relation between snr and eb no
We must prior understand our respectively "language": if You define Eb how the amount of energy to transmit a binary symbol and No how the monolateral power spectrum density, then Eb/No is the SNR.
In general, the error probability depends by SNR, so You must specify at least the Modulation Format and if Your signal is Codified or not (where with codified I refer to protection code how convolutional code).
Suppose You work at RF, the costellation is a 4-QAM, works with zero-ISI (the complete channel response satisfy the Nyquist condition) and explain by complex envelops. Then, the P(e) is equal to 2Q(1/No) + Q^2(1/No). The quantity Q^2() can be trascurate respect Q() if You work at high SNR (for example in correspondency to P(e) = 10^-5). Now, You desire to eplain by the SNR: remember that the energy Es=Eb because the signal is uncodified. With a 4-QAM, the energy at RF is Es=1. You can write then Es/No = 1/No, where Es/No is Your SNR. Finally You have: P(e) = 2Q(Es/No).
If You work with a convolutionl code with Rate R=k/n and Free Distance Df, (by some pages of pssages!!!) You can approximate the P(e) how a function of R, SNR and Df. Note that in this case, with SNR I consider the quantiy Eb/No where in this case Eb is the energy request to transimit an uncodified symbol.
How exerices for You (gurpreet) try to explain qualitatively the advantages by Soft Decoder vs Hard Decoder. Good Study and keep in touch!