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Simulation and Analysis of 3G Air interface Wideband Coded Division Multiple Access working in Downlink FDD Electronics and Communication Department, Institute.

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Presentation on theme: "Simulation and Analysis of 3G Air interface Wideband Coded Division Multiple Access working in Downlink FDD Electronics and Communication Department, Institute."— Presentation transcript:

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

2 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 Todays 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 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 Mobile Equipment : Radio Transmission & contains applications. Mobile Termination, Terminal Equipment USIM : Data and Procedures which unambiguously and securely identify itself in Smart Card. User Equipment:

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 3G standards TD-SCDMA CDMA2000 WCDMA CDMA is the main technology of 3G CDMA 2000 UWC

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 TDD Guard time FDD Guard frequency MS BS FDD and TDD systems frequency allocation Source: Information and Communication university. frequency 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 Channel bandwidth5 MHz Duplex modeFDD and TDD Downlink RF channel structureDirect spread Chip rate3.84 Mbps Frame length10 ms Data modulationQPSK (downlink), 8 PSK BPSK (uplink) Channel codingConvolutional and turbo codes Coherent detectionUser dedicated time multiplexed pilot (downlink and uplink), common pilot in the downlink. MultirateVariable spreading and multicode Spreading factors4–256 (Downlink), 4–512 (Uplink) Spreading (downlink)OVSF sequences for channel separation Gold sequences for cell Spreading (uplink)OVSF sequences, Gold sequence HandoverSoft 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 Fig. Block diagram of the mobile transmitter Fig. Block diagram of the base station receiver Selection of Code is Utmost Important

30 Spreading in WCDMA A bit stream of 1s and 0s occurring randomly, or almost randomly, with some unique properties. Pseudo Random (PN) sequence: A bit stream of 1s and 0s occurring randomly, or almost randomly, with some unique properties. Linear shift register anan a n-1 a n-2 a n-r c1c1 c2c2 c3c3 crcr

31 Spreading and Scrambling in WCDMA Spreading: To multiply the input information bits by a PN code and get processing gain, the chip level signals 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 doesnt 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] WCDMA Selecting codes high autocorrelation low cross correlation Suppressing interference

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

33 OVSF Code Fig OVSF code Matrix of 4 ×4 length. 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 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). Gold Code

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 Source: [6] Physical Channels

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 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) Dedicated Traffic Channel (DTCH) ODMA Dedicated Traffic Channel (ODTCH) Common Traffic Channel (CTCH) Traffic Channel (TCH)

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 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 DPDCH and DPCCH Field Slot Format # Channel Bit rate (kbps) Channel Symbol rate (ksps) SFBits/slotDPDCH Bits/slotDPCCH Bits/slotTransmitted Slot per Radio frame N Tr N Data1 N Data2 N TPC N Pilot N TFC Source: [25]

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

47 Simulation of Downlink Channels 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 Methodology.

48 DPCH According to 3GPP standards, one slot (10ms/15 =.666 ms) layout is as follows: |--Data1--|--TPC--|--TFCI--|--Data2--|--pilot--| | 248 | 8 | 8 | 1000 | 16 | 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 = Now PSC is Defined as C psc = (1 + j) ×

53 Synchronisation Code Generation SSC Define z = where b = 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) × Scrambling Code Group #0#1#2#3#4#5#6#7#8#9#10#11#12#13#14 Group

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 FilterFig. 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, [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, [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 [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 , August [16]D.L. Schilling, Wireless Communication Going into the 21 st Century, IEEE Trans. Veh. Technol., Vol. 43, No. 3, pp , August [17]W. Mohr and S. Onoe, The 3GPP proposal for IMT-2000, IEEE Commun. Mag., pp , Dec [18]B. Girod and N. F¨aber, Feedback-based error control for mobile video transmission, IEEE Proceedings, vol. 87, pp , Oct [19]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 , August 1994.

69 Reference [20]D.L. Schilling, Wireless Communication Going into the 21 st Century, IEEE Trans. Veh. Technol., Vol. 43, No. 3, pp , August [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, 1 st 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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