WCDMA Demo Presentation_Webex
37
© 2002 The MathWorks, Inc. 1 © 2002 The MathWorks, Inc. WCDMA Design using Simulink Alex Rodriguez [email protected] The MathWorks, Inc. May 30 th , 2002 You should here music now. If you do not, check that your PC speakers are on and you can play sounds on your computer.
Transcript of WCDMA Demo Presentation_Webex
© 2
00
2 T
he M
ath
Work
s, Inc.
1
© 2
00
2 T
he M
ath
Work
s, Inc.
WCDMA Design using Simulink
Alex Rodriguez
The MathWorks, Inc.
May 30th, 2002
You should here music now. If you do not, check that your PC speakers are on and you can play sounds on your computer.
© 2
00
2 T
he M
ath
Work
s, Inc.
2
Agenda
• About WCDMA
• WCDMA Simulink Model
– About the models
– Physical Layer
– Mask parameters
– Coding and Multiplexing
– Modulation and Spreading
– RAKE Receiver
– Channel Models
– Visualizing the results
• Enhancements
• Radiolab 3G
© 2
00
2 T
he M
ath
Work
s, Inc.
3
About WCDMA …
• WCDMA stands for Wideband Code Division Multiple Access.
• WCDMA is one of the five air-interfaces adopted by the ITU under the name "IMT-2000 Direct Spread”.
• WCDMA can support multiple and simultaneous communications such as voice, images, data, and video.
– Very high and variable bit rates:• 144 kbps: vehicle speed, rural environ.• 384 kbps: walking speed, urban outdoor.• 2048 kbps: fixed, indoor.
– Different QoS for different connections.– High spectrum efficient.– Coexistence with current systems.
• WCDMA is being specified by the 3GPP (Third Generation Partnership Project).
© 2
00
2 T
he M
ath
Work
s, Inc.
4
About WCDMA and the 3G Standardization Process
• References:
– ITU (International Telecommunication Union)
• http://www.itu.int
– 3GPP (3 Generation Partnership Project)
• http://www.3gpp.org
– UWCC (Universal Wireless Communications Consortium)
• http://www.uwcc.org
– UMTS Forum:
• http://www.umts-forum.org
– GSM World :
• http://www.gsmworld.com
– CDMA Development Group
• http://www.cdg.org
© 2
00
2 T
he M
ath
Work
s, Inc.
5
About the models
• WCDMA has two basic modes of operation:
– TDD (Time Division Duplex).
• Low Chip Rate TDD (TD-SCDMA)
– FDD (Frequency Division Duplex).
• Duplex communications:
– Downlink Channel
• From Node B (Base Station) to UE (User Equipment).
– Uplink Channel
• From UE to Node B
• Model simulates transmission of information data (DCH – Dedicated Channel) during a connection.
© 2
00
2 T
he M
ath
Work
s, Inc.
6
About the models
WCDMA Library
WCDMA Multiplexing
and Coding
WCDMA Spreading
and Modulation
WCDMA Physical
Layer
To open the models,
type wcdmademos
R12.1 !!
For NT, Linux and Unix
w/o accelerator
© 2
00
2 T
he M
ath
Work
s, Inc.
7
Physical Layer Specifications
• Physical layer provides data transport support to higher layers via Transport Channels.
• Functions of the Physical Layer:
– Error detection.
– FEC encoding/decoding.
– Rate Matching/Dematching.
– Multiplexing/Demultiplexing different Transport Channels into/from a Coded Composite Transport Channel (CCTrCH).
– Mapping/Demapping of CCTrCH into/from Physical Channels.
– Modulation and Spreading/Demodulation and Despreading.
– Power Weighting and combining of physical channels.
– RF Processing.
– …
© 2
00
2 T
he M
ath
Work
s, Inc.
8
WCDMA Physical Layer Transmitter
Channel Coding and
Multiplexing
Layer 2
MAC
Transport
Channels
Layer 1
CCTrCh Physical
Channel
Mapping
Spreading
And
Modulation
Channel
DPCH
Pilot Bits
TPC
TFCI
Control Channels
Interference (OCNS)Orthogonal
Codes
Slot
DPCH
- DL Scrambling Code
- Channelization Code
- Transmit Diversity- Slot Format
- Power Settings
- Transport Block Set Size
- Transport Block Size
- Transmission Time Interval
- Size of CRC
- Type of Error Correction
- Coding Rate
- Rate Matching Attribute
Transport Format
© 2
00
2 T
he M
ath
Work
s, Inc.
9
WCDMA Physical Layer Model
© 2
00
2 T
he M
ath
Work
s, Inc.
10
Initial Settings Mask – Layer 2
Multiplexing and Coding
Spreading and Modulation
Variables are stored in the workspace.
To view them, type who or whos
© 2
00
2 T
he M
ath
Work
s, Inc.
11
Coding and Multiplexing Specifications
• Physical layer provides data transport support to higher layers via Transport Channels.
• There is a Transport Format associated to each Transport Channel that describes the processing (CRC size, encoding scheme, coding rate, …) to be applied by the Physical Layer.
• Every transport block is generated every 10, 20, 40 or 80 ms (Time Transmission Interval – TTI).
© 2
00
2 T
he M
ath
Work
s, Inc.
12
Coding and Multiplexing Overview
CRC Concat/
Segment
Channel
Encoder
Rate
Matching
1st
Interleaver
Radio
Frame
Segment
CCTrCH
CRC Concat/
Segment
Channel
Encoder
Rate
Matching
1st
Interleaver
Radio
Frame
Segment
Layer 1
Coding Schemes:- No coding- Convolutional Coding- Turbocoding
Accommodates data rates
to a fixed channel bit rate
Interleaves bits within each Transport Channel
Limits Max Size
of CodewordsMultiplexes bits from different Transport Channels every 10 ms.
Attaches CRC
Size={0,8,12,16,24}
Transmission Time Interval
{10,20,40 and 80ms}
Radio Frame
{10ms}
© 2
00
2 T
he M
ath
Work
s, Inc.
13
Coding and Multiplexing Model
Layer 1Layer 2
Transmission Time Interval{10,20,40 and 80ms}
Radio Frame
{10ms}
Transport
ChannelsCCTrCh
CRCConcatenation
and
Segmentation
Channel
Encoder
Rate
MatchingFirst
Interleaver
© 2
00
2 T
he M
ath
Work
s, Inc.
14
Physical Channel Mapping Overview
Physical
Channel
Segmentation
2nd
Interleaver
One CCTrCH can be mapped onto one or
several PhCHs
Slot
Builder
CCTrCh DPCHDPCH DPCH
TFCI
Power Control Bits
Pilot Bits
Interleaves bits within a Radio Frame coming from
different Transport Channels
Transport Format Combination Index contains information of how the
different transport channel have been processed
Data 1 TPC TFCI Data 2 Pilot
Structure of slot is defined by the Higher Layers via
Slot Format
Data is sent to the Modulation and Spreading
block
© 2
00
2 T
he M
ath
Work
s, Inc.
15
Physical Channel Mapping Model
Slot
{10/15 ms}Radio Frame
{10ms}
Physical channel
segmentation
2nd Interleaver
Slot Builder
© 2
00
2 T
he M
ath
Work
s, Inc.
16
References
• 3GPP TS 25.302 – “Services provided by the Physical Layer”.
• 3GPP TS 25.211 – “Physical channels and mapping of transport channels onto Physical Channels (FDD)”.
• 3GPP TS 25.212 – “Multiplexing and channel coding”.
• 3GPP TS 25.944 – “Channel coding and multiplexing examples”.
© 2
00
2 T
he M
ath
Work
s, Inc.
17
Modulation and Spreading Specifications
• Modulation:– QPSK.– Same gain for I and Q components.
• Spreading or Channelization Operation:– Transforms every bit into a given number of chips, hence
increasing the bandwidth.– Chip Rate = 3.84 Mcps.– By using an orthogonal code for each physical channel, receiver
can separate them.– Orthogonal codes are real-valued OVSF codes (Orthogonal
Variable Spreading Factor) of different length.
• Scrambling:– Separates different Base Stations.– Complex-valued Gold Code Sequences.
© 2
00
2 T
he M
ath
Work
s, Inc.
18
Modulation and Spreading Specifications
• Power weighting:
– Different power is applied to each physical channel before being added together.
• Pulse shaping:
– Root-raised cosine filter with ß=0.22.
– Bandwidth is 5MHz.
© 2
00
2 T
he M
ath
Work
s, Inc.
19
Modulation and Spreading Specifications
• Physical channels required during a connection:
– Dedicated Channel:
• DPCH Dedicated Physical Channel
– Common Channels:
• P-CPICH Primary Common Pilot Channel– Could be used at the receiver end for channel estimation, tracking
• P-CCPCH Primary Common Control Physical Channel
• SCH Synchronization Channel– Not multiplied by orthogonal code.– Used mainly for cell search: slot and frame timing acquisition.
• PICH Paging Indicator Channel
• OCNS Orthogonal Channel Noise Simulator– Simulates interference caused by other users or signals.
© 2
00
2 T
he M
ath
Work
s, Inc.
20
Modulation and Spreading Overview
DPCH
Spreading
I&Q
Mapping
Common
Channels
Scrambling Power
Settings + To Channel
Orthogonal Codes
OVSF
PN Sequence
Gold Codes
OCNS SCH
QPSK Modulation
Bit Rate Chip Rate
{3.84Mcps}
Channelization
Common Channels are
introduced
Scrambling
Power Weighting
Physical Channels are added before being sent to
Pulse Shaping
© 2
00
2 T
he M
ath
Work
s, Inc.
21
Modulation and Spreading Model
Spreading
ScramblingPower
Adjustment
Pulse Shaping
Introduce Common Channels Introduce Interference
Modulation
© 2
00
2 T
he M
ath
Work
s, Inc.
22
References
• 3GPP TS 25.101 – “UE Radio Transmission and Reception”.
• 3GPP TS 25.211 – “Physical channels and mapping of transport channels onto Physical Channels (FDD)”.
• 3GPP TS 25.213 – “Spreading and Modulation (FDD)”.
© 2
00
2 T
he M
ath
Work
s, Inc.
23
RAKE Receiver
• Standard does not defined Receiver algorithms.
– Although specifications has been defined in a such a way that a RAKE receiver will satisfy most of the cases.
• RAKE receiver consists of several branches (RAKE Fingers) each of them assigned to a different receive paths, due to:
– Diversity reception (“echoes”) : sum of attenuated and delayed versions of the transmitted signal.
– Handoff.
• The outputs of the different RAKE fingers are aligned in time and coherently combined.
– Convert destructive interference into constructive interference.
© 2
00
2 T
he M
ath
Work
s, Inc.
24
RAKE Receiver
• Rake finger consists of:
– Downsampler
– Decorrelators for Data and Pilot
• Receiver requires knowledge of channelization codes used by Data (Dedicated Physical Channel) and Pilot.
– Channel Estimation
• By comparing receiving pilot signal with reference signal.
• Low Pass filter is introduced is smooth noise estimates.
– Data Derotation or Phase Correction
• Using channel estimates data is phase corrected.
• Current RAKE receiver assumes perfect carrier and timing synchronization.
© 2
00
2 T
he M
ath
Work
s, Inc.
25
RAKE Finger Overview
From Channel ↓ Correlator
Channel
Estimation
Phase
Correction +
From Other
Fingers
From Other
Fingers
To
Decoder
Pilot Sequence, Channelization and
Scrambling Code are generated at the receiver
Pilot Reference
Orthogonal
Codes
Data / Pilot
Tick Rate Bit RateChip Rate
Derotates data using channel estimates
Paths are aligned and added coherently
Oversampled data
© 2
00
2 T
he M
ath
Work
s, Inc.
26
RAKE Receiver Model
Sequence
Generators
Pilot Reference Generator
RAKE Combiner
Pilot and Data Correlators
Channel Estimator
Phase Correction
© 2
00
2 T
he M
ath
Work
s, Inc.
27
Channel Models
• 3GPP standard specifies minimum requirement tests under for different data rates under different propagation conditions:
– Static Channel (AWGN)
– Multipath Fading
• 6 different multipath profiles
– Moving Propagation Conditions• Non fading channel with two taps (static – moving).
– Birth-Death Propagation Conditions• Non fading channel with two taps that appear randomly.
• Channel models are implemented using a Configurable Subsystem.
© 2
00
2 T
he M
ath
Work
s, Inc.
28
Channel Models
• Use the mask of the demo, to select any predefined profile.
• To define any multipath profile, use the option User Defined.
© 2
00
2 T
he M
ath
Work
s, Inc.
29
References
• 3GPP TS 25.101 – “UE Radio Transmission and Reception”.
© 2
00
2 T
he M
ath
Work
s, Inc.
30
Visualizing the results
• There is an intrinsic delay between transmission and reception of at least 2 TTI.
• Simulink libraries contain several other types of displays such as eye diagrams, scatter plots or histograms.
Spreading and Modulation Demo
Multiplexing and Coding Demo
Physical Layer Demo
• BER
(Bit Error Rate)
• Time Scopes
• Frequency Scopes
• BER• BLER (Syndrome Detector)
• BER
• BLER
• Time Scopes
• Frequency Scopes
© 2
00
2 T
he M
ath
Work
s, Inc.
31
Visualizing the results
To open and close the scopes, double-click
on the switch icon
© 2
00
2 T
he M
ath
Work
s, Inc.
32
Enhancements
© 2
00
2 T
he M
ath
Work
s, Inc.
33
Enhancements
• Current model and library can be used as a baseline to test different algorithms such as:– Turbo coding– Power Control– AFC – AGC– Tracking– Space Time Transmit Diversity
• Two transmit antennae and one receiver antenna.– Open Loop– Close Loop Mode I and II
– Cell Search– Multi-user detection.– …
© 2
00
2 T
he M
ath
Work
s, Inc.
34
Radiolab 3G
© 2
00
2 T
he M
ath
Work
s, Inc.
35
Radiolab 3G: UMTS/W-CDMA Blockset
• 20 reference designs
• Uplink and downlink
• Transport channels and physical channels
• Viterbi and Turbo decoding
• Multi-user detection
• Vary data rates during simulation (Bursty)
• Fixed-point and floating-point
http://www.mathworks.com/products/connections/product_name.shtml, “RadioLab3G”
© 2
00
2 T
he M
ath
Work
s, Inc.
36
Remember to fill out the survey !!
© 2
00
2 T
he M
ath
Work
s, Inc.
37
Thank you
