Lets say, I have 10 randomly generated bits (0's and 1's) in matlab. From my other parameter calculations, I have about 5 samples, this means 1 bit/5 samples (each bit is replicated 5 times). My total data vector will be 1 x 50 length. After this i perform BPSK modulation and multiply the data (baseband) with a carrier wave to form a data signal (passband). After this I add AWGN and then again multiply the signal with the carrier (from passband, back to baseband).
After the above process is completed i have to make the decision to get back the 0's and 1's to compare it with the initially generated bits. How should i proceed with it?
Does the below code makes sense or am I missing something?
data = randi(1,[1,0],10);
...
...
...
(steps as explained above)
%----bits retrieval------
variable = [];
for i = 1:length(data)
sum = 0;
for j = (i*5-4):length(final)
sum = sum + final(j);
c = mod(j,5);
if c == 0
break
end
end
if sum > A
variable = [variable 1];
else
variable = [variable 0];
end
end
%--------------------------code ends-----------------------------
here,
A is the amplitude of the carrier wave
final is the vector onto which i have perform the decision to check if its a bit 1 or bit 0.
Hi,
it seems that you want to decide bits 0 or 1 using the "packets" of 5 bits, right?
You have two choices: hard or soft decision.
Hard decision: you make decision for every bits and decide afterward, with a majority for instance (e.g. 3 bits over 5 are 0 and you decide 0).
Soft decision: you make the sum of your 5 received symbols and decide afterward. It seems that it is your solution. Good choice, it is the best solution in the likelihood sense, even though it may be sensitive to outlayer.
To sum up, it seems to make sense, indeed.
However, I would like to indicate that your code could be improve: you can remove all for and if loops: use "reshape", "sum", and "sign" matlab functions, and your code would be 3 or 4 lines, and clearer.
Best,
Vincent
Hi @Tushar Tandon.
I there are some examples in the attached (http://www.dsplog.com ) website. I hope it helps.
Best,
thank you so much Vincent Savaux and Marwah Abdulrazzaq Naser for your answers, this has surely helped.
- Badges
- Science topic
- Similar topics
- Vectorization