Turbo Codes

Haming distance : the minimum derive of places in which any 2 computewords differ Draw backs of achieving the closest rule words in the de cypherr & the performance is approached as on;y ( K & N ) tend to infinity * Linear utter cypher Syndrome rewrite is a way to compute enter victor Convolutional work outs * It is not possible to sepa value enter into unsupported blocks * Each code endorsement depends on pre data oddball * We can encode using (shift testify , XOR , multiplexer) * We replace code word with code sequence * The continent of shift narrative defines the state of encoder * We use Systematic encoder and its trellis properties * It uses Viterbi algorithm The aim to Turbo codes: * We cant approach capacity limit of Shanons theory * We apply capacity limit lower than Shanons called cut-off rate bound * In 1993 cut-off rate bound significantly exceeded by ICC and approached to 0.7 db of Shanons. Concatenated codes : * By increasing (k) the power of FEC codes increases besides decoding conglomerateity increases too.. * We need outer encoder to feed up the railroad siding of encoder and then decoding would be considerably .

* The final examination encoder called (Inner encoder) * The final code is more complex The Drawback is error propagation which instrument the error that passes to the next decoder it overwhelms the ability of that code to crystalise the error . We fix it and alter the sys by distribution these errors surrounded by a numb er of separate code words. Interleaver: ! * We call it extraneous or block * Interleaver denoted by ( ?) and de-interleaver denoted by ( ?-1 ) * The rows of ( ?) = outer code word * The columns of ( ?) = versed data block * Outer code space (k1) code space (n1) * Inner code length (k2) code length (n2) * ? rows (k2) stand code word of outer code * ? columns (n1) contain para of inner code By encoding the relation of outer code in the inner...If you want to get a full essay, ensnare it on our website: OrderCustomPaper.com

If you want to get a full essay, visit our page: write my paper