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Channel performance of OFDM over an AWGN......

Started by mashhur March 3, 2009
hi all! 

i am going to simulate (myself for understanding more, not using Matlab
toolbox) wireless channel by M-QAM over an AWGN, so that I've to choose one
of the FEC coding method such as Rayleigh, LDPC, turbo, Red-Solomon or
BCH.

which is the better one? and is it possible to use AWGN with Rayleigh at
the time? if it is possible please explain me how to make a algorithm for
it.
and please give me an overview of channel procedures, i mean step by step
processes...

i appreciate feedback!
thanks a lot!


On Mar 3, 7:52&#2013266080;am, "mashhur" <mashh...@yahoo.com> wrote:
> hi all! > > i am going to simulate (myself for understanding more, not using Matlab > toolbox) wireless channel by M-QAM over an AWGN, so that I've to choose one > of the FEC coding method such as Rayleigh, LDPC, turbo, Red-Solomon or > BCH. > > which is the better one? and is it possible to use AWGN with Rayleigh at > the time? if it is possible please explain me how to make a algorithm for > it. > and please give me an overview of channel procedures, i mean step by step > processes... > > i appreciate feedback! > thanks a lot!
I think you're a bit confused. As far as I know, there is no "Rayleigh" coding. "Rayleigh fading" is a common fading distribution used in simulation of wireless systems, but it's not a coding scheme. And, there is no single "best" code to use; if there was, no one would use the others. It's all dependent upon the amount of overhead you can tolerate (i.e. how high your code rate needs to be) and the amount of processing you have available to encode and decode the data. I'd recommend some further study of FEC methods before you just dive in and try to implement them. And, I'll go out on a limb and predict that some might have heartburn with your request for "step by step processes." Implementing any of these codes is not a trivial task, and you're not going to find someone willing to do it all for you, for free. Jason
oh i am sorry, u a right thereis not a Rayleigh code, it is a channel.

could u give me some examle, i mean applications description like for
exam:

for WiMax (802.16d) which code (channel) is used?
On Mar 3, 8:05&#2013266080;pm, "mashhur" <mashh...@yahoo.com> wrote:
> oh i am sorry, u a right thereis not a Rayleigh code, it is a channel. > > could u give me some examle, i mean applications description like for > exam: > > for WiMax (802.16d) which code (channel) is used?
You can look up the specification to see exactly what they use, but I believe it is a type of LDPC code. Jason
On Mar 3, 8:05&#2013266080;pm, "mashhur" <mashh...@yahoo.com> wrote:
> oh i am sorry, u a right thereis not a Rayleigh code, it is a channel. > > could u give me some examle, i mean applications description like for > exam: > > for WiMax (802.16d) which code (channel) is used?
This is a standard, so you can look up what is in the standards online. Start with IEEE.org. Julius