Hi, I know this might take a while to answer,but can someone please explain the basic differences between OFDM vs OFDMA, TDM vs TDMA, FDD vs...

Hi, I know this might take a while to answer,but can someone please explain the basic differences between OFDM vs OFDMA, TDM vs TDMA, FDD vs TDD? Also, what is the difference between a symbol and a subcarrier? Any help would be appreciated! Thank you, Clay

Well not much I suppose since we use it for Wi-Fi - but what about commercial broadcast radio propagation? The UK has had digital radio for some...

Well not much I suppose since we use it for Wi-Fi - but what about commercial broadcast radio propagation? The UK has had digital radio for some time but it has not really caught on. I heard it had problems in moving vehicles though it is supposed to be immune to multipath. Hardy

Can any body let me know whether the simulations to determine the BER Vs. SNR for flat fading channels( May be rayleigh or Rician) are valid or...

Can any body let me know whether the simulations to determine the BER Vs. SNR for flat fading channels( May be rayleigh or Rician) are valid or not? Thanks, Neetu

Hi, here In the classic synchronization algorithm by Schemidl, the timing metric has a plateau as a result of Cyclic Prefix(CP). Why not...

Hi, here In the classic synchronization algorithm by Schemidl, the timing metric has a plateau as a result of Cyclic Prefix(CP). Why not remove the CP in order to get a more acurate peak? as the reason of channel impulse?

Hi everyone, Got Stuck with fresh doubt. I saw a very old post...

Hi everyone, Got Stuck with fresh doubt. I saw a very old post in comp.dsp http://www.dsprelated.com/showmessage/58605/1.php ------------------------------------------------------------------------------------------------ ------- in that post, phil says "This isn't quite right. Keep in mind that frequencies that appear to be beyond the Nyquist frequency will end up wrap

Used in the UK for DAB ie digital radio. I heard that it had been dumped for car radios because it doesn't work due to multipath. Any truth in...

Used in the UK for DAB ie digital radio. I heard that it had been dumped for car radios because it doesn't work due to multipath. Any truth in this? My contact was with Ford Radio. They stuck with FM instead and gave up on digital.

hi all, i am new to OFDM concept, i took a sequence of +1 and -1 levels for FFT and before that i ensured that i have to keep 0 at DC...

hi all, i am new to OFDM concept, i took a sequence of +1 and -1 levels for FFT and before that i ensured that i have to keep 0 at DC CARRIER and guard carriers in between. and i have ensured a cyclic prefix of 4 samples the FFT is of 16- point and IFFT is taken and then i am doing FFTSHIFT again but my answer is not same as (all along, i took it for granted, but now i see that ...

For OFDM system with the sampling frequency of 50MHz and BPSK modulation scheme,what will be the data rate at physical layer? Will it...

For OFDM system with the sampling frequency of 50MHz and BPSK modulation scheme,what will be the data rate at physical layer? Will it be 50Mbits/second as well? Please help. Thanks.

hi all , Currently I am generating Blind Channel Estimation OFDM in Matlab. Meanwhile I have a problem in generate the Channel Impulse...

hi all , Currently I am generating Blind Channel Estimation OFDM in Matlab. Meanwhile I have a problem in generate the Channel Impulse Respond. Example : C=[1 2 3 4 0 0 0 0]; R=[1 0 0 0 4 3 2]; H=toeplitz(C,R); 1 0 0 0 4 3 2 2 1 0 0 0 4 3 3 2 1 0 0 0 4 4 3 2 1 0 0 0 ...

Hi, I find that the number of subcarriers is a power of two in OFDM ? Any specific reason for such a design ? Is it not possible to go in for...

Hi, I find that the number of subcarriers is a power of two in OFDM ? Any specific reason for such a design ? Is it not possible to go in for odd number of subcarriers ? Thx in advans, Karthik Balaguru

Hey, What is the difference between multicarrier modulation and FSK (Frequency Shift Keying)? Can OFDM considered to be a hybrid of the...

Hey, What is the difference between multicarrier modulation and FSK (Frequency Shift Keying)? Can OFDM considered to be a hybrid of the two? Thanks TD

Hello, can you please help me in understanding the following lines taken from the book "Fundamentals of Wireless Communication" by David Tse...

Hello, can you please help me in understanding the following lines taken from the book "Fundamentals of Wireless Communication" by David Tse & Pramod Viswanath. I'm a student working on my comm engineering skills I quote section 3.4.4, page number 95 ------------------------------------------------------------------------------------------------ - Both the single-carrier system with ISI equa

Hi, I understand that zero prefix reduces the transmit power in OFDM based systems. Then, why is cyclic prefix(CP) used widely and is...

Hi, I understand that zero prefix reduces the transmit power in OFDM based systems. Then, why is cyclic prefix(CP) used widely and is more popular ? Why has WiMAX opted for Cyclic Prefix ? Any ideas . Thx in advans, Karthik Balaguru

I was wondering about demodulation. We woudl need phase coherence of both the main carrier and the sub-carriers. I assume the main carrier can...

I was wondering about demodulation. We woudl need phase coherence of both the main carrier and the sub-carriers. I assume the main carrier can be locked onto with a PLL but what about the sub-carriers? Do they use a pilot sequency of some sort when multiply up to get the other frequencies? Thanks Tom

On Thu, 15 Jan 2009 13:54:10 -0800 (PST), HardySpicer wrote: > Well not much I suppose since we use it for Wi-Fi - but what about >...

On Thu, 15 Jan 2009 13:54:10 -0800 (PST), HardySpicer wrote: > Well not much I suppose since we use it for Wi-Fi - but what about > commercial broadcast radio propagation? The UK has had digital radio > for some time but it has not really caught on. I heard it had problems > in moving vehicles though it is supposed to be immune to multipath. > > > Hardy There's more

Hello, Does anyone know how to estimate the BER of a Viterbi decoder when p = |H|^2 * |r-x|^2 is used as the decision metric ? Thanks...

Hello, Does anyone know how to estimate the BER of a Viterbi decoder when p = |H|^2 * |r-x|^2 is used as the decision metric ? Thanks for your cooperation. Engin |H|^2 = Channel's kth coefficient in frequency domain r = received symbol x = transmitted symbol This message was sent using the Comp.DSP web interface on www.DSPRelated.com

Subject states the question. Any information is appreciated. -- % Randy Yates % "And all that I can do %% Fuquay-Varina, NC ...

Subject states the question. Any information is appreciated. -- % Randy Yates % "And all that I can do %% Fuquay-Varina, NC % is say I'm sorry, %%% 919-577-9882 % that's the way it goes..." %%%% % Getting To The Point', *Balance of Power*, ELO http://home.earthlink.net/~yatescr

Hello, I am trying to implement a mimo-ofdm system. I have a question regarding the usage of the matlab command "rayleighchan" and "filter"....

Hello, I am trying to implement a mimo-ofdm system. I have a question regarding the usage of the matlab command "rayleighchan" and "filter". Take a look at the following code(adopted from an earlier post) ------------------------------------------ ts=5e-8; %sample time fd=30; %max doppler shift tau=[0 10 20 30 40 50 60 70 80 90 110 140 170 200 240 290 340 390]*1e-9; pdb=[0 -0.9 -1.7 -2....

Dear sirs, I have basic exposure to DSP but not much exposure to communication. Especially on the latest technology like LTE. Right now we are...

Dear sirs, I have basic exposure to DSP but not much exposure to communication. Especially on the latest technology like LTE. Right now we are working on a simulation model for LTE. I have some questions which I am putting below for your inputs. Thanks for the answers .. 1. In general, does how much bandwidth that can be achieved depend on the carrier frequency? That is, if my carriers ...

Hi, I'm somewhat of a newbie to the whole orthogonal frequency division multiplexed world, having come from the GSM, DCS, PCS, and...

Hi, I'm somewhat of a newbie to the whole orthogonal frequency division multiplexed world, having come from the GSM, DCS, PCS, and broadcast band power amplifier worlds, as well as some 2-18 GHz DLVA work. It's very interesting that they use 53 carriers: 48 data, 4 pilots, and one nulled carrier. My question is that it seems that after our product does the A/D conversio...