After receiving a word through a communication channel,
we hope to recover the original message.
We use a Decoding rule and analyse some properties of the channel.

We define two concepts:
Operational Channel Capacity
Information Channel Capacity

We prove they are the same in
Shannon’s noisy coding theorem (2nd coding theorem)

Example

A Binary Symmetric Channel (BSC) with error probability has capacity .

Proof

Calculate Information Channel Capacity.