DSSS signal below -174dBm

[youngjae2.kim]

hello

I'm designing communication system with dsss(direct sequence spread spectrum) waveform.

and one question came up.

If dsss signal power goes below -174dBm(thermal noise), then can I get the original signal
after de-spreading?

I just feel that's impossible but I can't say why..?

with normal AWGN, I would say yes, but why not with thermal noise?

what's the difference between those?

 

[zorro]

Thermal noise is a class of AWGN (to be more rigorous, I'd say that AWGN is a good model for it).
The term "thermal" refers to its origin. Shot noise is AWGN with the same effect but with a different origin.

In digital communications, the ability to detect signals is related to the ratio Es/No. What matters is the energy of the symbol, not the power spectral density of the signal.

Regards

Z