3. We have a convolutional encoder as shown in the following figure. (15 pts) 3.1 Write the expressions for xi,xi and xii (use "+" for the 'Xor" logic operation). 3.2 Encode the bit vector [0101] with flushing operations. 3.3 Draw the encoding path of [0101] in the Trellis Diagram. To make the diagram clear, you do not need to mark code symbols for all links. Show only the code symbols on the encoding path.) 3.4 The received code bit stream has two error bits: the 2 nd bit and the 12th bit. Draw the pattern of Viterbi decoding