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
Digital communication :: 04-12-2007 10:26 :: maomun :: Replies: 1 :: Views: 1166
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
Digital communication :: 05-01-2007 12:44 :: goosecool :: Replies: 8 :: Views: 2486
doppler has a devastating effect on ofdm signal due to ICI and loss of synchronizarion ,unless adequate compenasation techniques are applied
Digital communication :: 09-07-2007 05:05 :: sameerbabu :: Replies: 4 :: Views: 2693
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: email@example.com
Added after 5 hours 8 minutes:
help me！ how to add doppler shift to channel?
Digital communication :: 03-29-2008 03:14 :: zhouzhou1103 :: Replies: 2 :: Views: 848
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
Digital communication :: 03-10-2009 03:48 :: Communications_Engineer :: Replies: 6 :: Views: 3623
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.
Digital Signal Processing :: 07-15-2010 03:56 :: sanam86 :: Replies: 3 :: Views: 1745
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
Digital communication :: 02-08-2011 11:32 :: Ahmed Alaa :: Replies: 0 :: Views: 590
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
Digital communication :: 03-17-2011 01:00 :: watsup :: Replies: 1 :: Views: 456
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 (...)
Digital communication :: 08-12-2011 11:56 :: sdahan112 :: Replies: 3 :: Views: 810
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
Digital communication :: 12-03-2011 04:59 :: cokibolong :: Replies: 3 :: Views: 621
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 (...)
Digital communication :: 02-20-2012 01:46 :: Sherra :: Replies: 0 :: Views: 398
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 :
but unfortunally the results for BER not stable .
for doppler frequency = 0.0001
Digital communication :: 03-06-2012 13:19 :: ammaralwazzan :: Replies: 5 :: Views: 1165
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
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)
Digital communication :: 04-15-2012 19:36 :: ReComm :: Replies: 6 :: Views: 705
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
Digital communication :: 07-28-2012 03:07 :: ammaralwazzan :: Replies: 3 :: Views: 692
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
nBitPerSym = 64; % number of bits per ofdm symbol
nSym = 10^3; % number of symbol
Digital communication :: 10-10-2012 20:17 :: ReComm :: Replies: 0 :: Views: 831
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 (...)
RF, Microwave, Antennas and Optics :: 12-01-2002 18:05 :: savvasn :: Replies: 5 :: Views: 7037
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:
Other Design :: 07-25-2003 13:00 :: will0707 :: Replies: 7 :: Views: 2980
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!
Other Design :: 07-27-2003 12:15 :: will0707 :: Replies: 1 :: Views: 1577
Does anyone know where I can get schematics for a doppler ultrasound system that would detect blood flow?
Analog Circuit Design :: 12-12-2003 18:58 :: fredj :: Replies: 2 :: Views: 1528
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
Hobby Circuits and Small Projects Problems :: 12-17-2003 02:03 :: cherrytart :: Replies: 2 :: Views: 950
I need C/N vs BER data for ofdm .
Please help me
Thanks so much
RF, Microwave, Antennas and Optics :: 05-11-2004 06:48 :: aaiiwwaa :: Replies: 4 :: Views: 1640
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
Analog IC Design and Layout :: 05-30-2004 08:32 :: hrkhari :: Replies: 5 :: Views: 1886
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
Digital Signal Processing :: 06-30-2004 02:06 :: aravind :: Replies: 2 :: Views: 1266
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
Mathematics and Physics :: 06-29-2004 17:13 :: Krutarthbhatt :: Replies: 2 :: Views: 4523
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
Electronic Elementary Questions :: 07-04-2004 04:31 :: mukul :: Replies: 4 :: Views: 2519
Will someone supply any papers about combining BLAST and ofdm. Thanks.
Electronic Elementary Questions :: 07-10-2004 03:07 :: du_du :: Replies: 1 :: Views: 768
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. :?:
RF, Microwave, Antennas and Optics :: 07-13-2004 23:28 :: roustabout :: Replies: 0 :: Views: 662
I want some refernces papers related to Emerging Wireless Access Technologies: ofdm, MIMO, and UWB
RF, Microwave, Antennas and Optics :: 07-29-2004 08:25 :: mhadidy :: Replies: 5 :: Views: 1713
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
RF, Microwave, Antennas and Optics :: 08-04-2004 04:16 :: a_fischetti :: Replies: 2 :: Views: 1304
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?
Professional Hardware and Electronics Design :: 11-04-2004 20:02 :: cliffliu :: Replies: 0 :: Views: 858
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
Digital communication :: 08-15-2006 15:12 :: bauer :: Replies: 12 :: Views: 4483
Anyone has any sugestion? thank you
RF, Microwave, Antennas and Optics :: 12-03-2004 19:26 :: boy :: Replies: 1 :: Views: 1531
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
Digital Signal Processing :: 02-20-2005 13:00 :: gangadharreddy_s :: Replies: 0 :: Views: 957
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
Digital Signal Processing :: 03-23-2005 08:33 :: EchoAngel911 :: Replies: 0 :: Views: 823
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
RF, Microwave, Antennas and Optics :: 03-27-2005 17:00 :: flatulent :: Replies: 3 :: Views: 900
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?
RF, Microwave, Antennas and Optics :: 05-05-2005 08:28 :: xribbon :: Replies: 4 :: Views: 930
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
PLD, SPLD, GAL, CPLD, FPGA Design :: 05-21-2005 17:24 :: a_shawky :: Replies: 1 :: Views: 1272
In the UWB field , wireless USB wireless 1394, CDMA or ofdm, which is the better?
ASIC Design Methodologies and Tools (Digital) :: 06-25-2005 00:05 :: visualart :: Replies: 9 :: Views: 3506
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?
Digital Signal Processing :: 07-25-2005 08:39 :: Antonio_Magma :: Replies: 11 :: Views: 18106
who can tell me the relation between ofdm and DMT, and what's the different between them?
Digital Signal Processing :: 08-15-2005 02:37 :: mark_alin :: Replies: 5 :: Views: 2516
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 ofdm...like mulitpath, no.of subcarrier......n more......and how these parameters affect ofdm........like if subcarrier increase, what is the result.........on the ber...
Digital Signal Processing :: 08-24-2005 10:10 :: bleach :: Replies: 1 :: Views: 832
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.
Digital Signal Processing :: 08-27-2005 02:45 :: udit :: Replies: 1 :: Views: 978
I am confused with ofdm and ofdmA.
Can anyone tell me how distinguish them?
Professional Hardware and Electronics Design :: 09-01-2005 04:01 :: crenyen :: Replies: 1 :: Views: 8297
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
Digital Signal Processing :: 09-01-2005 23:59 :: Antonio_Magma :: Replies: 18 :: Views: 1550
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
Digital Signal Processing :: 09-04-2005 15:40 :: Antonio_Magma :: Replies: 4 :: Views: 4121