Having settled the huffman encoding/decoding and channel modeling(thanks to the previous part on bitwise operation), the last part would be hamming encoding/decoding.

Did some research as usual on hamming codes and how they work(well sort of) I got a general idea how to start constucting a (7,4) hamming code.

Unfortunately I have no idea how to start on the decoding/error correcting part and some direction would be nice.

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for encoding I figured out I woul have to take the first 4 bits and add 3 more behind as the parity check bit.

but for decoding/error correcting, I would have to construct sort of a list of possible codes and pick the one with the least "distance"?

This is how I know (7,4) Hamming code: positions 1, 2 and 4 are the parity

bit positions; the other four are the data bits:

p1 p2 d1 p4 d2 d3 d4

p1 is computed using the bits at positions 1, 3, 5, 7 (check 1, skip 1)

p2 is computed using the bits at positions 2, 3, 6, 7 (check 2, skip 2)

p4 is computed using the bits at positions 4, 5, 6, 7 (check 4, skip 4)

p1 p2 p4 form a three bit word itself and if one of them is incorrect the position

of the incorrect bit can be found by forming the three bit word from p1 p2 p4

(1 means incorrect, 0 means correct). The value of this word is the position

of the incorrect bit.

kind regards,

Jos

ps. Google is your friend here