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As Part of Pedagogy Activity in EC Department, 2011, 2012

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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:www.gsmarena.com

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] D.L. Schilling, “Wireless Communication Going into the 21st Century,” IEEE Trans. Veh. Technol., Vol. 43, No. 3, pp , August 1994. [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


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