UMTS, air interface et modulation

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Thanks to M CATTRYSSE Eric
2
Memoir

• Presented by Randaxhe Benjamin
• In order to receive
• Electronics Bachelor Diploma
• (Telecommunication oriented)
• Academic year 2005 2006

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UMTS, air interface et modulation

• Presented by Benjamin Randaxhe

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Agenda

• UMTS
• Overview
• Air interface
• Generality
• Coding
• Power
• Modulation
• UMTS modulator
• RAKE receiver

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Agenda

• UMTS
• Overview
• Air interface
• Generality
• Coding
• Power
• Modulation
• UMTS modulator
• RAKE receiver

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UMTS

• Universal Mobile Telecommunications System
• 3rd generation mobile
• Multimedia services
• High bitrate
• New services Video Call, TV,internet browsing,
  games,

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Why UMTS ?
GSM
SMS
Voice
Data
GPRS
PDA
Video
MP3
UMTS
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Agenda

• UMTS
• Overview
• Air interface
• Generality
• Coding
• Power
• Modulation
• UMTS modulator
• RAKE receiver

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Frequency

• Dissociation by code gt CDMA
• Two codes are used
• Channelisation
• Scrambling
• gt WCDMA

UMTS
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1
1
1
1
1
1
1
1
1
1
1
1
Frequency is used in every cell
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Globalisation
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Frequency Division Duplex
UMTS 1 Carrier 5Mhz WCDMA-FDD Uplink 1920 -
1980 Mhz WCDMA-FDD Downlink 2110-2170 Mhz ?
Proximus 3 carriers out of 12 WCDMA-TDD
1900-1920 Mhz and 2010 - 2025 Mhz ? Proximus 1
carrier out of 4
Power
Time
Frequency
1920 MHz
1980 MHz
2110 MHz
2170 MHz
Uplink Spectrum
Downlink Spectrum
Duplex Spacing 190MHz

• Full duplex
• Separate frequencies used for uplink and downlink
  traffic

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Agenda

• UMTS
• Overview
• Air interface
• Generality
• Coding
• Power
• Modulation
• UMTS modulator
• RAKE receiver

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Encoder

• Channelisation
• OVSF
• Separation of channels

• Scrambling
• Pseudo Noise codes
• Separation of transmitters MS or Node B

Modulator
Data CRC
Channelisation
Scrambling
Clock
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Downlink
Cchan 1
User 1
Cscr
Cchan 2
?
User 2
UE3
UE2
Cchan 3
UE1
User 3
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Uplink
Cscr 1
Cchan
User 1
Cscr 2
Cchan
UE3
User 2
UE2
Cscr 3
Cchan
UE1
User 3
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Agenda

• UMTS
• Overview
• Air interface
• Generality
• Coding
• Power
• Modulation
• UMTS modulator
• RAKE receiver

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Power Control

• Everyone use the same frequency
• Avoid interference between Node B s themselves
• Avoid  near-far effect 

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Type of Power Control

• Open loop
• Increases power step by step
• Closed loop
• Power is regulated 1500 time per second

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Power transmitted / received
NB Thermal noise -108 dBm (1,514 .10-14)
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Agenda

• UMTS
• Overview
• Air interface
• Generality
• Coding
• Power
• Modulation
• UMTS modulator
• RAKE receiver

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Downlink
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Channel encoder
I
Series Parallel
Data
?
Chips
Cchan
Power Control
j
jQ
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Downlink
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Uplink

• Two speparated signals
• Data
• Control
• HPSK Modulation

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Difference between QPSK / HPSK

• QPSK

• HPSK

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Agenda

• UMTS
• Overview
• Air interface
• Generality
• Coding
• Power
• Modulation
• UMTS modulator
• RAKE receiver

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Waves propagation

• Problems
• Reflected RF
• Absorbed RF
• Diffraction

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RAKE receiver

• With a reference channel, RAKE receiver is able
  to detect and to correct the corrupted signal

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Thank you
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Presentationand memoir

• http//users.skynet.be/bk331357/umts/

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Question

• http//users.skynet.be/bk331357/umts/

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Thank you