Presentation is loading. Please wait.

Presentation is loading. Please wait.

MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 10. Antenna Diversity and Space- Time.

Published byEdwin Horton Modified over 8 years ago

Similar presentations

Presentation on theme: "MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 10. Antenna Diversity and Space- Time."— Presentation transcript:

1 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 10. Antenna Diversity and Space- Time Coding Techniques

2 Page  2 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd Chapter 10. Antenna Diversity and Space-Time Coding Techniques  10.1 ANTENNA DIVERSITY - 10.1.1 Receive Diversity - 10.1.2 Transmit Diversity  10.2 SPACE-TIME CODING (STC) : Overview - 10.2.1 System Model - 10.2.2 Pairwise Error Probability - 10.2.3 Space-Time Code Design  10.3 SPACE-TIME BLOCK CODE (STBC) - 10.3.1 Alamouti Space-Time Code - 10.3.2 Generalization of Space-Time Block Coding - 10.3.3 Decoding for Space-Time Block Codes - 10.3.4 Space-Time Trellis Code

3 Page  3 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd Chapter 10. Antenna Diversity and Space- Time Coding Techniques 10.1 Antenna Diversity

4 Page  4 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.1 Antenna Diversity

5 Page  5 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.1 Antenna Diversity

6 Page  6 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.1.1 Receive Diversity

7 Page  7 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.1.1 Receive Diversity

8 Page  8 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.1.1 Receive Diversity

9 Page  9 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.1.1 Receive Diversity

10 Page  10 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2 Space-Time Coding (STC): Overview 10.2.1 System Model

11 Page  11 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.1 System Model

12 Page  12 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.1 System Model

13 Page  13 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.1 System Model

14 Page  14 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.1 System Model

15 Page  15 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.2 Pairwise Error Probability

16 Page  16 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.2 Pairwise Error Probability

17 Page  17 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.2 Pairwise Error Probability

18 Page  18 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.2 Pairwise Error Probability

19 Page  19 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.2 Pairwise Error Probability

20 Page  20 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.2 Pairwise Error Probability

21 Page  21 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.3 Space-Time Code Design

22 Page  22 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.3 Space-Time Code Design

23 Page  23 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.3 Space-Time Code Design

24 Page  24 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.3 Space-Time Code Design

25 Page  25 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.2.3 Space-Time Code Design

26 Page  26 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3 Space-Time Block Code (STBC) 10.3.1 Alamouti Space-Time Code

27 Page  27 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.1 Alamouti Space-Time Code

28 Page  28 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.1 Alamouti Space-Time Code

29 Page  29 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.1 Alamouti Space-Time Code

30 Page  30 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.1 Alamouti Space-Time Code

31 Page  31 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2 Generalization of Space-Time Block Coding

32 Page  32 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2 Generalization of Space-Time Block Coding

33 Page  33 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2.1 Real Space-Time Block Codes

34 Page  34 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2.1 Real Space-Time Block Codes

35 Page  35 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2.1 Real Space-Time Block Codes

36 Page  36 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2.1 Real Space-Time Block Codes

37 Page  37 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2.2 Complex Space-Time Block Codes

38 Page  38 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.2.2 Complex Space-Time Block Codes

39 Page  39 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

40 Page  40 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

41 Page  41 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

42 Page  42 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

43 Page  43 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

44 Page  44 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

45 Page  45 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

46 Page  46 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

47 Page  47 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

48 Page  48 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

49 Page  49 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.3 Decoding for Space-Time Block Codes

50 Page  50 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4 Space-Time Trellis Code 10.3.4.1 Space-Time Trellis Encoder

51 Page  51 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.1 Space-Time Trellis Encoder

52 Page  52 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.1 Space-Time Trellis Encoder

53 Page  53 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.1 Space-Time Trellis Encoder

54 Page  54 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.1 Space-Time Trellis Encoder ModulationGenerator SequencesRankDet.Trace QPSK2224.0 QPSK42212.0 QPSK4333216 8PSK32224 4223.5156

55 Page  55 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.1 Space-Time Trellis Encoder Modulatio n Generator SequencesRankDet.Trac e QPSK2224.010.0 QPSK4228.016.0 QPSK432-20.0 8PSK3220.6868.0 8PSK422-20.0

56 Page  56 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.2 Space-Time Trellis Code: Illustrative Example

57 Page  57 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.2 Space-Time Trellis Code: Illustrative Example

58 Page  58 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.2 Space-Time Trellis Code: Illustrative Example

59 Page  59 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.2 Space-Time Trellis Code: Illustrative Example

60 Page  60 MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho, Jaekwon Kim, Won Young Yang, and Chung G. Kang © 2010 John Wiley & Sons (Asia) Pte Ltd 10.3.4.2 Space-Time Trellis Code: Illustrative Example

Download ppt "MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 10. Antenna Diversity and Space- Time."

Similar presentations

II. Modulation & Coding. © Tallal Elshabrawy Design Goals of Communication Systems 1.Maximize transmission bit rate 2.Minimize bit error probability 3.Minimize.

II. Modulation & Coding. © Tallal Elshabrawy Design Goals of Communication Systems 1.Maximize transmission bit rate 2.Minimize bit error probability 3.Minimize.
Prakshep Mehta ( ) Guided By: Prof. R.K. Shevgaonkar

Prakshep Mehta ( ) Guided By: Prof. R.K. Shevgaonkar
The Impact of Channel Estimation Errors on Space-Time Block Codes Presentation for Virginia Tech Symposium on Wireless Personal Communications M. C. Valenti.

The Impact of Channel Estimation Errors on Space-Time Block Codes Presentation for Virginia Tech Symposium on Wireless Personal Communications M. C. Valenti.
EE359 – Lecture 16 Outline MIMO Beamforming MIMO Diversity/Multiplexing Tradeoffs MIMO Receiver Design Maximum-Likelihood, Decision Feedback, Sphere Decoder.

EE359 – Lecture 16 Outline MIMO Beamforming MIMO Diversity/Multiplexing Tradeoffs MIMO Receiver Design Maximum-Likelihood, Decision Feedback, Sphere Decoder.
Noise Cancelation for MIMO System Prepared by: Heba Hamad Rawia Zaid Rua Zaid Supervisor: Dr.Yousef Dama.

Noise Cancelation for MIMO System Prepared by: Heba Hamad Rawia Zaid Rua Zaid Supervisor: Dr.Yousef Dama.
Mohammad Jaber Borran, Mahsa Memarzadeh, and Behnaam Aazhang June 29, 2001 Coded Modulation for Orthogonal Transmit Diversity.

Mohammad Jaber Borran, Mahsa Memarzadeh, and Behnaam Aazhang June 29, 2001 Coded Modulation for Orthogonal Transmit Diversity.
Advanced Engineering Mathematics by Erwin Kreyszig Copyright  2007 John Wiley & Sons, Inc. All rights reserved. Page 602.

Advanced Engineering Mathematics by Erwin Kreyszig Copyright  2007 John Wiley & Sons, Inc. All rights reserved. Page 602.
Istanbul Technical University, Electronics & Communication Engineering Department 2nd COST 289 Workshop, Special Topics on 4G Systems, July 7, 2005, Antalya,

Istanbul Technical University, Electronics & Communication Engineering Department 2nd COST 289 Workshop, Special Topics on 4G Systems, July 7, 2005, Antalya,
ECE 559 VLSI – Design Project Viterbi Decoder VLSI Design Project Spring 2002 Dan Breen Keith Grimes Damian Nowak David Rust Advisor: Prof. Goeckel.

ECE 559 VLSI – Design Project Viterbi Decoder VLSI Design Project Spring 2002 Dan Breen Keith Grimes Damian Nowak David Rust Advisor: Prof. Goeckel.
10 th MCM - Novi Sad, 23-24 March 2006 Joaquim Bastos ( ) 1 The information in this document is provided as is and no guarantee or warranty.

10 th MCM - Novi Sad, March 2006 Joaquim Bastos ( ) 1 The information in this document is provided as is and no guarantee or warranty.
McCormick School of Engineering ECE 380: Wireless Communications Benefits of Coding and Diversity Michael L. Honig Department of ECE Northwestern University.

McCormick School of Engineering ECE 380: Wireless Communications Benefits of Coding and Diversity Michael L. Honig Department of ECE Northwestern University.
STBC BASED STTC CODES OPTIMIZED DESIGNS FOR THREE TRANSMIT ANTENNA SYSTEMS CANCES Jean-Pierre XLIM - Dépt. C 2 S 2 UMR CNRS 6172 ENSIL Parc ESTER - BP.

STBC BASED STTC CODES OPTIMIZED DESIGNS FOR THREE TRANSMIT ANTENNA SYSTEMS CANCES Jean-Pierre XLIM - Dépt. C 2 S 2 UMR CNRS 6172 ENSIL Parc ESTER - BP.
Advanced Engineering Mathematics by Erwin Kreyszig Copyright  2007 John Wiley & Sons, Inc. All rights reserved. Fourier Series & Integrals Text Chapter.

Advanced Engineering Mathematics by Erwin Kreyszig Copyright  2007 John Wiley & Sons, Inc. All rights reserved. Fourier Series & Integrals Text Chapter.
UCBC UCSC Broadband Communications (UCBC) Research Group Hamid R. Sadjadpour April 2004 Space-Time Signal Processing for Wireless Ad-hoc Networks.

UCBC UCSC Broadband Communications (UCBC) Research Group Hamid R. Sadjadpour April 2004 Space-Time Signal Processing for Wireless Ad-hoc Networks.
Multiple-input multiple-output (MIMO) communication systems

Multiple-input multiple-output (MIMO) communication systems
Space Time Block Codes Poornima Nookala.

Space Time Block Codes Poornima Nookala.
MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 11. Signal Detection for Spatially Multiplexed.

MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 11. Signal Detection for Spatially Multiplexed.
MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 7. PAPR Reduction.

MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 7. PAPR Reduction.
Advanced Engineering Mathematics by Erwin Kreyszig Copyright  2007 John Wiley & Sons, Inc. All rights reserved. Vector Integral Calculus Text Chapter.

Advanced Engineering Mathematics by Erwin Kreyszig Copyright  2007 John Wiley & Sons, Inc. All rights reserved. Vector Integral Calculus Text Chapter.
MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 8. Inter-Cell Interference Mitigation.

MIMO-OFDM Wireless Communications with MATLAB ® Yong Soo Cho | Jaekwon Kim Won Young Yang | Chung G. Kang Chapter 8. Inter-Cell Interference Mitigation.

Similar presentations

Ads by Google