radio Bearer Parameter.
 Transport Channels Parameter
 Physical channels Parameter.
41
LAYER 2 – DATA LINK LAYER
• To provide the local inter layer control services, the separate control
Service Access Points (SAPs) are defined between RRC and each
lower layer.
• These interfaces allow the RRC to control the configuration of the
lower layers.
• This control interface SAP exists between
–
–
–
–
–
RRC & MAC.
RRC & Physical layer (L1).
RRC & RLC.
RRC & PDCP.
RRC & BMC.
• These SAPs Interfaces are also used by RRC to configure the
parameters for the Physical, Transport and Logical Channels.
• These interfaces are also used by RRC to command the lower layer to
report measurement results and errors to the RRC.
42
RADIO LINK CONTROL (RLC) PROTOCOL




In the above example, RLC Layer receives a PDCP (Packet Data
Convergence protocol) PDU (Protocol Data Unit). In the RLC layer, data
will be known as an RLC SDU (Service Data Unit) and can be seen as
payload.
The RLC will in its turn perform segmentation of the receive data.
Finally it will also add a RLC header : PCI (Protocol Control Information)
to the SDU.
After the header is added, the data is called an RLC PDU and will be sent
to the lower layer.
43
EVOLUTION TOWARDS 4G
44
GSM / WCDMA DEPLOYMENT TODAY
45
LTE DEPLOYMENT & COMMITMENTS
Already deployed
Commitment to deploy
46
TOWARDS LTE ADVANCED (4G?)
3GPP LTE Advanced
Release 10
• Support for wider Bandwidth (Up to
100MHz)
• Downlink transmission scheme
– Improvements to LTE by using
8x8 MIMO
– Data rates of 100Mb/s with high
mobility and 1Gb/s with low
mobility
Up link transmission scheme
• Improvements to LTE
• Data rates up to 500Mb/s
Relay functionality
• Improving cell edge coverage
• More efficient coverage in
rural areas
CoMP (coordinated multiple point
transmission and reception)
• Downlink coordinated multipoint transmission
• Uplink coordinated multipoint reception
Local IP Access (LIPA) &
Enhanced HNB to allow traffic
off-load
47
TOWARDS LTE ADVANCED (4G?)
3GPP LTE Advanced
48
TOWARDS LTE ADVANCED (4G?)
LTE-Advanced is the 3GPP
submission for the ITU’s IMTAdvanced system
Study Item, “LTE-Advanced” approved in 3GPP
LTE-Advanced Requirements (TR 36.913)
- Mar 2008 
- Jun 2008 
LTE-Advanced “Early Submission” made to ITU-R
- Sep 2008 
“Complete Technology Submission” to ITU-R - Jun 2009 
“Final submission” to ITU-R
- Oct 2009 
Evaluation Process “Final Decision” by ITU-R
- Oct 2010 
Completion of LTE-Advanced specifications by 3GPP - …
49