Re: Spreading gain !
Good guess, but I think not. The spreading gain is most likely a matched filter gain that you get when you spread a modulated signal out over a bigger bandwidth than needed. I think the proper term is "coding gain". For instance, if you have a 1 MHz modulation, by by spread spectrum techniques you spread it out over a 100 MHz RF bandwidth, then it will reject noise and interferring signals by many additional dB's after it is demodulated.