[SOLVED] who can help me? how can I learn cooperative communication

Re: who can help me? how can I learn cooperative communicati

unless u use selective DF which forwards only if decoding is successful.it implies u use some error detection code like CRC. DF can also b improved if u use adaptive DF, which means u use some feedback in the form of Acknowledgement. again it will also need some means of error detection like CRC

Click to expand...

Yeah you must use a CRC code in Detect and Forward but I dont have much info about DF, I use DAF and AAF in my project (that I am preparing).

i have used MRC for combining. MRC is optimal for AF bt not for DF. that's y in the code i have provided, DF doesnt outperform AF.

Click to expand...

I have noticed that.

Dou you know a combining technique, that is both good at DAF and AAF.
or Do you know any combining technique that is simple as MRC and works for DAF as well.

Also Can I learn the subject of your thesis ?

Re: who can help me? how can I learn cooperative communicati

the title of my thesis is "comparative study of cooperative MIMO strategies"

im not sure bt i think i read it somewhere tht ML is optimal for DF. there are other sub-optimal techniques proposed for DF which are claimed to giving performance close to optimal. one is cooperative MRC (C-MRC) and other is lambda-MRC (sorry dont know how to use the lambda symbol,lolzz)... and there is another MRC called improved MRC.. u can find it in file Matlab_prototype uploaded by another user in this thread.

i havent implemented them.\]

hi blue angel,
quote..
"moreover, i have used MRC for combining. MRC is optimal for AF bt not for DF. that's y in the code i have provided, DF doesnt outperform AF"

question: could you show me the link or any references that state MRC technique is optimal for AF protocol.
thank you in advance

kindly regards

Re: who can help me? how can I learn cooperative communicati

here is the paper, "diversity order analysis of decode and forward cooperative networks with relay selection" by Z Yi and I Kim.

they have discussed optimal detectors for both AF and DF. follow the references from there.
MRC's optimality is referenced from this paper:
"exact symbol error probability of cooperative network in rayleigh fading environment" P A Anghel n M Kaveh, IEEE trans. wireless comm. vol 3,sept 2004.

Re: who can help me? how can I learn cooperative communicati

I am working on relay selection. I want to compare the outage probability with bit error rate. Could anyone pls help me on this.

Re: who can help me? how can I learn cooperative communicati

Hi

I am simulating Detect and Forward but not getting better BER than Direct link.
I am setting equal power at source and rely lets half at source and half at relay.
it it ok:

Re: who can help me? how can I learn cooperative communicati

aliazmat said:

Dear liuyong19820

what is your system model and how does your decoder work ?

Click to expand...

thanks for your reply, the model i have used for channel is flat-fading Rayleigh, in which two source nodes communicate with a destinaton node assisted by a relay, and i want to do some analysis on the model.
now I am reading a paper named "outage minimization with limited
feedback for the fading relay channel" , written by Nasir Ahmed, have you read it? I have some questions about it, but i can't contact the author.
another question, in the MARC model, can limited feedbck be applied? hope to hear from you?

Added after 4 minutes:

thanks for your kind reply, what is your system model? what is the difference between Detect - Forward & decode - Forward?
hope to hear from you

Added after 41 seconds:

barithegreat said:

Hi

I am simulating Detect and Forward but not getting better BER than Direct link.
I am setting equal power at source and rely lets half at source and half at relay.
it it ok:

Click to expand...

thanks for your kind reply, what is your system model? what is the difference between Detect - Forward & decode - Forward?
hope to hear from you

Re: who can help me? how can I learn cooperative communicati

liuyong19820

For me you are talking about the Multiple-Access channel with dedicated relay (MAC-DR). You can at least see the capacity expression for this channel in the book of Gerhard Kramer titled "Cooperative Communications".

Re: who can help me? how can I learn cooperative communicati

One confusion:

In cooperative setup this is is assumed that:

First the transmitter transmits and relay and the destination receives
Second only relay transmits

My question:

why next time only relay transmits, why not both the transmitter and relay trasmit ??
why origional transmitter remains silent during next time.

Ref:

J. N. Laneman, D. N. C. Tse, and G. W. Wornell, “Cooperative diversity
in wireless networks: efficient protocols and outage behavior,” IEEE
Trans. Inform. Theory, vol. 50, no. 12, pp. 3062–3080, Dec 2004.

Re: who can help me? how can I learn cooperative communicati

One confusion:

In cooperative setup this is is assumed that:

First the transmitter transmits and relay and the destination receives
Second only relay transmits

My question:

why next time only relay transmits, why not both the transmitter and relay trasmit ??
why origional transmitter remains silent during next time.

Ref:

J. N. Laneman, D. N. C. Tse, and G. W. Wornell, “Cooperative diversity
in wireless networks: efficient protocols and outage behavior,” IEEE
Trans. Inform. Theory, vol. 50, no. 12, pp. 3062–3080, Dec 2004.


Not necessary see the document here which discusses three protocols for data transmission in cooperative comm systems. Regarding your question, transmitter remains silent because simultaneous transmission of transmitter and relay will cause collisions in MAC layer.

doc/paper link:

Re: who can help me? how can I learn cooperative communicati

Dear thanks for the reply.
I will be back after reading the paper.

Re: who can help me? how can I learn cooperative communicati

Thank you very much for your reply.
I will be back once I read the paper.

Thanks