OFDM model

Hi, i am learning about OFDM currently. And i am learning to implement
the model in SIMULINK.

Yet, i am stuck at the 'training symbols'. I dont really understand
why training is needed in channel estimation and what forms those
training symbols.

Can recommend some nice books for OFDM or simulink?

Thanks for ur patience.

On Oct 15, 12:40 pm, kelvi...@gmail.com wrote:
> Hi, i am learning about OFDM currently. And i am learning to implement
> the model in SIMULINK.
>
> Yet, i am stuck at the 'training symbols'. I dont really understand
> why training is needed in channel estimation and what forms those
> training symbols.
>
> Can recommend some nice books for OFDM or simulink?
>
> Thanks for ur patience.

Training sequences aren't unique to OFDM systems. They can be used in
any communications system during channel estimation. Basically, if you
want to model the effects of the channel, it is useful to go through a
training period where the receiver compares its received signal with
the ideal received signal (the training sequence). Using this
information, an estimate of the channel can be made.

Jason

On Oct 15, 12:22 pm, cincy...@gmail.com wrote:
> On Oct 15, 12:40 pm, kelvi...@gmail.com wrote:
>
> > Hi, i am learning about OFDM currently. And i am learning to implement
> > the model in SIMULINK.
>
> > Yet, i am stuck at the 'training symbols'. I dont really understand
> > why training is needed in channel estimation and what forms those
> > training symbols.
>
> > Can recommend some nice books for OFDM or simulink?
>
> > Thanks for ur patience.
>
> Training sequences aren't unique to OFDM systems. They can be used in
> any communications system during channel estimation. Basically, if you
> want to model the effects of the channel, it is useful to go through a
> training period where the receiver compares its received signal with
> the ideal received signal (the training sequence). Using this
> information, an estimate of the channel can be made.
>
> Jason

To add to Jason's reply:

And not just the channel, but also other parameter ambiguities such
as phase, amplitude, etc.

Julius

On Thu, 18 Oct 2007 14:39:47 -0000, julius <juliusk@gmail.com> wrote:

>On Oct 15, 12:22 pm, cincy...@gmail.com wrote:
>> On Oct 15, 12:40 pm, kelvi...@gmail.com wrote:
>>
>> > Hi, i am learning about OFDM currently. And i am learning to implement
>> > the model in SIMULINK.
>>
>> > Yet, i am stuck at the 'training symbols'. I dont really understand
>> > why training is needed in channel estimation and what forms those
>> > training symbols.
>>
>> > Can recommend some nice books for OFDM or simulink?
>>
>> > Thanks for ur patience.
>>
>> Training sequences aren't unique to OFDM systems. They can be used in
>> any communications system during channel estimation. Basically, if you
>> want to model the effects of the channel, it is useful to go through a
>> training period where the receiver compares its received signal with
>> the ideal received signal (the training sequence). Using this
>> information, an estimate of the channel can be made.
>>
>> Jason
>
>To add to Jason's reply:
>
>And not just the channel, but also other parameter ambiguities such
>as phase, amplitude, etc.
>
>Julius

Yes, training sequences generally provide detection (i.e., detecting
signal presence) and synchronization.  If there's equalization, then
channel estimation goes along with it. 

Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.ericjacobsen.org

Thanks for all the replies. Training sequence is the ideal received
signal. Finally, I have some ideas about what's training about.

And i wish to ask is it a channel estimation can be carried out by
using a matrix product? How does it works? I saw this sentence from an
article with no further explaination.

Thanks for ur patience.