Lec 15 MIT 6.451 Principles of Digital Communication II
PROFESSOR: I'm sorry. I have to give this to you. Basically OK, except you didn't understand it the first time. OK. Good morning. Happy spring. Happy April. We're running a little late. I'll try to finish chapter nine today and start on chapter ten. Ashish may have chapter ten here later. If not, it'll be on the web. So we've been talking about convolutional codes. Specifically rate 1/n convolutional codes. One input n outputs. As you may imagine, there are also rate k/n convolutional codes. Generalization to k inputs n outputs. These have not been so much used in practice, because in general, we're using these binary codes in the power limited regime, and we want low rates. So 1/n is a good rate. 1/2, 1/3, 1/4, or down to 1/6 are common kinds of rates. So I haven't bothered to develop the more elaborate theory for rate k/n codes. The rate 1/n codes, just to review. The code is simply defined as the set of all possible output sequences of a...