S.D.M COLLEGE OF ENGINEERING AND TECHNOLOGY
|
|
- Lora Ford
- 5 years ago
- Views:
Transcription
1 VISHVESHWARAIAH TECHNOLOGICAL UNIVERSITY S.D.M COLLEGE OF ENGINEERING AND TECHNOLOGY A seminar report on Orthogonal Frequency Division Multiplexing (OFDM) Submitted by Sandeep Katakol 2SD06CS085 8th semester DEPARTMENT OF COMPUTER SCIENCE ENGINEERING
2 VISHVESHWARAIAH TECHNOLOGICAL UNIVERSITY S.D.M COLLEGE OF ENGINEERING AND TECHNOLOGY DEPARTMENT OF COMPUTER SCIENCE ENGINEERING CERTIFICATE Certified that the seminar work entitled Orthogonal Frequency Division Multiplexing (OFDM) is a bonafide work presented by Sandeep Katakol bearing USN NO:2SD06CS085 in a partial fulfillment for the award of degree of Bachelor of Engineering in Computer Science Engineering of the Vishveshwaraiah Technological University, Belgaum during the year The seminar report has been approved as it satisfies the academic requirements with respect to seminar work presented for the Bachelor of Engineering Degree. Staff in charge CSE H.O.D Name: Sandeep Katakol 2
3 USN: 2SD06CS085 INDEX 1. INTRODUCTION 4 2. MULTIPLEXING TDMA CDMA FDMA 6 3. OFDM 6 4. DATA TRANSMISSION USING MULTIPLE CARRIERS 8 5. GUARD TIME AND CYCLIC EXTENTION TRANSMISSION AND RECEPTION CHOICE OF OFDM PARAMETERS ADVANTAGES DISADVANTAGES CONCLUSION 14 3
4 Orthogonal Frequency Division Multiplexing (OFDM) ABSTRACT A number of new technologies are being combined by the telecommunications industry as it prepares for the next generation of mobile services. One of the key changes is the choice of OFDM for the air interface. This paper will describe OFDM and show why it has the ability to improve the spectral efficiency of digital radio links Orthogonal frequency division multiplexing (OFDM) is a special case of multicarrier transmission, where a single datastream is transmitted over a number of lower rate subcarriers. 1. INTRODUCTION In today s world cell phone have become the single greatest tool in day today life. It has become a necessity that business associates should be able to communicate on the go. That s why it has become so important to make choices in choosing which handheld device one should go for. A handheld device is selected according to its features and benefits, like does it provide access to internet and or does it look slick and more. An important question when designing and standardizing cellular systems is the selection of the multiple access schemes. There are three basic principles in multiple access, FDMA (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), and CDMA (Code Division Multiple Access). All three principles allow multiple users to share the same physical channel Orthogonal frequency division multiplexing (OFDM) is a communications technique that divides a communications channel into a number of equally spaced frequency bands. A subcarrier carrying a portion of the user information is transmitted in each band. Each subcarrier is orthogonal (independent of each other) with every other subcarrier, differentiating OFDM from the commonly used frequency division multiplexing (FDM). 2. MULTIPLEXING Multiplexing is the set of techniques that allows the simultaneous transmission of multiple signals across a single data link. As data and telecommunications use increases, so does traffic. We can accommodate. This increase by continuing to add individual links each time a new channel is needed. In a multiplexed system, n lines share the bandwidth of one link. Figure shows the basic format of a multiplexed system. The lines on the left direct their transmission streams to a multiplexer (MUX), which combines them into a single stream (many-to- one). At the receiving end, that stream is fed into a demultiplexer (DEMUX), which separates the stream back into its component transmissions (one-to-many) and directs them to their corresponding lines. In the figure, the word link refers to the physical path. The word channel refers to the portion of a link that carries a transmission between a given pair of lines. One link can have many (n) channels.[1] 4
5 2.1 TDMA: Time Division Multiplex Access is a type of multiplexing where two or more channels of information are transmitted over the same link by allocating a different time interval for the transmission of each channel. One major disadvantage using TDMA technology is that the users has a predefined time slot. When moving from one cell site to other, if all the time slots in this cell are full the user might be disconnected. Another problem in TDMA is that it is subjected to multipath distortion.[1] 2.2 CDMA CDMA gives the user entire spectrum all of the time. CDMA spread spectrum technology in which it uses unique spreading codes to spread the baseband data before transmission. The receiver then dispreads the wanted signal, which is passed through a narrow band pass filter. The unwanted signals are not dispread and will not be passed through the filter. The codes are a sequence of zeros and ones produced at a much higher rate of that of the baseband data. One major problem in CDMA technology is channel pollution, where signals from too many cell sites are present in the subscriber s phone but none of them is dominant. When this situation arises the quality of the audio degrades[1] 5
6 2.3 FDMA In frequency-division multiple access (FDMA), the available bandwidth is divided into frequency bands. Each station is allocated a band to send its data. In other words, each band is reserved for a specific station, and it belongs to the station all the time. FDMA specifies a predetermined frequency band for the entire period of communication. This means that stream data (a continuous flow of data that may not be packetized) can easily be used with FDMA. [1] 3. OFDM OFDM represents a different system-design approach. It can be thought of as a combination of modulation and multiple-access schemes that segments a communications channel in such a way that many users can share it. Whereas TDMA segments are according to time and CDMA segments are according to spreading codes, OFDM segments are according to frequency. It is a technique that divides the spectrum into a number of equally spaced tones and carries a portion of a user's information on each tone. A tone can be thought of as a frequency, much in the same way that each key on a piano represents a unique frequency. OFDM can be viewed as a form of frequency division multiplexing (FDM), however, OFDM has an important special property that each tone is orthogonal with every other tone. FDM typically requires there to be frequency guard bands between the frequencies so that they do not 6
7 interfere with each other. OFDM allows the spectrum of each tone to overlap, and because they areorthogonal, they do not interfere with each other. By allowing the tones to overlap, the overall amount of spectrum required is reduced. OFDM is a modulation technique in that it enables user data to be modulated onto the tones. The information is modulated onto a tone by adjusting the tone's phase, amplitude, or both. In the most basic form, a tone may be present or disabled to indicate a one or zero bit of information, however, either phase shift keying (PSK) or quadrature amplitude modulation (QAM) is typically employed. An OFDM system takes a data stream and splits it into N parallel data streams, each at a rate 1/N of the original rate. Each stream is then mapped to a tone at a unique frequency and combined together using the inverse fast fourier transform (IFFT) to yield the time-domain waveform to be transmitted. For example, if a 100-tone system were used, a single data stream with a rate of 1 megabit per second (Mbps) would be converted into 100 streams of 10 kilobits per second (kbps). By creating slower parallel data streams, the bandwidth of the modulation symbol is effectively decreased by a factor of 100, or, equivalently, the duration of the modulation symbol is increased by a factor of 100. Proper 7
8 selection of system parameters, such as the number of tones and tone spacing, can greatly reduce, or even eliminate, ISI, because typical multipath delay spread represents a much smaller proportion of the lengthened symbol time. Viewed another way, the coherence bandwidth of the channel can be much smaller, because the symbol bandwidth has been reduced. The need for complex multi-tap time-domain equalizers can be eliminated as a result. OFDM can also be considered a multiple-access technique, because an individual tone or groups of tones can be assigned to different users. Multiple users share a given bandwidth in this manner, yielding the system called OFDMA. Each user can be assigned a predetermined number of tones when they have information to send, or alternatively, a user can be assigned a variable number of tones based on the amount of information that they have to send. The assignments are controlled by the media access control (MAC) layer, which schedules the resource assignments based on user demand. OFDM can be combined with frequency hopping to create a spread spectrum system, realizing the benefits of frequency diversity and interference averaging previously described for CDMA. In a frequency hopping spread spectrum system, each user's set of tones is changed after each time period (usually corresponding to a modulation symbol). By switching frequencies after each symbol time, the losses due to frequency selective fading are minimized. Although frequency hopping and CDMA are different forms of spread spectrum, they achieve comparable performance in a multipath fading environment and provide similar interference averaging benefits. OFDM therefore provides the best of the benefits of TDMA in that users are orthogonal to one another, and CDMA, as previously mentioned, while avoiding the limitations of each, including the need for TDMA frequency planning and equalization, and multiple access interference in the case of CDMA. 4. DATA TRANSMISSION USING MULTIPLE CARRIERS An OFDM signal consists of a sum of subcarriers that are modulated by using phase shift keying (PSK) or qudrature amplitude modulation (QAM). In the following example, all subcarriers have the phase and amplitude, but in practice the amplitudes and phases may be modulated differently for each subcarrier. Note that each subcarrier has exactly an integer number of cycles in the interval T, and the number of cycles between adjacent subcarries differs by exactly one. This properly accounts for the orthogoality between subcarriers. 8
9 The orthogonality of different OFDM subcarriers can also be demonstrated in another way.if each OFDM symbol contains subcarriers that are nonzero over a T -seconds interval.then it has which has zeros for all frequencies f that are an integer multiple of 1/T. This effect is shown in figure which shows the overlapping sinc spectra of individual subcarriers. At the maximum of each subcarrier spectrum, all other subcarrier spectra are zero. Because an OFDM receiver calculates the spectrum values at those points that correspond to the maxima of individual subcarrier, it can demodulate each subcarrier free from any interference from the other subcarriers. Basically, below Figure shows that the OFDM spectrum fulfills Nyquist s criterion for an inter symbol interference free pulse shape. Notice that the pulse shape is present in frequency domain and note in the time domain, for which the Nyquist criterion usually is applied. Therefore, instead of intersymbol interference (ISI), it is intercarrier interference (ICI) that avoided by having the maximum of one subcarrier spectrum correspond to zero crossing of all the others 9
10 5. GUARD TIME AND CYCLIC EXTENTION One of the most important reasons to do OFDM is the efficient way it deals with multipath delay spread. By dividing the input data stream in N subcarriers, the symbol duration is made N times smaller, which also reduces the relative multipath delay spread, relative to symbol time, by the same factor. To eliminate intersymbol interference almost completely, a guard time is introduced for each OFDM symbol. The guard time is chosen larger than the expected delay spread, such that multipath components from one symbol cannot interfere with the next symbol. The guard time could consist of no signal at all. In that case, however, the problem of intercarrier (ICI) would arise. ICI is crosstalk between different subcarriers,which means they are no longer orthogonal. This effect is illustrated in figure in this example, a subcarrier 1 and a delayed subcarrier 2 are shown. When an OFDM receiver tries to demodulate the first subcarrier, it will encounter some interference from the second subcarrier, because within the FFT interval, there is no integer number of cycles difference between subcarrier 1and 2. At the same time, there will be crosstalk from the first to the second subcarrier for the same reason. To eliminate ICI, the OFDM symbol is cyclically extended in the guard time, as shown in figure. This ensures that delayed replicas of the OFDM symbol always have an integer number of cycles within the FFT interval, as long as the delay is smaller than the guard time. As result, multipath signals with delays smaller than the guard time cannot cause ICI. 10
11 6. TRANSMISSION AND RECEPTION OFDM modulation divides a broadband channel into many parallel subchannels. This makes it a very efficient scheme for transmission in multipath wireless channels. The use of an FFT/IFFT pair for modulation and demodulation make it computationally efficient as well. 11
12 The transmitted signals arrive at the receiver after being reflected from many objects. Sometimes the reflected signals add up in phase and sometimes they add up out of phase causing a fade. This causes the received signal strength to fluctuate constantly. Also, different subchannels are distorted differently as shown in Figure. An OFDM receiver has to sense the channel and correct these distortions on each of the subchannels before the transmitted data can be extracted. OFDM is effective in correcting such frequency selective distortions. OFDM has many advantages over other transmission techniques. One such advantage is high spectral efficiency (measured in bits/sec/hz). The Orthogonal part of the name refers to a precise mathematical relationship between the frequencies of the subchannels that make up the OFDM system. Each of the frequencies is an integer multiple of a fundamental frequency. This ensures that even though the subchannels overlap they do not interfere with each other. This results in high spectral efficiency. The use of IFFT and FFT for modulation and demodulation results in computationally efficient OFDM modems.[3] 12
13 7. CHOICE OF OFDM PARAMETERS The choice of various OFDM parameters is a tradeoff between various, often conflicting requirements. Usually, there are three main requirements to start with: bandwidth, bit rate, and delay spread. The delay spread directly dictates the guard time. As a rule, the guard time should be about two to four times the root-mean-squared delay spread. This value depends on the type of coding and QAM modulation. Higher order QAM (like 64-QAM) is more sensitive to ICI and ISI than QPSK; while heavier coding obviously reduces the sensitivity to such interference. Now the guard time has been set, the symbol duration can be fixed. To minimize the signal-to-noise ratio (SNR) loss caused by guard time, it is desirable to have the symbol duration much larger than the guard time. It cannot be arbitrarily large, however, because a larger symbol duration means more subcarriers with a smaller subcarrier spacing, a larger implementation complexity, and more sensitivity to phase noise and frequency offset, as well as an increased peak-to-average power ratio. Hence, a practical design choice to make the symbol duration at least five times the guard time, which implies a 1dB SNR loss because the guard time. After the symbol duration and guard time are fixed, the number of subcarriers follows directly as the required 3 db bandwidth divided by the subcarrier spacing,which is the inverse of the symbol duration less the guard time. Alternatively, the number of subcarriers may be determined by the required bit rate divided by the bit rate per subcarrier. The bit rate per subcarrier is defined by the modulation type, coding rate, and symbol rate. An additional requirement that can affect the chosen parameters is the demand for an integer number of samples both within the FFT/IFFT interval and in the symbol interval. 8. ADVANTAGES Efficient use of spread spectrum in modulation. It is conveniently implemented using simple FFT and IFFT. Robust against multi-path propagation. Robust again narrow-band interference 13
14 9. DISADVANTAGES Requires a more linear power amplifier. Sensitive to frequency offset and phase noise Accurate synchronization is required. 10. CONCLUSION This report describes the concept of OFDM with brief description of other multiplexing technologies.it also describes data transmission in OFDM,Guard time,cyclic prefix, Transmission and reception techniques,and some advantages and disadvantages of OFDM. Wireless LAN is a very important application for OFDM and the development of the standard promises to have not only a big market but also application in many different environments. REFERENCES [1] Data Communications and Networking - Behrouz A. Forouzan [2] Concepts of Orthogonal Frequency Domain Modulation (OFDM) By Dave Whipple, Agilent Technologies [3] The Engineer s introduction to mimo and Mimo-ofdm [4] The principles of OFDM By Louis Litwin and Michael Pugel 14
Lecture 13. Introduction to OFDM
Lecture 13 Introduction to OFDM Ref: About-OFDM.pdf Orthogonal frequency division multiplexing (OFDM) is well-known to be effective against multipath distortion. It is a multicarrier communication scheme,
More informationOFDM AS AN ACCESS TECHNIQUE FOR NEXT GENERATION NETWORK
OFDM AS AN ACCESS TECHNIQUE FOR NEXT GENERATION NETWORK Akshita Abrol Department of Electronics & Communication, GCET, Jammu, J&K, India ABSTRACT With the rapid growth of digital wireless communication
More informationMulti-carrier Modulation and OFDM
3/28/2 Multi-carrier Modulation and OFDM Prof. Luiz DaSilva dasilval@tcd.ie +353 896-366 Multi-carrier systems: basic idea Typical mobile radio channel is a fading channel that is flat or frequency selective
More informationComparative Study of OFDM & MC-CDMA in WiMAX System
IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-issn: 2278-2834,p- ISSN: 2278-8735.Volume 9, Issue 1, Ver. IV (Jan. 2014), PP 64-68 Comparative Study of OFDM & MC-CDMA in WiMAX
More informationLecture 3: Wireless Physical Layer: Modulation Techniques. Mythili Vutukuru CS 653 Spring 2014 Jan 13, Monday
Lecture 3: Wireless Physical Layer: Modulation Techniques Mythili Vutukuru CS 653 Spring 2014 Jan 13, Monday Modulation We saw a simple example of amplitude modulation in the last lecture Modulation how
More informationEC 551 Telecommunication System Engineering. Mohamed Khedr
EC 551 Telecommunication System Engineering Mohamed Khedr http://webmail.aast.edu/~khedr 1 Mohamed Khedr., 2008 Syllabus Tentatively Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week
More informationSHIV SHAKTI International Journal of in Multidisciplinary and Academic Research (SSIJMAR) Vol. 3, No. 4, August-September (ISSN )
SHIV SHAKTI International Journal of in Multidisciplinary and Academic Research (SSIJMAR) Vol. 3, No. 4, August-September (ISSN 2278 5973) Orthogonal Frequency Division Multiplexing: Issues and Applications
More informationOFDM Systems For Different Modulation Technique
Computing For Nation Development, February 08 09, 2008 Bharati Vidyapeeth s Institute of Computer Applications and Management, New Delhi OFDM Systems For Different Modulation Technique Mrs. Pranita N.
More informationPage 1. Overview : Wireless Networks Lecture 9: OFDM, WiMAX, LTE
Overview 18-759: Wireless Networks Lecture 9: OFDM, WiMAX, LTE Dina Papagiannaki & Peter Steenkiste Departments of Computer Science and Electrical and Computer Engineering Spring Semester 2009 http://www.cs.cmu.edu/~prs/wireless09/
More informationMultiple Access Schemes
Multiple Access Schemes Dr Yousef Dama Faculty of Engineering and Information Technology An-Najah National University 2016-2017 Why Multiple access schemes Multiple access schemes are used to allow many
More informationPractical issue: Group definition. TSTE17 System Design, CDIO. Quadrature Amplitude Modulation (QAM) Components of a digital communication system
1 2 TSTE17 System Design, CDIO Introduction telecommunication OFDM principle How to combat ISI How to reduce out of band signaling Practical issue: Group definition Project group sign up list will be put
More informationChannel Estimation in Multipath fading Environment using Combined Equalizer and Diversity Techniques
International Journal of Scientific & Engineering Research Volume3, Issue 1, January 2012 1 Channel Estimation in Multipath fading Environment using Combined Equalizer and Diversity Techniques Deepmala
More informationSC - Single carrier systems One carrier carries data stream
Digital modulation SC - Single carrier systems One carrier carries data stream MC - Multi-carrier systems Many carriers are used for data transmission. Data stream is divided into sub-streams and each
More informationOrthogonal Frequency Division Multiplexing & Measurement of its Performance
Available Online at www.ijcsmc.com International Journal of Computer Science and Mobile Computing A Monthly Journal of Computer Science and Information Technology IJCSMC, Vol. 5, Issue. 2, February 2016,
More informationKey words: OFDM, FDM, BPSK, QPSK.
Volume 4, Issue 3, March 2014 ISSN: 2277 128X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com Analyse the Performance
More informationOrthogonal Frequency Division Multiplexing (OFDM)
Orthogonal Frequency Division Multiplexing (OFDM) Presenter: Engr. Dr. Noor M. Khan Professor Department of Electrical Engineering, Muhammad Ali Jinnah University, Islamabad Campus, Islamabad, PAKISTAN
More informationTechnical Aspects of LTE Part I: OFDM
Technical Aspects of LTE Part I: OFDM By Mohammad Movahhedian, Ph.D., MIET, MIEEE m.movahhedian@mci.ir ITU regional workshop on Long-Term Evolution 9-11 Dec. 2013 Outline Motivation for LTE LTE Network
More informationOFDMA and MIMO Notes
OFDMA and MIMO Notes EE 442 Spring Semester Lecture 14 Orthogonal Frequency Division Multiplexing (OFDM) is a digital multi-carrier modulation technique extending the concept of single subcarrier modulation
More informationUnderwater communication implementation with OFDM
Indian Journal of Geo-Marine Sciences Vol. 44(2), February 2015, pp. 259-266 Underwater communication implementation with OFDM K. Chithra*, N. Sireesha, C. Thangavel, V. Gowthaman, S. Sathya Narayanan,
More informationPrinciples and Experiments of Communications
1 Principles and Experiments of Communications Weiyao Lin Dept. of Electronic Engineering Shanghai Jiao Tong University Textbook: Chapter 11 Lecture 06: Multicarrier modulation and OFDM Multicarrier Modulation
More informationMobile & Wireless Networking. Lecture 2: Wireless Transmission (2/2)
192620010 Mobile & Wireless Networking Lecture 2: Wireless Transmission (2/2) [Schiller, Section 2.6 & 2.7] [Reader Part 1: OFDM: An architecture for the fourth generation] Geert Heijenk Outline of Lecture
More informationOrthogonal frequency division multiplexing (OFDM)
Orthogonal frequency division multiplexing (OFDM) OFDM was introduced in 1950 but was only completed in 1960 s Originally grew from Multi-Carrier Modulation used in High Frequency military radio. Patent
More informationPerformance Evaluation of Wireless Communication System Employing DWT-OFDM using Simulink Model
Performance Evaluation of Wireless Communication System Employing DWT-OFDM using Simulink Model M. Prem Anand 1 Rudrashish Roy 2 1 Assistant Professor 2 M.E Student 1,2 Department of Electronics & Communication
More informationStudy of Performance Evaluation of Quasi Orthogonal Space Time Block Code MIMO-OFDM System in Rician Channel for Different Modulation Schemes
Volume 4, Issue 6, June (016) Study of Performance Evaluation of Quasi Orthogonal Space Time Block Code MIMO-OFDM System in Rician Channel for Different Modulation Schemes Pranil S Mengane D. Y. Patil
More informationSurvey on Effective OFDM Technology for 4G
Survey on Effective OFDM Technology for 4G Kanchan Vijay Patil, 2 R D Patane, Lecturer, 2 Professor, Electronics and Telecommunication, ARMIET, Shahpur, India 2 Terna college of engineering, Nerul, India
More informationPerformance Analysis of OFDM for Different Digital Modulation Schemes using Matlab Simulation
J. Bangladesh Electron. 10 (7-2); 7-11, 2010 Performance Analysis of OFDM for Different Digital Modulation Schemes using Matlab Simulation Md. Shariful Islam *1, Md. Asek Raihan Mahmud 1, Md. Alamgir Hossain
More informationPerformance Evaluation of STBC-OFDM System for Wireless Communication
Performance Evaluation of STBC-OFDM System for Wireless Communication Apeksha Deshmukh, Prof. Dr. M. D. Kokate Department of E&TC, K.K.W.I.E.R. College, Nasik, apeksha19may@gmail.com Abstract In this paper
More informationDifferential Modulation
Data Detection and Channel Estimation of OFDM Systems Using Differential Modulation A Thesis Submitted to the College of Graduate Studies and Research In Partial Fulfillment of the Requirements For the
More informationPerformance analysis of OFDM with QPSK using AWGN and Rayleigh Fading Channel
Performance analysis of OFDM with QPSK using AWGN and Rayleigh Fading Channel 1 V.R.Prakash* (A.P) Department of ECE Hindustan university Chennai 2 P.Kumaraguru**(A.P) Department of ECE Hindustan university
More informationChapter 5 OFDM. Office Hours: BKD Tuesday 14:00-16:00 Thursday 9:30-11:30
Chapter 5 OFDM 1 Office Hours: BKD 3601-7 Tuesday 14:00-16:00 Thursday 9:30-11:30 2 OFDM: Overview Let S 1, S 2,, S N be the information symbol. The discrete baseband OFDM modulated symbol can be expressed
More informationPart 3. Multiple Access Methods. p. 1 ELEC6040 Mobile Radio Communications, Dept. of E.E.E., HKU
Part 3. Multiple Access Methods p. 1 ELEC6040 Mobile Radio Communications, Dept. of E.E.E., HKU Review of Multiple Access Methods Aim of multiple access To simultaneously support communications between
More informationImplementation and Comparative analysis of Orthogonal Frequency Division Multiplexing (OFDM) Signaling Rashmi Choudhary
Implementation and Comparative analysis of Orthogonal Frequency Division Multiplexing (OFDM) Signaling Rashmi Choudhary M.Tech Scholar, ECE Department,SKIT, Jaipur, Abstract Orthogonal Frequency Division
More information3G long-term evolution
3G long-term evolution by Stanislav Nonchev e-mail : stanislav.nonchev@tut.fi 1 2006 Nokia Contents Radio network evolution HSPA concept OFDM adopted in 3.9G Scheduling techniques 2 2006 Nokia 3G long-term
More informationOutline / Wireless Networks and Applications Lecture 7: Physical Layer OFDM. Frequency-Selective Radio Channel. How Do We Increase Rates?
Page 1 Outline 18-452/18-750 Wireless Networks and Applications Lecture 7: Physical Layer OFDM Peter Steenkiste Carnegie Mellon University RF introduction Modulation and multiplexing Channel capacity Antennas
More informationOFDM for Mobile Data Communications
OFDM for Mobile Data Communications Definition Orthogonal frequency division multiplexing (OFDM) is a communications technique that divides a communications channel into a number of equally spaced frequency
More informationFundamentals of OFDM Communication Technology
Fundamentals of OFDM Communication Technology Fuyun Ling Rev. 1, 04/2013 1 Outline Fundamentals of OFDM An Introduction OFDM System Design Considerations Key OFDM Receiver Functional Blocks Example: LTE
More informationBER Performance of OFDM-IDMA Comparison to OFDM for Femtocell
International Journal of Scientific and Research Publications, Volume 4, Issue 3, March 2014 1 BER Performance of OFDM-IDMA Comparison to OFDM for Femtocell Sandeep Kumar Dwivedi, Vaibhav Purwar, Sanjiv
More informationA Research Concept on Bit Rate Detection using Carrier offset through Analysis of MC-CDMA SYSTEM
Available Online at www.ijcsmc.com International Journal of Computer Science and Mobile Computing A Monthly Journal of Computer Science and Information Technology ISSN 2320 088X IMPACT FACTOR: 5.258 IJCSMC,
More informationPerformance Evaluation of OFDM System with Rayleigh, Rician and AWGN Channels
Performance Evaluation of OFDM System with Rayleigh, Rician and AWGN Channels Abstract A Orthogonal Frequency Division Multiplexing (OFDM) scheme offers high spectral efficiency and better resistance to
More informationDecrease Interference Using Adaptive Modulation and Coding
International Journal of Computer Networks and Communications Security VOL. 3, NO. 9, SEPTEMBER 2015, 378 383 Available online at: www.ijcncs.org E-ISSN 2308-9830 (Online) / ISSN 2410-0595 (Print) Decrease
More informationBER Analysis for MC-CDMA
BER Analysis for MC-CDMA Nisha Yadav 1, Vikash Yadav 2 1,2 Institute of Technology and Sciences (Bhiwani), Haryana, India Abstract: As demand for higher data rates is continuously rising, there is always
More informationOptimal Number of Pilots for OFDM Systems
IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-issn: 2278-2834,p- ISSN: 2278-8735.Volume 8, Issue 6 (Nov. - Dec. 2013), PP 25-31 Optimal Number of Pilots for OFDM Systems Onésimo
More informationAn OFDM Transmitter and Receiver using NI USRP with LabVIEW
An OFDM Transmitter and Receiver using NI USRP with LabVIEW Saba Firdose, Shilpa B, Sushma S Department of Electronics & Communication Engineering GSSS Institute of Engineering & Technology For Women Abstract-
More informationANALYSIS OF BER AND SEP OF QPSK SIGNAL FOR MULTIPLE ANENNAS
ANALYSIS OF BER AND SEP OF QPSK SIGNAL FOR MULTIPLE ANENNAS Suganya.S 1 1 PG scholar, Department of ECE A.V.C College of Engineering Mannampandhal, India Karthikeyan.T 2 2 Assistant Professor, Department
More informationINTERFERENCE SELF CANCELLATION IN SC-FDMA SYSTEMS -A CAMPARATIVE STUDY
INTERFERENCE SELF CANCELLATION IN SC-FDMA SYSTEMS -A CAMPARATIVE STUDY Ms Risona.v 1, Dr. Malini Suvarna 2 1 M.Tech Student, Department of Electronics and Communication Engineering, Mangalore Institute
More informationOFDM (Orthogonal Frequency Division Multiplexing) SIMULATION USING MATLAB Neha Pathak MTech Scholar, Shri am Institute of Technology
OFDM (Orthogonal Frequency Division Multiplexing) SIMULATION USING MATLAB Neha Pathak MTech Scholar, Shri am Institute of Technology ABSTRACT This paper discusses the design and implementation of an OFDM
More informationAnalysis of Interference & BER with Simulation Concept for MC-CDMA
IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-issn: 2278-2834,p- ISSN: 2278-8735.Volume 9, Issue 4, Ver. IV (Jul - Aug. 2014), PP 46-51 Analysis of Interference & BER with Simulation
More informationOFDM system: Discrete model Spectral efficiency Characteristics. OFDM based multiple access schemes. OFDM sensitivity to synchronization errors
Introduction - Motivation OFDM system: Discrete model Spectral efficiency Characteristics OFDM based multiple access schemes OFDM sensitivity to synchronization errors 4 OFDM system Main idea: to divide
More informationMITIGATING CARRIER FREQUENCY OFFSET USING NULL SUBCARRIERS
International Journal on Intelligent Electronic System, Vol. 8 No.. July 0 6 MITIGATING CARRIER FREQUENCY OFFSET USING NULL SUBCARRIERS Abstract Nisharani S N, Rajadurai C &, Department of ECE, Fatima
More informationPerformance of Orthogonal Frequency Division Multiplexing System Based on Mobile Velocity and Subcarrier
Journal of Computer Science 6 (): 94-98, 00 ISSN 549-3636 00 Science Publications Performance of Orthogonal Frequency Division Multiplexing System ased on Mobile Velocity and Subcarrier Zulkeflee in halidin
More informationReceiver Designs for the Radio Channel
Receiver Designs for the Radio Channel COS 463: Wireless Networks Lecture 15 Kyle Jamieson [Parts adapted from C. Sodini, W. Ozan, J. Tan] Today 1. Delay Spread and Frequency-Selective Fading 2. Time-Domain
More informationDesign and Implementation of OFDM System and Reduction of Inter-Carrier Interference at Different Variance
Design and Implementation of OFDM System and Reduction of Inter-Carrier Interference at Different Variance Gaurav Verma 1, Navneet Singh 2 1 Research Scholar, JCDMCOE, Sirsa, Haryana, India 2 Assistance
More informationSimulation Study and Performance Comparison of OFDM System with QPSK and BPSK
Simulation Study and Performance Comparison of OFDM System with QPSK and BPSK 1 Mr. Adesh Kumar, 2 Mr. Sudeep Singh, 3 Mr. Shashank, 4 Asst. Prof. Mr. Kuldeep Sharma (Guide) M. Tech (EC), Monad University,
More informationWireless Medium Access Control and CDMA-based Communication Lesson 16 Orthogonal Frequency Division Medium Access (OFDM)
Wireless Medium Access Control and CDMA-based Communication Lesson 16 Orthogonal Frequency Division Medium Access (OFDM) 1 4G File transfer at 10 Mbps High resolution 1024 1920 pixel hi-vision picture
More informationAnju 1, Amit Ahlawat 2
Orthogonal Frequency Division Multiplexing Anju 1, Amit Ahlawat 2 1 Hindu College of Engineering, Sonepat 2 Shri Baba Mastnath Engineering College Rohtak Abstract: OFDM was introduced in the 1950s but
More informationCSCD 433 Network Programming Fall Lecture 5 Physical Layer Continued
CSCD 433 Network Programming Fall 2016 Lecture 5 Physical Layer Continued 1 Topics Definitions Analog Transmission of Digital Data Digital Transmission of Analog Data Multiplexing 2 Different Types of
More informationBit Loading and Peak Average Power Reduction Techniques for Adaptive Orthogonal Frequency Division Multiplexing Systems
University of Tennessee, Knoxville Trace: Tennessee Research and Creative Exchange Masters Theses Graduate School 8-2004 Bit Loading and Peak Average Power Reduction Techniques for Adaptive Orthogonal
More informationINTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND TECHNOLOGY
INTERNATIONAL JOURNAL OF PURE AND APPLIED RESEARCH IN ENGINEERING AND TECHNOLOGY A PATH FOR HORIZING YOUR INNOVATIVE WORK REVIEW ON ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING: STUDY AND SURVEY SANJOG P.
More informationMulti-Carrier Systems
Wireless Information Transmission System Lab. Multi-Carrier Systems 2006/3/9 王森弘 Institute of Communications Engineering National Sun Yat-sen University Outline Multi-Carrier Systems Overview Multi-Carrier
More informationPEAK TO AVERAGE POWER RATIO REDUCTION USING BANDWIDTH EFFICIENCY INCREASING METHOD IN OFDM SYSTEM
www.arpapress.com/volumes/vol6issue/ijrras_6.pdf PEAK TO AVERAGE POWER RATIO REDUCTIO USIG BADWIDTH EFFICIECY ICREASIG METHOD I OFDM SYSTEM A.A. Abdul Wahab and M. F. Ain School of Electrical and Electronic
More informationChannel Estimation in Wireless OFDM Systems
Estimation in Wireless OFDM Systems Govind Patidar M. Tech. Scholar, Electronics & Communication Engineering Mandsaur Institute of Technology Mandsaur,India gp.patidar10@gmail.com Abstract Orthogonal frequency
More informationOrthogonal Frequency Division Multiplexing (OFDM) based Uplink Multiple Access Method over AWGN and Fading Channels
Orthogonal Frequency Division Multiplexing (OFDM) based Uplink Multiple Access Method over AWGN and Fading Channels Prashanth G S 1 1Department of ECE, JNNCE, Shivamogga ---------------------------------------------------------------------***----------------------------------------------------------------------
More informationDesign and Simulation of COFDM for High Speed Wireless Communication and Performance Analysis
Design and Simulation of COFDM for High Speed Wireless Communication and Performance Analysis Arun Agarwal ITER College, Siksha O Anusandhan University Department of Electronics and Communication Engineering
More informationOFDMA PHY for EPoC: a Baseline Proposal. Andrea Garavaglia and Christian Pietsch Qualcomm PAGE 1
OFDMA PHY for EPoC: a Baseline Proposal Andrea Garavaglia and Christian Pietsch Qualcomm PAGE 1 Supported by Jorge Salinger (Comcast) Rick Li (Cortina) Lup Ng (Cortina) PAGE 2 Outline OFDM: motivation
More informationWorking Party 5B DRAFT NEW RECOMMENDATION ITU-R M.[500KHZ]
Radiocommunication Study Groups Source: Subject: Document 5B/TEMP/376 Draft new Recommendation ITU-R M.[500kHz] Document 17 November 2011 English only Working Party 5B DRAFT NEW RECOMMENDATION ITU-R M.[500KHZ]
More informationPerformance Analysis Of Hybrid Optical OFDM System With High Order Dispersion Compensation
Performance Analysis Of Hybrid Optical OFDM System With High Order Dispersion Compensation Manpreet Singh Student, University College of Engineering, Punjabi University, Patiala, India. Abstract Orthogonal
More informationFeature (Claims) Preamble. Clause 1. Clause 2. Clause 3. Clause 4. Preamble. Clause 1. Clause 2. Clause 3. Clause 4
Claim Feature (Claims) 1 9 10 11 Preamble Clause 1 Clause 2 Clause 3 Clause 4 Preamble Clause 1 Clause 2 Clause 3 Clause 4 A method for transmitting ACK channel information by the base station in an orthogonal
More informationChapter 2 Overview - 1 -
Chapter 2 Overview Part 1 (last week) Digital Transmission System Frequencies, Spectrum Allocation Radio Propagation and Radio Channels Part 2 (today) Modulation, Coding, Error Correction Part 3 (next
More informationCHAPTER 1 INTRODUCTION
CHAPTER 1 INTRODUCTION High data-rate is desirable in many recent wireless multimedia applications [1]. Traditional single carrier modulation techniques can achieve only limited data rates due to the restrictions
More informationFading & OFDM Implementation Details EECS 562
Fading & OFDM Implementation Details EECS 562 1 Discrete Mulitpath Channel P ~ 2 a ( t) 2 ak ~ ( t ) P a~ ( 1 1 t ) Channel Input (Impulse) Channel Output (Impulse response) a~ 1( t) a ~2 ( t ) R a~ a~
More informationANALYSIS AND STUDY OF MULTI-SYMBOL ENCAPSULATED ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING
ANALYSIS AND STUDY OF MULTI-SYMBOL ENCAPSULATED ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF Bachelor of Technology In Electronics
More informationEE678-Application Assignment Discrete Wavelet Multitone Modulation
EE678 WAVELETS APPLICATION ASSIGNMENT 1 EE678-Application Assignment Discrete Wavelet Multitone Modulation Group Members: Chirag Jain chiragjn@ee.iitb.ac.in 01D07018 Abhijeet Bhorkar bhorkar@ee.iitb.ac.in
More informationWireless Physical Layer Concepts: Part III
Wireless Physical Layer Concepts: Part III Raj Jain Professor of CSE Washington University in Saint Louis Saint Louis, MO 63130 Jain@cse.wustl.edu These slides are available on-line at: http://www.cse.wustl.edu/~jain/cse574-08/
More informationSPARSE CHANNEL ESTIMATION BY PILOT ALLOCATION IN MIMO-OFDM SYSTEMS
SPARSE CHANNEL ESTIMATION BY PILOT ALLOCATION IN MIMO-OFDM SYSTEMS Puneetha R 1, Dr.S.Akhila 2 1 M. Tech in Digital Communication B M S College Of Engineering Karnataka, India 2 Professor Department of
More informationBER ANALYSIS OF BPSK, QPSK & QAM BASED OFDM SYSTEM USING SIMULINK
BER ANALYSIS OF BPSK, QPSK & QAM BASED OFDM SYSTEM USING SIMULINK Pratima Manhas 1, Dr M.K Soni 2 1 Research Scholar, FET, ECE, 2 ED& Dean, FET, Manav Rachna International University, Fbd (India) ABSTRACT
More informationIntroduction to OFDM Systems
Introduction to OFDM Systems Dr. Prapun Suksompong prapun@siit.tu.ac.th June 23, 2010 1 Outline 1. Overview of OFDM technique 2. Wireless Channel 3. Multi-carrier Transmission 4. Implementation: DFT and
More informationMODULATION AND MULTIPLE ACCESS TECHNIQUES
1 MODULATION AND MULTIPLE ACCESS TECHNIQUES Networks and Communication Department Dr. Marwah Ahmed Outlines 2 Introduction Digital Transmission Digital Modulation Digital Transmission of Analog Signal
More informationP. 241 Figure 8.1 Multiplexing
CH 08 : MULTIPLEXING Multiplexing Multiplexing is multiple links on 1 physical line To make efficient use of high-speed telecommunications lines, some form of multiplexing is used It allows several transmission
More informationPerformance Analysis of LTE System in term of SC-FDMA & OFDMA Monika Sehrawat 1, Priyanka Sharma 2 1 M.Tech Scholar, SPGOI Rohtak
Performance Analysis of LTE System in term of SC-FDMA & OFDMA Monika Sehrawat 1, Priyanka Sharma 2 1 M.Tech Scholar, SPGOI Rohtak 2 Assistant Professor, ECE Deptt. SPGOI Rohtak Abstract - To meet the increasing
More informationPhase Modulator for Higher Order Dispersion Compensation in Optical OFDM System
Phase Modulator for Higher Order Dispersion Compensation in Optical OFDM System Manpreet Singh 1, Karamjit Kaur 2 Student, University College of Engineering, Punjabi University, Patiala, India 1. Assistant
More informationIntroduction to WiMAX Dr. Piraporn Limpaphayom
Introduction to WiMAX Dr. Piraporn Limpaphayom 1 WiMAX : Broadband Wireless 2 1 Agenda Introduction to Broadband Wireless Overview of WiMAX and Application WiMAX: PHY layer Broadband Wireless Channel OFDM
More informationLecture 9: Spread Spectrum Modulation Techniques
Lecture 9: Spread Spectrum Modulation Techniques Spread spectrum (SS) modulation techniques employ a transmission bandwidth which is several orders of magnitude greater than the minimum required bandwidth
More informationWith a lot of material from Rich Nicholls, CTL/RCL and Kurt Sundstrom, of unknown whereabouts
Signal Processing for OFDM Communication Systems Eric Jacobsen Minister of Algorithms, Intel Labs Communication Technology Laboratory/ Radio Communications Laboratory July 29, 2004 With a lot of material
More informationBit Error Rate Performance Evaluation of Various Modulation Techniques with Forward Error Correction Coding of WiMAX
Bit Error Rate Performance Evaluation of Various Modulation Techniques with Forward Error Correction Coding of WiMAX Amr Shehab Amin 37-20200 Abdelrahman Taha 31-2796 Yahia Mobasher 28-11691 Mohamed Yasser
More informationPerformance Analysis Of OFDM Using QPSK And 16 QAM
Performance Analysis Of OFDM Using QPSK And 16 QAM Virat Bhambhe M.Tech. Student, Electrical and Electronics Engineering Gautam Buddh Technical University (G.B.T.U.), Lucknow (U.P.), India Dr. Ragini Tripathi
More informationISHIK UNIVERSITY Faculty of Science Department of Information Technology Fall Course Name: Wireless Networks
ISHIK UNIVERSITY Faculty of Science Department of Information Technology 2017-2018 Fall Course Name: Wireless Networks Agenda Lecture 4 Multiple Access Techniques: FDMA, TDMA, SDMA and CDMA 1. Frequency
More informationAdvanced 3G & 4G Wireless Communication Prof. Aditya K. Jagannatham Department of Electrical Engineering Indian Institute of Technology, Kanpur
Advanced 3G & 4G Wireless Communication Prof. Aditya K. Jagannatham Department of Electrical Engineering Indian Institute of Technology, Kanpur Lecture - 30 OFDM Based Parallelization and OFDM Example
More informationNew Cross-layer QoS-based Scheduling Algorithm in LTE System
New Cross-layer QoS-based Scheduling Algorithm in LTE System MOHAMED A. ABD EL- MOHAMED S. EL- MOHSEN M. TATAWY GAWAD MAHALLAWY Network Planning Dep. Network Planning Dep. Comm. & Electronics Dep. National
More informationPage 1. Outline : Wireless Networks Lecture 6: Final Physical Layer. Direct Sequence Spread Spectrum (DSSS) Spread Spectrum
Outline 18-759 : Wireless Networks Lecture 6: Final Physical Layer Peter Steenkiste Dina Papagiannaki Spring Semester 2009 http://www.cs.cmu.edu/~prs/wireless09/ Peter A. Steenkiste 1 RF introduction Modulation
More information4x4 Time-Domain MIMO encoder with OFDM Scheme in WIMAX Context
4x4 Time-Domain MIMO encoder with OFDM Scheme in WIMAX Context Mohamed.Messaoudi 1, Majdi.Benzarti 2, Salem.Hasnaoui 3 Al-Manar University, SYSCOM Laboratory / ENIT, Tunisia 1 messaoudi.jmohamed@gmail.com,
More informationUNIFIED DIGITAL AUDIO AND DIGITAL VIDEO BROADCASTING SYSTEM USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) SYSTEM
UNIFIED DIGITAL AUDIO AND DIGITAL VIDEO BROADCASTING SYSTEM USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) SYSTEM 1 Drakshayini M N, 2 Dr. Arun Vikas Singh 1 drakshayini@tjohngroup.com, 2 arunsingh@tjohngroup.com
More informationOptimized BPSK and QAM Techniques for OFDM Systems
I J C T A, 9(6), 2016, pp. 2759-2766 International Science Press ISSN: 0974-5572 Optimized BPSK and QAM Techniques for OFDM Systems Manikandan J.* and M. Manikandan** ABSTRACT A modulation is a process
More informationT325 Summary T305 T325 B BLOCK 3 4 PART III T325. Session 11 Block III Part 3 Access & Modulation. Dr. Saatchi, Seyed Mohsen.
T305 T325 B BLOCK 3 4 PART III T325 Summary Session 11 Block III Part 3 Access & Modulation [Type Dr. Saatchi, your address] Seyed Mohsen [Type your phone number] [Type your e-mail address] Prepared by:
More informationLecture 7: Centralized MAC protocols. Mythili Vutukuru CS 653 Spring 2014 Jan 27, Monday
Lecture 7: Centralized MAC protocols Mythili Vutukuru CS 653 Spring 2014 Jan 27, Monday Centralized MAC protocols Previous lecture contention based MAC protocols, users decide who transmits when in a decentralized
More informationChapter 2 Overview - 1 -
Chapter 2 Overview Part 1 (last week) Digital Transmission System Frequencies, Spectrum Allocation Radio Propagation and Radio Channels Part 2 (today) Modulation, Coding, Error Correction Part 3 (next
More informationPerformance Study of OFDM Over Fading Channels for Wireless Communications
University of Denver Digital Commons @ DU Electronic Theses and Dissertations Graduate Studies 1-1-2012 Performance Study of OFDM Over Fading Channels for Wireless Communications Ahmed Alshammari University
More informationMultiplexing Module W.tra.2
Multiplexing Module W.tra.2 Dr.M.Y.Wu@CSE Shanghai Jiaotong University Shanghai, China Dr.W.Shu@ECE University of New Mexico Albuquerque, NM, USA 1 Multiplexing W.tra.2-2 Multiplexing shared medium at
More informationAdvanced 3G & 4G Wireless Communication Prof. Aditya K. Jaganathan Department of Electrical Engineering Indian Institute of Technology, Kanpur
(Refer Slide Time: 00:17) Advanced 3G & 4G Wireless Communication Prof. Aditya K. Jaganathan Department of Electrical Engineering Indian Institute of Technology, Kanpur Lecture - 32 MIMO-OFDM (Contd.)
More informationPerformance Analysis of OFDM System with QPSK for Wireless Communication
IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-issn: 2278-2834,p- ISSN: 2278-8735.Volume 11, Issue 3, Ver. I (May-Jun.2016), PP 33-37 www.iosrjournals.org Performance Analysis
More informationCognitive Radio Transmission Based on Chip-level Space Time Block Coded MC-DS-CDMA over Fast-Fading Channel
Journal of Scientific & Industrial Research Vol. 73, July 2014, pp. 443-447 Cognitive Radio Transmission Based on Chip-level Space Time Block Coded MC-DS-CDMA over Fast-Fading Channel S. Mohandass * and
More information