1. As Part of Pedagogy Activity in EC Department, 2011, 2012
Simulation and Analysis of 3G Air interface Wideband Coded Division Multiple Access working in Downlink FDD
4th August, 2012
Presented By: Prof. Amit Degada
Electronics and Communication Department, Institute of Technology, Nirma University, Ahmedabad

2. ज्ञानं ज्ञेयं परिज्ञाता त्रिविधा कर्म च यत्तु दना । करणं कर्म कर्तेति त्रिविधः कर्मसंग्रहः ॥१८- १८॥
Meaning
Knowledge, the Object of knowledge, and the knower are the three factors that motivate the action; the senses, the work, and the doer
are the three constituents of action The Bhagavad Gita(18.18)

3. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

4. The Objective of the Lecture
How the Technology has evolved.
Various Air Interfaces of 3G
Physical Layer of WCDMA Working In Downlink FDD

5. First Mobile Radio Telephone

6. Today’s Mobile
Source:

7. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

8. Migration to 3G

9. Migration to 3G
Source: univ.zte.com/cn

10. 3GPP- A Global Initiative
3GPP - Third Generation Partnership Project
ARIB - Association of Radio Industries and Businesses
CWTS - China Wireless Telecommunication Standard group
ETSI - European Telecommunications Standards Institute
T1 - Standards Committee T1 Telecommunications
TTA - Telecommunications Technology Association
TTC - Telecommunication Technology Committee
IETF - Internet Engineering Task Force
ITU-R - International Telecommunication Union -Radiocommunication
ITU-T - International Telecommunication Union - Telecommunication Standardization
Source: univ.zte.com/cn

11. IMT-2000 Vision Includes
Source:

12. UMTS General Architecture
Figure : General Architecture
User Equipment:
Mobile Equipment : Radio Transmission & contains applications.
Mobile Termination, Terminal Equipment
USIM : Data and Procedures which unambiguously and securely identify itself in Smart Card.

13. 3GPP Rel.6 Objectives
Migration from GSM based Network to 3G standard WCDMA
Scope and definition in progress
IP Multimedia Services, phase 2
„IMS messaging and group management
Wireless LAN interworking
Speech enabled services
„ Distributed speech recognition (DSR)
Number portability
Other enhancements

14. 3GPP2 Defines 3rd Generation Partnership Project “Two”„
Separate organization, as 3GPP closely tied to GSM and UMTS„
Goal of ultimate merger (3GPP + 3GPP2) remains

15. Various Air interfaces of 3G
WCDMA
CDMA2000 3G
TD-SCDMA
CDMA 2000
standards
UWC
CDMA is the main technology of 3G

16. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

17. Architecture of channel Adaptive Hybrid ARQ/FEC

18. CDMA Vs. WCDMA

19. Concepts We have to know
Simplex Vs. Duplex
Circuit Switching Vs. packet switching
TDD Vs. FDD
Symmetric Vs. Asymmetric Transmission
TDMA Vs FDMA
Spread Spectrum

20. Simplex Vs. Duplex
Fig. Simplex Scenario

21. Simplex Vs. Duplex Fig. Duplex Scenario
While in Duplex we have access to both transmitter and receiver Simultaneously.
Mobile can Send and receive data Simultaneously

22. Circuit Switching Vs. packet Switching
Traditional Connection for Voice Communication requires that a Physical path Connecting the users at the end of the line and that path stays open until the Conversation ends. This is Called Circuit Switching.
Most Modern Technology Defers from this Traditional Model because they uses packet data.
Chopped into pieces
Given a destination address
Mixed with other data from other Source
Transmitted over channel with other data
Reconstructed at other end
Packet Data was originally developed for Internet.

23. WCDMA Works in Two mode FDD and TDD systems frequency allocation
Source: Information and Communication university.
frequency
Time
FDD
Guard frequency MS BS
FDD and TDD systems frequency allocation
TDD
Guard time

24. FDD - WCDMA Improved performance over 2G systems:
Improved Capacity and coverage
Coherent uplink using a user-dedicated pilot
Fast power control in the downlink
Seamless inter-frequency handover
High degree of service flexibility:
Multi-rate service : with maximums of Kb/s for full coverage and 2 Mb/s for limited coverage
Packet access mode
High degree of operator flexibility:
Support of asynchronous inter-base-station   
Support of different deployment scenarios, including hierarchical cell structure (HCS) and hot-spot scenarios
Support of new technologies like multi-user detection (MUD) and adaptive antenna arrays (SDMA)

25. Symmetric vs. Asymmetric Transmission
Same Data rate for Uplink and downlink
Different Data Rate

26. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

27. WCDMA Parameters Source: [21] Channel bandwidth 5 MHz Duplex mode
FDD and TDD
Downlink RF channel structure
Direct spread
Chip rate
3.84 Mbps
Frame length
10 ms
Data modulation
QPSK (downlink), 8 PSK
BPSK (uplink)
Channel coding
Convolutional and turbo codes
Coherent detection
User dedicated time multiplexed pilot (downlink and uplink), common pilot in the downlink.
Multirate
Variable spreading and multicode
Spreading factors
4–256 (Downlink), 4–512 (Uplink)
Spreading (downlink)
OVSF sequences for channel separation
Gold sequences for cell
Spreading (uplink)
OVSF sequences, Gold sequence 241-1
Handover
Soft handover
Interfrequency handover
Source: [21]

28. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

29. CDMA Transmitter And Receiver
Selection of Code is Utmost Important
Fig. Block diagram of the mobile transmitter
Fig. Block diagram of the base station receiver

30. Spreading in WCDMA
Pseudo Random (PN) sequence: A bit stream of ‘1’s and ‘0’s occurring randomly, or almost randomly, with some unique properties.
Linear shift register an
an-1
an-2
an-r c1 c2 c3 cr

31. Spreading and Scrambling in WCDMA
Spreading: To multiply the input information bits by a PN code and get processing gain, the
chip level signal’s bandwidth is much wider than that of input information bits.
It maintains the orthogonality among different physical channels of each user.
Scrambling: To separate the signals from the different users. It doesn’t change the signal
bandwidth. Each cell has a unique scrambling code in the system.
Fig. Relation between spreading and scrambling [11]
Fig. Spreading for all downlink physical channels except SCH [11]
Selecting codes
high autocorrelation low cross correlation
Suppressing
interference
WCDMA

32. Spreading in WCDMA OVSF Code and Gold Code OVSF Code:
Purpose: Spreading
Generation Methedology: Code-Tree
C2,1=1 1
Fig. Auto-correlation and cross correlation between
the OVSF codes of length 128
C1,1= 1
C2,2=1 -1
C4,3=
C4,4=
Gold Code:
Purpose: Scrambling
Generation: modulo-2 sum of 2 m-sequences
Fig. Auto and cross correlation of Gold Code

33. OVSF Code Fig OVSF code Matrix of 8 ×8 length.
Fig OVSF code plot for code number 6 from 128 ×128 OVSF code Matrix

34. Gold Code
Fig Scrambling code generation

35. Gold Code
A set of Gold codes can be generated with the following steps.
Pick two maximum length sequences of the same length    such that their absolute cross-correlation is less than or equal to
where   is the size of the LFSR used to generate the maximum length sequence (Gold '67).

36. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

37. Air Interface Protocol Architecture
Physical Channels
Source: [6]

38. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

39. Logical Channel Control Channel (CCH) Broadcast Control Channel (BCCH)
Paging Control Channel (PCCH)
Dedicated Control Channel (DCCH)
Common Control Channel (CCCH)
Shared Channel Control Channel (SHCCH)
ODMA Dedicated Control Channel (ODCCH)
ODMA Common Control Channel (OCCCH)
Control Channel (CCH)
Traffic Channel (TCH)
Dedicated Traffic Channel (DTCH)
ODMA Dedicated Traffic Channel (ODTCH)
Common Traffic Channel (CTCH)

40. Transport Channel Dedicated channels. Common channels.
Broadcast Channel (BCH)
Forward Access Channel (FACH)
Paging channel (PCH)
Random Access Channel (RACH)
Common Packet Channel (CPCH)
Downlink Shared Channel (DSCH)

41. Physical Channel Downlink Channels Uplink Channels
Dedicated physical Channel
Common physical Channel
Downlink Channels
Downlink Dedicated Physical Channel (DPCH)
Physical Downlink Shared Channel (DSCH)
Primary and Secondary Common Pilot Channels (CPICH)
Primary and Secondary Common Control Physical Channels (CCPCH)
Synchronization Channel (SCH)

42. Mapping of Transport channel into Physical Channel
Source: [3]
The Transport Channels are Channel Coded and matched to the data
rate offered by physical Channels.

43. Downlink Physical Channels
The length of a radio frame is 10 ms and one frame consists of 15 time slots.
The number of bits per time slot depends on the physical channel.
There is one downlink dedicated physical channel, one shared and five common control channels
Dedicated Downlink physical channel (DPCH)
Physical downlink shared channel (DSCH)
Primary and secondary common pilot channels (CPICH)
Primary and secondary common control physical channels (CCPCH)
Synchronization channel (SCH)

44. Dedicated Downlink Physical Channel (DPCH)
Source: [25]

45. Channel Symbol rate (ksps)
DPDCH and DPCCH Field
Slot
Format #
Channel Bit rate
(kbps)
Channel Symbol rate (ksps) SF
Bits/slot
DPDCH Bits/slot
DPCCH Bits/slot
Transmitted
Slot per
Radio frame NTr
NData1
NData2
NTPC
NPilot
NTFC1 15
7.5
512 10
248
1000 8 16
Source: [25]

46. Downlink Dedicated Physical channel (DPCH)
Fig. Data After Spreading
Fig Data after Scrambling

47. Simulation of Downlink Channels
Methodology.
Generation of Data
Mapped to I and Q branch
Adjust into Frame by Adding TPC, TFCI bits……
Spreading & Scrambling
Divide to Real and Imag branch
Modulation

48. DPCH
According to 3GPP standards, one slot (10ms/15 = .666 ms) layout is as
follows:
|--Data1--|--TPC--|--TFCI--|--Data2--|--pilot--|
| | | | | |
Total bits = 1280, SF=4 ==>num_chips=1280*4=5120chips/slot
Channel rate is 1280(bit/slot)*15(slot) =1920 kbps.
To form a slot and then a frame we need to break our data stream into
according to Data1 and Data2(format#0).

49. Common Downlink Physical channel
Common Pilot Channel (CPICH)
P-CPICH
S-CPICH
Fig Common Pilot Channel (CPICH) [25]

50. Common Control Physical Channel
Primary-CCPCH
Secondary-CCPCH
Fig Primary-CCPCH [25]
Fig Secondary-CCPCH [25]

51. Synchronisation Channel (SCH)
The Synchronisation Channel (SCH) is a downlink signal used for cell search.
Consists of Two Channel
Fig. Structure of Synchronisation Channel (SCH) [25]

52. Synchronisation Code Generation
PSC
Define:
a = <x1, x2, x3, …, x16>
a= <1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, -1, -1, 1 >
Now PSC is Defined as
Cpsc = (1 + j) × <a, a, a, -a, -a, a, -a, -a, a, a, a, -a, a, -a, a, a>

53. Synchronisation Code Generation
SSC
Define
z = <b, b, b, -b, b, b, -b, -b, b, -b, b, -b, -b, -b, -b, -b>
where
b = <x1, x2, x3, x4, x5, x6, x7, x8, -x9, -x10, -x11, -x12, -x13, -x14, -x15, -x16>
The Hadamard sequences

54. Synchronisation Code Generation
The k:th SSC, Cssc,k = 1, 2, 3, …, 16 is then defined as:
m=16*(k-1)
Cssc,k = (1 + j) × <hm(0) × z(0), hm(1) × z(1), hm(2) × z(2), …, hm(255) × z(255)>
Scrambling
Code Group #0 #1 #2 #3 #4 #5 #6 #7 #8 #9
#10
#11
#12
#13
#14
Group 0 1 2 8 9 10 15 16 7

55. PSCH Search
Fig PSCH search

56. Presentation Outline The Objective Standardization Body
Motivation to work
WCDMA Parameters
CDMA Transmitter and Receiver: A General Approach
Air Interface Architecture
WCDMA Channels
WCDMA Transmitter

57. Transmitter Fig. Combining Different Downlink Physical channel [26]
Fig. Modulation in WCDMA [26]

58. Square Root Raised Cosine Filter
Fig. Magnitude response of Square-Root Raised Cosine Filter
Fig. Phase response of Square-Root Raised Cosine Filter
Fig. Impulse response of Square-Root Raised Cosine Filter
Fig. Step response of Square-Root Raised Cosine Filter

59. Square Root Raised Cosine filter
It is characterised by two values; , the roll-off factor, and , the reciprocal of the symbol-rate.

60. Square Root Raised Cosine Response

61. Square Root Raised Cosine Filter
Fig. Pole/Zero Plot of Square-Root Raised Cosine Filter

62. QPSK modulation of DPCH
Fig. DPCH I channel Modulated by Cos(ωt)
Fig DPCH Q channel Modulated by –Sin(ωt)
Fig Transmitted signal Constellation

63. Primary Common Control Physical Channel (P-CCPCH)
Fig. Primary Common Control Physical Channel
with SSC I branch
Fig. Primary Common Control Physical Channel
with SSC Q branch

64. Secondary-CCPCH Fig. Secondary Common Control Physical
Channel I branch
Fig. Secondary Common Control Physical
Channel Q branch

65. Questions

66. This Can Be Downloaded From

67. Reference
[1]
J. Schiller, “Mobile Communication”, second edition Pearson Education Private LTD.
[2]
Rudolf Tanner and Jason woodword, “WCDMA Requirements and practical design”, John Wiley and Sons LTD.
[3]
Holama H. and Toskala A. “WCDMA for UMTS”, John Wiley and Sons LTD.
[4]
T Rappaport, “Wireless Communications, Principles and Practices”, Second Edition, Prentice Hall, 2002.
[5]
Viterbi Andrew J “CDMA: Principles of spread spectrum communication”, second edition prentice hall LTD.
[6]
Proakis J. G. “Digital Communication”, third edition prentice hall LTD.
[7]
M. R. Karim and Sarraf M., “W-CDMA and CDMA 2000 for 3G Mobile Networks”, McGrawHill, 2002.
[8]
Stallings, W “Wireless Communications and Networks” Prentice Hall LTD.
[9]
Widrow, B., & Stearns, S.D “Adaptive Signal Processing” Prentice Hall: New Jersey
[10]
Haykin, S “Adaptive Filter Theory” Prentice Hall: Eaglewood Cliffs

68. Reference
[8]
E. Berruto, M. Gudmundson, R. Menolascino, W. Mohr, and M. Pizarroso, “Research activities on UMTS radio interface, network architectures, and planning,” IEEE Commun. Mag., vol. 36, pp. 82–95, Feb
[9]
D. Grillo, Ed., “Special section on third-generation mobile systems in Europe”,” IEEE Personal Commun. Mag., vol. 5, pp. 5–38, Apr
[10]
Bahl P. and Girod B., Eds., “Special section on wireless video,” IEEE Commun. Mag., vol. 36, pp , June 1998.
[11]
W. Mohr and S. Onoe, “The 3GPP proposal for IMT-2000,” IEEE Commun. Mag., pp , Dec
[12]
Homer, J., Bitmead, R.R., & Mareels, I “Quantifying the effects of dimension on the convergence rate of LMS adaptive FIR estimator,” IEEE Transactions on Signal Processing, 46 (10):
[13]
Homer, J “A review of the developments in adaptive echo cancellation for telecommunications,” Journal of Electrical and Electronics Engineering, Australia, 18(2):
[14]
Homer J., Mareels I., Bitmead R.R., Wahlberg B., & Gustafsson F. “LMS estimation via structural detection” IEEE Transactions on Signal Processing, 46(10): , 1998
[15]
A.J. Viterbi, “The Evolution of Digital Wireless Technology from Space Exploration to Personal Communication Ser vices,” IEEE Trans. Veh. Technol., Vol. 43, No. 3, pp. 638—644, August 1994.
[16]
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[17]
[18]
B. Girod and N. F¨aber, “Feedback-based error control for mobile video transmission,” IEEE Proceedings, vol. 87, pp , Oct
[19]

69. Reference
[20]
D.L. Schilling, “Wireless Communication Going into the 21st Century,” IEEE Trans. Veh. Technol., Vol. 43, No. 3, pp , August 1994.
[21]
W. Mohr and S. Onoe, “The 3GPP proposal for IMT-2000,” IEEE Commun. Mag., pp , Dec
[22]
Zhang X., Gang. H., “Strategies of improving QoS for Video Transmission over 3G Wireless Network”, Hohai university.
[23]
Cherriman P., Hanzo L., “ Robust H.263 Video Transmission over Mobile Channels In interference Limited Environment”, 1st IEEE wireless video communication workshop.
[24]
Gharvi H., “Video Transmission for Third Generation Mobile Communication Systems”, Milcom, 2001.

70. Reference [3GPP Technical specification]
[25]
3GPP TSG Technical Specification TS “Physical channels and mapping of transport channels”.
[26]
3GPP TSG Technical Specification TS “Spreading and modulation”
[27]
3GPP TSG Technical Specification TS “Multiplexing and channel coding (FDD)”
[28]
3GPP TSG Technical Specification TS “Physical layer procedures (FDD)”

71. Reference [Websites] [29]
CDMA Development Group RAKE Receiver: Another Advantage of CDMA over Other Systems. [Accessed Oct ].
[30]
CDMA seminars on
[31]
WCDMA chapter-6:

72. Thank You