Consider the turbo encoder given in Fig. 9.1. Assume that the RichardsonUrbanke construction for the code termination is used and that the length of the encoder input information sequence is K˜ = 4....

Consider the turbo encoder given in Fig. 9.1. Assume that the RichardsonUrbanke construction for the code termination is used and that the length of the encoder input information sequence is K˜ = 4. The information symbols un, n = 0, 1, 2, 3, are a priori equiprobable. The index permutation vector for the SBP is π = 1 4 2 5 3 0  . a) What is the length of the codeword?

b) Use the algorithm described in Section 9.4 to decode the received sequence r = 101 010 010 011 01

Fig. 9.1