IPv6 IPv6 and 3G/UMTS Mobile and 3G/UMTS Mobile Core Core ...
Introduction to 3G UMTS
-
Upload
abd-el-rahman-essam-anis -
Category
Documents
-
view
103 -
download
11
description
Transcript of Introduction to 3G UMTS
Introduction to UMTS
Ayman Gomaa
Contents
• Part 1 Introduction to UMTS
• Part 2 UMTS Air interface
• Part 3 UMTS Radio Access Network
• Part 4 UMTS Core Network
Contents
• Part 1 Introduction to UMTS
• Section 1 History of 3G
• Section 2 UMTS Network Structure
• Section 3 UMTS Network services
Evolution of Mobile communication
AMPS = Advanced Mobile phone service GSM=Global system for Mobile Communications
TACS=Total Access Communications Systems D-AMPS=Digital-AMPS
NMT=Nordic Mobile Telephone PDC=personal digital cellular
1st Generation 1980s (analog)
2nd Generation 1990s (digital)
3rd Generation current (digital)
AMPS
Analog to DigitalTACS
NMT
OTHERS
GSM
CDMA IS95
D-AMPS
PDC
WCDMAFDD
CDMA 2000
WCDMA TDD
Voice to Broadband
History of 3G
• At 1985 : ITU started the process of defining the standard for third generation systems, referred to as International Mobile Telecommunications 2000 (IMT-2000)
• Some of the features that IMT-2000 3G network must include1-Circuit and packet oriented services2-Simultaneous multiple services3-Symmetrical and Asymmetrical services4-Migration path from 2G systems5-Supporting Multimedia services
Car speed environment: 144kbpsWalk speed environment: 384kbpsIndoor environment: 2048kbps
• 1992: 230MHz spectrum was allocated in 2GHz band (WARC92)
History of 3G
• Based on the IMT-200 performance objectives and frequency allocation the ITU-R formally requested a submission of RTT proposals with a closing date at the end of July 1998 .
• By the closing date , there were a total of 10 RTT proposals were submitted from Europe , United states , Japan , Korea and, China. All these proposal where accepted .
• Five RTT for IMT2000• WCDMA FDD• CDMA2000 (1X-EV-DO and 3X modes)• WCDMA-TDD• UWC-136 (based on D-AMPS)• DECT
History of 3G
• Only three 3G network implemented and currently deployed 1-CDMA 2000 (1X-EV-DO)2-WCDMA FDD (UMTS FDD)3-WCDMA TDD (UMTS TDD)
3G standardization organizations
• Standardization organizations such as 3GPP, 3GPP2 were established
3G systemWCDMA
3GPPFDD/TDD mode
CDMA2000
3GPP2
UMTS is a 3rd Generation Mobile System
GSM1993
UMTS2002
EDGE2001
GPRS2000
HSCSD1999
9.6 K57.6 K
115 Kto 171 K
384 K
2 M
UMTS FDD and TDD
• FDD (Frequency Division Duplex)
• TDD (Time Division Duplex)
Base stationMobile Terminal
f 1: for Up Link
f 2: for Down Link
Base stationMobile Terminal
f 1: for Up & Down Link
Up DownTS TS
TS: Time slot
Frequency allocation for IMT2000
• WARC in 1992 230MHz in 2GHZ Band was allocated to IMT2000
USA
1800 2100 2200MHz1900 2000
IMT-2000 IMT-2000
MSS
1980 2010 2025
MSS
21702110
21702110
MSSUMTS
2110
IMT-2000 MSS2170
IMT-2000 MSSPHS
1895 1918 1980 20252010
1850 1930 1990
Unlicensed
MSSUMTSDECT
1880 20101980 2025
1885
PCS
2155
2025
IMT-2000 IMT-2000
IMT-2000
MSS(Reg.2)
MSS(Reg.2)
UMTS
MSSMSS
1900 1920
1910 2110 2150 2165
Reserve MSS
ITU
Japan
Europe/Australia
MSS: Mobile Satellite Service
Frequency spectrum allocation for IMT-2000
• In WARC-92 two frequency bands are allocated to IMT-2000Lower frequency band 1885 – 2025 MHzUpper frequency band 2110 – 2200 MHZ
both bands contain allocation for terrestrial and satellite components• Due to the existing use of parts of these frequency bands in different
regions of the world , there is no common spectrum available world wide for the 3G
• In Europe , the lower band of WARC-92 allocation is shared with the DECT Cordless phone system between 1880 to 1900 MHZ
• In Europe , the IMT-2000/ UMTS will use of the frequencies 1900 – 2025 in the lower band2110 - 2200 in the upper band
Frequency spectrum allocation for IMT-2000
• Within Europe • (1920 – 1980) MHz and (2110 to 2170)MHz are paired bands (FDD mode )• (1900 – 1920) MHz and (2010 – 2025) MHz are unpaired bands (TDD mode)• (1980 – 2010) MHZ and (2170 – 2200 ) MHz are satellite allocation
20 1530 3060 60
1900 1950 2025 2140 2200 MHz
GSM
1800
DE
CT
UM
TS-
TD
D
UM
TS-
FDD
UM
TS-
sat
UM
TS-
TD
D
UM
TS-
FDD
UM
TS-
sat
GSM
Frequency spectrum allocation for IMT-2000
• WRC2000 Conference has decided to allocate additional bands for IMT-2000, 800MHz, 1.8GHz, and 2.5GHz Band.
IMT-2000
GSM(Current)
PDC(Current)
800 1000 1500 2500 MHz960 1885 2690
2010
2110 2170
19801710806
20252000
880 960 1710 1990
: Additionally assigned for IMT-2000
810 958 1429 1513
UMTS FDD frequency allocations
Operating Band UL Frequencies
UE transmit, Node B receive
DL frequencies
UE receive, Node B transmit
I 1920 – 1980 MHz 2110 –2170 MHz
II 1850 –1910 MHz 1930 –1990 MHz
III 1710-1785 MHz 1805-1880 MHz
IV 1710-1755 MHz 2110-2155 MHz
V 824 – 849 MHz 869-894 MHz
VI 830-840 MHz 875-885 MHz
Operating Band TX-RX frequency separation
I 190 MHz
II 80 MHz.
III 95 MHz.
IV 400 MHz
V 45 MHz
VI 45 MHz
Contents
• Part 1 Introduction to UMTS
• Section 1 History of 3G
• Section 2 UMTS Network Structure
• Section 3 UMTS Network services
GSM network architecture
A
A Gb
VLR
MSC
GMSCPSTN
PSTN
EIRF
HLR
AUC
D
C
H
GsSGSN
Abis
BSC
BTSBTS
BSS
Gb
GGSN
Gn
PDNGi
Gf
Gr
Gc
Abis
BSC
BTSBTS
BSS
MS = ME + SIM
Um Um
NSS
UMTS network architecture
Iu-CS
Iu-CS Iu-PS
Iu-PS
Iub
RNC
Node BNode B
RNS
Iur
Iub
RNC
Node BNode B
RNS
VLR
MSC
A
GMSC
Abis
BSC
BTSBTS
BSS
PSTNPSTN
EIRF
HLR
AUC
D
C
H
GsSGSN
Abis
BSC
BTSBTS
BSS
Gb
GGSN
Gn
PDNGi
Gf
Gr
Gc
RAN
UTRAN
UE = ME + USIMMS = ME + SIM
UuUm Uu Um
CS PSCN
UMTS Network Components
• Network Elements• Core Network
• GMSC: Gateway Mobile Services Switching CenterSwitches circuit switched (CS) data to the external network.
• MSC: Mobile Services Switching CenterSwitches circuit switched (CS) data.
• VLR: Visitor Location RegisterStores copy of visiting user’s service profiles.
• HLR: Home Location RegisterStores user’s service profiles.
• GGSN: Gateway GPRS Support NodeHandles packet switched (PS) data to the external network.
• SGSN: Serving GPRS Support NodeHandles packet switched (PS) data.
UMTS Network Components
• Network Elements• UTRAN• RNC: Radio Network Controller
Controls radio resources.• Node-B
Converts Data flow between Iub and Uu interface.• UE
• ME: Mobile EquipmentRadio terminal used for radio communication.
• USIM: UMTS Subscriber Identity ModuleSmart card that stores subscriber identity.
Contents
• Part 1 Introduction to UMTS
• Section 1 History of 3G
• Section 2 UMTS Network Structure
• Section 3 UMTS Network services
UMTS Network Services
• Person to person services • Content to person services• Business connectivity services
UMTS Network Services
• Person to person circuit switched services• 1- AMR speech services
• The speech codec in UMTS will employ the Adaptive Multirate(AMR) technique.
• The AMR speech coder has eight source rates: 12.2 ,10.2, 7.95,7.40 , 6.70 , 5.90, 5.15 and 4.75 kbps.
• The bit rate of the AMR speech connection can be controlled by the RAN depending on the air interface loading.
• During high loading, such as during busy hours, it is possible to use lower AMR bit rates to offer higher capacity while providing slightly lower speech quality.
• If the mobile is running out of the cell coverage area and using its maximum transmission power, a lower AMR bit rate can be used to extend the cell coverage area.
• The AMR speech codec is capable of switching its bit rate every 20 ms speech frame upon command.
UMTS Network Services
• The coding scheme for the multirate coding modes is the so-called Algebraic Code Excited Linear Prediction Coder (ACELP).
• Discontinuous transmission (DTX) has some advantages : in the user terminal, battery life will be prolonged or a smaller battery could be used for a given operational duration. From the network point of view, leading to a lower interference level and hence increased capacity.
• Further optimization through AMR Source based rate adaptation
UMTS Network Services
• Person to person circuit switched services• 2-Video telephony
Technical specifications of UMTS recommend ITU-T Rec. H.324M (AMR-H.263) for video telephony.
UMTS Network Services
• Person to person packet switched services• Images and multimedia services
• MMS (multimedia messaging)• Real time video sharing (one way video )
UMTS Network Services
• Push-to-Talk over Cellular (PoC)• voice connection is established by simply pushing a single button and
the receiving user hears the speech without even having to answer the call.
• Voice over IP • Multiplayer Games
UMTS Network Services
• Content to person services• internet browsing • Audio and Video streaming
• Business Connectivity• Remote access to the intranets using UMTS
Contents
• Part 1 Introduction to UMTS
• Part 2 UMTS Air interface
• Part 3 UMTS Radio Access Network
• Part 4 UMTS Core Network
Contents
• Part 2 UMTS Air interface
• Section 1 Air interface basic principles
• Section 2 Air interface protocol stack
Multiple Access Techniques
Traffic channels: different users are assigned unique code and transmitted over the same frequency band, for example, WCDMA and CDMA2000
Traffic channels: different frequency bands are allocated to different users,for example, AMPS and TACS
Traffic channels: different time slots are allocated to different users, for example: GSM
FrequencyTime
Power
FrequencyTime
Power
FrequencyTime
Power
FDMA
TDMA
User
User
User User
User User
CDMA
Multiple Access Techniques
Multiple Access Techniques
FDMA/TDMA
Frequency is different in each sector.
CDMA
Frequency is same.
Need for
frequency plan (Frequency ReuseFrequency Reuse)
No need for frequency plan
f1 f
6
f5
f2f
3f4
f1
f7
f7
f4
f6f
7
f1
f3f4
f6f
7f2
f5f6f2 f
2f5 f
3
f1f7
f6
f5
f2
f4
f1
f1
f7
f1f
7f1f1
f1 f
1f1
f1
f1
f1
f1
f1
f1
f1
f1
f1f1
f1f1f1
f1
f1
DS-CDMA
User-A
A
Code 1
User-B
B
Code 2
User-C
C
Code 3
User-A
A
Code 1
User-B
B
Code 2
User-C
C
Code 3
De-spreadingCode
Narrow BandSignal
Wide BandSignal
(Multiple Signal)Spreading DespreadingNarrow BandSignal
CBA
(Receiver A)
(Receiver B)
(Receiver C)
DS-CDMA
• Any two codes x and y are orthogonal if Rxy(0) = ∑ xi yi =0 (correlation or Cross correlation)
i=0• Example of two orthogonal codes are
x= -1-1 1 1 and y= -1 1 1 -1 Rxy(0) = -1 x-1 + -1 x 1 + 1 x 1 + 1 x -1 = 0
• Spreading factor (SF) = chip rate/symbol rate
DS-CDMA
Spreading & de-Spreading
Data xCode
Tx Data
Same code
Code(SF=8)
bitbit Spectrumchip
Multiply(spreading) Tx operation
Bandwidth determinedby chip rate
code of length 8
Multiply
Integrate & Dump
Soft Decisions
In the absence of noise and interference from other non-orthogonal codes the soft decisions would be exactly +8 or -8, however this is never the true in reality
Spreading & de-Spreading with wrong orthogonal code
Data xCode
Tx Data
Different orthogonal
codes
Code(SF=8)
bitbit chip
Multiply(spreading) Tx operation
Multiply
Integrate & Dump
In the absence of noise and interference from other non-orthogonal codes the soft decisions would be exactly 1 in this case, however this is never the true in reality
OVSF code #7
OVSF code #5
Spreading & de-Spreading with incorrect timing
Data xCode
Tx Data
Same code
Code(SF=8)
bitbit chip
Multiply(spreading) Tx operation
Multiply
Integrate & Dump
The soft decisions are garbage => timing / synchronization is very important !!
Code offset by 1 chip
Rake Receiver
A B C
A B C
ABC
Rake
Rake receiver
RXRX
Searcher Searcher
CombinerCombiner
CalculationCalculation
Combined Signal
Electric PowerElectricPower
Delay Profile
Delay Time
Multiple Signal 1Multiple Signal 2
Multiple Signal 3
Delay Time
Finger CircuitFinger Circuit
Finger CircuitFinger Circuit
Finger CircuitFinger Circuit
Output Power
Power control in WCDMA
• Need for uplink power control • Near far problem
Power control in WCDMA
• Need for Power control in Downlink • The downlink signals transmitted by one base station are orthogonal.
Signals that are mutually orthogonal do not interfere with each other• It is impossible to achieve full orthogonality in typical usage
environments. Signal reflections cause nonorthogonal interference even if only one base station is considered
• Signals sent from other base stations are, of course, nonorthogonal and thus they increase the interference level
Power control in WCDMA
• Two basic types of power control:1- Open loop power control • the transmitting entity measures the channel interference of the received
signal and adjusts its transmission power accordingly. This can be done quickly
• the problem is that, the interference estimation is done on the received signal, and the transmitted signal probably uses a different frequency, which differs from the received frequency by the system’s duplex offset. As uplink and downlink fast fading (on different frequency carriers) do not correlate, this method gives the right power values only on average.
2- Closed loop power control • the quality measurements are done on the other end of the connection
in the base station, and the results are then sent back to the mobile’s transmitter so that it can adjust its transmission power.
• This method gives much better results than the open loop method, but it cannot react to quick changes in channel conditions.
Power control in WCDMA
• The UMTS FDD uses a fast closed-loop power control technique both in the uplink and downlink. In this method the received signal-to interference ratio (SIR) is measured over a 667-microsecond period, and based on that value, a decision is made about whether to increase or decrease the transmission power in the other end of the connection.
• The fast closed-loop power control is also called the inner loop power control.
• In the uplink there is also outer loop power control , the RNC adjust the target SIR to the NodeB
• In the Downlink outer loop power control is implemented in the UE• The UMTS FDD uses open loop power control in the uplink random access
channels
WCDMA handover types
• Soft Handover
• UE is connected simultaneously to more than one base station (up to 3 sectors) using the same frequency
• The UE receives the downlink transmissions of two or more base stations. For this purpose it has to employ one of its RAKE receiver fingers for each received signal.
• in the uplink direction , the code channel of the mobile station is received from both base stations, but the received data is then routed to the RNC for combining
• The RNC selects the better frame between the two possible candidates based on frame reliability indicator
WCDMA handover types
• Softer Handover
• UE is connected simultaneously to two sectors of one base station using the same frequency
• The UE receives the downlink transmissions from the two sectors. For this purpose it has to employ one of its RAKE receiver fingers for each received signal.
• in the uplink direction , the code channel of the mobile station is received in each sector, then routed to the same baseband Rake receiver and the maximal ratio combined there in the usual way.
WCDMA handover types
• Hard Handover
• The UE stops transmission on one frequency before it moves to another frequency and starts transmitting again
• During Hard Handover the used radio frequency (RF) of the UE changes
WCDMA handover types
• Inter-system Handover• Handover between two different radio access technologies• Handover between UMTS FDD and GSM• Handover between UMTS FDD and UMTS TDD
Spreading process in WCDMA
• 1st Step: Channelization• Variable Rate Spreading ( According to user data rate)
• 2nd Step: Scrambling Code• Fixed Rate Spreading (3,840 Kchips)
Σ
ChannelizationCode
ScramblingCode
3,840 KcpsCoding &
Interleaving
Spreading process in WCDMA
• Downlink (NodeB to UE )• Scrambling Code: Identifies cell (sector).• Channelization Code: Identifies user channels in cell (Sector).
Scrambling Code A
Scrambling Code B
Scrambling Code C
ChannelizationCode 1
ChannelizationCode 2 Channelization
Code 3
ChannelizationCode 1 Channelization
Code 2
ChannelizationCode 2
ChannelizationCode 1
Spreading process in WCDMA
• Up Link (UE to NodeB )• Scrambling Code: Identifies user terminal.• Channelization Code: Identifies channels in user terminal.
Scrambling Code A
Scrambling Code B
Scrambling Code C
ChannelizationCode 1
ChannelizationCode 2
ChannelizationCode 1
ChannelizationCode 1
Spreading process in WCDMA
• Orthogonal Variable Spreading Factor [OVSF] codes are the channelizationcodes used for signal spreading in the uplink and downlink
Spreading process in WCDMA
Spreading process in WCDMA
Spreading process in WCDMA
• The code used for scrambling of the uplink Channels may be of either long or short type, There are 224 long and 224 short uplink scrambling codes. Uplink scrambling codes are assigned by higher layers.
• For downlink physical channels, a total of 218 -1 = 262,143 scrambling codes can be generated. Only scrambling codes k = 0, 1, …, 8191 are used.
• In the downlink direction 512 of scrambling codes are used to identify the cells in the downlink so downlink code planning is required
Spreading process in WCDMA
Scrambling codes for downlink physical channels
Set 0
Set 1
…
Set 511
Primary scrambling code 0
……
Secondary scrambling code 1
Secondary scrambling code
15
Primary scrambling code
511×16
……
Secondary scrambling code
511×16+158192
scrambling codes
512 sets
A primary scrambling code and 15 secondary scrambling codes are included in a set.
Spreading process in WCDMA
Group 0
Groupe1
…
Group 63
512 primary scrambling codes
64 primary scrambling code groups
Each group consists of 8 primary scrambling codes
Primary scrambling codes for downlink physical channels
Primary scrambling code 0
……
Primary scrambling code 1
Primary scrambling code 7
Primary scrambling code
8*63
……
Primary scrambling code
63*8+7
W-CDMA Specification
Contents
• Part 2 UMTS Air interface
• Section 1 Air interface basic principles
• Section 2 Air interface protocol stack
UMTS FDD Air interface protocol stack
UMTS FDD Air interface protocol stack
UMTS FDD Air interface protocol stack
UMTS FDD Air interface protocol stack
UMTS FDD Air interface protocol stack
UMTS FDD Air interface Channels
Logical channels
Transport channels (DL)
Transport channels (UL)
Physical channels
UMTS channel mapping
Cell search procedure
Cell search procedure#0 #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14
1 1 2 8 9 10 15 8 10 16 2 7 15 7 161 1 5 16 7 3 14 16 3 10 5 12 14 12 101 2 1 15 5 5 12 16 6 11 2 16 11 15 121 2 3 1 8 6 5 2 5 8 4 4 6 3 71 2 16 6 6 11 15 5 12 1 15 12 16 11 21 3 4 7 4 1 5 5 3 6 2 8 7 6 81 4 11 3 4 10 9 2 11 2 10 12 12 9 31 5 6 6 14 9 10 2 13 9 2 5 14 1 131 6 10 10 4 11 7 13 16 11 13 6 4 1 161 6 13 2 14 2 6 5 5 13 10 9 1 14 101 7 8 5 7 2 4 3 8 3 2 6 6 4 51 7 10 9 16 7 9 15 1 8 16 8 15 2 21 8 12 9 9 4 13 16 5 1 13 5 12 4 81 8 14 10 14 1 15 15 8 5 11 4 10 5 41 9 2 15 15 16 10 7 8 1 10 8 2 16 91 9 15 6 16 2 13 14 10 11 7 4 5 12 31 10 9 11 15 7 6 4 16 5 2 12 13 3 141 11 14 4 13 2 9 10 12 16 8 5 3 15 61 12 12 13 14 7 2 8 14 2 1 13 11 8 111 12 15 5 4 14 3 16 7 8 6 2 10 11 131 15 4 3 7 6 10 13 12 5 14 16 8 2 111 16 3 12 11 9 13 5 8 2 14 7 4 10 152 2 5 10 16 11 3 10 11 8 5 13 3 13 82 2 12 3 15 5 8 3 5 14 12 9 8 9 142 3 6 16 12 16 3 13 13 6 7 9 2 12 72 3 8 2 9 15 14 3 14 9 5 5 15 8 122 4 7 9 5 4 9 11 2 14 5 14 11 16 162 4 13 12 12 7 15 10 5 2 15 5 13 7 42 5 9 9 3 12 8 14 15 12 14 5 3 2 152 5 11 7 2 11 9 4 16 7 16 9 14 14 42 6 2 13 3 3 12 9 7 16 6 9 16 13 122 6 9 7 7 16 13 3 12 2 13 12 9 16 62 7 12 15 2 12 4 10 13 15 13 4 5 5 102 7 14 16 5 9 2 9 16 11 11 5 7 4 142 8 5 12 5 2 14 14 8 15 3 9 12 15 92 9 13 4 2 13 8 11 6 4 6 8 15 15 112 10 3 2 13 16 8 10 8 13 11 11 16 3 52 11 15 3 11 6 14 10 15 10 6 7 7 14 32 16 4 5 16 14 7 11 4 11 14 9 9 7 53 3 4 6 11 12 13 6 12 14 4 5 13 5 143 3 6 5 16 9 15 5 9 10 6 4 15 4 103 4 5 14 4 6 12 13 5 13 6 11 11 12 143 4 9 16 10 4 16 15 3 5 10 5 15 6 63 4 16 10 5 10 4 9 9 16 15 6 3 5 153 5 12 11 14 5 11 13 3 6 14 6 13 4 43 6 4 10 6 5 9 15 4 15 5 16 16 9 103 7 8 8 16 11 12 4 15 11 4 7 16 3 153 7 16 11 4 15 3 15 11 12 12 4 7 8 163 8 7 15 4 8 15 12 3 16 4 16 12 11 113 8 15 4 16 4 8 7 7 15 12 11 3 16 123 10 10 15 16 5 4 6 16 4 3 15 9 6 93 13 11 5 4 12 4 11 6 6 5 3 14 13 123 14 7 9 14 10 13 8 7 8 10 4 4 13 95 5 8 14 16 13 6 14 13 7 8 15 6 15 75 6 11 7 10 8 5 8 7 12 12 10 6 9 115 6 13 8 13 5 7 7 6 16 14 15 8 16 155 7 9 10 7 11 6 12 9 12 11 8 8 6 105 9 6 8 10 9 8 12 5 11 10 11 12 7 75 10 10 12 8 11 9 7 8 9 5 12 6 7 65 10 12 6 5 12 8 9 7 6 7 8 11 11 95 13 15 15 14 8 6 7 16 8 7 13 14 5 169 10 13 10 11 15 15 9 16 12 14 13 16 14 119 11 12 15 12 9 13 13 11 14 10 16 15 14 169 12 10 15 13 14 9 14 15 11 11 13 12 16 10
1 Frame = 10 ms
0 1 2 3 14..........
1 Time Slot = 2560 Chips
SCH
0 1 2 3 14..........
0 1 2 3 14..........
256 Chips
S S S S S S
78321 1
Cell SearchCell Search
•Slot Timing•Frame Timing - Code Group•NodeB PSC Acquisition
P-SCH
S-SCH
•Same Word in all the Slots•Same Word for all BS
•Same Combination of 15 Words in all the Frames•Each Word of the Combination Can Be One of 16•UMTS Use Only 64 Different Combinations•Neighbours BS Should Use Different Combinations
1 2 3 1 8 6 5 2 5 8 4 4 6 3 71 2 3 1 8 6 5 2 5 8 4 4 6 3 7
t
a
aa
t
1 2 3 1 8 6 5 2 5 8 4 4 6 3 7
Node B 256
Contents
• Part 1 Introduction to UMTS
• Part 2 UMTS Air interface
• Part 3 UMTS Radio Access Network
• Part 4 UMTS Core Network
Contents
• Part 3 UMTS Radio Access Network
• Section 1 ATM basic principles
• Section 2 UTRAN protocol stack
Types of switching
• Circuit Switching• Data is sent from the same route, so time delay is fixed • High-speed switching• Fixed rate
• Packet Switching• Support multi-rate switching• Take full advantage of bandwidth• Time delay is not fixed
• Packet switching effects on RT ( voice and Video) traffic transmission • Delay• Jitter ( variable inter-arrival time)
ATM can provides both CBR and VBR services
ATM Network Model
UNI
UNI NNI
NNINNI
NNI NNI
UNI
ATM Switch ATM End terminal
UNI = User to Network InterfaceNNI = Network to Network Interface
VP and VC
• think VP as a bundle of virtual channels. (256 VC on one VP)• the individual virtual channels have unique VCI. The VCI values may be
reused in each virtual path.
ATM Connections
ATM Virtual Connection
UNI cellVPI =1 VCI =1
UNI cellVPI =20 VCI =30
NNI cellVPI =26 VCI =44
NNI cellVPI =6 VCI =44
NNI cellVPI =2 VCI =44
1
2
3
1
2
3
1
3 2
2
31
ATM Virtual ConnectionPort VPI VCI
1 26 44
2 2 44
Port VPI VCI
1 2 44
2 6 44
Port VPI VCI
2 6 44
3 20 30
Port VPI VCI
1 1 1
2 26 44A B
In order to exchange cells between A and B, several tables must be set up in network node where the cells passed. After these tables have been set up, all the cells will be transferred along this route. This route is called Virtual Connection.
ATM Protocol stack
ATM traffic classes
ATM applications in UMTS network
• UTRAN
Iub
NodeB
RNC SGSN
RNC
NodeB
NodeB
NodeB
MSC
UE
UE
Uu Iu
Iur
Iu-CS
Iu-PS
ATM applications in UMTS network
Contents
• Part 3 UMTS Radio Access Network
• Section 1 ATM basic principles
• Section 2 UTRAN protocol stack
UTRAN Terrestrial interfaces protocol Stack
• All UTRAN terrestrial interfaces follow a common protocol stack
UTRAN Terrestrial interfaces protocol Stack
• Iub interface protocol stack
UTRAN Terrestrial interfaces protocol Stack
• Iu-cs interface protocol stack
UTRAN Terrestrial interfaces protocol Stack
• Iu-ps interface protocol stack
UTRAN Terrestrial interfaces protocol Stack
• Iur interface protocol stack
Contents
• Part 1 Introduction to UMTS
• Part 2 UMTS Air interface
• Part 3 UMTS Radio Access Network
• Part 4 UMTS Core Network
3GPP R99 CN structure
3GPP R99 CN structure
• CN elements
• MSC (Mobile services switching center)• Responsible for routing of traffic and signaling information in the
network• MSC has special functionality to handle mobility • MSC handles handover
• GMSC (Gateway Mobile services switching center)• Specialized MSC used to interface with fixed networks as PSTN and
ISDN• Used to interface with other mobile network
3GPP R99 CN structure
• HLR (Home Location Register )• Centralized data base stores all administration and subscription
information related to registered subscriber to the network • HLR also stores the current location of the subscribers and any
supplementary services to which they have access • The permanent data stored for the subscriber includes
• IMSI number and MSISDN number• Authentication information
• VLR (Visitor Location Register)• Data base stores all the information related to subscriber in one MSC
service area• There is one VLR to each MSC
3GPP R99 CN structure
• SGSN (Serving GPRS Support Node)• Handles mobility management and authentication • Protocol conversion between interface to RAN or BSS and interface to
GGSN• GGSN (Gateway GPRS Support Node)
• It is connected to external network like internet or X.25 network• When the GGSN receives data addressed to a specific user, it checks if
the address is active. If it is, the GGSN forwards the data to the SGSN serving the MS, but if the address is inactive, the data are discarded
3GPP R4 CN structure
3GPP R4 CN structure
• The 3GPP R4 introduces separation of the connection, its control, and services for CS domain of CN.
• Media Gateway (MGW): an element for maintaining the connection and performing switching function when required.
• MSC server: an element controlling MGW and responsible for signaling• Packet switched voice
• The CS call is changed to the packet switched call in MGW.
3GPP R5 CN structure