DEVELOPMENT OF OFDM SYSTEM IN MATLAB
|
ACKNOWLEDGEMENTS 7
ABSTRACT 8
INTRODUCTION 9
1. THE ANALYSIS OF THE SUBJECT AREA 12
1.1. Analyze the domain of problem 12
1.2. OFDM Basics 13
1.3. The best current development technology OFDM available 14
1.4. Technologies used to develop the project 16
1.4.1. Long Term Evolution 16
1.4.2. Code division multiple access 17
1.4.3. Global system Mobility 18
1.5. Comparative analysis between LTE, CDMA,GSM systems in OFDM 19
1.6. IP data operation 21
1.7. Working and using othogonal Frequency division multiplexing 21
1.8. Data Multiplexing 23
1.8.1. Frequency division multiplexing 24
1.8.2. Work Frequency division multiplexing 25
1.8.3. De frequency division multiplexing 26
1.8.4. Comparative analysis between FDM and OFDM system 28
1.9. IEEE 802.11 and Wi-Fi in OFDM 29
2. DESIGN OF MANAGEMENT INFORMATION SYSTEM FOR
DEVELOPMENT OFDM 30
2.1. Functional requirements 30
2.2. Use case diagram 30
2.3. Great model of OFDM 32
2.4. Structure of OFDM 33
3. SIMULATION USING MATLAB CODE OFDM 35
3.1. Source code 36
3.2. Original signal 38
3.3. QPSK Modulation 40
3.4. Dividing data by sub-carrier OFDM 42
3.5. IFFT on all the sub-carrier 43
3.6. Cyclic prefix added to all the sub-carrier 44
3.7. OFDM signal 45
3.8. OFDM Signal after passing during medium 47
3.9. Cyclic prefix removed from the four subcarrier 49
3.10. Inverse IFFT of the four sub-carrier 50
3.11. Received signal with error 52
4. TEST RESULTS 54
CONCLUSION 57
REFERNCES 58
ABSTRACT 8
INTRODUCTION 9
1. THE ANALYSIS OF THE SUBJECT AREA 12
1.1. Analyze the domain of problem 12
1.2. OFDM Basics 13
1.3. The best current development technology OFDM available 14
1.4. Technologies used to develop the project 16
1.4.1. Long Term Evolution 16
1.4.2. Code division multiple access 17
1.4.3. Global system Mobility 18
1.5. Comparative analysis between LTE, CDMA,GSM systems in OFDM 19
1.6. IP data operation 21
1.7. Working and using othogonal Frequency division multiplexing 21
1.8. Data Multiplexing 23
1.8.1. Frequency division multiplexing 24
1.8.2. Work Frequency division multiplexing 25
1.8.3. De frequency division multiplexing 26
1.8.4. Comparative analysis between FDM and OFDM system 28
1.9. IEEE 802.11 and Wi-Fi in OFDM 29
2. DESIGN OF MANAGEMENT INFORMATION SYSTEM FOR
DEVELOPMENT OFDM 30
2.1. Functional requirements 30
2.2. Use case diagram 30
2.3. Great model of OFDM 32
2.4. Structure of OFDM 33
3. SIMULATION USING MATLAB CODE OFDM 35
3.1. Source code 36
3.2. Original signal 38
3.3. QPSK Modulation 40
3.4. Dividing data by sub-carrier OFDM 42
3.5. IFFT on all the sub-carrier 43
3.6. Cyclic prefix added to all the sub-carrier 44
3.7. OFDM signal 45
3.8. OFDM Signal after passing during medium 47
3.9. Cyclic prefix removed from the four subcarrier 49
3.10. Inverse IFFT of the four sub-carrier 50
3.11. Received signal with error 52
4. TEST RESULTS 54
CONCLUSION 57
REFERNCES 58
Is one of the technologies used in networks and communication systems, a technique that has been used since 1970 but has not been used on a wide tally because this technique needed expensive possibilities and was then difficult to use on a wide range.
OFDM it has already been used to sender information for FM channels, digital broadcasting (AB), DVB-T and ADSL, but Now it is more used, mostly in cellular and wireless communications systems, mostly the fourth generation such as LTE and Wi-MAX [5].
The main ideas comes after the development for communication systems and the rising demand for the need for speed of data sender. Hence the idea of FDM, but this techniques which be divided the channel into a sub- channel and dividing the carrier into a sub- carrier so that we send more than two different signals on the same band Given to us at the same time and this helps solve many several problems were in the former where we used to use the band given to us in transmission one signal and then we send the other where this caused several problems, especially in the television where we send the image and then the sound and thus the picture precedes the sound Often there means there is a delay between the two signals.
So using FDM was divided into band and also divided the information into Farm means to say I divide our band into many parts as we divide the information into parts and send each part after the other to assume that the information voice and video and image we are dividing the sound into parts as well as pictures and then we carry the first part of the image on Carrier At the same time we carry the first part of the sound on the Carrier secondary and send them and then repeat the process for the other parts of the sound and picture sure they will arrive at the same time without interference if we eliminate the first problem With the rapid growth of the digital communications sector in recent years, demand for high speed data transmission systems has increased. In addition, future wireless systems are expected to support a wide range of services including video, data and voice.
OFDM is a promising candidate to ensure high speed data transmission in the wireless medium due to its resistance to ISI, which is a common problem that limits the speed of data transfers and this mean send many data on one channel without any interference between them so and this technology very important in this time because the main reason for the evolution of our current world is the application of this technique in all devices phone but we did not know where and when in other word it is applied in 2G and 3G and 4G and maybe in 5G.
Despite being a nearly 50 year old concept, it is only in the last decade that OFDM becomes the modem of choice in wireless applications. One of the biggest advantages of an OFDM modem is the ability to convert dispersive broadband channels into parallel narrowband sub-channels, thus significantly simplifying equalization at the receiver end. Another intrinsic feature of OFDM is its flexibility in allocating power where we send the image and then the sound and thus the picture precedes the sound often there means there is a delay between the two signals, the rapid growth of the digital communication sector in recent years, the demand for high speed data sender systems has increased, in addition, future wireless system are expected to support a wide range of services including video, data and voice, OFDM is a promising candidate to ensure high speed data sender on the wireless medium due to its resistance to the speed of data transfer, in OFDM the include is done in a differential or read a modulation, there is no need to estimate the radio channel.
Orthogonal frequency division multiplexing is commonly implemented in many emerging communications protocols because it provides several advantages over the traditional FDM approach to communications channels. More specifically, OFDM systems allow for greater spectral efficiency reduced inter symbol interference (ISI). Relative resistance to multipath fading and frequency domain equalization is relatively simpler compared to single carrier system.
Research goal and objectives
The goal of the research is the development technology OFDM for wireless networks and communication system digital.
For the reaching this goal we must achieve following objectives.
1. Analyze of the subject area.
2. Send and receive packages from information.
3. Analyze of modern tools that used in OFDM and choose tools for project development.
4. Design the system.
5. Design the system function requirement by using case diagram.
6. Implement the system (coding).
7. Test all of system.
The practical significance
In OFDM data is transmitted by multiple carriers and every two adjacent channel is perpendicular to frequency and no guard band is placed between them but guard time is placed and added to each symbol where we can overcome the delay separated for each channel.
This project useful, because it contains important many features of it.
1. Digital television.
2. OFDM is a key wireless technology used in WI-FI, WIMAX, LTE (3G and 4G cellular network and maybe in 5G).
3. South America and European and Australian standard.
4. High data rates in 4G, WI-FI, WIMAX are possible because of OFDM technology.
5. Wireless Local Area Network (LAN).
6. OFDM is a key broadband wireless technology.
7. Low cost and high gain.
8. High efficiency in send and receive.
9. Less losses in 4G.
Structure of the thesis
The thesis comprises of four chapters, introduction, conclusion and references list
In chapter one, the problem statement is given as well as the overview and comparative analysis of OFDM system. Additionally we talked about all technologies that support OFDM and what is the difference between them.
In chapter two, there is a description of functional requirement, use case diagram, structure of OFDM, great model of OFDM system.
In chapter three, we enter the data after that we receive this data on the shape signals and we analyze each signal according to success and failure rate of the transmitter.
In chapter four, is devoted to the testing of the system.
The thesis has 60 pages; the list of references 21 resources.
OFDM it has already been used to sender information for FM channels, digital broadcasting (AB), DVB-T and ADSL, but Now it is more used, mostly in cellular and wireless communications systems, mostly the fourth generation such as LTE and Wi-MAX [5].
The main ideas comes after the development for communication systems and the rising demand for the need for speed of data sender. Hence the idea of FDM, but this techniques which be divided the channel into a sub- channel and dividing the carrier into a sub- carrier so that we send more than two different signals on the same band Given to us at the same time and this helps solve many several problems were in the former where we used to use the band given to us in transmission one signal and then we send the other where this caused several problems, especially in the television where we send the image and then the sound and thus the picture precedes the sound Often there means there is a delay between the two signals.
So using FDM was divided into band and also divided the information into Farm means to say I divide our band into many parts as we divide the information into parts and send each part after the other to assume that the information voice and video and image we are dividing the sound into parts as well as pictures and then we carry the first part of the image on Carrier At the same time we carry the first part of the sound on the Carrier secondary and send them and then repeat the process for the other parts of the sound and picture sure they will arrive at the same time without interference if we eliminate the first problem With the rapid growth of the digital communications sector in recent years, demand for high speed data transmission systems has increased. In addition, future wireless systems are expected to support a wide range of services including video, data and voice.
OFDM is a promising candidate to ensure high speed data transmission in the wireless medium due to its resistance to ISI, which is a common problem that limits the speed of data transfers and this mean send many data on one channel without any interference between them so and this technology very important in this time because the main reason for the evolution of our current world is the application of this technique in all devices phone but we did not know where and when in other word it is applied in 2G and 3G and 4G and maybe in 5G.
Despite being a nearly 50 year old concept, it is only in the last decade that OFDM becomes the modem of choice in wireless applications. One of the biggest advantages of an OFDM modem is the ability to convert dispersive broadband channels into parallel narrowband sub-channels, thus significantly simplifying equalization at the receiver end. Another intrinsic feature of OFDM is its flexibility in allocating power where we send the image and then the sound and thus the picture precedes the sound often there means there is a delay between the two signals, the rapid growth of the digital communication sector in recent years, the demand for high speed data sender systems has increased, in addition, future wireless system are expected to support a wide range of services including video, data and voice, OFDM is a promising candidate to ensure high speed data sender on the wireless medium due to its resistance to the speed of data transfer, in OFDM the include is done in a differential or read a modulation, there is no need to estimate the radio channel.
Orthogonal frequency division multiplexing is commonly implemented in many emerging communications protocols because it provides several advantages over the traditional FDM approach to communications channels. More specifically, OFDM systems allow for greater spectral efficiency reduced inter symbol interference (ISI). Relative resistance to multipath fading and frequency domain equalization is relatively simpler compared to single carrier system.
Research goal and objectives
The goal of the research is the development technology OFDM for wireless networks and communication system digital.
For the reaching this goal we must achieve following objectives.
1. Analyze of the subject area.
2. Send and receive packages from information.
3. Analyze of modern tools that used in OFDM and choose tools for project development.
4. Design the system.
5. Design the system function requirement by using case diagram.
6. Implement the system (coding).
7. Test all of system.
The practical significance
In OFDM data is transmitted by multiple carriers and every two adjacent channel is perpendicular to frequency and no guard band is placed between them but guard time is placed and added to each symbol where we can overcome the delay separated for each channel.
This project useful, because it contains important many features of it.
1. Digital television.
2. OFDM is a key wireless technology used in WI-FI, WIMAX, LTE (3G and 4G cellular network and maybe in 5G).
3. South America and European and Australian standard.
4. High data rates in 4G, WI-FI, WIMAX are possible because of OFDM technology.
5. Wireless Local Area Network (LAN).
6. OFDM is a key broadband wireless technology.
7. Low cost and high gain.
8. High efficiency in send and receive.
9. Less losses in 4G.
Structure of the thesis
The thesis comprises of four chapters, introduction, conclusion and references list
In chapter one, the problem statement is given as well as the overview and comparative analysis of OFDM system. Additionally we talked about all technologies that support OFDM and what is the difference between them.
In chapter two, there is a description of functional requirement, use case diagram, structure of OFDM, great model of OFDM system.
In chapter three, we enter the data after that we receive this data on the shape signals and we analyze each signal according to success and failure rate of the transmitter.
In chapter four, is devoted to the testing of the system.
The thesis has 60 pages; the list of references 21 resources.
An OFDM system is successfully simulated using MATLAB in this project. All major components of an OFDM system are covered. This has demonstrated the basic concept and feasibility of OFDM, which was thoroughly described and explained in Chapter 3 of this report. Some of the challenges in developing this OFDM simulation program were carefully matching steps in modulator and demodulator, keeping track of data format and data size throughout all the processes of the whole simulation, designing an appropriate frame detector for the receiver, and debugging the MATLAB codes.
Chapter 4 showed and explained some analyses of the performance and characteristics of this simulated OFDM system. It was noted that for some
combinations of OFDM parameters, the simulation may fail for some trials but may succeed for repeated trails with the same parameters. It is because the random noise generated on every trial differs, and trouble may have been caused for the frame detector in the OFDM receiver due to certain random noise. Future work is required to debug this issue and make the frame detector free of error.
Other possible future works to enhance this simulation program include adding ability to accept input source data in a word size other than 8-bit, adding an option to use QAM (Quadrature amplitude modulation) instead of M-DPSK as the modulation method.
Chapter 4 showed and explained some analyses of the performance and characteristics of this simulated OFDM system. It was noted that for some
combinations of OFDM parameters, the simulation may fail for some trials but may succeed for repeated trails with the same parameters. It is because the random noise generated on every trial differs, and trouble may have been caused for the frame detector in the OFDM receiver due to certain random noise. Future work is required to debug this issue and make the frame detector free of error.
Other possible future works to enhance this simulation program include adding ability to accept input source data in a word size other than 8-bit, adding an option to use QAM (Quadrature amplitude modulation) instead of M-DPSK as the modulation method.
