# parameter that limits data rate in communication

In communication, the maximum data rate that can be achieved is given by Shannon as

C=B*log2(1+SNR) bits/sec. Supposing that I've a very high SNR and an infinite bandwidth, then can data be transmitted at infinite rate? If no, then what are the conditions that limit my system to operate at a fixed rate.

thanks in advance phani tej

• ewwwww it sounds like a homework question for telecomms 101.. Nothing stops your system from being at a "fixed" rate, but certainly cannot be infinite, because nothing in the real world can do that for many reasons (conductors, parasitic inductances/capacitance/resistance, physics in general). This is digital communications, not RF/Analogue yes? – KyranF Oct 20 '14 at 13:27

## 2 Answers

Yes, in the limit as B goes to infinity, C goes to infinity. But there is no real- world situation where B->infinity is a reasonable model.

You are stating the Shannon Channel Capacity theorem .The very purpose of this theorem is to find limits of information transfer through a medium.Now the Question is When SNR is very high and bandwidth is infinite can infinite rate is possible .Answer is No because as Noise Power is directly proportional to Band Width when Band Width is infinite your SNR will become Very Low .So the situation which you are mentioning cannot happen.This is a Special case of Shannon_Hartley Law obtained by using the trigonometric form of logarithm function and applying the limit tends to infinity. (Assume white noise with Gaussian distribution)