Introduction to WCDMA Fundamentals Nokia

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Transcript of Introduction to WCDMA Fundamentals Nokia

WCDMA Technology and Radio Fundamentals

Nokia Siemens Networks

Agenda1. WCDMA Fundamentals Introduction WCDMA Network Architecture and Interfaces Basic Concepts: Spreading, Processing Gain WCDMA codes Radio Fundamentals : RSCP, Ec/Io WCDMA channels 2. WCDMA Network Dimensioning and Planning WCDMA Network Dimensioning Process Overview Cell Breathing Concept Input Planning Parameters Link Budget 3G Planning : Key Results analysis

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What 3G can offer to End Users..

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Drivers for 3G evolution and broadband mobileDemand model Analogies from fixed broadband usage for both business and consumers Average DSL user consumes today 1-2 GB per month (data, voice, video) Drivers for 3G evolution Changing service & underlying technology mix Volume & ARPU shift from voice to data Circuit switched to packet data (VoIP, IMS) Internet as a major source for mobile services

Advances in acc. Tech. development Flarion, WiMax, 3GPP2 camp, WLAN Technology politics (e.g., Korea-US-Japan-ChinaEurope) Spectrum and regulatory drivers Refarming

Price/performance of technology

Efficient use of spectrum

Improved broadband experience

New spectrum

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GSM evolution to 3GHigh Speed Circuit Switched Data Dedicate up to 4 timeslots for data connection ~ 50 kbps Good for real-time applications Inefficient -> ties up resources, even when nothing sent Enhanced Data Rates for Global Evolution GSM Uses 8PSK modulation HSCSD 9.6kbps (one timeslot) 3x improvement in data rate on short distances GSM Data Can fall back to GMSK for greater distances Also called CSD Combine with GPRS (EGPRS) ~ 384 kbps

GSM

GPRS EDGE

WCDMA

General Packet Radio Services Data rates up to ~ 115 kbps Max: 8 timeslots used at any one time Packet switched; resources not tied up all the time GSM / GPRS core network re-used by WCDMA (3G)

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New services demand higher speedFaster business connectivity Faster streaming Faster content download

Voice SMS

MMS WAP Download Presence Audio streaming

Web browsing Mobile intranet access Video streaming Video sharing

Video sharing Video telephony Real time IP Real time games High speed mobile intranet

GSM 10-40 kbps

GPRS 30-40 kbps

EDGE 80-160 kbps

WCDMA 128-384 kbps

HSPA 1-14 MbpsClose to WLAN bit rates and high efficiency

Non-real time Interactive, medium Real time background and bit rate streaming, connections, narrowband business connectivityefficient business streaming connectivity

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What can be done to meet DemandsEV-DO rev. A, Rev B NxEV-DO

CDMA

EDGE EvolutionGSM WCDMA UMTS-TDD WiMAX (802.16-2004) HSPA I-HSPA 3.9 G

WiMAX (802.16-2005)Flarion Flash-OFDM WLAN (unlicensed) 05 06 109 Nokia Siemens Networks

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Standardisation of 3G Cellular Networks

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Standardisation of 3G cellular networksITU (Global guidelines and recommendations) IMT-2000: Global standard for third generation (3G) wireless communications

3GPP is a co-operation between standardisation bodies ETSI (Europe), ARIB/TTC (Japan), CCSA (China), ATIS (North America) and TTA (South Korea) GSM, EDGE UMTS WCDMA - FDD WCDMA - TDD

3GPP2 is a co-operation between standardisation bodies ARIB/TTC (Japan), CCSA (China), TIA (North America) and TTA (South Korea) CDMA2000 CDMA2000 1x CDMA2000 1xEV-DO

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Structure of 3GPPTSG STRUCTURE

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UMTS ReleasesUMTS Release 99 UMTS CN UTRAN & WCDMA

1999 2001

UMTS Release 4

Low chip rate TDD mode

2002

UMTS Release 5

High Speed Downlink Packet Access (HSDPA) Wideband AMR Initial phase of the IP Multimedia Subsystem IP transport in the UTRAN etc. FDD Enhanced Uplink (HSUPA) IMS Phase 2 Wireless LAN/UMTS Inter-working Multimedia Broadcast/Multicast Service (MBMS) 64 QAM modulation MIMO HSPA+ LTE

2005

UMTS Release 62007

UMTS Release 7200813 Nokia Siemens Networks

UMTS Release 8

3G evolution performance

WCDMA R99 3GPP 5.0 MHz 100-200 ms 384 kbps 384 kbps

WCDMA HSPA 3GPP 5.0 MHz 0 3. Take next two chips = (1,-1).(1,-1) = 1+1 = 2 = +ve => 1 4. Take next two chips = 1,-1).(1,-1) = 1+1 = 2 = +ve => 1

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Spreading

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Spreading & Processing Gain Spreading Operation helps the signal resist interference and also enables the original data to be recovered if data bits are damaged during transmission

Power density (Watts/Hz)

User bit rate

R

Unspread narrowband signal

Spread wideband signal

Frequency

Bandwidth W (3.84 Mchip/sec)

Processing gain:

W G p dB R

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ExampleVoice user (R=12,2 kbit/s)R

Power density (W/Hz)

Gp=W/R=24.98 dB

Frequency (Hz)

Packet data user (R=384 kbit/s)R

Spreading sequences have a different length Processing gain depends on the user data rate

Power density (W/Hz)

Gp=W/R=10 dB

Frequency (Hz)65 Nokia Siemens Networks

WCDMA Spreading and Scrambling OperationIn WCDMA two separate codes are used in the spreading operation Channelisation code (spreading code) Scrambling code scrambling Chanelization code code (SF)

Data Bit rate chip rate chip rate

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WCDMA CodesIn WCDMA two separate codes are used in the spreading operation Channelisation code Scrambling code

Scrambling code DL: separates cells in same carrier frequency UL: separates users

Channelisation code DL: separates different users within a cell UL: separates physical channels of one user

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DL Spreading and Scrambling in WCDMACHANNELISATION codes:Channlisation code 1

SCRAMBLING CODE

Node B

XUser 1 Signal

Channelisation Code 2

XUser 2 Signal

+3.84 MHz RF carrier RF

Channelisation Code 3

X XUser 3 Signal

3.84 MHz bandwidth68 Nokia Siemens Networks

UL Spreading and Scrambling in WCDMACHANNELISATION codes:Scrambling Code 1 Channlisation code 1

RF X XNode BScrambling Code 2

User 1 Signal

Channelisation Code 2

XUser 2 Signal

X

Scrambling Code 3 Channelisation Code 3

RF

XUser 3 Signal

X

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DL Spreading and Multiplexing in WCDMARadio frame = 15 time slots

CHANNELISATION codes:CODE 1

Pilot BCCH

P-CPICH Pilot XCODE 2

User 1 User 2 User 3

BCCH

P-CCPCHXCODE 3

SUM

Time

User 1

X

DPCH1

CODE 4

+SCRAMBLING CODE X RF 3.84 MHz RF carrier

User 2

XCODE 5

DPCH2

User 3

X

DPCH3

3.84 MHz bandwidth70 Nokia Siemens Networks

Property of the Chanalization (Spreading) Codes

OrthogonalityTwo codes are said to be orthogonal when their inner product is zero.

Let: let S1 be one SF code & S2 another

Then : S1* S2 = 0Eg:(1, 1, 1, 1) and (1, 1, -1, -1) are orthogonal: (1 * 1) + (1 * 1) + (1 * -1) + (1 * -1) = 0

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Orthogonal spreading code Tree & Generation

Top sub-elementCch,4,0 =(1,1,1,1) Cch,2,0 = (1,1)

Cch,4,1 = (1,1,-1,-1)Cch,1,0 = (1)

Cch,4,2 = (1,-1,1,-1)Cch,2,1 = (1,-1)

Bottom sub-elementSF = 1 SF = 2

Cch,4,3 = (1,-1,-1,1) SF = 4

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Channelisation Code TreeSF= 1 SF= 2 SF= 4C4(0)=[1111 ] C2(0)=[11]

SF= 8C8(0)=[11111111 ]

C4(1)=[11-11]C0(0)=[ 1] C4(2)=[1-111] C2(1)=[11] C4(3)=[1-111]

.....] C16(1)=[....... .....] C16(2)=[....... C8(1)=[1111-1-1-1- .....] 1] C16(3)=[....... .....] C16(4)=[....... C8(2)=[11-1-111-1- .....] 1] C16(5)=[....... .....] C16(6)=[....... C8(3)=[11-1-1-1-111] .....] C16(7)=[....... .....] C16(8)=[....... C8(0)=[1-11-11-11- .....] C16(9)=[....... 1] .....] C16(10)=[....... C8(5)=[1-11-1-11-11] ....] C16(11)=[......... ..] C16(12)=[..... C8(6)=[1-1-111-1-11] ......] C16(13=[...... .....] C16(14)=[..... C8(7)=[1-1-11-111- ......] 1] C16(15)=[..... ......]

SF=1 6 C16(0)=[.......

...

SF=25 SF=51 6 2

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ExampleSpreading code 1 = (1, -1) Date to spread = (1,0,1,1) Data after spreading = (1, -1).(1), (1,-1).(0), (1,-1).1, (1,-1).1 = (1,-1, -1,1,1-1,1,-1) Spreading code 2 = (1,1) Date to spread = (0,0,1,1) Data after spreading = (-1,-1, -1,-1, 1,1, 1,1 ) Combined signal = (1,-1,-1,1,1,-1,1,-1) + (-1,-1,-1,-1,1,1,1,1) = (0,-2,-2,0,2,0,2,0) User 1 decodes it by simple vector multiplication (0,-2, -2,0, 2,0, 2,0) . (1,-1)

1. 2. 3. 4.

Take first 2 bits = (0,-2).(1,-1) = (0).(1) + (-2).(-1) = 0+ 2 = 2 => +ve => 1 Take next 2 bits = (-2,0).(1,-1) = (-2).(1) + (0).(-1) = -2+0 = -2 => -ve => 0 Take next 2 bits (2,0).(1,-1) = 2.1 + 0.-1 = 2 + 0 = 2 => =+ve => 1 Take next 2 bits (2,0).(1,-1) = 2 => +ve => 1

That way all 4 bits are retrieved at the receiver side.74 Nokia Siemens Networks

Multipath and Rake Receiver

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Multipath Propagation

Scramblin g code C1

C1+2

Scramblin g c