Hello,

The following basic concepts might help you:

- Transmission rate or bit rate = Nbits / t  [bps]

- According to Shannon, the theoretical maximum capacity C of a channel can be estimated by: C = BW x log2(1+S/N)   [bps], where BW is the bandwidth, S/N is the signal to noise ratio (SNR).

One can conclude that the lower the SNR the lower the channel capacity.

I hope this answer can give you a start point to move forward.