Relay selection in cooperative communication !

relay selection in cooperative communication

I am a PhD student working on coopcom with relay selection.
You may know the journal of Bletsas about "Simple Cooperative diversity method based on network path selection".

In my system, there are 2 relays ,I select the best relay, and send my BPSK signal to the destination.

The relay selection algorithm that Bletsas published, is as follows

CSI's :

h_sr1 = CSI between source to relay 1
h_r1d = CSI between relay1 to dest

h_sr2 = CSI between source to relay 2
h_r2s = CSI between relay2 to dest

Algorithm :

h1 = min(abs(h_sr1).^2,abs(h_r1d).^2)
h2 = min(abs(h_sr2).^2,abs(h_r2d).^2)

As Bletsas told, every relay has its own clock and the relay whose clocks' finishes first it the best relay.

T1 = lambda/h1;
T2 = lambda/h2;

Lambda is scalar

QUESTION :

I dont understand the algorithm, how can this select the best relay?
How can each relay has a clock ?
Implementation to matlab code doesn't give correct results ?
In the implementation part, what should be the value of lambda ?

Thanks for your help.

relay selection

Any info about relay selection would be helpfull !

Re: relay selection

dear
you can scheck this paper :Relay Selection Methods for Wireless Cooperative Communications
Seunghoon Nam, Mai Vu, and Vahid Tarokh

or visit

IEEE Xplore - Relay selection methods for wireless cooperative communications

I think it is helpful for you

All the Best
Ayad