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i have question if the mobile channel cause a frequency modulation of the subacarriers in an ofdm based syste? And i want to know what is the physical explanation of the doppler shift from the communications point of view?
Hi all I want a sample source code in matlab for simple ofdm modulation that shows the doppler shift effect I have some source codes for ofdm but none of them has the doppler effect I'm wondering if anybody can help thanks :|
Hello, I am looking for a MATLAB code for ofdm that introduces doppler effect due to relative motion of Tx/Rx. Thanks in advance
in ofdm sytems carrier frequency offset can occur due to doppler shift and local oscillator mismatch. you have understood the first part. When the baseband signal is converted to RF signal at the Tx, there will be a oscillator used to generate the RF carrier wave. Now, at the Rx end, there will be a similar oscillator used, it may so happen that
So that means.....ofdm is used in frequency selective fading channel.....but...actually.....each symbol from the subcarrier suffers flat I right? Therefore, to model it during simulation......received signal for each subcarrier is equivalent to: Let say this is the 1st subcarrier: received_signal=rayleigh_flat_fading_variable*trans
Hi,QMA From the Rx side, assume perfect operation (1) is the position of time index start for DFT window process of N point (only useful data length) mean as find the first edge of each symbol or some point between channel length
hi udit .. my MS thesis was in channel estimation for ofdm transmission in fast fading doppler channels so that would be phy layer. righ now I am inclined towards getting to know WiMax so want to focus more on mac layer, though interesting ideas in phy are still welcome
doppler has a devastating effect on ofdm signal due to ICI and loss of synchronizarion ,unless adequate compenasation techniques are applied
Some one have code about ofdm Pilot based channel estiamtion in time domain? Could you send the to me?I need them urgently. :cry: My Email: Thanks. Added after 5 hours 8 minutes: help me! how to add doppler shift to channel?
Actually if you look at the frequency domain plot, the peak of one carrier is on the point where the the two carriers; one on its right and one on its left have their zero crossing. And you know at zero crossing they would contribute to zero energy to the center carrier, And this is how, even after 'overlapping' they dont mix. In fact if you loo
How can I use doppler signal in my M_File in MATLAB?Is there a function or command for it? I'm not good in MATLAB!please help me.
Hi all, I'm performing ofdm equalizer for a pilot assisted system. The system parameters are: Signal BW = 6 MHz Carrier = 700 MHz chip rate = 5.55 MHz doppler shift corresponds to max 200 km/s receiver speed Fading channel is a Rayleigh fading channel, the problem is that when I apply the channel to signal, the channel has a very ra
hi , frequency offsets are due to channel delay spread (coz of channel impairments ) and doppler spread ( movin vehicles) suppose ur upconvertin RF frquency is @ 2 Ghz and IF :100 MHZ , ur transmitting frequency will be 2100 MHZ so if ur channel delay spread is say 10 HZ ur recieved signal at RX will be 2100. 000 010 hz , ur receiver d
hi, i'm doing a comprfassion between ofdm and cdma. doppler spread destroy the orthogonality between the sub carriers in ofdm and cause ICI. but i cant figure if and how doppler spread effects CDMA (not MC CDMA but DS CDMA) i mean, every user spread its information with PN code on all the BW can somone explein how and (...)
frequency offset (FO) occurred by the mismatch between the oscillators in the transmitter and receiver or doppler frequency and it can cause performance degradation or we can say it can increase BER
Hi All, I would like to include doppler shift to a 2x2 multipath MIMO-ofdm channel because i am considering fastfading channel instead of block fading channel. How do I implement this? Do I have to "cut" my ofdm symbol into several parts and at each part apply a different channel/? If so, those channels need some kind of link whjat (...)
hi everybody i have a bad problem with my code .... First of all i write a matlab code for ofdm-CDMA system. the following picture shows the structure of the system : 70365 but unfortunally the results for BER not stable . for doppler frequency = 0.0001 [ATTACH=
AA The following code gives higher BER than the theoretical. Can anyone help me why? and give me the way to modify the code. code of BPSK- ofdm =============== clc; clear all nFFT = 4; % fft size nDSC = 4; % number of data subcarriers nBitPerSym = 4; % number of bits per ofdm symbol (same as the number of subcarriers for BPSK) nSym =
hi i am working on MC-CDMA channel estimation cdma + ofdm(802.11a) i try two types of channel estimation : Block type and Comb type i am using MATLAB built in function (rayleighchan) more specificlly (stdchan) as follow: bitrate = 20000000; % Bit Rate ts
I used an matlab example " syncCarrierFreqMSKSignalRecovery" to construct my model and apply it for QPSK system,it works . but when i applied it to ofdm-QPSK , it doesn't work. Kindly advice Matlab Code ============ %Initilization %%%%%%%%%%%%%%%%%%%% nBitPerSym = 64; % number of bits per ofdm symbol nSym = 10^3; % number of symbol
Hi all Simple doppler radar circuit Basically is a form of transmitter and receiver which may also used as simple doppler radar. This is the following diagram i have for the doppler radar. But i can not find any circuit related with my bolck diagram. Any ideas wher i can find some info (books / web pages) Thanks a lot (...)
I am actually doing a Master in Electronic Instrumentation Systems, my project is the following: CW doppler Ultrasound Blood Flow Detector. I have a very interesting pdf about it:
I am actually doing a project and I am a bit stuck! If anyone has information about how to design a CW doppler to give me I will be very pleased!!! It s quit urgent because I have to finish my project for the 15th of september! Thank you in advance!
Does anyone know where I can get schematics for a doppler ultrasound system that would detect blood flow?
comparing the moving sound with a steady stationary source would be easier and might be more impressive, ears are very good at picking up beat frequencies. even simpler might be to swing a loudspeaker around your head at the end of a wire. as the wire gets longer the rise and fall of the source frequency gets more noticable, demonstrating dop
I need C/N vs BER data for ofdm . Please help me Thanks so much
Hai Guys: I would appreciate if anyone of you could explain the ofdm modulation scheme in a nutshell. Below are some questions in parallel to this inquiry: 1. What type of carrier signal used in this modulation scheme?. 2. What is the time domain equivalent signal used as the baseband signal?. 3. What type of transmitter preferred in compli
i wanna designs and how to design an ofdm transceiver im also new to eda tools pls help to me to deign transceiver chip if any body having codes of ifft/fft pls send thanks
Hello Mukul Here is the file attched for you. It is actallly Design project report submitted by Francisco Bastidas, Rahul Kopikare and Gaëlle Protat to Engineering Division of the Graduate School of Cornell University The second file is also simulation of ofdm Modem for Audio Channel Both the simulation are performed in Matlab abd
i am doing research in ofdm. and studying everything about that. don't know whats going on these days in this research. if anyone have some idea or suggestions on this??? I need to decide my research topic urgently. So please be quick
Will someone supply any papers about combining BLAST and ofdm. Thanks.
Is spectral frequencies related to doppler effect shift.For example. the doppler shift effect will be positive if the recever (mobile phone) is moving towards to the base station. :?: Thank you,..
Hi all I want some refernces papers related to Emerging Wireless Access Technologies: ofdm, MIMO, and UWB
Hi! I know that aircraft navigation is based on DME equipments which provide a measure of distance and VOR equipments which provide a measure of angle. DME measure is done by measuring the time distance between pulses generated by aircraft and echoed by DME. I've heard that the measure of the angle is achieved by doppler effect of RF signal gener
I want to design GPS receiver, enable doppler shift to reach 40KHz. Which part of commercial GPSR do I need to implement? What the a bit more most difficult? Which chips developed can be used? Or where is there information and is suitable for studying?
Orthogonal frequency-division multiplexing (ofdm), also sometimes called discrete multitone modulation (DMT), is a complex modulation technique for transmission based upon the idea of frequency-division multiplexing (FDM) where each frequency channel is modulated with a simpler modulation. In ofdm the frequencies and modulation of FDM are arranged
Anyone has any sugestion? thank you
I am using the unused carriers for the removal of INTERCARRIER INTERFERENCE at the transmitter in ofdm (I am not using the cyclic prefix). When the channel length is greater than the number of unused carriers ICI and ISI are introduced. For ICI, it can be removed with corresponding cyclic prefix. But for the removal of INTERSYMBOL INTERFERENCE I a
Hello Everyone, I am in Canada and currently I have this project to complete. I want to transmit the s video + the audio L and R. The other end should receive back the s video + the audio L and R. I know the S video has mainly the critical Y and C signal. In total, I would have to transmit 4 unique signals. As such I was thinking of ofdm
Would people who have run ofdm simulations and compared the results to theory and also to the measured performance of hardware comment on the simulator they used and how happy they are with it. Simulators I am curious about are: 1. mathematical programs like matlab 2. specialized low cost simulators like system view 3. expensive micr
Motorola amplifier MHL9838 used to amplify -23dBm 746MHz DVB-T signal (ofdm+16QAM).The gain is -5dB,but the one tone test gain is 19dB. Another amplifier module (Mini-circuits company provided) has 44dB gain in one tone test,but has only 20dB gain in DVB-T signal test.Why?
dear all my graduation project is power line communications and i was looking for a complete implementation of an ofdm(orthogonal frequency division multiplexing) modem so that i can try its performance on power lines so if anyone can help me in that topic i will be thankful
In the UWB field , wireless USB wireless 1394, CDMA or ofdm, which is the better?
Elementary questions, hope u guys dun mind.. I often see 1024 point or 1024 bin length FFT & IFFT for ofdm. At first i thought 1024 represents the number of subcarriers for ofdm, but i later realized it wasn't. So what does 1024 represents? And what is the relationship between the point number/bin lenght and the number of subcarriers?
Hi all, who can tell me the relation between ofdm and DMT, and what's the different between them?
Can anyone help me bout this? what actually is the ofdm parameters? subcarrier....and what else more ..????? what parameter that affect the performance of the mulitpath, no.of subcarrier......n more......and how these parameters affect if subcarrier increase, what is the result.........on the ber... actually (...)
I would like to know about cyclix prefix in ofdm.I have heard that cyclic prefix is added inorder to avoid inter carrier interference.will addition of this cyclix prefix result in frequency shift.Why don't we zero pad instead of using this cyclic prefix.
I am confused with ofdm and ofdmA. Can anyone tell me how distinguish them? Thanks
Went to see my project supervisor today, he cast some doubt on my understanding of ofdm... Lets say i have a string of bits . To transmit it with ofdm with 4 subcarriers, i have to convert it from serial to parallel, 1 1 1 0 0 0 1 0 with rows representing ofdm symbols, columns representing subcarriers. Each subcarrier will c
How do i add a guard interval (cyclic prefix) for an ofdm simulation in Matlab? Coz in matlab the datas are represented in a matrix, however guard interval is in us how do i code it in matlab? and since the guard interval is a cyclic prefix, how do i copy the end and append it to the front of the ofdm symbol? Thx in advanc