3 ms·
That is in fact incorrect. Capacity scales as Blog2(1+SNR) so increasing bandwidth at the same power (which would decrease SNR linearly assuming AWGN) will resu
by cycomanic 3y ago
That is in fact incorrect. Capacity scales as Blog2(1+SNR) so increasing bandwidth at the same power (which would decrease SNR linearly assuming AWGN) will result in increased capacity.
Although pratically you can do that only so far, because you're going to be limited by the bandwidth of your receiver.
- lxgr 3y agoIt’s only theoretically incorrect. Practically, satellite communications are power-limited and accordingly will always be so close to the noise floor (i.e. S/N << 1) that the logarithm can be approximated with a constant and the bandwidth dependency is negligible and drops out of the equation. It only matters in the bandwidth-limited regime, i.e. for S/N >> 1.
- CraigJPerry 3y agoThis thread is why I like HN. Thanks for sharing the insights both.
- lxgr 3y agoPlease take all of this with a grain of salt! It's quite possible that the limiting factor here is already spectral efficiency and not power; I don't know the link budgets involved and am mainly basing this on the very low observed data rates of systems I'm familiar with. I don't have the exact S/N numbers for these systems, and there might well be some potential gain that's not being exploited for reasons of spectral efficiency (after all, these systems want to serve multiple phones at least somewhat efficiently). The spectrum is limited in any case, both by receiver capabilities and the fact that it's a very scarce resource in useful frequency ranges.